Charging device

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Industrial application field]

The present invention relates to a charging device used for charging a secondary battery mounted on a portable electronic device such as a mobile phone.

【0002】

[Conventional technology]

In portable electronic devices such as mobile phones and laptop computers, a rechargeable secondary battery is installed as a battery pack, and the charging terminal of the secondary battery is connected to the charging terminal of the charging device connected to the commercial power supply. Is designed to be charged. In this case, charging is normally performed with the battery pack mounted on the main body of the portable electronic device.

【0003】

FIG. 3 is a flowchart showing charge control performed by a conventional charger. Here, in order to charge the secondary battery (the required power can be supplied by connecting five 1.2V NiCd batteries in series) mounted on a mobile phone composed of a 5V circuit. The control operation performed by the charge control microcomputer for the charger of the above will be described.

【0004】

First, when it detects that the battery pack is installed (S31), it starts the abnormality detection timer (S32) and displays that charging is in progress (S33). Subsequently, the battery voltage V detected by the battery voltage detection circuit_BCheck if is less than 5.5V (S34), and if it is less than 5.5V (Yes in S34), trickle charge (S35). In addition, trickle charging means that a minute current of about 20mA is passed at the start of charging in order to avoid quick charging of the short-circuit battery and protect the charger.

【0005】

If the battery voltage is still below 5.5V even after 24 minutes have passed by the abnormality detection timer (Yes in S36), it is determined that the battery to be charged is an abnormal battery and an abnormality is detected. Is displayed (S37), and charging is stopped immediately (S38). On the other hand, if the detected battery voltage exceeds 5.5V (No in S34), quick charging is performed (S41). Then, when a full charge is detected (Yes in S42), a full charge is displayed (S43).

【0006】

It should be noted that there is a time limit for detecting this full charge, and an abnormality detection is also displayed, but since it is not directly related to the present invention, the description of the flow is omitted.

【0007】

[Problems to be Solved by the Invention]

However, in the above-mentioned conventional charging operation, for example, when trying to charge a mobile phone equipped with an over-discharged battery having a battery voltage of 2V, the battery voltage naturally rises due to trickle charging at first, but 5.5V. If the system is started once when a certain voltage (for example, 4.5V) is reached, the current exceeding the trickle current (about 100 to 150mA) will be consumed in the mobile phone circuit, and at that time. All the charging current in the above will be consumed by the mobile phone circuit. As a result, the charging current to the secondary battery is completely lost, the battery voltage does not rise any more, and there is a problem that an abnormality detection display is displayed when the detection time of 24 minutes has passed. ..

【0008】

The present invention has been made to solve such a problem, and stably and surely charges a secondary battery mounted on a portable electronic device without being affected by load fluctuations during charging. It is an object of the present invention to provide a charging device capable of capable of providing a charging device.

【0009】

[Means for solving problems]

In order to achieve the above object, the invention according to claim 1 is a charging device for charging a secondary battery mounted on a portable electronic device, a timer for measuring the charging time, and a predetermined detection time. A battery voltage detecting means for detecting the battery voltage over a period of time, a first charging means for performing trickle charging over the first charging time when the detected battery voltage is below the first threshold value, and the first charging means. When the battery voltage is still below the first threshold value as a result of charging by the first charging means, the second charging means that performs trickle charging following the rapid charging over the second charging time, and the above-mentioned As a result of charging by the second charging means, the battery voltage has not yet exceeded the first threshold value, and the charging voltage by the second charging means and the charging voltage by the first charging means As a result of charging by the recharging instruction means for instructing the first charging means and the second charging means when the difference between the above does not exceed the second threshold value, the battery voltage Is characterized in that it is provided with a third charging means that performs rapid charging until a full charge is reached when the first threshold value is exceeded.

【0010】

Further, in the invention described in claim 2, the first threshold value is set as a lower limit value of the secondary battery voltage sufficient to ensure normal circuit operation of the portable electronic device, and the second threshold value is set. The value is set as a lower limit value of the increase in the charging voltage to be brought about by the charging of the second charging means. Further, in the invention according to claim 3, the first charging time is set as a voltage rise time sufficient to charge the secondary battery in the over-discharged state, and the second charging time is the second charging time. It is characterized in that it is set as a time sufficient to quickly charge the secondary battery while covering the current consumption that may occur during charging by the charging means of 2.

【0011】

[Action]

According to the configuration of the invention of claim 1, the timer measures the time for charging the secondary battery. Further, the battery voltage detecting means detects the battery voltage for a predetermined detection time. Here, when the detected battery voltage is below the first threshold value, the first charging means performs trickle charging for the first charging time. Further, when the detected battery voltage as a result of charging by the first charging means is still below the first threshold value, the second charging means performs rapid charging for the second charging time. , Then, Tokuriru charging is performed.

【0012】

Then, as a result of charging by the second charging means, the detected battery voltage does not still exceed the first threshold value, and the difference between that voltage and the previous charging voltage by the first charging means. If does not exceed the second threshold value, the recharge instruction means gives an instruction for recharge to the first charging means. If the detected battery voltage exceeds the first threshold value as a result of charging by the second charging means, the third charging means rapidly waits until the secondary battery reaches full charge. Charging is done.

