Magnetically coupled galvanically isolated communication using lead frame

Related Application This application was filed on November 14, 2012, entitled "Noise Cancellation for A Magnetically Coupled Communication Link Utilizing A Lead Frame". In connection with Kung et al.'S US Patent Application No. 13 / 677,068, which is assigned to the assignee of the present application.

This application was filed on November 14, 2012, entitled "Switch Mode Power Converters Using Magnetically Coupled Galvanically Isolated Lead Frame Communication". It is also related to Balakrishnan et al.'S US Patent Application No. 13 / 677,120, which is assigned to the assignee.

Background Information Disclosure The present invention generally relates to communication between circuits requiring DC insulation. More specifically, the examples of the present invention relate to communication across isolation barriers in switch mode power converters such as power supplies and power inverters.

Background Switch mode power converters are commonly used in mobile electronics, for household or industrial appliances that require a regulated direct current (DC) source for their operation, such as chargers. Widely used for An offline AC-DC converter converts a low frequency (eg 50Hz or 60Hz) high voltage AC (alternating current) input voltage to the required level of DC output voltage. Due to its well-tuned output, high efficiency, and small size, along with safety and protection features, various types of switch-mode power converters are in widespread use. Popular topologies for switch-mode power converters include flyback, forward, step-up, step-down, half-bridge, and full-bridge, including resonant types in particular.

The safety requirements for isolated switch-mode power converters generally include the use of high-frequency transformers to provide DC insulation between the inputs and outputs of switch-mode power converters, in addition to changes in voltage levels at the output. Make it a requirement.

<p><patcit num="1"><text>U.S. Patent Application No. 13 / 677,068</text></patcit><patcit num="2"><text>U.S. Patent Application No. 13 / 677,120</text></patcit></p>

<p> A major challenge in the switch mode power converter market is to reduce the size and cost of switch mode power converters while maintaining high performance operating specifications. In known isolated switch mode power converters, the detection of the output of the switch mode power converter and the communication of feedback signals to adjust switch mode power converter output parameters such as current or voltage are typically external insulation, such as optical couplers. Achieved using components. These known methods add unwanted additional size and cost to the switch mode power converter. In addition, optical couplers are slow and often limit the feedback bandwidth and transient response of switch mode power converters.</p><p> Non-limiting and non-exhaustive embodiments of the present invention are described with reference to the following figures. In the figure, the same reference number refers to the same part throughout the various figures, unless otherwise indicated.</p><p> Corresponding reference numerals indicate corresponding components throughout some of the drawings. One of ordinary skill in the art will appreciate that the elements in the figure are illustrated for brevity and clarity and are not necessarily drawn to scale. For example, some dimensions of the elements in the figure may be exaggerated relative to other elements to aid in a better understanding of the various embodiments of the invention. Also, a general but well-understood, generally useful or necessary, in a commercially feasible embodiment to facilitate the appearance of these various embodiments of the present invention in a more unobstructed manner. I often don't draw the elements that are.</p>

<figref num="1A">For the purposes of this disclosure, it is a diagram illustrating the conceptual operation of a magnetically coupled conduction loop that transmits and receives signals to communicate digital or analog information.</figref><figref num="1B">FIG. 5 illustrates another conceptual example of a conduction loop suitable for bidirectional operation according to the teachings of this disclosure.</figref><figref num="2A">FIG. 5 is an external view of an example of an integrated circuit package having a DC insulated magnetic coupling conduction loop formed by an insulated conductor of a lead frame inside an enclosed portion of the integrated circuit package according to the teachings of the present invention.</figref><figref num="2B">It is an internal view of the structure of an example of a DC insulated magnetic coupling conduction loop formed by an insulated conductor of a lead frame inside an exemplary integrated circuit package of FIG. 2A, according to the teachings of the present invention.</figref><figref num="2C">FIG. 5 is an external view of an example of an integrated circuit package having a DC insulated magnetic coupling conduction loop formed by an insulated conductor of a lead frame inside an enclosed portion of the integrated circuit package according to the teachings of the present invention.</figref><figref num="2D">It is an internal view of the structure of an example of a DC insulated magnetic coupling conduction loop formed by the insulated conductors of the lead frame inside the exemplary integrated circuit package of FIG. 2C, according to the teachings of the present invention.</figref><figref num="3A">FIG. 5 is an external view of an example of an integrated circuit package having a magnetically coupled communication link formed by an insulated conductor of a lead frame inside an enclosed portion of the integrated circuit package according to the teachings of the present invention.</figref><figref num="3B">An example of a lead frame inside an integrated circuit package having a magnetic coupling communication link formed by a magnetic coupling conduction loop of an insulated conductor of the lead frame inside the enclosed portion of the integrated circuit package according to the teachings of the present invention. It is an internal view.</figref><figref num="3C">It is an internal view of an example of a lead frame of a multi-die isolated controller integrated circuit package having a magnetically coupled communication link between controller dies according to the teachings of the present invention, the communication link being inside an enclosed portion of the integrated circuit package. Formed by magnetically coupled conduction loops of the insulated conductors of the lead frame.</figref><figref num="3D">It is an exemplary side view of a conduction loop of an insulated conductor of a lead frame inside an integrated circuit package according to the teachings of the present invention and a jumper bond wire coupled to an integrated circuit die.</figref><figref num="4A">An internal view of an example lead frame of an integrated circuit package having a magnetic coupling communication link formed by a magnetic coupling conduction loop of an insulated conductor of the lead frame inside an enclosed portion of the integrated circuit package according to the teachings of the present invention. It is a tilted 3D (three-dimensional) diagram of.</figref><figref num="4B">Multiple die insulation with communication links between controller dies formed by magnetically coupled conduction loops formed by the insulated conductors of the lead frame inside the enclosed portion of the integrated circuit package according to the teachings of the present invention. It is a tilt 3D diagram of the internal diagram of an example of a lead frame of a controller integrated circuit package.</figref><figref num="5">An example of a multi-die isolated controller integrated circuit package having a magnetically coupled communication link between controller dies formed by an insulated conductor of a lead frame inside an enclosed portion of the integrated circuit package according to the teachings of the present invention. It is a schematic diagram of an example of a synchronous flyback switch mode power converter having a secondary control utilizing.</figref><figref num="6">A controller inside an enclosed portion of an integrated circuit package in which output information is transferred to the primary side through a magnetically coupled communication link and line zero cross detection signals are transferred to the secondary side through a magnetically coupled communication link according to the teachings of the present invention. It is a schematic diagram of an example of a flyback switch mode power converter using an example of a multi-die isolated controller integrated circuit package including a bidirectional magnetic coupling communication link between dies.</figref>

