Double switch for current inverter encapsulated in a case with flat exterior pins

p0001The present invention relates to an electronic power switch encapsulated in a plastic stacked and intended in particular to be used as a power switching device in an inverter, this member being referred to hereinafter as dual switch because it comprises essentially two elements controlled switch (transistors or thyristors) and two diodes called "coasting".

p0002It seeks to solve the very real problem in the most economic industrial manufacturing can be a double switch that can meet the needs of users (eg inverter manufacturers) even when those needs change over time: for example, we want power sale, in hardly modifying the production line, a lot of switches suitable for inverters of low-end and a lot of switches suitable for high-end inverters. However, the electrical installation of the switch in the inverter depends on the type of course chosen inverter; in particular, a switch designed for low range can comprise, in addition to switching control pins, only three external pins power respectively representing a midpoint and two output terminals of power transistors, while an inverter premium will include six external pins: four pins for access to the emitter and collector of each transistor and two pins for access to the anode or cathode of two diodes called "freewheeling" forming part of the switch.

p0003It is therefore conceivable that a priori the two types of dual switches must be manufactured on very different production lines from one another.

p0004The present invention provides a clean switch construction to allow the manufacture of one type of switch suitable for both purposes, the differentiation being carried out at a very late stage of the manufacturing, allowing in particular the storage of large quantities of undifferentiated switches can very quickly be completed as needed, to become essentially:<ul><li>Or - switches to three power pins for simple applications,</li><li>- Or switches to six power pins for more sophisticated applications.</li></ul>

p0005The switch of the invention is encapsulated in a plastic stacked from which emerge, in addition to control pins, six flat metal pins for the external connections of power, and its characteristics are as follows:<ul><li>a) almost final manufacturing stage (stage storage), external mechanical switch configuration is as follows: the upper surface of the casing has nine clean recesses to receive and block rotation of each one nut, these recesses being grouped in three parallel rows with three recesses, two external pins being located in facing relation on either side of each group of three, the pins on one side being disposed in a common plane perpendicular to the upper surface of the casing and the pins in vis-a-vis the other side being disposed in another plane parallel to the first, intermediate recesses groups of three themselves being aligned in a substantially median plane between the two parallel planes; the length of all the pins is such that, by folding of the pins, the intermediate recess can be totally covered by the pins in vis-a-vis that frame;</li><li>b) the inside electric stacked configuration is as follows: a first switching element (transistor or thyristor) has one terminal connected to a first external pin; the spindle vis-a-vis thereof is connected to a diode also connected to a second controlled switching element; the second element has one terminal connected to another external pin; the spindle vis-a-vis thereof is connected to a further diode connected also to the first switching element; the first and second switching elements finally each have another terminal and the other terminals are connected respectively to two external pins in vis-a-vis.</li></ul>

p0006To move from the intermediate storage in a clean final configuration mechanical configuration has to be marketed based on user needs, the only operations required are: cutting and drilling of external pins, setting up the nuts in those recesses which are to be used, folding spindles vis-a-vis, towards each other, above the recesses they frame.

p0007The two major configurations which are then results are the following:<ul><li>- Configuration with recovery, or two pins in vis-a-vis both cover, one on the other, the central recess of the group they back up,</li><li>- No overlap configuration, where two pins vis-à-vis each cover only the nearest recess of the group they frame.</li></ul>

p0008Other features and advantages of the invention apparattront on reading the detailed description which is given with reference to the accompanying drawings in which:<ul><li>- Figure 1 shows the outer configuration of the dual mechanical switch according to the invention at an intermediate stage of manufacture,</li><li>- Figure 2 shows the final external configuration constituting a three-terminal switch,</li><li>- Figure 3 shows the final external configuration constituting a six-terminal switch,</li><li>- 4 shows the internal configuration of the double switch,</li><li>- Figure 5 shows an application diagram of the switch of Figure 2,</li><li>- Figures 6 and 7 show diagrams of application of the switch of Figure 3.</li></ul>

p0009The double switch of the invention includes an electrical circuit enclosed in a plastic stacked 10 which is preferably a rectangular block fixed to a metal base 12.

p0010Of the substantially planar upper surface 14 of the casing emerge six-pin flat metal connection, connected to the internal electrical circuit and for the power section of the circuit. These pins are designated by references C1, Dl, El, C2, D2, E2, respectively.

p0011In almost final stage of manufacture, the six pins amounted all perpendicular to the plane of the upper surface 14. They are arranged in three groups of two pins being vis-a-vis the spindle El being vis-à spindle screw C2, E2 pin vis-a-vis of the pin D2 and the spindle C1 vis-a-vis the DI pin.

p0012El, E2 pins, Cl are located in the same plane (the pins are flat) plane which is perpendicular to the upper surface 14 and which passes substantially through a longitudinal edge 16 of the rectangular stacked. C2 pin, D2, Dl are also located in the same plane, parallel to the first, and substantially passing through another longitudinal edge 18 of the casing.

p0013The pins thus define two parallel planes which are virtually the plans of two longitudinal edges of the casing.

p0014Carved into the upper surface 14 are provided new blind recesses or cavities, arranged in three groups of three, each group comprising three recesses aligned with two respective pin vis-a-vis.

p0015Thus, the recesses 20, 22, 24 are aligned between El and C2 pin, the recesses 26, 28, 30 between the pin E2 and D2, the recesses 32, 34, 36 between the Cl and Dl pins.

