JPS6427450U - - Google Patents

Description

[Brief explanation of the drawing]

Fig. 1 is a schematic system diagram of an electronic control unit equipped with a memory backup circuit according to this invention, Fig. 2 is a diagram of a specific example of a delay circuit and relay drive circuit, and Fig. 3 is a diagram showing various points and terminals on the circuit. FIG. DESCRIPTION OF SYMBOLS 1...Microcomputer, 2...Nonvolatile memory, 3...Stabilized power supply circuit, 5...Ignition switch, 6...Relay, 9...Delay circuit, 10...Relay drive circuit.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) In order to back up the non-volatile memory provided for storing various information such as parts to be controlled from the microcomputer built into the in-vehicle electronic control unit, this memory must be stabilized. two power supply paths that supply power from an automobile battery in parallel through an ignition switch and a relay to a stabilized power supply circuit that supplies power, and a relay drive circuit for the relay that is activated by a signal from a microcomputer; Equipped with a delay circuit that shuts off the operation of the relay drive circuit after a predetermined delay when receiving a cutoff signal from the ignition switch, and can transfer and store information from the microcomputer in non-volatile memory from when the ignition switch is shut off to when the relay is shut off. A memory backup circuit characterized in that: (2) The delay circuit is constructed using a diode, a capacitor,
The memory backup circuit according to claim 1, characterized in that it is constructed by combining resistors. (3) The scope of the utility model registration claim characterized in that the relay drive circuit is composed of three transistors, and the relay is operated by activating the relay drive circuit in response to a rising signal from a microcomputer. The memory backup circuit according to item 1.