JP2012120270A - Switching device, charge control device of secondary battery, and secondary battery device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a switching device, a charge control device of a secondary battery provided with the switching device, and a secondary battery device provided with the charge control device of the secondary battery, capable of reducing the number of terminals of a semiconductor device by coupling with a peripheral circuit.SOLUTION: In the case where two MOSFETs 41 and 42 of a charge control IC4 come to be off, a voltage of a signal terminal 40 is fixed to a dividing voltage of a voltage dividing circuit 31, and the dividing voltage causes a first switching circuit 32 to be off while causing a second switching circuit 33 to be on. In the case where the MOSFET 41 (or MOSFET 42) connected to a DC power source 400 (or ground potential) comes to be on, both first and second switching circuits 32 and 33 turn on (or off). In short, the first and second switching circuits 32 and 33 are controlled to be one of three different on/off states by the voltage (signal level) of a connection point of the two MOSFETs 41 and 42.

Description

  The present invention relates to a switch device including a series circuit of two switching elements to be connected in series to a power supply voltage, a secondary battery charge control device including the switch device, and a secondary battery charge control device. The present invention relates to a secondary battery device.

  In order to safely and reliably charge the secondary battery at a constant voltage and / or constant current, a charge control IC (semiconductor integrated circuit) equipped with a charge control circuit is used for the secondary battery charger. There are many. The charging control IC includes a plurality of terminals for inputting and outputting signals such as a detection signal, a control signal, and a display signal in addition to the power supply terminal and the ground terminal.

  For example, in Patent Document 1, a detection signal for a voltage of a secondary battery, a detection signal for a charging current, a control signal for controlling on / off of a switching element that cuts off the charging current, a display signal for displaying a charging state on a display unit, A charging control unit including a microcomputer to which a signal such as a battery temperature detection signal is input and output is disclosed.

JP 2007-259532 A

  However, there are severe demands for cost reduction for electric appliances in recent years, and reduction of the number of terminals is one issue for the charge control IC. However, in the charging control unit disclosed in Patent Document 1, when a control signal for controlling the charging voltage and charging current to be output from the power source unit and a detection signal for the charging voltage are added, the number of terminals becomes nine. This is over 8 terminals, which is one standard for the number of terminals whose size and cost are suppressed.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a switch device capable of reducing the number of terminals of a semiconductor device in combination with a peripheral circuit, and a secondary device including the switch device. A battery charge control device and a secondary battery device including the charge control device for the secondary battery are provided.

  A switch device according to the present invention includes a semiconductor device having a series circuit of two switching elements to be connected to a DC power supply, and a voltage dividing circuit for dividing a predetermined DC voltage, and the voltage dividing circuit of the voltage dividing circuit In the switch device in which the point is connected to the connection point of the two switching elements, each control terminal is connected to the voltage dividing point, and the absolute value is larger (or smaller) than the divided voltage by the voltage dividing circuit. And a first switching circuit (or a second switching circuit) that is turned on by a control voltage.

  In the switch device according to the present invention, a series circuit of two switching elements to be connected to a DC power source and a voltage dividing point are connected to a connection point of the two switching elements, and a predetermined DC voltage should be divided. In a switch device including a semiconductor device having a voltage dividing circuit, each control terminal is connected to the voltage dividing point, and is turned on by a control voltage whose absolute value is larger (or smaller) than the voltage divided by the voltage dividing circuit. And a first switching circuit (or a second switching circuit).

In the present invention, the connection point of the two switching elements, the voltage dividing point of the voltage dividing circuit to divide a predetermined DC voltage, and the control terminals of the first and second switching circuits are connected. In this case, the absolute value of the divided voltage when the voltage dividing circuit divides the predetermined DC voltage is smaller than the absolute value of the control voltage for turning on the first switching circuit, and the control for turning on the second switching circuit. Greater than absolute voltage.
Thereby, when both of the two switching elements are turned off, the voltage at the connection point of the two switching elements becomes the divided voltage of the voltage dividing circuit. When a predetermined DC voltage is applied to the voltage dividing circuit, the first switching circuit is turned off and the second switching circuit is turned on by the divided voltage. On the other hand, when a specific one (or the other) of the two switching elements is turned on, both the first and second switching circuits are turned on (or turned off).
That is, the first and second switching circuits are controlled to three different on / off states by the voltage (signal level) at the connection point of the two switching elements.