Detailed Description The following description provides a number of specific details to give a complete understanding of the present invention. However, it will be apparent to those skilled in the art that it is not necessary to use specific details to practice the present invention. In other cases, well-known materials or methods are not described in detail in order to avoid obscuring the present invention.

References to "one embodiment," "example," or "example" throughout this specification have specific features, structures, or properties described in connection with the embodiment or example of the present invention. Means included in at least one embodiment of. Thus, the appearance of the words "in one embodiment", "in an embodiment", "one example", or "example" at various locations throughout this specification is not necessarily all the same embodiment or I'm not referring to an example. Further, in one or more embodiments or examples, specific features, structures, or properties may be combined in any suitable combination and / or secondary combination. Specific features, structures, or properties may be included in integrated circuits, electronic circuits, combinatory logic circuits, or other suitable components that provide the functionality described. Furthermore, it is acknowledged that the figures given herein are for illustration purposes only to those skilled in the art and that the drawings are not necessarily drawn to scale.

In some applications, multiple controllers may be contained within a single integrated circuit package. Each controller is manufactured as a semiconductor die. The present application discloses an integrated circuit package structure that enables communication between controllers by DC insulation using magnetic coupling between parts of the lead frame at little or no cost to the entire package.

Integrated circuit packages typically include leadframes. The lead frame provides mechanical support for a single die or multiple dies that can be housed in an integrated circuit package. In general, the lead frame typically includes a die mounting pad on which a semiconductor die can be mounted. In addition, the lead frame generally also includes conductors that provide electrical connections to circuits outside the integrated circuit package. The lead frame is generally composed of a flat sheet of metal. The flat metal sheet may be punched, etched, punched, etc. to have a pattern defining the various conductors of the die mounting pad and lead frame.

As mentioned above, in known switch mode power converters, insulation is often extra on the transformer core, either using an external insulation component, such as an optical coupler, or magnetically coupled to the secondary winding. Bias (eg feedback) given by the use of windings. These known methods add an undesired additional size and overall cost to the switch mode power converter. In an example following the teachings of the present invention, the insulation is formed by the DC insulated conductors of the lead frame inside the enclosed portion of the integrated circuit package structure, which provides a magnetically coupled communication link between the insulated circuits. Provided by a magnetically coupled conduction loop. In various examples, the insulation provided by the magnetically coupled communication links formed by the insulated conductors of the leadframes of the integrated circuit package according to the teachings of the present invention is provided between the primary and secondary sides of the switch mode power converter. It may be used in various applications including switch mode power converters that require DC insulation. Some exemplary switch-mode power converters that utilize integrated circuit packages with magnetically coupled communication links formed by the insulated conductors of the leadframes of the integrated circuit package are synchronous flybacks, according to the teachings of the present invention. Includes, but is not limited to, insulated flyback, isolated synchronous flyback, buck, forward, half-bridge, and full-bridge topologies.

For the purposes of this disclosure, the physically closed path for the current is referred to as the loop. The loop may include different elements such as conductors (which in this disclosure example can be formed by lead frames and bond wires inside the IC package) and electrical components in the path of circulating current. Each element in the loop forms part of the loop, and the combination of one or more elements in the loop is called a partial loop. In the context of magnetic field coupling, a loop surrounding a magnetic field is typically referred to as having one or more turns. Each number of turns corresponds to one enclosure of magnetic field.

1A and 1B show the conceptual operation of a magnetically coupled conduction loop that sends and receives signals to communicate operation information in a controller IC of a switch mode power converter, for example according to the teachings of the present invention. In FIG. 1A, the magnetically coupled communication link 100 includes an outer conducting loop 102 coupled to the transmitting circuit 110 and an inner conducting loop 105 coupled to the receiving circuit 130. The outer conduction loop 102 includes, in one example, a pulse current source 114 that injects a pulse current 120 into the conduction loop 102. In the embodiment, the transmitter circuit 110 is the transmitter current I._TInformation can be communicated using 120. In one example, the circuit in transmitter circuit 110 is transmitter current I._TInformation can be communicated to the receiving circuit 130 by controlling various properties of 120. Transmitter current I_TIf the magnitude of 120 changes or changes over time, this creates a fluctuating magnetic field near the conductor of the inner conduction loop 105. According to the law of electromagnetic induction, a voltage is generated across a conductor that receives a fluctuating magnetic field. Pulse current I in one example_T120 has a rise time, a fall time, and an amplitude. Transmitter current I_TThe fluctuating magnetic flux generated by the outer conduction loop 102 by 120 has a direction into the surface of the page. Marker 108 illustrates the overall magnetic field through both transmitter loop 102 and receiver loop 105. In general, the "X" sign as illustrated for the marker 108 indicates the magnetic flux or magnetic flux into the page, while the point code for the marker code indicates the magnetic flux or magnetic flux out of the page.

