JPH0534227Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power saving circuit for reducing battery consumption in devices that use a battery as an operating power source, particularly in a light wave distance meter.

A light wave rangefinder is a well-known type of rangefinder that is currently widely used, but its electrical circuit mainly uses a battery as its operating power source. Therefore, it is desirable to reduce the consumption of this battery, and therefore the power switch must be turned off when not measuring. However, since people often forget to turn off the power switch, it is desirable to automatically stop the operation of electrical circuits, especially circuits that consume power, when not making measurements.

FIG. 2 shows a conventional circuit for this purpose. In the figure, 31 is a battery, and 32 is a power switch. A switch circuit 33 is provided between the power switch 32 and the DC/DC converter 34.
The DC/DC converter 34 is operated and the boosted voltage is applied to the load 35. The switch circuit 33 is configured to remain on while the timer 36 is in operation, and the timer 36 starts operating by a power-on reset circuit 37 that operates when the power switch 32 is turned on, and also by input to the external trigger terminal 38. It is about to be reset.

That is, in the conventional circuit, the power switch 32 is turned on to operate the timer 36 via the power-on reset circuit 37, and the output of the timer is used to turn on the switch circuit 33 to operate the DC/DC converter 34. When time-up occurs, the switch circuit 33 is turned off to stop the operation of the DC/DC converter 34. During distance measurement, a reset signal is sent from the external trigger terminal to the timer 36 for each measurement operation, and the timer 36
The switch circuit 33 is kept turned on by resetting the switch circuit 33. Further, once the time has elapsed and the switch circuit 33 is turned off, a power-on reset circuit 37 operates so that the timer 36 does not operate even if the power switch 32 is in the on state. Therefore, in order to restart the operation after stopping the operation, it is necessary to turn off the power switch 32 and then turn it on again.

Therefore, in the above circuit, when the non-measurement time continues for a certain period of time, the timer 36 times up, the switch circuit 33 is turned off, and the operation of the DC/DC converter 34 is automatically stopped. In other words, even if you forget to turn off the power switch, the DC/DC will automatically switch off after a certain period of time.
Since the operation of the converter 34 is stopped, battery consumption can be reduced.

However, since the conventional system requires the switch circuit 33 as described above, the circuit generates a loss and prevents effective use of electric power. If a mechanical switch such as a relay is used to avoid this loss, there are problems with its reliability and lifespan, as well as the large size of the components, which poses a major obstacle to miniaturizing the device.

The present invention aims to solve these conventional problems, eliminate the occurrence of loss in the circuit, and provide a power save circuit that can automatically stop the operation of the circuit using a simpler circuit. This is the purpose.

The present invention will be specifically explained based on FIG. 1, which is a block diagram of an embodiment of the present invention.

1 is a battery, 2 is a power switch, 3 is a power-on reset circuit, and 4 is a timer, and their operation is the same as that of the conventional circuit. 5 is a DC/DC converter, which in this embodiment is connected to the power switch 2 without intervening other switch circuits, etc.
Moreover, it is configured to operate based on the output of the timer 4 while it is operating. 6 is a load supplied with power from the DC/DC converter 5, and 7 is an external reset terminal for resetting the timer 4.

Therefore, when the power switch 2 is turned on, the timer 4 starts operating by the power reset circuit 3, and the DC/DC converter 5 is operated to reset the load 6.
supply voltage to. At this time, the power of battery 1 is not consumed on the way, so DC/DC converter 5
be used efficiently. When a certain period of time has elapsed after the operation, the timer 4 times up and stops its output. Therefore, the operation of the DC/DC converter 5 is automatically stopped. During this time, when a distance measurement operation is performed, a pulse is input to the external reset terminal 7, the timer 4 is reset, and the DC/DC converter 5 continues to operate.

Once the operation of the DC/DC converter 5 stops due to time-up of the timer 4, the timer 4 will not start operating even if the power switch 2 is turned on. In order to operate this again, it is necessary to turn off the power switch 2 and then turn it on again, as in the conventional case.

As described above, the present invention allows the electrical circuit to continue operating while the device is being operated, but automatically stops operating when the device is not operated for a certain period of time. Therefore, unnecessary consumption of the battery can be prevented.

Furthermore, unlike the conventional method, the present invention does not connect other circuits such as a switch circuit to the DC/DC converter circuit, so there is no loss caused by the circuit.

Furthermore, since no switch circuit is required, the device can be made more compact.

It goes without saying that the power save circuit of the present invention can be used in electrical circuits of devices other than light wave distance meters.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is a block diagram of a conventional power save circuit. 1...Battery, 2...Power switch, 3...
...Power-on reset circuit, 4...Timer, 5
...DC/DC converter, 6...Load, 7...External reset terminal.

Claims (1)

[Scope of utility model registration request] In a device that uses a battery as a power source and boosts the voltage with a DC/DC converter to supply power to a load, a power switch is connected between the battery and the DC/DC converter without intervening any other circuit, and the power switch is The DC/DC converter is started to operate by the start of operation of a timer that is started by an on operation and reset by input to an external reset terminal, and the DC/DC converter continues to operate while the timer is operating. A power save circuit characterized by: