JPS6229968Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a battery check circuit for checking the condition of a power supply battery in a camera, electronic equipment, etc.

As a method of checking the voltage of a low-voltage power supply battery built into a camera or the like, a simple battery check circuit using a light emitting diode has conventionally been used in many cases. When such a simple battery check circuit is used, all that is needed is to check the voltage of the battery by turning on the light emitting diode, and if the light goes out, the only indication is that the battery needs to be replaced. It was not possible to display the state of voltage drop due to wear and tear. For example, when using batteries such as silver batteries, mercury batteries, etc. whose discharge characteristics drop rapidly, a simple battery checker like the one described above is not inconvenient in practice, but unit type dry batteries, etc. In some cases, due to its discharge characteristics, the operation of the device becomes unstable when the power supply voltage drops to a certain extent, and this state remains relatively long, so it is desirable for a battery checker to also display this state. . For this purpose, a method has been proposed that uses a pair of light emitting diodes that emit light of different colors and lights up to indicate whether the battery is good, cautionary, or unsuitable. For example, green when there is enough battery, red when it is slightly depleted,
When using an indicator that turns off the light when it is consumed to an unsuitable state, using a light-emitting diode chip with green and red light-emitting diodes housed in one case can save space in the battery checker device. It is especially suitable as a battery checker for cameras and the like.

The purpose of the present invention is to provide a battery check circuit for clearly displaying the three battery states by blinking a pair of light emitting diodes as described above. This invention relates to a check circuit suitable for incorporation into equipment.

The present invention will be explained in detail below with reference to the drawings.

FIG. 1 is a circuit connection diagram showing an embodiment of a battery check circuit according to the present invention. In the figure, 1 is a power supply battery to be checked, 2 is a check switch, 3 is a capacitor, 4 is a PNP type transistor, 5 is an NPN type transistor, 6 is a light emitting diode chip, which includes a red light emitting diode 6' and a green light emitting diode 6''. are incorporated into one chip.Reference numerals 7 to 12 are resistance elements constituting the circuit.

Next, the operation of the circuit shown in the first diagram will be explained. In the check circuit shown in the figure, it is assumed that the power supply battery 1 has a voltage higher than the voltage at which the light emitting diode can emit light.
In the figure, when check switch 2 is turned on,
When the voltage of the battery 1 is sufficient, current flows through the circuit consisting of the resistor R12 and the red light emitting diode (LED) 6', and the voltage drop across R12 is applied between the base and emitter of the transistor Tr4 through R11. In this case, the V _BE of Tr4 is higher than 0.6 volts, so Tr4 is turned on. When Tr4 is turned on, current flows to R8, and the voltage drop across it is applied between the base and emitter of Tr5 through R9, turning Tr5 on. By turning on Tr5
Since both ends of LED 6' are short-circuited, LED 6' does not light up. Also, the voltage of R8 is connected to the green color through R10.
The voltage is applied to the LED 6'', and since this voltage is higher than the voltage at which the LED can emit light, the LED 6'' emits light. this
LED 6'' lights up green to indicate that the voltage of battery 1 is high enough.Next, when battery 1 is slightly depleted and reaches about 2.5 volts, turn on check switch 2 to check R12.
Since the voltage applied between the base and emitter of Tr4 due to the current flowing to LED6' becomes lower than V _BE = 0.6 volts, Tr4 turns off and R8
Since the collector current of Tr4 does not flow to Tr5, Tr5 is turned off. Therefore, both ends of the LED 6' are not short-circuited and a voltage higher than the voltage capable of emitting light is applied to the LED 6' through R12, so that the LED 6' emits red light. At this time, since no voltage is applied to the LED 6'', the LED 6'' does not emit light, and therefore a red light is displayed, allowing you to check that the battery 1 is exhausted (caution). Furthermore, if the power supply battery 1 is further consumed and its voltage drops below 2.0 volts, turn on switch 2 and pass it through R12.
Since the voltage applied to LED6' is lower than the voltage at which the light emitting diode can emit light (2.0V), the LED
6' does not light up. Also, since the voltage of R12 becomes low, both Tr4 and Tr5 are turned off, and the LED
In this case, both LEDs are turned off, and it is checked that the battery 1 is not suitable for use.