Therefore, in the embodiment, the current I_TReceiver voltage V due to fluctuating magnetic field generated by 120 changes_R140 is induced, resulting in receiver current I in the direction illustrated in FIG. 1A._R138 can occur.

The receiving circuit 130 may include a circuit capable of receiving the voltage and / or current induced by the transmitting circuit 110, interpreting the voltage and / or current as information. Transmitter current I that can be controlled to communicate information_TThe nature of 120 is the transmitter current I_TIt can include 120 magnitudes and rates of change. Transmitter current I illustrated_TIn the example of 120, the rise and fall slopes defined by the pulse waveform 120 have a pulsating voltage V with a positive amplitude during the rise time and a negative amplitude during the fall time of the transmitter current pulse waveform 120._RInduce 140. The receiving circuit 130 in the example has a threshold voltage V._Th134 and the induced voltage pulse V of the receiving circuit 130_RA comparator 132 that responds to comparisons with 140 amplitudes may be included.

The communicated signal may take the form of digital or analog information. In the case of digital information, communication can be in the form of binary signals or more complex encoded digital data, as known to those of skill in the art. It is accepted that other communication technologies may be used. In another example, transmitter current I_T120 and the resulting induced receiver voltage V received by the receiver circuit 130_R140 and receiver current I_RCommunication technology that utilizes the relationship with 138 may be used.

FIG. 1B illustrates another example of a magnetically coupled communication link 150. In one example, the communication link 150 may be suitable for bidirectional communication and includes two conduction loops. The first loop 152 and the second loop 155 are positioned so as to surround the largest common magnetic field area. Contrary to the example of FIG. 1A, which may be more suitable for one-way communication, the loops 152 and 155 of the bidirectional example of FIG. 1B have approximately the same dimensions. For the best bidirectional movement, the physical symmetry of the loop that results in nearly equal bidirectional behavior is important. The magnetic field or magnetic flux in the first loop 152 and the second loop 155 has a direction into the page.

The operational / functional difference between FIGS. 1A and 1B is that in FIG. 1B, both the first loop 152 and the second loop 155 are coupled to transceiver (transmit / receive) circuits 160 and 180, respectively. Is Rukoto. Transceiver circuits 1,160 may couple either transmit circuit 162 or receive circuit 165 into first loop 152 via selection switch S1 163.

Transceiver circuits 2,180 may couple either transmit circuit 182 or receive circuit 185 into a second loop 155 via select switch S2 183.

Transceiver circuit 1 160 is coupled as a transmit circuit and current pulse I_TR1Is injected into the first loop, the transceiver circuit 2 180 is coupled as a receiving circuit via the second loop 155 and switch S2 183 to pass the communicated signal to the current pulse I._TR2190 or voltage pulse V_TR2Will receive as 187.

On the other hand, the transceiver circuit 2 180 is coupled as a transmit circuit and the current pulse I_TR2When the 190 is injected into the second loop, the transceiver circuit 1 160 is coupled as a receiving circuit through the first loop 152 and by the controlled function of switch S1 163 to current pulse the communicated signal. I_TR1As 170 or voltage pulse V_TR1Will receive as 167.

Transmit circuits 162 and 182 in transceiver circuits 160 and 180 can include pulse current sources 164 and 184, respectively, and receive circuits 165 and 185 in transceiver circuits 160 and 180 have threshold voltages 168 and 188, respectively. Comparator circuits 166 and 186 having are included.

To illustrate examples of practical applications in the IC industry, FIGS. 2A and 2B are formed by DC insulated conductors of a lead frame inside an enclosed portion of an integrated circuit package according to the teachings of the present invention. An exemplary integrated circuit package 210 with a DC insulated magnetically coupled conductive loop is shown. In the example illustrated in FIGS. 2A and 2B, there are external pins 201, 202, 203, and 204, as well as external pins 205, 206, 207, and 208 on two sides of the integrated circuit package 210. In the example, all of the external pins are part of a lead frame 298 with internal conductive elements 296 and 297, where internal conductive elements 296 and 297 are introduced with any bond wire, such as bond wire 295, as shown. And, before extending from the enclosure 299 of the integrated circuit package 210, it is basically a part of the integrated circuit package 210. In one example, the lead frame 298 may comprise a known conductive material used for the lead frame during integrated circuit packaging, such as copper, which is substantially flat and of the integrated circuit package 210. Embedded in the molding compound. In the example, the lead frame 298 provides electrical connectivity to or from a circuit configuration coupled to pins 201-208 of the package 210, as well as providing mechanical support for the connection of the bond wire 295.

For the purposes of this disclosure, the "enclosed portion" of an integrated circuit package includes one or more integrated circuit dies and integrated circuit die pads disposed therein to connections to the lead frames and pins of the integrated circuit package. It can be thought of as any external structure, container, or mold that surrounds or surrounds a portion of the lead frame obtained. An exemplary enclosure can be made from a molded non-ferrous insulating material, plastic, ceramic cover, or the like. In some examples, the enclosure of an integrated circuit package may or may not provide an airtight seal that protects the articles contained therein from external elements.

For the purposes of this disclosure, the term "integrated circuit" package refers to a type of package commonly used for integrated circuits. It is acknowledged that some embodiments of the invention, such as the examples in FIGS. 2A, 2B, 2C, and 2D, may not have integrated circuits in the package.