【0013】

As a result, when charging the secondary battery while it is mounted on the portable electronic device, even if the load fluctuates, it is possible to surely reach the full charge. If the battery voltage does not exceed the threshold value within the predetermined detection time, it is determined that the battery is abnormal and charging is stopped. Further, according to the configuration of the invention of claim 2, in the charging device according to claim 1, the first threshold value is a secondary battery voltage sufficient to ensure normal circuit operation of the portable electronic device. The lower limit value is set, and the second threshold value is set to the lower limit value of the increase in the charging voltage to be brought about by the charging of the second charging means.

【0014】

Further, according to the configuration of the invention of claim 3, in the charging device according to claim 1 or 2, the first charging time is such that the voltage rise due to the charging of the secondary battery in the over-discharged state is difficult. The time required and sufficient for the voltage rise is set in consideration of the fact that the voltage does not advance. The second charging time is a time sufficient to quickly charge the secondary battery while covering the current consumption, considering that the portable electronic device starts the system and generates current consumption during charging. Is set to.

【0015】

[Example]

Hereinafter, an embodiment of the present invention will be specifically described with reference to the drawings. FIG. 1 is a block diagram showing a circuit configuration of a charging device according to the present invention. As shown in the figure, the charging device 1 displays a charging control microcomputer 2 that receives power supply to perform charging control, a quick charging constant current circuit 3, a trickle charging constant current circuit 4, and a charging state. A display unit 5 (composed of a charge indicator lamp 51, a fully charged indicator lamp 52, and an abnormal battery indicator lamp 53) is provided. In addition, there are two types of charging modes, one is the trickle charging mode in which a minute current (about 20mA) is passed to avoid quick charging of the short battery at the start of charging, and the other is the original charging mode. It is in a certain quick charge (current of about 650mA) mode. Then, the charge control microcomputer 2 switches between these two charge modes.

【0016】

In the charge control microcomputer 2, the trickle charge constant current circuit 4 is operated by turning on the trickle charge ON signal 7 during trickle charging, and the quick charge constant current is turned on by turning on the quick charge ON signal 6 during quick charging. Circuit 3 is turned on. On the other hand, as shown in the figure, here, the charging constant current circuits 3 and 4 are connected to the charging plus terminal of the battery pack 11 through the charging plus terminal. Then, when the battery pack 11 is attached to the mobile phone body 14, the secondary battery 12 (1.2V x 5 = 6.0V) provided inside the battery pack 11 is charged through the respective charging plus terminals. It is supposed to be done. Further, when the system is started during charging, a part of the charging current is directly supplied to the mobile phone main body 14.

【0017】

The negative terminals of the charging device 1, the battery pack 11, and the mobile phone body 14 are connected to GND. The charge control microcomputer 2 also monitors the battery voltage, and the voltage at the positive terminal of the charging device 1 is divided by the resistors R1 and R2 and input as the battery voltage detection signal 9. Then, the abnormality detection timer 20 is used to measure a predetermined time (for example, 24 minutes), during which the battery voltage is detected. Further, the charging timer 21 measures the charging time of the battery 12 by the charging constant current circuits 3 and 4. The battery temperature detection signal 8 provided by the thermistor 13 provided in the battery pack 11 is also input to the charge control microcomputer 2.

【0018】

FIG. 2 is a flowchart showing charging control performed by the charging device 1 shown in FIG. First, the presence / absence of battery pack 11 is detected by a battery mounting detection circuit (not shown) (S1). Then, when the battery pack 11 is attached, the time counting operation of the abnormality detection timer 20 is started (S2), and the charging indicator lamp 51 is turned on (S3).

【0019】

Next, the battery voltage V is generated by the input battery voltage detection signal 9._BIf is detected to be below 5.5V (Yes in S4), the charging timer 21 and trickle charge constant current circuit 4 are operated to perform trickle charge for 1 minute (S5). Here, the 5.5V value set as the judgment threshold value of the battery voltage is the voltage value required for the circuit of the connected mobile phone main body 14 to operate normally when using a 6V specification battery. The value is empirically derived. Regarding the trickle charge time of 1 minute, the voltage of the secondary battery 12 in the over-discharged state (for example, 4.5 V or less) does not rise easily even if it is charged. The value that is empirically derived is set to a value sufficient for the rise.

【0020】

Next, the battery voltage immediately after the trickle charge for 1 minute is completed is detected, and the voltage value is set to V._B1And memorize (S6). And this V_B1Check if the voltage exceeds 5.5V (S7), and if it does not exceed 5.5V (No in S7), use the charging timer 21 and the quick charge constant current circuit 3 for 10 seconds. Fast charge over (S8).

【0021】

Regarding this 10-second quick charge time, if the connected mobile phone body 14 starts the system during charging and the current (about 100 to 150 mA) is consumed, it is still fast enough to compensate for this. The value is empirically derived so that it can be charged (for example, 650mA x 10 seconds). Then, after completing this 10-second quick charge, the trickle charge constant current circuit 4 is switched again to perform trickle charge (S9), and the battery voltage value at that time is set to V._B2Memorize as (S10). And this V_B2Check if is over 5.5V (S11), and if it is not over 5.5V yet (No in S11), then V_B2-V_B1(S12) and check if the calculated value exceeds 1.5V (S12).

【0022】

Here, regarding the value of 1.5V set as the judgment threshold value of the battery voltage rise, as a result of rapid charging for 10 seconds, the secondary battery 12 in the over-discharged state (for example, 4.5V) rises in voltage (for example). For example, when the battery is not fully charged (for example, 6V) even though it has increased by 1.5V), it is assumed that the battery to be charged is an abnormal battery, and the value is empirically derived.

【0023】

And V_B2-V_B1If the calculation result of is over 1.5V (Yes in S12), it is judged that the battery is normal, and quick charging is performed using the quick charging constant current circuit 3 (S21), and the battery is full. Detects charging (S22). Further, when the battery is fully charged (Yes in S22), the fully charged indicator lamp 52 is turned on (S23).

【0024】

In addition, the battery voltage is constantly monitored, and if the battery voltage exceeds 5.5V (No in S4, Yes in S7, Yes in S11), quick charging is performed (S21) to detect full charge. (S22). The trickle charge is performed after the rapid charge for 10 seconds in order to prevent the charging device 1 from being destroyed when the battery is abnormal.

【0025】

On the other hand, even if the above charging operation is performed, V_B2-V_B1If the calculated value of is still not exceeding 1.5V (No in S12), check that 24 minutes have not passed by the abnormality detection timer 20 (No in S13), and process in step S4. Return to. Even if it is confirmed by the abnormality detection timer 20 that 24 minutes have passed (Yes in S13), if it cannot be put into the conventional quick charge, it is judged that the battery is abnormal and the abnormality indicator lamp 53 is turned on. Lights up (S14) and stops charging (S15).

【0026】

According to the above charging method, when charging with the over-discharged battery attached to the mobile phone body 14, a current exceeding the trickle charging current (for example, about 100 mA) is consumed by the mobile phone body 14. As a result, even if the voltage rise stops during the first minute of trickle charging, quick charging with a current (about 650mA) much larger than the circuit current of the mobile phone body 14 after that one minute of trickle charging is completed. Therefore, the charging current surely flows through the secondary battery 12, the voltage rises, and the secondary battery 12 can be fully charged.

【0027】

In addition, even if the battery voltage does not rise sufficiently in the first minute of trickle charging and the current consumption of the mobile phone body 14 increases during the next 10 seconds of rapid charging, the rapid charging causes it. Since a sufficient charging current flows through the battery to increase the battery voltage, the final quick charge can be started and the battery can be fully charged. Furthermore, when the circuit current of the mobile phone body 14 is almost nonexistent, the battery voltage exceeds 5.5 V and enters rapid charging during trickle charging for 1 minute unless there is an abnormality in the battery. Performs the same operation as the operation.

【0028】

In this way, the secondary battery is surely charged regardless of when the current consumption of the mobile phone main body 14 fluctuates and increases when the voltage rises during charging.

【0029】

[Effect of the invention]

According to the above invention, when the secondary battery mounted on the portable electronic device is charged while it is in the over-discharged state, even if the circuit current exceeding the trickle current is consumed during charging, the circuit Since a current much larger than the current is supplied to the secondary battery by quick charging, it is possible to surely bring the secondary battery to a fully charged state.

【0030】

Also, on the portable electronic device side, the secondary battery will be charged without any problem even if the load fluctuates during charging, so even if the system is started during charging, the circuit will operate normally. Is guaranteed. Therefore, when designing a system for a portable electronic device, the system can be designed without noticing the problem of current consumption during charging, which greatly increases the degree of freedom in design.

【0031】

Further, since the charging device according to the present invention can be dealt with only by changing the software without adding a new circuit, it also has a secondary effect that effective charging control can be performed without accompanying a price increase. ..

[Simple explanation of drawings]

[Figure 1]

It is a block diagram which shows the circuit structure of the charging device which concerns on this invention.

[Figure 2]

It is a flowchart which shows the charge control performed by the charging device 1 shown in FIG.

[Fig. 3]

It is a flowchart which shows the charge control performed by the conventional charger.

[Explanation of symbols]

1 Charging device 2 Charge control microcomputer 3 Quick charge constant current circuit 4 trickle charge constant current circuit 5 Display 6 Quick charge ON signal 7 Tokrill charge ON signal 8 Temperature detection signal 9 Battery voltage detection signal 11 Battery pack 12 Rechargeable battery 13 Thermistor 14 Mobile phone body 20 Anomaly detection timer 21 Charging timer 51 Charging indicator lamp 52 Full charge indicator lamp 53 Abnormal battery indicator lamp