p0016The central recesses 22, 28, 34, three groups themselves are aligned substantially in a median plane between the parallel planes containing the pins.

p0017Non-central recesses are also preferably aligned in parallel to the planes of the pins.

p0018The recesses are shaped so as to each receive and rotationally lock nut. Nuts will be subsequently deposited in three or six recesses depending on the needs.

p0019The height of emergence of the pin above the surface 14 is such that it will:<ul><li>- Drill a hole at their end,</li><li>- Folding two pins vis-a-vis the one on the other,</li><li>- Obtain a mutually overlapping holes in the two pins, the holes themselves covering the central recess of the group located between these pins.</li></ul>

p0020To complete the exterior description of the switch in the state it is in Figure 1, state it can be stored, waiting for user commands, you can report the switch control pins that were represented six in number and designated by references c, b, e, c ', b', e '.

p0021These control pins are small; they may be flat or cylindrical and can be located for example in a shoulder 38 of the upper surface 14 of the casing.

p00222 shows the dual switch of the invention in one possible configuration that has the end of manufacture.

p0023In this configuration, the external pins of power were pierced with holes for screws to nuts which are adapted to lodge in the recesses; nuts 40, 42, 44 have been implemented only in the central recesses 22, 28, 34 respectively. Then, the pins El, E2, C1 have been folded parallel to the plane of the surface 14, close enough to the surface to prevent the nuts out of the recesses; finally the pin C2, D2, Dl on the other side have been folded over the first. Only holes 46, 48, 50 drilled at the end of the pin C2, D2, Dl are truly visible in Figure 2, but it is understood that the pin holes in two side-by-vis folded and are superimposed exactly above the central recesses corre sponding to these pins, so that by placing three screws, one can at the same time electrically connecting together the pin folded one on the other and connect these pins to three conductors exterior.

p00243 shows another possible configuration of the switch after the final manufacturing step.

p0025External power pins were first cut to a sufficiently short length so that when folded they could no longer touch; subsequently or simultaneously, the pins are pierced at a location such that when folded the holes come over the non-central recesses. After placement of six nuts 54, 56, 58, 60, 62, 64 in non-central recesses (20, 26, 32, 24, 30, 36 respectively in Figure 1), one then proceeds to the folding pins, low enough to prevent the nuts out of the recesses. The holes 66, 68, 70, 72, 74, 76 in the pin end then come over the nuts and allow the screw mounting of the pins on six outer conductors (or other elements).

p00264 shows the internal configuration of the double electric switch according to the invention: the external pins of power were redesignated El, E2, Cl, C2, Dl, D2 as the preceding figures and the control pins by c, b, e, c ', b', e '.

p0027The circuit comprises two switching elements controlled Tl and T2 (here transistors or Darlington circuits), and two diodes called free wheel dl and d2.

p0028The transistor T has two power terminals (collector and emitter) connected to power pins and El Cl respectively, as well as control pins C and E; it has a control terminal (base) connected to the spindle b.

p0029Similarly, the transistor T2 has two power terminals (collector and emitter) connected to power pins and C2 and E2 respectively as control pins c 'and e'; it has a control terminal (base) connected to the spindle b '.

p0030The first diode dl has its anode connected to the pin C2 and its cathode to the DI pin; the second diode d2 has its anode connected to the pin D2 and its cathode to the spindle El.

p0031However, in another possible configuration, one could have the diode dl is connected with its cathode to the Dl terminal and with its anode to terminal E2 and the diode d2 is connected with its cathode to terminal Cl and by its anode to terminal D2 .

p0032In all cases, it should be noted that one of the power terminals (collector) of the first transistor (Tl) to be connected to a spindle (Cl) in vis-a-vis a pin (Dl) connected to a diode (dl); the other power terminal (transmitter) is to be connected to a spindle (El) vis-à-vis a spindle (C2) connected to a power terminal (collector) of the other transistor (T2); and the other power terminal (emitter) of the second transistor (T2) must be connected to a pin (E2) vis-a-vis a pin (D2) connected to the other diode (d2).

p0033Figures 5, 6, 7 show diagrams of possible application of the switch according to the invention.

p0034The diagram of Figure 5 corresponds to the use of a switch made according to Figure 2: Short-circuit between the terminals El and C2 that are connected to an output conductor S, short-circuit between terminals E2 and D2 that is connected to a supply conductor B to a negative or zero potential, short-circuit between the terminals C1 and Dl that is connected to a supply conductor a to a positive potential.

p0035The diagrams of Figures 6 and 7 correspond to the use of a switch according to Figure 3.

p0036In Figure 6, a short circuit is made between the terminals Cl and Dl, either by a conductive strip, or by connecting the two terminals C1 and Dl to the same positive power supply conductor A; a resistor R1 is attached between terminals E2 and D2, the terminal D2 is connected to a supply conductor B to zero or negative potential; another resistor R2 is set between the terminals El and C2, C2 terminal being also connected to an output conductor S (connected to a load).

p0037In Figure 7, for a high frequency application, a supply conductor is provided to connect A to the terminal Cl, a conductor B to terminal E2, a diode D3 in parallel with an inductance L1 between terminal Dl and the terminal C1, a d4 diode in parallel with an inductor L2 between the bonre E2 and the terminal D2, and finally an inductor L3 between El and C2 terminals with an intermediate tap on said inductor for connection to an output conductor S .