JPH07235334A - Battery device - Google Patents

Abstract

PURPOSE:To enhance the reliance upon displaying the residual amount of a battery device by preventing internal battery from undeliberate exhaustion, over-discharge, and deep discharge resulting from a dark current flowing in an apparatus connected, and allowing the sensed voltage fed to a voltage sensing part for displaying the residual amount when a load exists to remain identical to the corresponding value when no load exists despite drop of the voltage when load exists. CONSTITUTION:When a load sensing part 5 senses that any load exists, a discharge switch 4 is turned on in conformity to the emitted sensing signal so that the discharge path to the load is put in continuity, and also a correct switch is turned on so that the supply voltage not divided by resistances R2, R3 is supplied to the line A on the comparator 7, 8 side. If no load exists, on the other hand, the discharge switch 4 is turned off in conformity to the given sensing signal so that the discharge path to the load is shut, and at the same time, the correct switch is turned off so that the supply voltage divided by the resistances R2, R3 is supplied to the line A.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery device having a built-in rechargeable secondary battery such as a nickel-cadmium (hereinafter referred to as NiCd) battery or a lithium-ion battery and used as a driving power source for various portable devices. Is.

[0002]

2. Description of the Related Art For example, in various types of portable electronic equipment such as camcorders, lighting for photographing with camcorders, portable cassette players and disk players, a rechargeable secondary battery is generally used as a power source for driving the equipment. A built-in battery device can be used.For example, by connecting a single secondary battery such as a nickel-cadmium battery (NiCd battery) or a lithium-ion battery in series to form an assembled battery, the required DC power supply voltage can be increased. It is possible to obtain a battery device having the same.

The battery device as described above is configured as, for example, a power pack housed in a casing that can be attached to the electronic device and the charger. Then, by mounting or incorporating this power pack at a predetermined position of the electronic device body, the electrodes come into contact with each other and the power supply voltage can be supplied from the power pack to the device side. Therefore, for example, when the power of the electronic device is turned on, the device is driven by the secondary battery inside the power pack. When the power pack is attached to the corresponding charger, the built-in secondary battery is charged by the operation on the charger side.

As a battery device provided separately from the power pack, it is also known to mount a so-called power adapter on an electronic device to drive the device. 4 (a) and 4 (b) each show an example of a power supply adapter, and the power supply adapter 1 shown in FIG. 4 (a) has a housing 20 formed so as to be attachable to a predetermined electronic device, for example. The power pack 21 that cannot be directly attached to the inside of the housing 20 because it is not compatible with the electronic device is accommodated as shown by an arrow. Thereby, for example, a power pack originally corresponding to another device can be attached to the electronic device to supply power. 2 provided on the side surface of the housing 20
Reference numerals 3 and 24 respectively represent LEDs. For example, a detection circuit capable of detecting the voltage of the built-in battery is provided inside the power supply adapter 1, and the LEDs 23 and 24 are turned on, turned off, or blinked based on the voltage detected here, respectively, so that the remaining amount is The display and the charge amount display during charging can be shown step by step.

Further, the power adapter 1 shown in FIG.
In the case of, in the case 22 formed so as to be attachable to a predetermined electronic device, another unit battery E such as a secondary battery or a primary dry battery is provided according to the required voltage and capacity as shown by the broken line in the figure. It is possible to store more than one. Also in the power adapter 1, the LEDs 23 and 2 for displaying the remaining amount / charge amount
4 are provided.

If the power supply adapter 1 is adapted to the camcorder C as shown in FIG. 5, for example, the camcorder (VRT
The power supply adapter 1 can be mounted at a predetermined mounting position on the bottom surface of the integrated television camera C to serve as a driving power supply. At this time, the remaining amount can be confirmed by the LEDs 23 and 24. In addition, 1a and 1a provided in the power supply adapter 1 have shown the positive electrode and the negative electrode. Further, on the electronic device side such as the camcorder C, for example, a power pack mounting portion and a power adapter mounting portion are individually provided, and the device is continuously operated as long as either the power pack or the power adapter is connected. It is also configured as a so-called series power source capable of supplying power to the.

