JPH02133038A - Power supply system - Google Patents

Abstract

PURPOSE:To obtain a power supply system having a battery-checking function by installing a battery, terminal voltage of which fluctuates by stages, a circuit detecting the output voltage of a voltage-dividing circuit, a display circuit, a constant current circuit, and a control circuit operating each circuit only for a fixed time by a switch circuit and a timer circuit. CONSTITUTION:The temperature characteristics of a battery 1 are compensated by a voltage dividing circuit 2 composed of a resistor and a temperature dependent resistor. An effect by a discharge load change is removed by controlling discharge currents to constant currents by a constant current circuit 6. The terminal voltage of the battery, terminal voltage of which fluctuates by stages at the time of discharge, is detected by a voltage detector 5, thus accurately detecting discharge depth by stages, then displaying the residual capacity of the battery by stages.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is a power supply system relating to a power supply for a portable electronic device and a pack amplifier power supply.

BACKGROUND OF THE INVENTION In recent years, electronic devices have become smaller and lighter, and by using batteries as power sources, they are rapidly becoming more portable. However, when using batteries as a power source, the electrical capacity is limited, and it is important to know in advance when it is time to replace a primary battery and when to charge a secondary battery, and there are many battery check functions. A power supply system has been proposed.

A conventional power supply system will be explained below.

FIG. 6 shows a circuit diagram of a conventional power supply system. FIG. 7 and FIG. 8 show an example of the characteristics of a coin-type lithium battery. In FIG. 6, 61 is a battery, 62
is a voltage divider circuit that divides the battery terminal voltage, 521k,
It consists of a 52C resistor and a 62b temperature dependent resistor, such as a thermistor.

63 is a reference voltage generator, for example a Zener diode. A voltage comparator 64, for example a converter, compares the output voltage of the voltage dividing circuit 62 with the reference voltage of the reference voltage generator 63. FIG. 7 is an example of a characteristic curve showing the relationship between the discharge load and the terminal voltage of the battery, which varies depending on the type, shape, size, discharge depth, etc. of the battery. Figure 8 is an example of a characteristic curve showing the relationship between discharge load and electric capacity.
Type of battery. Each differs depending on shape, size, end-of-discharge voltage, etc.

The operation of the power supply system configured as above will be explained below.

First, the terminal voltage of the battery 51 is divided by the voltage dividing circuit 62, and then compared with the reference voltage of the reference voltage generator 63 by the voltage comparator 64 to detect whether it is higher or lower than the reference voltage. As can be seen from FIGS. 7 and 8, the terminal voltage and electric capacity of the battery 61 change depending on the temperature, so
The output voltage of the voltage dividing circuit 62 is determined by resistors 522L and 62C.
and the temperature-dependent resistor 52b, it has temperature dependence, and it becomes possible to correct the temperature characteristics of the battery 61 and perform voltage detection.

Problems to be Solved by the Invention However, in the conventional configuration described above, as can be seen from FIGS. 7 and 8, the terminal voltage and electric capacity of the battery change depending on the discharge load, so fluctuations due to the discharge load cannot be corrected. . Furthermore, considering variations in battery performance, storage conditions, etc., the method of determining battery life by detecting relatively small changes in discharge voltage cannot provide high detection accuracy and can only determine the end of life. It was necessary to replace or charge the battery as soon as possible after the life test. Portable electronic devices that use batteries as a power source are often used outdoors, and it is often not possible to replace or charge the batteries immediately. The problem was that it stopped working.

The present invention solves the above-mentioned conventional problems, and is a power supply system with an easy-to-use and highly reliable battery check function that can detect remaining capacity in stages, rather than only detecting the end of life. is intended to provide.

Means for Solving the Problems In order to achieve this object, the power supply system of the present invention includes a battery whose terminal voltage changes stepwise during charging and discharging, and a terminal of the battery that is composed of a resistor and a temperature-dependent resistor. A voltage dividing circuit that divides the voltage, a voltage detection circuit that detects the output voltage of the voltage dividing circuit, a display circuit that drives a display element by the output signal of the voltage detection circuit, and a discharge current of the battery to a constant current. It has a configuration consisting of a constant current circuit for controlling, and a control circuit that operates each of the above circuits for a certain period of time using a switch circuit and a timer circuit.

Function: With this configuration, the remaining capacity of the battery can be detected in stages by detecting the terminal voltage of the battery that changes in stages during charging and discharging.

Further, a voltage divider circuit consisting of a resistor and a temperature dependent resistor,
A constant current circuit that controls the discharge current to a constant level can compensate for battery terminal voltage and capacitance that change depending on temperature and discharge load, making it easy to use and highly reliable as it can accurately detect the battery's remaining capacity. It is possible to provide a power supply system with a battery check function.

EXAMPLE An example of the present invention will be described below with reference to the drawings.