  In the switch device according to the present invention, the voltage dividing circuit includes a plurality of resistors.

  In the present invention, since the voltage dividing circuit includes a plurality of resistors, the divided voltage varies linearly according to the voltage of the DC power supply. In addition, the voltage dividing circuit is manufactured at a low cost.

  In the switching device according to the present invention, the first switching circuit (or the second switching circuit) includes a voltage divider composed of a plurality of resistors for dividing the voltage at the voltage dividing point, and a voltage divided by the voltage divider. And a transistor that is turned on.

In the present invention, each of the first and second switching circuits includes a voltage divider that further divides the divided voltage by the voltage dividing circuit and a transistor, and each transistor is divided by the divided voltage of each voltage divider. Turn on.
Thereby, the first and second switching circuits are configured at low cost.

  The switch device according to the present invention includes a semiconductor device having a series circuit of two switching elements to be connected to a DC power supply, and one end connected to a connection point of the two switching elements, and other than a predetermined DC potential. A switching device including a resistor circuit to which an end is connected, each control terminal is connected to one end of the resistor circuit, and the DC potential is generated by a voltage dividing circuit including the resistor circuit and an input resistance of the control terminal. A first switching circuit (or a second switching circuit) that is turned on by a control voltage having an absolute value larger (or smaller) than the divided voltage is provided.

In the present invention, a connection point of two switching elements, one end of a resistance circuit whose other end should be connected to a predetermined DC potential, and a control terminal of each of the first and second switching circuits are connected. . In this case, the absolute value of the divided voltage obtained by dividing the predetermined DC potential by the voltage dividing circuit including the resistance circuit and the input resistance of the control terminal is smaller than the absolute value of the control voltage for turning on the first switching circuit, and The absolute value of the control voltage for turning on the second switching circuit is larger.
Thereby, when both of the two switching elements are turned off, the voltage at the connection point of the two switching elements becomes the divided voltage of the voltage dividing circuit. When a predetermined DC voltage is applied to the other end of the resistance circuit, the first switching circuit is turned off and the second switching circuit is turned on by the divided voltage. On the other hand, when a specific one (or the other) of the two switching elements is turned on, both the first and second switching circuits are turned on (or turned off).
That is, the first and second switching circuits are controlled to three different on / off states by the voltage (signal level) at the connection point of the two switching elements.

  A secondary battery charge control device according to the present invention includes the above-described switch device, a secondary battery and a switching element to be connected between an external power source that supplies a charging current to the secondary battery, and the secondary battery. In a charge control device for a secondary battery comprising a display that displays corresponding to the state of charge, the switching element is turned on / off by turning on / off each of the first and second switching circuits provided in the switch device, And the display on the display is switched.

In the present invention, when the first switching circuit is turned on, the switching element that should cut off the supply of the charging current from the external power source to the secondary battery is turned on and should correspond to the charged state of the secondary battery. The display that performs the display performs one display. Further, when the first switching circuit is turned off, one / other display by the display is switched by turning the second switching circuit off / on. For example, when the first switching circuit is turned on, the display is lit in green as one display, and when the first switching circuit is turned off, the display is turned on / off according to the off / on of the second switching circuit. Or a two-color switching display of green lighting / red lighting. Further, the second switching circuit may be periodically turned on / off to blink the display.
Thereby, in response to three or more states (for example, a normal charge state, a normal stop state, and an abnormal stop state) included in the charging state and the charging stop state of the secondary battery, the display on the display is turned on, Switches to off, flashing, 2-color display, etc.

  When the two switching elements included in the semiconductor device are complementarily turned on / off, the secondary battery charge control device according to the present invention turns on / off the switching element to be connected between the secondary battery and an external power source. When the two switching elements included in the semiconductor device are turned off, the switching element to be connected between the secondary battery and the external power supply is turned off. In addition, the display is lit.