[Problems to be Solved by the Invention]

By the way, even if the power supply of the electronic device is turned off, if the battery device such as the power pack or the power adapter is left attached to the device, the dark current flowing in the circuit of the electronic device, which is a load, may occur. Electric current also flows through the battery device. As a result, the discharge of the battery built into the battery device will continue for a while even if it is slight.

If the above state continues for a long time,
For example, when the battery built in the battery device is a primary battery such as an alkaline dry battery, its consumption will be faster than usual. Further, when the built-in battery is a secondary battery, there is a problem that it goes beyond the overdischarge state and falls into a so-called deep discharge state.

For example, FIG. 6 shows the general charging characteristics of a nickel-cadmium battery, which is a secondary battery, in which the vertical axis represents the battery voltage and the horizontal axis represents the charge amount. When charging a nickel-cadmium battery, for example, trickle charging is first performed with a current having a relatively small level, and if a voltage above a certain level is obtained, the level of the charging current is increased and the mode is shifted to rapid charging. Then, at this stage, the supply of the rapid charging current is stopped when -ΔV shown in the figure is obtained, after which trickle charging is performed again, and the charging is terminated when the predetermined time set by the timer elapses. . In this way, the secondary battery is appropriately charged.

However, when the secondary battery in the deeply discharged state is charged by the above-described method, for example, a voltage sufficient to shift to the quick charge regardless of how much the first trickle charge is performed. It falls into the state of inactivation that does not reach. Therefore, even if the rechargeable battery once in the deactivated state is charged by the charging device, it cannot be restored so as to obtain the proper fully charged state.

Further, in the power adapter 1 shown in FIG. 4 and FIG. 5, when the remaining amount is displayed by the LED or the like, for example, the device is driven by the power pack and a load is applied to the built-in battery. Will also be referred to as a load) when the power adapter is detached from the device or the device is turned off even when the power adapter is attached to the device, and the built-in battery is not loaded. In the non-loaded state (hereinafter, also referred to as no load), the actually detected voltage of the power supply line is different. For example, when there is a load, a load current flows, so a voltage drop occurs due to the load. Then, as a result of performing detection based on the voltage of the power supply line when the voltage drops as described above and controlling the display of the display unit, the voltage indicated by the remaining amount display and the actual battery voltage are different. Inconvenience also occurs.

[0012]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a battery device capable of driving an electronic device by means of a built-in battery, and turns on / off conduction of a discharge path to a load by the battery. With a switch part that can
A voltage detection unit that can detect the power supply voltage obtained from the battery,
Supplied to a battery level indicator that can display the battery level based on the detection signal from the voltage sensor, a load sensor that can detect the load on the battery, and a voltage sensor that fluctuates depending on the load. And a voltage correction unit that corrects the detected voltage. The switch unit is configured to perform on / off control based on the detection signal of the load detection unit, and the voltage correction unit is configured to correct the power supply voltage based on the detection result of the load detection unit. Alternatively, the switch unit is configured to perform on / off control based on the detection signal of the voltage detection unit.

[0013]

According to the above structure, the discharge path for the load of the battery can be made conductive when the load is present, and the discharge path can be cut off when the load is not present, and the fluctuation of the power supply voltage due to the load is corrected. The detection unit can properly detect the battery voltage and perform the remaining amount display control regardless of the presence or absence of the load. Further, by controlling the conduction of the discharge path with respect to the load of the battery based on the detection signal of the voltage detection unit, it is possible to interrupt the discharge path when the battery voltage falls below a predetermined level. Becomes

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a circuit diagram showing an embodiment of the battery device of the present invention. In this case, the case of applying the above-mentioned power supply adapter will be described. In this figure, reference numeral 1 denotes a power supply adapter, and its appearance may be similar to that shown in FIGS. 3 and 4, for example. Reference numerals 1a and 1b denote positive and negative electrodes, respectively, which are actually provided on the housing as shown in FIG. 5, for example. Reference numeral 2 denotes a load connected to the power supply adapter 1, which is specifically a circuit of the electronic device. Reference numeral 3 denotes a battery built in the power adapter 1, which has a required voltage by using a rechargeable secondary battery or a primary battery such as an alkaline dry battery as an assembled battery.