As described above, in the battery check circuit of the present invention, both ends of one light emitting diode are short-circuited using a switching element such as a transistor.
The three states “NOTICE” and “NOTUSE” are green,
It is very clearly displayed in red and off, and there is no wasted power consumption in cases where two LEDs turn on together due to a change in status.
An unclear display due to a mixture of green and red colors does not occur, and the circuit can be useful as a battery checker for built-in batteries in cameras and the like.

Next, FIG. 2 is a circuit diagram showing another embodiment of the present invention, in which this embodiment is a battery checker suitable for use with a low voltage power source battery such as a single unit battery. In the figure, 101 is a power supply battery, a unit battery of about 1.5 volts, 10
2 is a check switch, and 103 is a known direct voltage booster, which is composed of, for example, an oscillation circuit and a rectifying and smoothing circuit. 116 is a Zener diode with a resistance of 1
It is connected together with 19 to the output of the circuit 103 to obtain a reference constant voltage. 113 is an operational amplifier whose output is connected to a voltage dividing circuit made up of resistors 118, 119 and 120. Reference numerals 114 and 115 designate operational amplifiers, the voltage of the battery to be checked is applied to their non-inverting inputs, and the reference voltage from the voltage dividing circuit is applied to each inverting input. 105 is a short-circuiting transistor, and 106 is a light emitting diode chip, which have the same structure as the circuit shown in FIG.

The operation of the circuit shown in FIG. 2 is such that if the voltage of the battery 101 to be checked is sufficient, the operational amplifier 1
The (+) inputs of 14 and 115 are higher than the (-) reference input, and the outputs of 114 and 115 are at H level, so LED 106'' (green) lights up and Tr 105 turns on, causing both ends of LED 106' to turn on. Tr.
105 is off and LED 106' (red) lights up.
LED 106'' goes out. When the battery voltage drops to an unsuitable state, the non-inverting inputs of operational amplifiers 114 and 115 both become lower than the inverting reference input, and 1
Since both 14 and 115 output L level,
Both LEDs 106' and 106'' will turn off to indicate unsuitable use.

If the circuit shown in FIG. 2 is used, the power supply voltage is lower than the voltage at which the light emitting diode can emit light, and even in the case of a 1.5 volt unit battery, for example, it can be clearly checked.

As described above, the battery check circuit of the present invention uses a pair of light emitting diodes that emit light of different colors to clearly indicate the battery's suitability for use, use caution state, and unusability state. Since it can be configured compactly, it is effective as a device for checking the built-in power supply battery of cameras, etc., and is particularly suitable for being incorporated into portable equipment that uses a low-voltage battery as a power source. It is.

[Brief explanation of the drawing]

FIG. 1 is a circuit connection diagram showing one embodiment of a battery check circuit according to the present invention, and FIG. 2 is a circuit connection diagram showing another embodiment of the present invention. 1,101...Power battery, 2,102...Check switch, 3...Capacitor, 4,5,1
05...Transistor, 6,106...Light emitting diode chip, 7,8,9,10,11,12...
...Resistor, 103...DC booster, 113, 11
4,115...Operation amplifier, 116...Zener diode, 109,110,117,118,
119,120...Resistance.

Claims (1)

[Scope of utility model registration request] In a battery check circuit that checks the voltage of a power supply by turning on or off first and second light emitting elements emitting light of different colors, a first light emitting element and a first light emitting element detecting whether or not the power supply voltage is at a predetermined level. A series circuit in which the first transistor is connected in series with the power supply, and the second light emitting element and the first transistor are energized, and are de-energized when the first transistor is de-energized. and a parallel circuit in which a second transistor is connected in parallel to the power supply, and when the voltage is at or above the predetermined level, the first and second transistors are energized to cause the first light emitting element to emit light and the second transistor to emit light. the second light emitting element is turned off, the power supply voltage is less than the predetermined level, and at least the second light emitting element is turned off;
When the voltage is higher than the light emitting level of the light emitting element, the first and second transistors are de-energized and the first
1. A battery check circuit comprising a control circuit that prohibits the second light emitting element from emitting light and causes the second light emitting element to emit light.