FIG. 2B is a DC insulated magnetic coupling conduction loop 215 formed by the insulated first and second conductors 297 and 296 of the lead frame 298 of the exemplary integrated circuit package 210 of FIG. 2A, according to the teachings of the present invention. And 211 shows a diagram of the interior of the enclosure 299, revealing one exemplary structure. In particular, as shown in the illustrated example, the lead frame 298 includes a first conductor 297 and a second conductor 296 encapsulated in the insulating molded compound material in the encapsulation 299. In one example, the first and second conductors 297 and 296 of the lead frame 298 are formed from a flat sheet of metal by etching, punching, punching, etc., and the first conducting part loop 215 in the first conductor 297. And a second conductive portion loop 211 in the second conductor 296 may be formed. In the example depicted in FIG. 2B, the bond wire 295 is coupled to the second conductor 296, as shown, together with the portion of the second conducting portion loop 211. In the example depicted, the second conductor 296 is DC insulated from the first conductor 297. In one example, the bond wire 295 has a sufficient path length to provide sufficient insulation space from the first conductor 297 to maintain DC insulation between the first conductor 297 and the second conductor 296. Has. In another example not shown, it is acknowledged that it may include one or more additional bond wires that couple together the portions of the first conduction loop 215 and / or the second conduction loop 211. It is acknowledged that the circuit elements connected between pins 201, 202 and pins 203, 204 need to complete the indicated partially conducting loop 215 in order to transmit or receive signals through the communication link. Similarly, the circuit elements connected between pins 205, 206 and pins 207, 208 must truly complete the indicated partially conducting loop 211 in order to transmit or receive signals through the communication link. Is recognized. However, for the purposes of this description, the partially conducting loops 211 and 215 may be referred to as conduction loops. This description is shown in the figure below

As shown in the example, the second conducting loop 211 is disposed within the enclosure 299, is close to and magnetically coupled to the first conducting loop 215, and is directed according to the teachings of the present invention. It provides a communication link between the insulated first conductor 297 and the second conductor 296. In one example, the magnetic coupling portions of the first conduction loop 215 and the second conduction loop 211 are substantially flat and are arranged in substantially the same plane. As shown in the illustrated example, the first conduction loop 215 and the second conduction loop 211 each consist of one turn. In one example, the DC-insulated second conductor of the lead frame 298 is made use of the communication link provided by the magnetic coupling between the second conducting loop 211 and the first conducting loop 215 and according to the teachings of the present invention. Communicate one or more signals between the 296 and the first conductor 297. In one example, the transmit signal is applied between pins 205 and 206 of the first terminal T1 and pins 207 and 208 of the second terminal T2. For convenience of assembly on the circuit board, it may be desirable to have more external pins than one common to the terminals.

Continuing with the illustrated example, the signal is first conducted through magnetic coupling from the second conduction loop 211 between pins 201 and 202 of the first terminal R1 and pins 203 and 204 of the second terminal R2. Received by loop 215. In another example, it is acknowledged that the signals can also be communicated in opposite directions to provide bidirectional communication.

As shown in the example, pins 201 and 202 of the first terminal R1 are coupled to the first conduction loop 215 through the lead frame connection 216, and pins 203 and 204 of the second terminal R2 are connected through the lead frame connection 218. It is coupled to the first conduction loop 215. In the example, the signals at terminals T1 and R1 are in-phase according to the laws of magnetic coupling and induction. In one example, each terminal T1 214, T2 212, R1 216 to each pair of outer pins 205/206, 207/208, 201/202, and 203/204 as described above by providing multiple assembly options. , And the R2 218 connection simplifies the physical connection on the circuit board on which the integrated circuit package 210 is mounted.

FIG. 2C is an appearance of an example of an integrated circuit package 250 having a DC insulated magnetic coupling conduction loop formed by an insulated conductor of a lead frame 298 inside an enclosed portion of the integrated circuit package 250 according to the teachings of the present invention. The figure is shown. It is recognized that the integrated circuit package 250 of FIG. 2C shares many similarities with the integrated circuit package 210 of FIG. 2A. For example, the integrated circuit package 250 of FIG. 2C includes an enclosure 299 in which the lead frame 298 is located. However, one difference is that instead of having external pins located on two sides of the integrated circuit package, the integrated circuit package 250 has external pins 252, 254, located on one side of the integrated circuit package 250. It includes 256, and 258. In the example, all of the external pins are part of the lead frame 298 of the integrated circuit package 250 and extend from a single side of the enclosure 299 of the integrated circuit package 250 as shown.

FIG. 2D shows the DC insulated magnetic coupling conduction loop 215 and the DC insulated magnetic coupling conduction loop 215 formed by the insulated first and second conductors 297 and 296 of the lead frame 298 of the exemplary integrated circuit package of FIG. 2C, according to the teachings of the present invention. A diagram showing the interior of an enclosure 299 of one exemplary structure of 211 is shown. It is acknowledged that the diagram inside the enclosure 299 of the integrated circuit package 250 shares many similarities with the diagram inside the enclosure 299 of the integrated circuit package 210. For example, as shown in FIG. 2D, the lead frame 298 includes a first conductor 297 and a second conductor 296 that are encapsulated in the insulating material within the encapsulation 299. In the example depicted, the second conductor 296 is DC insulated from the first conductor 297. As shown in the example, the second conducting loop 260 of the second conductor 296 is in close proximity to and magnetically coupled to the first conducting loop 255 contained in the first conductor 297 within the enclosure 299. A communication link is provided between the first conductor 297 and the second conductor 296, which are arranged and DC-insulated according to the teachings of the present invention. One difference from the example illustrated in FIG. 2B is that in the example illustrated in FIG. 2D, the bond wire 295 is not included in the first conduction loop 255 and / or the second conduction loop 260.