Reference numeral 4 denotes a discharge switch which is connected between the load 2 and the battery 3 as shown in the figure and is capable of turning on / off the conduction of the discharge path by the battery 3, and is used as a detection signal of the load detection circuit 5 described later. Based on this, the conduction control is performed.

Reference numeral 5 denotes a load detecting section capable of detecting the presence or absence of a load, which is composed of, for example, a comparator and the like, and the connection point between the negative electrode 1b and the detection resistor R ₁ is used as the detection input as shown in the figure. The presence or absence of a load is detected based on the voltage obtained between the detection resistor R ₁ and the ground. For example, when there is a load, the current (load current) that should flow through the load increases, so the amount of current flowing through the detection resistor R ₁ also increases, and the voltage between the detection input resistor R ₁ and ground rises. The load detection unit 5 of the present embodiment is configured to output, for example, an H level detection signal when detecting this voltage. On the other hand, when there is no load, the load current does not flow or decreases, and the voltage between the resistor R ₁ and the ground also decreases. However, when this voltage is detected, an L level detection signal is output. To be done.
In the present embodiment, the detection signal is supplied to the discharge switch 4 and the correction switch 5 as an on / off control signal as shown in the figure.

[0017] 6 shows the correction switch for according to the correction of the variation of the detection voltage used to detect the battery voltage at later comparators 7 and 8 to the presence or absence of the load, the resistance as shown in FIG R ₂ And a detection signal input from the load detection unit 5 as a ON / OFF control signal. Then, in this case, when the detection signal of the load detection unit 5 is H level and the load is present, it is turned on,
It is turned off when there is no load at the L level.

Reference numerals 7 and 8 respectively denote comparators, which detect the voltages of the batteries 3 having different predetermined levels, and control the display of the LED display section 23 and the LED display section 24 based on the detection signals. Reference numeral 9 denotes a reference voltage unit that inputs a power supply voltage and outputs a voltage of a predetermined level.

For example, the output of the reference voltage 9 is input to the inverting input of the comparator 7, and the line A is input to the non-inverting input.
A voltage obtained by dividing the voltage of 2 by resistors R ₄ and R ₅ is input as a detection voltage. The output of the reference voltage 9 is also input to the inverting input of the comparator 8, and the voltage obtained by dividing the voltage of the line A by the resistors R ₆ and R ₇ is input to the non-inverting input as the detection voltage. In this embodiment, the common reference voltage is input to the comparators 7 and 8 as described above, but the voltage to be detected by the comparator 7 is the comparator 8.
Resistor R ₄ to be higher than the power supply voltage to be detected at
The values of R ₅ and resistors R ₆ and R ₇ are set respectively.

Further, 23 and 24 to which the detection signals of the comparators 7 and 8 are respectively supplied are LEDs.
The display section is shown, and the LEDs are driven to display based on the detection signals of the comparators 7 and 8. The LED portion may be the same as that provided in the housing 20 or 22 of the power adapter 1, for example, as shown in FIG.