In the present invention, when only one (or the other) of the two switching elements included in the semiconductor device is turned on, the switching element to be connected to the external power supply is turned on (or off) and the display is turned on ( Or turn off). When both of the two switching elements included in the semiconductor device are turned off, the switching element to be connected to the external power supply is turned off and the display is turned on.
Thus, depending on the three cases except when both of the two switching elements included in the semiconductor device are simultaneously turned on, the switching element to be connected to the external power source is turned on / off and the display is turned on / off. Three determined states are switched.

  A secondary battery device according to the present invention includes the above-described secondary battery charge control device and a secondary battery whose charge is controlled by the secondary battery charge control device.

  In the present invention, since the charging control device for the secondary battery controls the charging of the secondary battery, corresponding to three or more states included in the charging state and the charging stop state of the secondary battery, A charge control device for a secondary battery whose display on the display is switched is applied to the secondary battery device.

According to the present invention, when both of the two switching elements are turned off, the voltage at the connection point of the two switching elements becomes the divided voltage of the voltage dividing circuit. When a predetermined DC voltage is applied to the voltage dividing circuit, the first switching circuit is turned off and the second switching circuit is turned on by the divided voltage. On the other hand, when a specific one (or the other) of the two switching elements is turned on, both the first and second switching circuits are turned on (or turned off). That is, the first and second switching circuits are controlled to three different on / off states by the voltage (signal level) at the connection point of the two switching elements.
Therefore, it is possible to assign two signals, in which the four states due to the respective on / off combinations are reduced to the three states, to one terminal of the semiconductor device, and to reduce the number of terminals of the semiconductor device by combining with the peripheral circuit. It becomes possible to reduce.

It is a block diagram which shows the structural example of the secondary battery apparatus which concerns on Embodiment 1 of this invention. It is a circuit diagram which shows an example of the circuit structure of the charge control part which concerns on Embodiment 1 of this invention. It is a graph for demonstrating the state operation | movement of each part based on the combination of a charge control signal and a charge display signal. It is a circuit diagram which shows an example of the circuit structure of the charge control part which concerns on Embodiment 2 of this invention.

Hereinafter, the present invention will be described in detail with reference to the drawings illustrating embodiments thereof.
(Embodiment 1)
FIG. 1 is a block diagram showing a configuration example of a secondary battery device according to Embodiment 1 of the present invention. In the figure, reference numeral 100 denotes a secondary battery device (pack battery). The secondary battery device 100 includes a secondary battery 20 made of a lithium ion battery, a thermistor 21 that detects the temperature of the secondary battery 20, and the secondary battery. And a charging control device 10 that controls charging to the charging unit 20. The secondary battery 20 is not limited to a lithium ion battery, and may be another secondary battery such as a nickel metal hydride battery or a nickel cadmium battery. The secondary battery 20 may be a battery in which a plurality of lithium ion batteries are connected in series, parallel, or series-parallel.

  The charge control device 10 includes a charge control unit 3 that detects the voltage of the secondary battery 20 and the terminal voltage of the thermistor 21. The charging control unit 3 includes a control electrode (gate electrode) of the P-channel MOSFET 6 that cuts off the supply of the charging current to the secondary battery 20 and a display that performs display corresponding to the charging state of the secondary battery 20. 7 and a DC power supply (Vcc) 400 are connected. The drain electrode of the MOSFET 6 is connected to the secondary battery 20. The source electrode of the MOSFET 6 is connected to the constant voltage / constant current output terminal (+ side) of the charging power source unit 200 that steps down, rectifies, and smoothes the AC voltage of the commercial power source 300. The voltage supplied to the source electrode is The charging control unit 3 detects the charging. A PNP transistor may be used instead of the MOSFET 6.

The charging control device 10 is also a resistor that detects the charging current of the secondary battery 20 between the constant voltage and constant current output terminal (− side) of the charging power supply unit 200 and the ground potential (signal ground potential, 0 V). 8 is provided. Both ends of the resistor 8 are connected to the charging control unit 3, and the detected value of the charging current is taken into the charging control unit 3.
The charging control unit 3 calculates the voltage and current to charge the secondary battery 20 based on each detected voltage, and the calculated voltage and current are supplied from the constant voltage and constant current output terminal of the charging power source unit 200 to the source of the MOSFET 6. A feedback signal for controlling to be applied to the electrode is provided to the charging power supply unit 200.