FIG. 1 shows a diagram of a power supply system according to a first embodiment of the present invention, and the second and third sides show an example of battery characteristics. FIG. 4 shows a circuit diagram of the voltage dividing circuit, voltage detection circuit, and display circuit in FIG. 1. FIG. 6 shows a circuit diagram of the current detection circuit and constant current circuit in FIG. 1. In Figure 1, 1 is a battery in which the terminal voltage changes stepwise during charging and discharging; one example is a battery in which the active material of the positive electrode is panadium pentoxide (
v205), a button-shaped lithium secondary battery with a diameter of 20 ffff and a thickness of 2.6 mm, which is composed of lithium or lithium aluminum alloy as a negative habitus active material,
It has the characteristics shown in FIG. 2 is a voltage dividing circuit that divides the terminal voltage of battery 1;

Reference numeral 3 denotes a voltage detection circuit, which is composed of three voltage comparators each having a different reference voltage, and compares the output voltage of the voltage dividing circuit 2 with the reference voltage. 4 is a display circuit, which drives a display element using an output signal from the voltage detection circuit 3; A current detection circuit 6 detects the discharge current of the battery 1 and converts it into a voltage. A constant current circuit 6 controls the discharge current of the battery 1 to a constant current based on a signal from the current detection circuit 6. 7 is a switch,
Generates a signal that activates the battery check function. 8 is a timer circuit, which is a timer for operating the battery check function for a certain period of time. Reference numeral 9 denotes a control circuit which, after turning on the switch, connects each circuit to the power source, starts the timer circuit 8, and when the time is up, disconnects each circuit processor from the power source.

Figure 2 shows an example of the discharge characteristics of battery 1.
A shows the change in terminal voltage of battery 1 during constant current discharge.

Figure 3 is an example of the charging characteristics of battery 1, showing changes in terminal voltage and charging current of battery 1 during 3.6V constant voltage charging (with a 300Ω resistor connected in series for current limiting). It is something.

In FIG. 4, 1 is a battery. Reference numeral 2 denotes a voltage dividing circuit, which divides the terminal voltage of the battery 1, and is made up of resistors 2&, 2b, 20 and a temperature-dependent resistor 2d, such as a thermistor or a vosistor. 3 is a voltage detection circuit, which includes a reference voltage generator 3a, such as a Zener diode or constant voltage IC, and resistors 3c, 3d, 3.
6 and voltage comparators, e.g. comparators 3f, 3g, 3h
The voltage dividing circuit 2 converts the reference voltage of the reference voltage generator 3a when the terminal voltage of the battery 1 is v1, v2, ■ as shown in FIG.
The resistors 3b, 3(j, 3
d, 351, voltage comparator a f + 3g +
By comparing with the output voltage of voltage divider circuit 2 at 3h,
In the voltage detection circuit 3, three voltage comparators 3f, 3g, 3h
The terminal electronic voltage of battery 1 is v, lv21 shown in FIG.
v! Detect whether l is low or high.

4 is a display circuit, 4 2L, 4 b, 4 d
, 4 f Nono < Iasu resistor, 4g, 4h,
The display element 4m is composed of a current limiting resistor 4i, a drive transistor 4j, 4k, 4β, and a display element 4111.4n, 40, for example, an IICD. The display element 4n is driven when the terminal voltage of the battery 1 is higher than V2 shown in FIG. It is driven when the voltage is higher than V shown in FIG.

In FIG. 5, 1 is a battery, and 6 is a current detection circuit, which is a resistor, which detects the discharge current of the battery 1 and converts it into a voltage. 6 is a constant current circuit, which consists of a reference voltage generator 62L, an error amplifier 6b (for example, an operational amplifier), bias resistors 60 and 6d, and a current adjustment transistor 68, which is converted by the current detection circuit 6. The error amplifier 6b compares the generated voltage with the reference voltage of the reference voltage generator 6a, and the difference is amplified, and the current adjustment transistor 6C controls the discharge current to be constant.

The operation of the power supply system having the bath battery check function configured as above will be described below.

First, as shown in FIG. 1, when the switch 7 is turned on, each circuit is connected to the battery 1 by the control circuit 9 and is operated by being supplied with power, and the timer circuit 8 starts counting. Next, the terminal voltage of battery 1 is divided by voltage dividing circuit 2. As shown in Fig. 4, the output voltage of voltage dividing circuit 2 is a function of the terminal voltage of battery 1 and temperature, and has a positive characteristic or a negative characteristic. Temperature characteristics can be freely set by combining characteristic thermistors and resistors,
By correcting the temperature characteristics of battery 1, the influence of temperature is eliminated when detecting the terminal voltage of battery 1, and the discharge current of battery 1 is controlled at a constant current (lower than the maximum discharge load current) using the constant current circuit shown in Figure 6. By setting the current value to a large value), the influence of discharge load fluctuations is eliminated when detecting the terminal voltage of the battery 1. The output voltage of the voltage dividing circuit 2 is compared with the reference voltage by voltage comparators 3f, 3g, and 3h of the voltage detection circuit 3, and the terminal voltage of the battery 1 is v1+v2+V as shown in FIG.
It is detected whether it is higher or lower and displayed on the display circuit 4.