In the example illustrated in FIG. 2D, according to the teachings of the present invention, the lead frame 298 is DC insulated using a communication link provided by a magnetic coupling between the second conducting loop 260 and the first conducting loop 255. One or more signals are communicated between the second conductor 296 and the first conductor 297. In the example, the transmitted signal is applied between pin 258 of the first terminal T1 and pin 252 of the second terminal T2. As shown in the example, pin 258 of the first terminal T1 and pin 258 of the second terminal T2 252 are coupled to the second conduction loop 260. The signal is received by the first conduction loop 255 through magnetic coupling from the second conduction loop 260 between pin 256 of the first terminal R1 and pin 254 of the second terminal R2. In another example, it is acknowledged that the signal can be communicated in the opposite direction to provide bidirectional communication as well.

FIG. 3A shows an outside view of an example of an integrated circuit package 315 having a magnetically coupled communication link formed by an insulated conduction loop of a lead frame 398 inside an enclosure 399 of the integrated circuit package 315 according to the teachings of the present invention. .. In the example illustrated in FIG. 3A, there are external pins 301, 302, 303, 304, 305, 306, 307, 308, 309, 310, 311 and 312, as shown. In the example, as shown, all of the external pins are part of the lead frame 398 of the integrated circuit package 315 and extend from the enclosure 399 of the integrated circuit package 315. In one example, the lead frame 398 may include a known conductive material used for the lead frame during integrated circuit packaging, such as copper, which is substantially flat and in the molded compound. It is enclosed. In the example, the lead frame 398 provides electrical connectivity to and from the internal circuit configuration within the enclosure of the integrated circuit package 315, as well as mechanical support for the integrated circuits and bond wires inside the package 315. ..

FIG. 3B is a DC insulated magnet formed by the insulated first and second conductors 397 of the lead frame 398 of the exemplary multi-die isolated controller integrated circuit package 315 of FIG. 3A, according to the teachings of the present invention. A diagram showing the interior of an enclosure 399 revealing one exemplary structure of coupled conduction loops 337 and 335 is shown. In particular, as shown in the illustrated example, the lead frame 398 includes a first conductor 397 and a second conductor 396 that are encapsulated in the insulating material within the encapsulation 399. As shown in the illustrated example, the first conductor 397 includes a first conducting loop 337 and the second conductor 396 contains a second conducting loop 335. As shown in the example, the second conducting loop 335 is placed in the enclosure 399 in close proximity to and magnetically coupled to the first conducting loop 337, and is DC insulated according to the teachings of the present invention. It also provides a communication link between the first conductor 397 and the second conductor 396. In one example, the first conductor 397 may be used for noise elimination as shown in the example, and also includes an optional third conducting loop 338 attached to the tie bar 339. In one example, the tie bar 339 provides a mechanical support connection during the manufacture of package 315 prior to encapsulating the lead frame 398 with encapsulation 399. In one example, the encapsulation 399 is injection molded using a molding compound. Utilizing the communication link provided by the magnetic coupling between the second conducting loop 335 and the first conducting loop 337, according to the teachings of the present invention, the DC insulated second conductor 396 and the second conductor of the lead frame 398 Communicates one or more signals with one conductor 397.

In FIG. 3B, in one example, a current signal from the transmit circuit 367 included in the controller die 360 and assembled on the die pad 334 is injected from the node 341 of the transmit circuit 367 through the bond wire 344. The current signal flows to the end node 343 of the bond wire 344, then completes the second loop 335 and flows back through the lead frame to the transmit circuit 367 through the bond wire 361. The injected signal creates a fluctuating magnetic field that induces a voltage signal in the first conduction loop 337, which is a current that closes from the first conduction loop 337 to the receiving circuit 355 through bond wires 377 and 357. The result is a signal. The receiving circuit 355 may be included in a first control die 350 assembled on a die pad 333 which is the primary ground.

In FIG. 3C, according to the teachings of the present invention, the first insulated control die 350 is mounted on and coupled to the first conductor 397, and the second insulated control die 360 is the second conductor. Another figure is shown inside the enclosure 399 mounted on and coupled to the 396. In the illustrated example, as shown, a first insulated control die 350 is mounted on the die pad 333 and a second insulated control die 360 is mounted on the die pad 334. In the illustrated example, the die pads 333 and 334 are used as isolated primary and secondary ground pads, respectively. In the example shown in FIG. 3, the magnetically coupled communication link between the first isolated control die 350 and the second insulated control die 360 follows the teachings of the present invention with a first conduction loop 337 and a first Formed by a magnetically coupled communication link between the two conduction loops 335. In one example, according to the teachings of the present invention, the multi-die isolated controller integrated circuit package 315 may be used in a switch mode power converter such as a synchronous flyback switch mode power converter with secondary control, for example.

Products and applications that require low output voltages, such as 5V or less, may use synchronous rectification to achieve high efficiency and small Scherrer equations. Synchronous rectification reduces voltage drops and power loss by utilizing MOSFETs (metal oxide semiconductor field effect transistors) that are switched to behave like rectifiers instead of output rectifier diodes. The switching action of the output MOSFET rectifier is synchronized with the main power switching by a well-controlled gate signal. In one example, the first isolated control die 350 includes a primary control circuit and a switch (MOSFET in one example) for use on the primary side of a synchronous flyback switch mode power converter, and a second isolated control die 360. Includes a secondary control circuit for use on the secondary side of a synchronous flyback switch mode power converter. In various examples, the primary control circuit and switch / MOSFET can be implemented in a monolithic or hybrid construction for the first isolated control die 350.