Below, the detail of the charge control part 3 is demonstrated.
FIG. 2 is a circuit diagram showing an example of a circuit configuration of the charging control unit 3 according to Embodiment 1 of the present invention. In FIG. 1, nine types of signals including the DC power supply 400 are input / output to / from the charge control unit 3, but only the portion related to the gate electrode of the MOSFET 6 and the signal output to the display 7 is shown in FIG. 2. Will be described. The display 7 is formed by connecting an LED 71 and a resistor 72 in series. The charge control unit 3 shown in FIG. 2 includes a charge control IC 4 that inputs and outputs five types of signals that are not shown in FIG. 2 except for the DC power supply 400 and the ground potential among the nine types of signals described above.

  The charging control IC 4 includes a DC power supply 400 and a P-channel MOSFET 41 and an N-channel MOSFET 42 connected in series between the ground potential. A connection point between the drain electrodes of the MOSFET 41 and the MOSFET 42 is connected to the signal terminal 40. The outputs of the NAND gate 43 and the NOR gate 44 are given to the gate electrodes of the MOSFET 41 and the MOSFET 42, respectively. The outputs of both the buffer gate 45 and the OR gate 46 are applied to the inputs of the NAND gate 43 and the NOR gate 44, respectively. A charge control signal is applied to one input of the buffer gate 45 and the OR gate 46, and a charge display signal is applied to the other input of the OR gate 46. The buffer gate 45 is for adjusting the propagation delay time of the charge control signal.

The charging control unit 3 also includes a voltage dividing circuit 31 in which a voltage dividing point 313 is connected to the signal terminal 40 of the charging control IC 4. The voltage dividing circuit 31 is formed by connecting the other ends of resistors 311 and 312 having one ends connected to the DC power supply 400 and the ground potential, respectively. Control terminals 320 and 330 of the first switching circuit 32 and the second switching circuit 33 are connected to the voltage dividing point 313 of the voltage dividing circuit 31. In this case, the divided voltage of the voltage dividing circuit 31 is a control voltage applied to the control terminals 320 and 330.
Note that the voltage dividing circuit 31 may divide a predetermined DC voltage different from the DC power supply 400. Further, the resistor 311 and / or the resistor 312 may be included in the charge control IC 4.

  The first switching circuit 32 includes a voltage divider composed of resistors 321 and 322 that further divide the voltage at the voltage dividing point of the voltage dividing circuit 31. A base electrode of an NPN transistor 323 having a collector electrode connected to the gate electrode of the MOSFET 6 is connected to the voltage dividing point of the voltage divider. Similarly, the second switching circuit 33 includes a voltage divider including resistors 331 and 332 that further divide the voltage at the voltage dividing point of the voltage dividing circuit 31. A base electrode of an NPN transistor 333 having a collector electrode connected to the display 7 is connected to the voltage dividing point of the voltage divider. An N-channel MOSFET may be used in place of the transistors 323 and 333, or an N-channel MOSFET having a different ON voltage may be used in place of the switching circuits 32 and 33.

  The charge control IC 4 has a microcomputer (not shown), and when the secondary battery 20 is charged, the charge control signal is turned on (logic 1). As a result, both the outputs of the NAND gate 43 and the NOR gate 44 become logic 0 (L level), the MOSFET 41 is turned on, and the signal terminal 40 becomes H level. When the charge control signal is off (logic 0), the level of the signal terminal 40 changes depending on on / off of the charge display signal. For example, when both the charge control signal and the charge display signal are off, the outputs of the NAND gate 43 and the NOR gate 44 are both logic 1 (H level), the MOSFET 42 is turned on, and the signal terminal 40 is at the L level. On the other hand, when the charge control signal is off and the charge display signal is on, the outputs of the NAND gate 43 and the NOR gate 44 are logic 1 (H level) and logic 0 (L level), respectively, and both the MOSFET 41 and the MOSFET 42 are off. To do. In this case, the voltage at the signal terminal 40 becomes the divided voltage of the voltage dividing circuit 31.