Therefore, the remaining amount display in this embodiment is as follows. That is, when the charged amount (charged amount) of the battery 3 is sufficient, the comparators 7 and 8 respectively supply the detection voltage higher than the detection level to the non-inverting input, so that the H level is output from both. . Then, for example, in the LED display units 23 and 24, the LEDs are turned on when the H level is respectively input. Therefore, in the above case, both LEDs of the LED display units 23 and 24 are turned on. To be Then, when the battery 3 is consumed, the remaining amount decreases to some extent, and the power supply voltage decreases, the detection voltage lower than the reference voltage is input to the comparator 7, the LED of the LED display unit 23 is turned off, and the LE is turned off.
Only the D display section 24 is in a lighted state. If the remaining amount further decreases from here and the power supply voltage drops, the comparator 7
In addition, the detection voltage input to the comparator 8 becomes lower than the reference voltage, and the LEDs of the LED 23 display section and the LED display section 24 are turned off. LED display unit 2 as described above
The user can check the remaining amount of the built-in battery 3 from the lighting states of 3 and 24. In the above case, the two LED display sections 23 and 24 are turned on / off to display the levels in stages. However, a more blinking state may be added to this, or more LED display sections may be provided. It is also possible to configure so as to be able to display the remaining amount in stages.

The power supply voltage correction operation by turning on / off the discharge switch 4 and the correction switch 6 in the power supply adapter 1 having the above configuration will be described. First, the operation of the discharge switch 4 will be described. ,

FIG. 2 is a circuit diagram showing a specific example of the configuration of the discharge switch 4, and the portion indicated by the broken line is the discharge switch 4.
It is said that In this figure, the same parts as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. Further, the detection output of the load detection unit 5 in this figure is supplied only to the discharge switch 4, but the detection output of the load detection unit 6 is actually only supplied to the discharge switch 4 as shown in FIG. Instead, it is also supplied to the correction switch 6. However, the illustration of the discharge switch 4 is omitted here for the sake of convenience.

In the discharge switch 4 of FIG. 2, Q ₁ , Q
₂ and Q ₃ are bipolar transistors,
The transistor Q ₁ is actually a switch for turning on / off the conduction of the discharge path applied to the load 2 of the battery 3, and the collector-emitter is inserted in series in the power supply line between the battery 3 and the load 2 as shown in the figure. Thus, the base is connected to the collector of the transistor Q _{3 and} the collector of the transistor Q ₂ through the resistor R ₁₁ . The transistor Q ₂ controls the conduction of the transistor Q ₁ , the base is connected to the output of the load detection unit 5 via the resistor R ₁₄ , the collector is connected to the power supply line via the resistor R ₁₂ , and the emitter is connected. Is connected to the collector of the transistor Q ₃ via the resistor R ₁₃ and is also connected to the base of the transistor Q ₁ via the resistor R ₁₁ .
Further, the transistor Q ₃ is provided for biasing the base current of the transistor Q ₁ , and its base is connected to the connection point of the resistor R ₁₅ and the resistor R ₁₆ connected in series between the power supply line and the ground, The collector is connected to the end of the resistor R _{11 and} the end of the resistor R ₁₃ as described above, and the emitter is grounded. The resistance values of the resistors R ₁₁ and R ₁₃ are not specifically limited, but R ₁₁ >> R ₁₃ .

Therefore, the operation of the discharge switch having the above-described structure under load is as follows. For example, when the battery 3 is loaded with a load, as described above, the load detection unit 5 outputs the H level as a detection signal, and the H level is supplied to the discharge switch 4 and the correction switch 6. The operation of the discharge switch 4 in this case, first of all, that the detection signal of H level is applied via a base resistor R ₁₄ of the transistor Q ₂ to which is shown in FIG. 2, a base current flows collector - emitter Conducts. At this time, as described above, the resistors R ₁₁ >> R ₁₃ , and since the base of the transistor Q ₁ and the collector of the transistor Q ₂ are connected, the base current of the transistor Q ₁ is amplified and the transistor Q ₂ is amplified. collector - resistance from the emitter R _13, further collector of the transistor Q ₃ - route to flows to ground via the emitter is formed. In this state, since the base current of the transistor Q ₁ is sufficiently flowing, the so-called ON resistance generated when the current flows between the collector and the emitter of the transistor Q ₁ is very small. That is, the transistor Q ₁ is turned on to form a discharge path in which the load current is sufficiently supplied from the battery 3 to the load 2.

