JPS63253277A - Battery service life display device - Google Patents

Abstract

PURPOSE:To exactly display a consumed state of a secondary battery by expanding and contracting the count time of a timer circuit for counting the use time of the secondary battery, in accordance with magnitude of a load current, converting an integrating value of a consumable current to time and detecting it. CONSTITUTION:A battery 1 is connected to a start terminal 7 of a load 3 and a timer circuit 4 through a power source switch 2, and a count operation is started. To a terminal 2 of the timer circuit 4, a capacitor C1 and a resistance R for determining a clock frequency of a timer are connected. Also, in order to expand and contract the count time of the timer in accordance with magni tude of a load current, and output of a load state detector 6 is connected to a transistor 7, and by controlling a capacitor C2 which has been connected in parallel to the capacitor C1 and the resistance R, by the transistor 7, the clock frequency is varied. As a result, a count value of a counter 8 is displayed on light emitting diodes 5a-5d, and a consumed state of the batter is displayed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a battery life display device for devices powered by secondary batteries, such as portable radios, receivers, and tape recorders.

2. Description of the Related Art In recent years, there has been an increasing demand for secondary batteries to replace primary batteries, such as manganese batteries and alkaline batteries, as power sources for Votaple type radio receivers, tape recorders, and the like. Furthermore, the number of devices that use these primary and secondary batteries in combination is increasing.

Conventional devices that use primary batteries as a power source usually detect the voltage across the battery to display the battery consumption status, and when the voltage reaches a set value, the display switches from on to off. many. FIG. 2 shows a conventional simple battery life display circuit. In Fig. 2, the voltage across the battery 1 is expressed by the resistance aa,
When the battery discharge progresses and becomes less than the set value, as detected by setting the minute-to-positive ratio using ab, the light emitting diode 5 changes from being lit to being turned off, indicating the battery consumption state.

Problems to be Solved by the Invention However, in such a battery life display device, when a secondary battery is used as a power source, due to the characteristics of the secondary battery, the voltage across the battery is almost constant from the start of discharge to just before the end of discharge. There is a problem that the battery consumption state cannot be displayed correctly because the voltage does not change and the voltage suddenly drops just before the end of discharge. For this reason,
The battery consumption state of the secondary battery is often detected by the usage time, and when a preset time is reached, the light turns off to indicate the battery life and the time to recharge. In general, when a radio receiver is a composite device such as a cassette tape recorder, there is a slight difference in the current consumption value depending on the usage conditions of the radio receiver and tape recorder, and when detecting at the above usage time, the battery life Detection accuracy could not be achieved.

Means for Solving the Problems The battery life display device of the present invention includes a timer circuit that counts the usage time of a secondary battery, and an indicator that turns off when the timer circuit reaches a preset time. The count time of the timer circuit is expanded or contracted by detecting the state of the load.

Function: The battery life display device of the present invention expands or contracts the count time of the timer circuit according to the load condition, converts the integrated value of current consumption into time, and detects it without being affected by changes in the load condition. This is a relatively accurate display of the battery consumption status.

EXAMPLE Hereinafter, a battery life display device according to an example of the present invention will be explained with reference to the drawings. As shown in FIG. 1, both ends of the battery 10 are connected to power terminals 8 and 1 of the timer circuit 4. At the same time as a voltage is applied to the load 3 by the power switch 2, a voltage is also applied to the start terminal 7 of the timer circuit 4 to start a counting operation. Terminal 2 of timer circuit 4 has
Connect a capacitor C1 and a resistor R that determine the clock frequency of the timer. Further, the terminals 3, 4, and 5.6 are terminals that are sequentially turned on by dividing the count time of the timer, and are connected to light emitting diodes 61 to 6d. Here, when the current capacity of the secondary battery 1 is n5I (muh) and the current value of the load is l), the secondary battery 1 will stop discharging in about n hours, but the setting of the timer circuit 4 The time is set to n hours, and the light emitting diodes 5a, 50, 6b, and 51L are sequentially turned on according to the elapsed time after the power switch 2 is turned on, and the light emitting diode S& is set to be turned off last after n hours. When the load is switched and the current starts discharging at I/X (mu), it is possible to discharge for one time the set time n, so if this continues, the battery consumption state will not be displayed correctly.

Therefore, when the load becomes 1/x of the initial set time, the load condition detection circuit 6 outputs a control output to turn on the transistor 7, and connects the capacitor C2 in parallel to reduce the clock frequency. If the count time is increased by 1, the time for the light emitting diode Ha to finally turn off will be n-x, but the integrated value of the discharge current will be (1/x)Ixnx=n-I. The first time the load matches the time n set in the factory, even if the load is switched and the current changes, the light emitting diode 51L-6 (1
The 0 lighting/lighting out timing can be made to correspond to the integrated value of the discharge current of the battery and the remaining capacity of the battery.

Note that the counting time can also be expanded or contracted in the same way by keeping the clock frequency constant and changing the frequency division ratio of the timer circuit depending on the load condition.

Effects of the Invention As described above, the battery life display device of the present invention can detect the battery consumption state by expanding or contracting the count time of the timer circuit in accordance with the current value even when the load is switched. It is possible to display the discharge life of a secondary battery relatively easily without providing an accurate voltage detection circuit, and is extremely advantageous in practice.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a battery life display device according to an embodiment of the present invention, and FIG. 2 is a circuit diagram of a conventional battery life display device. 1...Battery, 2...Power switch, 3
...Load, 4...Timer circuit, sa
, sb, ac, sd... Light emitting diode, e.
...Load state detection circuit, 7...Transistor, R...Resistor, CI, C2...Capacitor. Name of agent: Patent attorney Toshio Nakao and 1 other person/-
--Battery 2-m-Power switch 2a, 2b=-Low 7 mo 3--One member

Claims (3)

[Claims] (1) A timer circuit that uses a secondary battery as a power source and counts the time the power source is used, and an indicator that lights up while the power source is in use and turns off when the timer circuit reaches a preset time. A battery life display device comprising: a battery life display device that expands or contracts the count time of the timer circuit according to the magnitude of the load current connected to the secondary battery, converts the accumulated state of current consumption into time, and lights up or A battery life display device characterized in that the state of consumption of the secondary battery is displayed by turning off the light. (2) The means for expanding or contracting the count time of the timer circuit is characterized in that the clock frequency of the timer circuit is fixed and the frequency division ratio of the timer circuit is changed depending on the magnitude of the load current value. Battery life indicator as described. (3) The battery life display device according to claim 1, wherein the means for expanding or contracting the count time of the timer circuit switches the clock frequency of the timer circuit.