  In FIG. 2, the voltage of the DC power supply (Vcc) 400 is 5 V, and the resistance values of the resistors 311 and 312 of the voltage dividing circuit 31 are 10 k ohms. The resistance values of the resistors 321 and 322 of the first switching circuit 32 are 47 k ohms and 10 k ohms, respectively, and the resistance values of the resistors 331 and 332 of the second switching circuit 33 are 10 k ohms and 47 k ohms, respectively. is there. The above-described specification values are examples. Although detailed calculation is omitted, the voltage at the voltage dividing point 313 of the voltage dividing circuit 31 is approximately 2.2 V when both the MOSFETs 41 and 42 are turned off due to these specification values. In the first embodiment, the voltage at the voltage dividing point 313 in a state where the control terminals 320 and 330 are connected in this way is referred to as a divided voltage of the voltage dividing circuit 31.

  When the voltage at the voltage dividing point 313 is 2.2 V, a voltage of about 0.4 V, which is a voltage divided by the resistors 321 and 322, is applied to the base electrode of the transistor 323. Therefore, the transistor 323 is not turned on. On the other hand, since the divided voltage obtained by dividing the resistors 331 and 332 by 2.2 V is approximately 1.8 V in the calculation, a sufficient base current flows into the base electrode and the transistor 333 is turned on. 7 LED 71 lights up. For this reason, it can be said that the divided voltage of the voltage dividing circuit 31 is lower than the control voltage for turning on the first switching circuit 32 and higher than the control voltage for turning on the second switching circuit 33.

  When the MOSFET 41 is turned on and the voltage at the voltage dividing point 313 becomes H level (approximately 5V), the divided voltage obtained by dividing the resistors 321 and 322 by 5V is approximately 0.9V in the calculation. A sufficient base current flows into the base electrode and the transistor 323 is turned on. On the other hand, when the MOSFET 42 is turned on and the voltage at the voltage dividing point 313 becomes L level (approximately 0 V), both the transistors 323 and 333 are clearly turned off. That is, when the MOSFET 41 is turned on, both the first switching circuit 32 and the second switching circuit 33 are turned on, and when the MOSFET 42 is turned on, both the first switching circuit 32 and the second switching circuit 33 are turned off.

Next, the state change of each part of the charge control unit 3 will be described using a chart.
FIG. 3 is a chart for explaining the state operation of each unit based on the combination of the charge control signal and the charge display signal. When the charge control signal is turned on (logic 1) and charging is in progress, the MOSFET 41 is turned on and the MOSFET 42 is turned off and connected to the signal terminal 40 regardless of the on / off state of the charge display signal as described above. The divided voltage point 313 becomes H level. Thereby, the transistors 323 and 333 are both turned on, the MOSFET 6 is turned on, and the display unit 7 is lit.
Since the charge control signal is turned on only when the charge state is normal (that is, when charge display should be actively performed), the state where the charge control signal is on (logic 1) Is on (logic 1). That is, the four states depending on the combination of on / off of the charge control signal and the charge display signal are degenerated into three states.

  Next, when the charging control signal is turned off (logic 0) and charging is stopped, the state of each unit changes depending on the on / off of the charging display signal. For example, when the charge display signal is off (logic 0), as described above, the MOSFET 41 is turned off, the MOSFET 42 is turned on, and the voltage dividing point 313 becomes L level. Thereby, the transistors 323 and 333 are both turned off, the MOSFET 6 is turned off, and the display 7 is turned off. On the other hand, when the charge display signal is on (logic 1), the MOSFETs 41 and 42 are both turned off as described above, so that the signal level at the voltage dividing point 313 is the divided voltage of the voltage dividing circuit 31. Accordingly, the transistor 323 is turned off and the MOSFET 6 is turned off, and the transistor 333 is turned on and the display device 7 is turned on.

When the charge display signal is on (logic 1), the charge state includes a quasi-normal state and an abnormal state. As an example of quasi-normality, when the secondary battery 20 becomes high temperature, the charging itself is stopped, but the user wants to recognize that it is “charging”. The abnormality is a state where charging is stopped due to some abnormality being detected during charging. When the secondary battery 20 is fully charged, the display 7 is turned off.
In the present embodiment, the display 7 is continuously lit in both cases of quasi-normality and abnormality. For example, in the case of abnormality, the display is performed by periodically turning on / off the charging display signal. The vessel 7 may be blinked. Alternatively, the display unit 7 may be turned on during charging, blinked after the end of charging, and turned off when there is an abnormality.