On the other hand, when there is no load, the load detection unit 5 outputs the L level detection signal as described above, so that the base current is not supplied to the base of the transistor Q ₂ in the discharge switch 4, and the transistor Q ₂ is not supplied. Q ₂
The collector-emitter is turned off. In this case, the base current of the transistor Q ₁ flows from the resistor R ₁₁ (R ₁₁ >> R ₁₃ ) to the ground via the collector-emitter of the transistor Q ₃ , and the base current is the resistor R _11.
Is significantly limited by. Therefore, the on-resistance of the transistor Q ₁ becomes extremely high, and the collector-emitter is almost turned off, that is, the discharge path can be in the same state as when it is cut off. As a result, even if the power adapter is connected to the electronic device whose power is off for a long time, for example, unnecessary discharge of the built-in battery 3 due to dark current can be prevented. The discharge switch 4 in the present embodiment is not limited to the one shown in FIG. 2 as long as it is configured so that ON / OFF control is performed by the detection signal of the load detection unit 5. However, the cost will not be high if the electronic switch is composed of at least an inexpensive bipolar transistor as shown in FIG. In this case, the low current consumption can be achieved by limiting the current that should flow to the base of the transistor Q ₁ of the discharge switch 4 when there is no load, as described above.

Next, the correction of the detection voltage of the remaining amount display by turning on / off the correction switch 6 will be described. Like the discharge switch 4, the correction switch 6 is supplied with the detection signal of the load detection unit 5 as an on / off control signal. Therefore, as described above, when the load detection section 5 supplies the H level on / off control signal when the load is applied, the correction switch 6 is turned on and becomes conductive, so that the resistor R ₂ is passed. . As a result, a power supply voltage which is not divided by the resistors R ₂ and R ₃ is obtained on the line A shown in the figure. However, at this time, since the load is applied, the power supply voltage reduced by that amount can be obtained. Further, since the detection signal of the L level is supplied from the load detection unit 5 as the ON / OFF control signal when there is no load, the correction switch 6 is turned off and becomes non-conductive. A value divided by R ₂ and resistance R ₃ can be obtained. As a result, the voltage obtained on the line A under load is higher in voltage level than that under no load because it is not divided by the resistors R ₂ and R ₃ . By the way, in reality, when there is a load, a voltage drop occurs due to the load current, and the voltage across the battery at this time also decreases by that amount. Therefore, in this embodiment, the correction switch 6 is turned on / off.
The values of the resistors R ₂ and R ₃ are set such that the voltage difference of the line A generated with and without a load corresponding to the OFF state corresponds to the voltage drop with and without a load. As a result, the voltage obtained on the line A becomes the same with and without load. Then, by using the voltage of the line A obtained as described above to obtain the detection voltage in the comparators 7 and 8,
The remaining battery level display on the LED display units 23 and 24 can be made to correspond to the actual battery voltage regardless of whether or not there is a load.

The discharge switch 4 of the above embodiment is not necessarily limited to the circuit configuration shown in FIG.
Various changes can be made as long as the ON / OFF control of conduction is performed by the load detection signal.

Next, another embodiment will be described with reference to FIG. In this figure, the same parts as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. In this figure, the output signal of the comparator 8 is supplied as a conduction control signal for the discharge switch 4. That is, although the detection signal of the load detection unit is used as the ON / OFF control signal of the discharge switch 4 in the previous embodiment, the LE signal is used as in the present embodiment.
It is also possible to control the conduction of the discharge switch 4 by the detection signal of the comparator 8 for controlling the display of the D display unit 24. In this case, for example, when the battery 3 has a sufficient remaining capacity, the LED display unit 23 and the LED display unit 2
4 are both lit or only the LED display unit 24 is lit, that is, at least from the comparator 8 to H
When the level is output, the H level is supplied as the ON / OFF control signal to the discharge switch 4, so that the discharge switch 4 maintains the conductive state. Then, when the remaining amount of the battery 3 decreases and the power supply voltage becomes lower than the voltage detected by the comparator 8, the L level is output from the comparator 8. As a result, the L level on / off control signal is supplied to the discharge switch 4, the discharge switch is switched to the off state, and the discharge path between the battery 3 and the load is cut off. Therefore, for example, even when the power adapter 1 of this embodiment is attached to the electronic device whose power is off for a long time, it is possible to prevent the battery 3 from being over-discharged or deep-discharged due to the dark current flowing to the device side. Is possible. In the case of the present embodiment as well, the detection voltages of the comparators 7 and 8 are corrected by the operation of the load detection unit 5 and the correction switch 6 as in the previous embodiments.

