JPH02210564A - Information holding circuit - Google Patents

Abstract

PURPOSE:To hold information without requiring a backup battery even at the time of break of power supply by using a single stable type relay driven and controlled in accordance with the monitor result of a supply voltage and a latching type relay which controls information holding to a latch circuit. CONSTITUTION:A supply voltage monitor circuit 1, a single stable type relay 4 driven through a first relay driver 2 by the output of this circuit 1, and a latch circuit 6 which loads held information at the time of power-on and updates information to be held are provided. A latching type relay 5 is provided to which the supply voltage is supplied from the contact of the single stable type relay 4 and in which information to the latch circuit 6 is held through a second relay driver 3. When a power source is turned off, driving of the single stable type relay 4 is released through the relay driver 2, and the supply voltage supplied to the latching type relay 5 is broken. Thus, information before break of power supply is stored in the latch circuit 6 without requiring a battery backup system.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an information holding circuit, and more particularly to an information holding circuit that uses a relay to hold a small amount of information even in the event of a device failure due to power interruption.

[Conventional technology]

Conventionally, this type of information has been retained using a battery backup method by storing information prior to power supply being renewed.

[Problem to be solved by the invention]

The conventional information retention methods described above require battery backup systems and are therefore large-scale regardless of the amount of information that must be stored. In addition, there is a drawback that there is an inconvenience in operating the device, such as replacing the battery.

[Means to solve the problem]

The information holding circuit of the present invention includes a power supply voltage monitoring circuit, a single stable relay driven by the output of the power supply voltage monitoring circuit via a first relay driver, and a load of information held at power-on. and a latch circuit that updates information to be held, and a latching type relay to which power supply voltage is supplied through the contacts of the single stable type relay and information held in the latch circuit is performed via a second relay driver. It is characterized by comprising:

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a circuit block diagram showing an embodiment of the information holding circuit of the present invention.

When the power is turned on, the contact information held by the contact 5a of the latching type relay 5 is loaded into the latch circuit 6. A power supply voltage monitoring circuit 1 monitors the power supply voltage, and when the power supply voltage rises to a certain standard, a relay driver 2 drives a single stable relay 4. This closes the contact 4a of the single stable relay 4 and opens the contact 4b. As a result, the loading of the contact information to the latch circuit 6 is stopped, and the power supply voltage is supplied to the latching type relay 5. Therefore, latch circuit 6
The information is held again in the latching type relay 5 by the relay driver 3.

While the power is on, the information held in the latching type relay 5 can be changed by applying an external input to the latch circuit 6.

When the power is turned off, the power supply voltage monitoring circuit 1 detects that the voltage has dropped to a certain standard, and the relay driver 2
The drive of the single stable type relay 4 is released through the latching type relay 5, and the power supply voltage supplied to the latching type relay 5 is cut off. As a result, the unstable state occurring in the latch circuit 6 is cut off, and the latch circuit 6 continues to hold information.

Note that the information held as an external output can be outputted by the contact 5b of the latching type relay 5.

〔Effect of the invention〕

As explained above, according to the present invention, by using a single stable type relay that is driven and controlled based on the monitoring result of the power supply voltage and a latching type relay that controls information retention in a latch circuit, the backup battery This has the effect of retaining information even when the power supply is cut off without the need for

[Brief explanation of the drawing]

FIG. 1 is a circuit block diagram showing an embodiment of the information holding circuit of the present invention. DESCRIPTION OF SYMBOLS 1... Power supply voltage monitoring circuit, 2, 3... Relay driver, 4... Single stable type relay, 4a. 4, b, 5a, 5b... Contact, 5... Latching type relay, 6... Latch circuit.

Claims (1)

[Claims] A power supply voltage monitoring circuit, a single stable relay driven by the output of the power supply voltage monitoring circuit via a first relay driver, and loading of information held at power-up and updating of information to be held. and a latching type relay to which a power supply voltage is supplied through the contacts of the single stable type relay and information retention in the latch circuit is performed via a second relay driver. Information retention circuit.