When the timer circuit 8 counts up to the set time, it outputs a signal to the control circuit 9 and
stops supplying power to each circuit, and the battery check function ends its operation. As shown in FIG. 2, the depth of discharge of the battery 1 is approximately 25% at time t1, approximately 60% at time t2, and approximately 85% at time t3. When switch 7 is turned on and all three display elements are driven, the discharge depth of battery 1 is less than 25%, and when display elements other than 4 are driven, the discharge depth is 26% to 60%. can be,
When only the display element 40 is driven, the discharge depth is 60 inches to 8 inches.
5, it can be seen that when all three display elements are not driven, the depth of discharge exceeds 86%, and the remaining capacity of the battery 1 can be displayed in four stages.

As described above, there is a battery whose terminal voltage changes stepwise during discharge, a voltage divider circuit that divides the terminal voltage of the battery consisting of a resistor and a temperature-dependent resistor, and an output voltage of the voltage divider circuit. A voltage detection circuit that includes three voltage comparators that compare with different reference voltages, a display circuit that drives a display element using the output electric signal of the voltage detection circuit, and a constant current circuit that controls the discharge current of the battery to a constant current. By providing a control circuit that operates each of the above circuits for a certain period of time using a switch circuit and a timer circuit, the temperature characteristics of the battery can be corrected with a voltage divider circuit consisting of a resistor and a temperature-dependent resistor, and a constant current can be generated. The circuit controls the discharge current to a constant current to eliminate the influence of discharge load fluctuations, and the voltage detection circuit detects the battery's terminal voltage, which changes in stages during discharge, to adjust the depth of discharge in stages. The remaining capacity of the battery can be displayed in four levels.

In addition, if the amount of charging electricity is calculated in advance at t, , t2, t, 'j by detecting the voltages v4, v5, and v6 in FIG. 3, it can also be used as a charging indicator.

Effects of the Invention As described above, the present invention provides a battery whose terminal voltage changes stepwise during charging and discharging, a voltage divider circuit that divides the terminal voltage of the battery, which is composed of a resistor and a temperature-dependent resistor, and A voltage detection circuit that detects the output voltage of the voltage divider circuit, a display circuit that drives a display element using the output signal of the voltage detection circuit, a constant current circuit that controls the discharge current of the battery to a constant current, and a switch circuit. By providing a control circuit that uses a timer circuit to operate each of the above circuits for a certain period of time, this battery has an excellent battery check function that can accurately display the remaining capacity of the battery without being affected by the battery's temperature characteristics or discharge load. This makes it possible to realize a power supply system with high efficiency.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the power supply system in the first embodiment of the present invention, FIG. 2 is a battery discharge characteristic curve diagram, FIG. 3 is a battery charging characteristic curve diagram, and FIG. 4 is a diagram showing the divisions in FIG. Figure 5 is a circuit diagram of the voltage circuit, voltage detection circuit, and display circuit. Figure 5 is a circuit diagram of the current detection circuit and constant current circuit in Figure 1. Figure 6 is a circuit diagram of a conventional power supply system. Figure 7 is a discharge load. FIG. 8 is a characteristic curve diagram showing the relationship between the voltage and the terminal voltage of the battery, and FIG. 8 is a characteristic curve diagram showing the relationship between the discharge load and the electric capacity. 1...Battery, 2...Voltage divider circuit, 3...
... Voltage detection circuit, 4... Display circuit, 6.
... Constant current circuit, 7 ... Switch, 8.
...Timer circuit, 9...Control circuit. Name of agent: Patent attorney Shigetaka Awano and 1 other person 1st
Figure f・-4: Go to O7--S 4 Norah 1st illustration Shikikaku-kakuhen ■ Danomachi E Saikaku E-r! II3c 2d 』 A pity 4 雛 resisting the dead ~ 17-

Claims (1)

[Claims] A battery whose terminal voltage changes stepwise during charging and discharging, a voltage divider circuit that divides the terminal voltage of the battery consisting of a resistor and a temperature-dependent resistor, and a voltage detector that detects the output voltage of the voltage divider circuit. A display circuit that drives a display element using the output signal of the voltage detection circuit, a constant current circuit that controls the discharge current of the battery to a constant current, and a switch circuit and a timer circuit that operate each of the circuits for a certain period of time. A power supply system equipped with a control circuit and a control circuit.