Further, the configurations, appearances and the like of the above-mentioned respective embodiments can be variously modified as long as the objects and effects of the present invention are the same. For example, the comparators 7 and 8 and the LED display section 23,
It is also possible to provide a switch that can be turned on / off manually on the circuit side for displaying the remaining battery level on the 24 side so that the display unit is driven only when the display is required. Regarding the on / off control of the discharge switch 4, the configuration shown in FIGS. 1 and 3 is combined so that the on / off control is performed by both the load detection signal and the voltage detection signal of the battery 3. It is also possible to do it. Furthermore, in each of the above-mentioned embodiments, the case where the present invention is applied to the power supply adapter has been described, but the present invention is not limited to this, and is naturally applied to a battery device such as a power supply pack having a built-in secondary battery. It is possible.

[0031]

As described above, the battery device of the present invention is provided with a switch in the discharge path so that it is turned off when no load is detected, or when the battery voltage is below a predetermined level. When it is detected that there is a certain presence, it has an effect of preventing over-discharge and deep-discharge of the battery due to dark current flowing in the electronic device, for example. In addition, by correcting the detection voltage for remaining capacity display based on the result of detecting the presence or absence of load, the battery voltage is properly detected and the remaining capacity is detected regardless of voltage fluctuations due to the presence or absence of load. Since the display can be performed, there is an effect that the actual remaining amount of the battery and the display always correspond to each other and the reliability of the device is improved.

[Brief description of drawings]

FIG. 1 is a block circuit diagram showing an embodiment of a battery device of the present invention.

FIG. 2 is a circuit diagram showing an example of a configuration of a discharge switch of this embodiment.

FIG. 3 is a block circuit diagram showing a battery device of another embodiment.

FIG. 4 is a perspective view showing an appearance of a power adapter.

FIG. 5 is a perspective view showing how to use the power adapter.

FIG. 6 is an explanatory diagram showing the charging characteristics of a NiCd battery.

[Explanation of symbols]

1 Power Adapter 2 Load 3 Battery 4 Discharge Switch 5 Load Detector 6 Correction Switch 7, 8, Comparator 9 Reference Voltage 20, 22 Case 21 Secondary Battery 23, 24 LED Display Q ₁ , Q ₂ , Q ₃ Transistor R _{1 to} R ₇ , R _{11 to} R ₁₆ resistance

Claims (2)

[Claims] 1. A battery device capable of driving an electronic device by means of a built-in battery, and a switch part capable of turning on / off conduction of a discharge path to a load by the battery, and a power supply voltage obtained from the battery. A possible voltage detection unit, a remaining amount display unit capable of displaying the remaining amount of the battery based on the detection signal of the voltage detection unit, a load detection unit capable of detecting the presence or absence of a load on the battery, A voltage correction unit that corrects the detection voltage supplied to the voltage detection unit that varies depending on the presence or absence, and the switch unit performs on / off control based on a detection signal of the load detection unit, and the voltage The battery unit, wherein the correction unit is configured to correct the power supply voltage based on the detection result of the load detection unit. 2. The battery device according to claim 1, wherein the switch unit is configured to perform on / off control based on a detection signal of the voltage detection unit.