As shown in the example illustrated in FIG. 3C, the primary switch (or MOSFET) is included in the first isolated control die 350. In one example, the drain terminal D 340 of the MOSFET is coupled to pin 301 through bond wire 342. The MOSFET source terminal S 345 is coupled to the primary ground die pad 333 through bond wire 347 and is accessible through source pin 302. In the illustrated example, there is a large gap (ie, the pin is missing) between the drain pin 301 and the source pin 302, often referred to as creepage distance. In the illustrated example, the wide pad of source pin 302 is internally coupled to a primary ground pad 333 that can also act as a heat sink. In one example, pins 303 and 304 are coupled to a first insulated control die 350 through bond wires 352 and 354, respectively, to provide the first insulated control die 350, for example, line under voltage. ) (Example of UV536 in FIG. 5) and supply bypass capacitor (example of BP531 in FIG. 5) and other external circuit configurations.

The bond wire 336 couples the third conduction loop 338 to the first insulated control die 350. A fluctuating magnetic field generated by a changing current flowing through the second conduction loop 335 induces a voltage signal into the first conduction loop 337. In the example of FIG. 3C, the first conduction loop 337 is coupled to the third conduction loop 338 (an optional noise elimination loop that is an extension of the first conduction loop). The induced voltage signal is coupled through bond wires 336 and 347 to a receiving circuit contained in the primary die 350, for example on the primary ground die pad 333.

In the example, the pin 305 is attached to the second conducting loop 335 of the second conductor 396 for mechanical support. The signal communicated from the second isolated control die 360 is coupled to the second conduction loop 335 through the bond wires 344 and 361 that complete the second conduction loop 335. As shown in the example, the bond wire 344 is a connection at point 343 that connects the second conduction loop 335 to the second insulated control die 360 at point 341. The pin 312 of the example is coupled to the secondary ground pad 334 through the current sensing bond wire 371 and the detected voltage drop on the bond wire 371 is coupled to the second insulated control die 360 through the bond wires 370 and 372. At the same time, it is used for secondary current measurement. In one example, bond wires 362, 364, 365, and 366 are coupled between a second isolated control die 360 and pins 306, 307, 308, 309, and 310, respectively, to input secondary signals. / Used for output. In one example, pin 311 provides access to the secondary ground pad 334 as shown.

In one example, the slot on the secondary ground pad 334 under the second insulated control die 360 connects the second conduction loop 335 by forcing a current through the second conduction loop 335 to the ground pad 334. It is made longer and flows closer to and parallel to the first conduction loop 337 to improve magnetic coupling. The smaller first conducting loop 337, which is close to and surrounded by the second conducting loop 335, provides a strong magnetic coupling between the first conducting loop and the second conducting loop according to the teachings of the present invention. In one example, the lead frame 398 is flat, while in another example, a portion of the lead frame 398 accommodates die thickness to optimize the bond wire profile and accommodates tie bars and external pins in integrated circuit package 315. They may be set up and / or down for optimal longitudinal positioning so that they are aligned.

FIG. 3D is an electrical connection as mentioned above, according to the teachings of the present invention, coupled to a second insulated control die 360 at point 341 of the second conduction loop 335 and at point 343. An exemplary side view of the bond wire 336 coupled to the conduction loop 335 of 2 is shown. As shown in the example, the bond wire 336 is at a higher level than the level of the second conduction loop 335 and the pin pad 334 of the lead frame 398. As shown, the bond wire 336 has sufficient distance to complete the second conduction transmitter loop 335 and be isolated from the first conduction loop 337.

FIG. 4A shows the leads of an integrated circuit package with a magnetically coupled communication link formed using magnetically coupled conductive loops of insulated conductors of the lead frame inside the enclosed portion of the integrated circuit package according to the teachings of the present invention. An inclined 3D (three-dimensional) view of an internal view of an example of a frame is shown. FIG. 4A shows that the illustrated lead frame structure shares similarities with the structure of lead frame 398 in FIGS. 3B and 3C. In particular, in the example of FIG. 4A, the lead frame structure corresponds to the die pads 333, first conduction loop 337, and third conduction loop 338 of FIGS. 3B and 3C, respectively, with the primary die pads 433 and the first conduction loop. Includes a first conductor, including a 437 and a third conducting loop 438. Further, in the example of FIG. 4A, the lead frame structure is a second conductor containing a secondary die pad 434 and a second conduction loop 435 corresponding to the die pads 334 and the second conduction loop 335 of FIGS. 3B and 3C, respectively. Also includes. In FIGS. 4A and 4B, the tie bar connection 439A supporting the third conduction loop 438 is located at a different location than the tie bar connection 339 supporting the third conduction loop 338 in FIGS. 3B and 3C, FIG. 4A. And the tie bar connection 439B of FIG. 4B is not present in the lead frame 398 of FIGS. 3B and 3C. As a result, the lead frame design shown in FIGS. 3A, 3B, and 3C measures the external creepage distance between the primary and secondary conductors of the lead frame along the outer surface of the enclosure, external. It does not have top and bottom tie bar connections on the encapsulation that increase to the smaller minimum distance between pins 304 and 305 or between external pins 301 and 312.

FIG. 4B has communication links between controller dies formed using magnetically coupled conduction loops of insulated conductors of lead frames inside an enclosed portion of an integrated circuit package, as taught in the present invention. An inclined 3D diagram of another diagram inside the enclosure of an example lead frame of a multi-die isolated controller integrated circuit package is shown. FIG. 4B shows a lead frame structure that shares similarities with the lead frame structure shown in FIG. 4A. In the example illustrated in FIG. 4B, the primary and secondary dies are shown mounted on the lead frame. As shown in the illustrated example, the primary switch 450 and controller 451 are-on different dies, commonly referred to as hybrid structures. In the example of FIG. 4B, the power MOSFET has a high power rating, resulting in a separate die 450 with a large size that covers virtually all of the primary ground die pads 433. In the illustrated example, the primary control die 451 is mounted over a portion of the third conduction loop 438 as shown. The secondary control die 452 is mounted on the secondary ground die pad 434 as shown.

An integrated circuit package having a magnetically coupled communication link between DC insulated conductors of a lead frame inside an enclosed portion of an integrated circuit package according to the teachings of the present invention may be utilized in a variety of different applications. Is recognized. Several different switch-mode power converter topologies that utilize such integrated circuit packages with magnetically coupled communication links are described herein, but the specific examples provided in this disclosure are for purposes of illustration. To provide, another application may utilize a magnetically coupled communication link between DC insulated conductors of a lead frame inside an enclosed portion of an integrated circuit package according to the teachings of the present invention. Is recognized.

For illustration purposes, FIG. 5 shows magnetic coupling communication between controller dies formed using DC insulated conductors of a lead frame inside an enclosed portion of integrated circuit package 560 according to the teachings of the present invention. One such exemplary application with a schematic of an exemplary synchronous flyback switch mode power converter 500 with secondary control utilizing an example of a multi-die isolated controller integrated circuit package 560 with a link 540. Is shown.

Secondary control for flyback converters is found to have the advantages of tighter power regulation and faster response to transient loads. However, as discussed earlier, conventional methods of secondary control often use external isolation devices, such as optical couplers, which increase the complexity and cost of switch-mode power converters. According to the teachings of the present invention, the insulation added to the outside, such as an optical coupler, by using an exemplary multi-die isolated controller integrated circuit package 560 with a magnetically coupled communication link 540 with isolated primary and secondary control dies. Components are no longer needed. Further, the integrated circuit package 560 provides a magnetically coupled communication link by using the lead frame of the integrated circuit package as previously discussed, so that according to the teachings of the present invention, there is no need to add external insulating components. Maintains DC isolation between the primary and secondary sides of the switch mode power converter with almost zero additional cost.

In the exemplary synchronous flyback switch mode power converter 500, the primary and secondary controllers are DC isolated from each other, but there is still reliable communication between the primary and secondary controllers. Although the example of FIG. 5 shows a synchronous flyback converter, it is acknowledged that a standard flyback converter in which the synchronous MOSFET 550 is replaced with a diode will also benefit from the teachings of the present invention.

In the example illustrated in FIG. 5, the synchronous flyback switch mode power converter 500 includes an input coupled to AC wiring 505 as shown. The full bridge rectifier 510 is coupled to the AC wiring 505 to produce a rectified AC515, which has a capacitance of C._FFiltered by 517. The rectified AC515 is coupled to be received by an energy transfer element 520 that includes a primary winding 521 and a secondary winding 522 as shown. In the illustrated example, the clamp circuit 525 is coupled to both ends of the primary winding 521 of the energy transfer element 520, as shown.

In the example depicted, the switching device S1 530 is coupled to the input of the synchronous flyback switch mode power converter 500 at primary ground 501 and to the energy transfer element 520 at primary winding 521. In the illustrated example, the switching device S1 530 may be included in the monolithic or hybrid structure in the integrated circuit package 560. As shown in the example depicted, the switching device S1 is controlled by a control signal 539 from the primary controller die 535 and in response to changes in wiring and load, the secondary winding through the primary winding 521 of the transformer 520. Adjust the energy transfer to line 522. The clamp circuit 525, which is a diode-resistor-capacitor circuit in the illustrated example, is coupled to clamp a turn-off spike resulting from a leakage inductance from the primary winding 521 across the switching device S1 530.

As shown in the example of FIG. 5, the switch S2 550 and the antiparallel diode D2 555 are coupled to the secondary winding 522 on the secondary side and act as a synchronous rectifier for the synchronous flyback switch mode power converter 500. In one example, the diode D2 555 is an externally connected Schottky diode. In one example, switch S2 550 is controlled by a signal from the SR pin of the secondary controller die 565. Whenever the voltage at SR terminal 575 rises above the gate threshold voltage, the synchronous rectifier provided by switch S2 550 begins to conduct current. The secondary ripple is smoothed by the output filter capacitance C1 586 and a DC output voltage Vo580 is applied to the load 585 along with the load current Io582. The output voltage Vo580 is detected through a resistor divider with resistors 572 and 574, which are coupled to the feedback pin FB573 of the secondary controller. In another example, it is found that resistors 574 and 572 can be integrated into integrated circuit 560, still benefiting from the teachings of the present invention.

Upon startup, the primary die 535 relative to the primary ground 501 initiates switching of switch S1 530, which initiates the transfer of energy to the secondary side. The bypass pin BP531 is externally coupled to the bypass capacitor 532. The line undervoltage pin UV536 is externally coupled through a resistor 537 to an AC input wire that, in another example, can be coupled to a rectified AC bus 515. Communication between the primary die 535 and the secondary die 565 is through a magnetic coupling provided by a magnetic coupling communication link 540 formed by an insulated conductor in the lead frame of an integrated circuit package according to the teachings of the present invention. is there. In various examples, the communication link 540 is implemented using the DC isolated conduction loop contained in the lead frame of the integrated circuit package described above, according to the teachings of the present invention.