As described above, according to the first embodiment, the signal terminal to which the connection point of the two MOSFETs included in the charge control IC is connected, the voltage dividing point of the voltage dividing circuit that divides the voltage of the DC power supply, The control terminals of the first and second switching circuits are connected. In this case, the divided voltage of the voltage dividing circuit is lower than the control voltage for turning on the first switching circuit and higher than the control voltage for turning on the second switching circuit.
As a result, when the two MOSFETs of the charge control IC are both turned off, the voltage at the signal terminal becomes the divided voltage of the voltage dividing circuit. As a result, the first switching circuit is turned off by the divided voltage, and the second switching circuit is turned on. On the other hand, when the MOSFET connected to the DC power supply (or ground potential) is turned on, both the first and second switching circuits are turned on (or turned off). That is, the first and second switching circuits are controlled to three different on / off states by the voltage (signal level) at the connection point of the two MOSFETs.
Therefore, the charge control signal and the charge control signal that are degenerated from the four states according to the respective combinations of on / off to the three states can be assigned to the signal terminals of the charge control IC. The number of terminals of the charging control IC can be reduced by the combination.

  In addition, since the voltage dividing circuit for dividing the voltage of the DC power supply includes two resistors, the divided voltage can be linearly changed according to the voltage of the DC power supply. In addition, the voltage dividing circuit can be manufactured at low cost.

Furthermore, each of the first and second switching circuits includes a voltage divider composed of two resistors that further divide the voltage divided by the voltage dividing circuit, and an NPN transistor, and the divided voltage of each voltage divider. Each transistor is turned on.
Therefore, the first and second switching circuits can be configured at a low cost.

Furthermore, when the first switching circuit is turned on, the MOSFET that should cut off the supply of the charging current from the charging power supply unit to the secondary battery is turned on, and a display that displays a display corresponding to the charged state of the secondary battery Lights up. In addition, when the first switching circuit is turned off, the lighting / extinguishing of the display is switched by turning the second switching circuit off / on.
Therefore, when the supply of the charging current to the secondary battery is cut off, the charging is performed in accordance with two states included in the secondary battery charging stop state (normally stopped state and semi-normal or abnormal state). It is possible to switch the display on the display of the control device.

Furthermore, when only one (or the other) of the two MOSFETs included in the charge control IC is turned on, the MOSFET that should be disconnected from the supply of the charging current to the secondary battery is turned on (or off), and the indicator is Turns on (or turns off). Further, when both of the two MOSFETs included in the charge control IC are turned off, the MOSFET that should be cut off from the supply of the charging current is turned off and the display device is turned on.
Thus, depending on the three cases except when both of the two MOSFETs included in the charging control IC are simultaneously turned on, the on / off of the MOSFET that should be disconnected from the supply of the charging current and the lighting / extinguishing of the display It is possible to switch between the three states determined by.

  Furthermore, since the charging control device controls the charging of the secondary battery, the charging control in which the display on the display is switched in accordance with three or more states included in the charging state and the charging stop state of the secondary battery. The device can be applied to a secondary battery device.

  In the first embodiment, the case where the DC power supply 400 supplies a positive voltage has been described. However, when the DC power supply 400 supplies a negative voltage, each of the MOSFETs 41, 6 and 42 is connected. The present invention can be applied by changing to N-channel type and P-channel type and changing the transistors 323 and 333 to PNP type.

  In addition, when the charge display signal is off (logic 0), the display unit 7 is not displayed. However, the display unit 7 is not limited to this. For example, the display unit 7 is displayed in green by turning on / off the charge display signal. / You may make it light up red.

(Embodiment 2)
In the first embodiment, the charge control IC 4 has two MOSFETs 41 and 42 connected in series between the DC power source 400 and the ground potential, whereas in the second embodiment, the charge control IC 4 has the above-described configuration. In this embodiment, the two MOSFETs 41 and 42 are further connected in series. Further, in the second embodiment, the resistance value 312 is omitted from the voltage dividing circuit 31 of the first embodiment, and the resistance value of the voltage divider included in the first and second switching circuits 32 and 33 is decreased accordingly. The point to do is different.

  FIG. 4 is a circuit diagram showing an example of a circuit configuration of the charging control unit 3 according to Embodiment 2 of the present invention. In the figure, the charging control IC 4 includes a DC power supply 400 and P-channel MOSFETs 51 and 41 and N-channel MOSFETs 42 and 52 connected in series between the ground potential. A connection point between the drain electrodes of the MOSFET 41 and the MOSFET 42 is connected to the signal terminal 40. The output of the inverter whose input is common to the gate electrode of the MOSFET 52 is given to the gate electrode of the MOSFET 51.

  The MOSFETs 51 and 52 are for disabling a signal output to the signal terminal 40 (a non-operating state having a high impedance). The MOSFETs 51, 41, 42, and 52 and the inverter 53 are so-called tri-states. It consists of a state buffer. The output of the inverter 54 to which the charge control signal is given at the input is given to the gate electrodes of the MOSFETs 41 and 42. The output of the OR gate 55 is given to the input of the inverter 53, and the charge control signal and the signal obtained by inverting the charge display signal by the inverter 56 are given to the input of the OR gate 55.

The charging control unit 3 includes a resistor 311 connected between the signal terminal 40 of the charging control IC 4 and the DC power source 400. Control terminals 320 and 330 of the first switching circuit 32 and the second switching circuit 33 are connected to a connection point between the signal terminal 40 and the resistor 311. In this case, a divided voltage obtained by dividing the voltage of the DC power supply 400 by a voltage dividing circuit including the resistor 311 and the input resistors of the control terminals 320 and 330 becomes a control voltage applied to the control terminals 320 and 330.
Note that the resistor 311 may be connected to a predetermined DC potential different from that of the DC power supply 400. Further, the resistor 311 may be included in the charge control IC 4.

  When the charge control signal is turned on (logic 1) in the charge control IC 4, the output of the OR gate 55 becomes logic 1 (H level) and the outputs of the inverters 53 and 54 become L level, so that the MOSFETs 51, 41, 52 Is turned on and the signal terminal 40 becomes H level. When the charge control signal is off (logic 0), the level of the signal terminal 40 changes depending on on / off of the charge display signal. For example, when both the charge control signal and the charge display signal are off, the output of the OR gate 55 is logic 1 and both the MOSFETs 51 and 52 are turned on, and the output of the inverter 54 is H level and the MOSFET 42 is turned on. The signal terminal 40 becomes L level. On the other hand, when the charge control signal is off and the charge display signal is on, the output of the OR gate 55 becomes logic 0 (L level), which is equivalent to the case where the MOSFETs 51 and 52 are turned off and the MOSFETs 41 and 42 are turned off. become. In this case, the voltage of the signal terminal 40 becomes the above-described divided voltage (hereinafter referred to as a unit divided voltage). Thus, the logical operation of the charge control IC 4 is equivalent to that of the charge control IC 4 shown in FIG.

  In FIG. 4, the voltage of the DC power supply (Vcc) 400 is 5 V, and the resistance value of the resistor 311 is 10 k ohms. The resistance values of the resistors 321 and 322 of the first switching circuit 32 are 12 k ohms and 2.7 k ohm, respectively, and the resistance values of the resistors 331 and 332 of the second switching circuit 33 are 2.7 k ohms, respectively. And 12k ohms. The above-described specification values are examples. Although detailed calculation is omitted, due to these specification values, when both the MOSFETs 41 and 42 are off (including equivalently off), the divided voltage is approximately 2.2V. The 2.2 V is lower than the control voltage for turning on the first switching circuit 32 and higher than the control voltage for turning on the second switching circuit 33, as in the case of the first embodiment. Therefore, the table of FIG. 3 is also applied to the circuit shown in FIG.

  In addition, the same code | symbol is attached | subjected to the location corresponding to Embodiment 1, and the detailed description is abbreviate | omitted.