FIG. 6 is a flyback switch utilizing an example of a multi-die isolated controller integrated circuit package that includes a bidirectional magnetically coupled communication link between controller dies inside the enclosed portion of the integrated circuit package, in accordance with the teachings of the present invention. An example of the mode power converter 600 is outlined, in which the output information is transferred to the primary side through the magnetically coupled communication link and the line zero cross detection signal is transferred to the secondary side through the magnetically coupled communication link.

In the example illustrated in FIG. 6, the flyback switch mode power converter 600 includes an input coupled to AC wiring 605, as shown. The full bridge rectifier 610 is coupled to AC wiring 605 to produce rectified AC615, which has capacitance C._FFiltered by 617. The rectified AC615 is coupled to be received by an energy transfer element 620, including a primary winding 621 and a secondary winding 622, as shown. In the illustrated example, clamp circuits 625 are coupled to both ends of the primary winding 621 of the energy transfer element 620, as shown.

In the example depicted, the switching device S1 630 is included in the integrated circuit package 660. In one example, the switch die and the primary control die may be constructed as a monolithic or hybrid die. In the example, the switching device S1 630 is coupled to the input of the flyback switch mode power converter 600 at the primary ground 601, and to the energy transfer element 620 at the primary winding 621. As shown in the example depicted, the switching device S1 630 is controlled by a control signal 639 from the primary controller die 635 and in response to changes in wiring and load, the secondary through the primary winding 621 of the transformer 620. Adjust the energy transfer to winding 622. The clamp circuit 625, which is a diode-resistor-capacitor circuit in the illustrated example, is coupled to clamp a turn-off spike resulting from a leakage inductance from the primary winding 621 across the switching device S1 630. In the illustrated example, the secondary rectifier diode D2 655 during flyback conducts current only during the off time of the primary switch 630.

The secondary ripple is filtered by the output filter capacitance C1 686, and a DC output voltage Vo 680 is applied to the load 685 along with the load current Io 682. The output voltage Vo680 is detected through a resistor divider with resistors 672 and 674, which is coupled to the feedback pin FB673 of the secondary controller die 665 and is relative to the secondary ground 691 isolated from the primary ground 601. .. In one example, the feedback signal 673 is a data signal transmitted through the magnetic coupling of the readframe communication loop 641 and received by the primary die 635 with reference to the primary ground 601. In one example, the FB signal 673 transferred by the readframe magnetic coupling of the communication link 640 to the primary controller die 635 can be either a digital or analog signal. Switch S1 using the FB signal in combination with the input wiring information received at pin 634 through resistor 637 Generates a gate control signal 639 to control the switching of the 630 to regulate the transfer of energy to the output through the energy transfer element 620. In one example, the readframe communication link 640 includes one-way communication links 641 and 642 that transmit one or more control signals between the dies 665 and 635 according to the teachings of the present invention. In another example, the leadframe communication link 640 uses the same magnetically coupled leadframe loop to transmit one or more control signals in any direction between the dies 665 and 635, according to the teachings of the present invention. Includes a single bidirectional communication link (as depicted in Figure 1B).

In one example, the specific control function of the exemplary flyback switch mode power converter 600 in FIG. 6 is through shunted resistors 602 and 603 at a common point 604 relative to primary ground 601 as shown. The zero cross signal of the AC wiring detected by the AC wiring input 605 is also used. In the example, the zero detection signal 606 is coupled to the primary die 635 and is transmitted through the magnetic coupling of the readframe communication loop 642 with reference to the primary ground 601 and received by the secondary die 665 with reference to the secondary ground 691. , This can be used as an isolated remote control signal. For example, a zero-cross signal (a pulse that synchronizes with an AC input voltage that passes through zero in every other line cycle) is used as an isolated signal for some electrical equipment, such as a washing machine, to detect line frequencies. Alternatively, the timing signals required for efficient load switching in the equipment can be generated.

As shown in the illustrated example, the readframe communication link 640 is bidirectional and includes two unidirectional communication links 641 and 642. The communication link 642 is unidirectional in the opposite direction of the readframe communication link 641. Although the individual readframe communication links are described as one-way communication links in the illustrated example, another example uses a single leadframe communication link instead of the two one-way communication links according to the teachings of the present invention. It is acknowledged that it can be used in bidirectional implementations (as presented in Figure 1B, for example).

Even if a magnetically coupled communication link constructed according to the teachings of the present invention provides DC insulation, one of ordinary skill in the art would benefit from the benefits of the present invention by means of an entire system such as a switch mode power converter practicing the present invention. It will be acknowledged that the input and output of the system do not necessarily have to be DC isolated. For example, in a non-isolated converter, a DC isolated communication link according to the teachings of the present invention communicates between two parts of a switch mode power converter relative to different voltages that are fixed or changeable over time with respect to each other. To enable.

The above description of the illustrated examples of the invention, including those described in the abstract, is not intended to be exhaustive or limited to the exact form disclosed. Specific embodiments of the invention and examples thereof are set forth herein for illustration purposes, but various equal modifications are possible without departing from the broader spirit and scope of the invention. In fact, specific exemplary voltages, currents, frequencies, power range values, time, etc. are given for purposes of illustration and other values in other embodiments and examples according to the teachings of the present invention. It is recognized that may also be used.

100,150,540,640 Communication link, 102,105,152,155,211,215,255,260,335,337 Loop, 210,315,560 Integrated circuit package, 295,342,347 Bond wire, 296,297,396,397 Conductor, 298,398 Lead frame, 299,399 Encapsulation, 333,334 Die pad, 350,360,369,451,452 Control die, 350,360,369,451,452