As described above, according to the second embodiment, the signal terminal to which the connection point of the two MOSFETs included in the charge control IC is connected, the one end of the resistor having the other end connected to the DC power source, and the first And a control terminal of each of the second switching circuits. In this case, the divided voltage obtained by dividing the voltage of the DC power supply by the voltage dividing circuit composed of the resistor and the input resistance of the control terminal is lower than the control voltage for turning on the first switching circuit, and turns on the second switching circuit. Higher than control voltage.
As a result, when the two MOSFETs of the charge control IC are both turned off, the voltage at the signal terminal becomes the divided voltage. As a result, the first switching circuit is turned off by the divided voltage, and the second switching circuit is turned on. On the other hand, when the MOSFET connected to the DC power supply (or ground potential) is turned on, both the first and second switching circuits are turned on (or turned off). That is, the first and second switching circuits are controlled to three different on / off states by the voltage (signal level) at the connection point of the two MOSFETs.
Therefore, the charge control signal and the charge control signal that are degenerated from the four states according to the respective combinations of on / off to the three states can be assigned to the signal terminals of the charge control IC. The number of terminals of the charging control IC can be reduced by the combination.

  In the first and second embodiments, the charging control IC 4 includes the two MOSFETs 41 and 42. However, instead of the MOSFETs 41 and 42, a PNP-type and NPN-type transistor may be provided. These switching elements may be used.

  The embodiment disclosed this time is to be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the meanings described above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

3 Charge control unit (switch device)
31 Voltage divider circuit 32, 33 First and second switching circuit 320, 330 (first and second switching circuit) control terminal 321, 322 Resistor (voltage divider)
331, 332 Resistor (voltage divider)
323, 333 Transistor 4 Charge control IC (semiconductor device)
41, 42 MOSFET (switching element)
6 MOSFET (switching element)
7 Display 10 Charge control device (charge control device for secondary battery)
20 Secondary battery 100 Secondary battery device 200 Charging power source (external power source)
400 DC power supply (predetermined DC potential)

Claims (8)

A semiconductor device having a series circuit of two switching elements to be connected to a DC power supply, and a voltage dividing circuit for dividing a predetermined DC voltage, wherein the voltage dividing point of the two switching elements In the switch device connected to the connection point,
Each control terminal is connected to the voltage dividing point, and includes a first switching circuit (or second switching circuit) that is turned on by a control voltage whose absolute value is larger (or smaller) than the divided voltage by the voltage dividing circuit. A switch device characterized by that. A semiconductor device having a series circuit of two switching elements to be connected to a DC power source, and a voltage dividing circuit having a voltage dividing point connected to a connection point of the two switching elements and to divide a predetermined DC voltage In a switch device comprising:
Each control terminal is connected to the voltage dividing point, and a first switching circuit (or second switching circuit) which is turned on by a control voltage whose absolute value is larger (or smaller) than the divided voltage by the voltage dividing circuit, A switch device characterized by comprising.   The switch device according to claim 1, wherein the voltage dividing circuit includes a plurality of resistors.   The first switching circuit (or the second switching circuit) includes a voltage divider composed of a plurality of resistors that divide the voltage at the voltage dividing point, and a transistor that is turned on by the voltage divided by the voltage divider. The switch device according to any one of claims 1 to 3, wherein: A semiconductor device having a series circuit of two switching elements to be connected to a DC power supply, and a resistance circuit having one end connected to a connection point of the two switching elements and the other end connected to a predetermined DC potential In a switch device comprising:
Each control terminal is connected to one end of the resistor circuit, and the absolute value is larger (or smaller) than the divided voltage obtained by dividing the DC potential by a voltage dividing circuit composed of an input resistance of the resistor circuit and the control terminal. A switch device comprising a first switching circuit (or a second switching circuit) that is turned on by a control voltage. 6. The switch device according to claim 1, a switching element to be connected between a secondary battery and an external power source for supplying a charging current to the secondary battery, and an indication to correspond to a charging state of the secondary battery A charge control device for a secondary battery comprising a display for performing
Charging control of a secondary battery, wherein the switching element is turned on and off and the display on the display is switched by turning on and off each of the first and second switching circuits included in the switch device. apparatus. When two switching elements included in the semiconductor device are complementarily turned on / off, the switching element to be connected between the secondary battery and an external power source is turned on / off and the display is turned on / off. And
When the two switching elements included in the semiconductor device are both turned off, the switching element to be connected between the secondary battery and the external power supply is turned off, and the display is turned on.
The charge control device for a secondary battery according to claim 6.   8. A secondary battery device comprising: the secondary battery charge control device according to claim 6; and a secondary battery whose charge is controlled by the secondary battery charge control device.

Images