Static information storage and retrieval – Magnetic bubbles – Guide structure
Patent
1991-01-03
1994-12-20
MacDonald, Allen R.
Static information storage and retrieval
Magnetic bubbles
Guide structure
365229, G05F 100, G06F 1100
Patent
active
053752473
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to circuitry for switching a microcomputer to a standby mode once the microcomputer is in a defined state, normally a reset state.
It is known that, if one wishes to retain information in a random access memory (RAM), it is necessary to provide a standby power supply connected to the RAM even when an associated microprocessor is switched off. Care must be taken, however, to ensure that the information contained in the RAM is not changed when the microcomputer is switched off in the middle of accessing a RAM.
Various circuits have been proposed for achieving a controlled switch-over to standby supply for a RAM. Unfortunately, many of these circuits utilize a number of components and occupy a relatively large amount of space. Until now, this has rendered them inappropriate for incorporation in hybrid devices used for multicircuit electronic equipment used in motor vehicles.
U.S. Pat. No. 4,512,019 describes a circuit for monitoring a microcomputer and, in particular, a circuit for resetting the microcomputer when a malfunction occurs or when the supply voltage drops to a value below a predetermined level.
In Patent Abstracts of Japan, Vol. 9, No. 214, p. 384 and JP 60-73 720 a device for preventing the destruction of stored data in a RAM is described. In this device the base of a switching transistor installed between the main power source and the power input terminal of the RAM is connected to the output terminal of a voltage-drop detecting element.
A device for maintaining operation as long as the voltage fluctuations of a main power source are within a predetermined range of recommended working source voltages of a CMOS-RAM is described in Patent Abstracts of Japan, Vol. 10, No. 389, P. 531 & JP 61-177 523. Therefore a relay contact for switching between the main power source and a chargeable type secondary backup battery is proposed.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an apparatus for switching a random access memory of a microcomputer to standby power.
The present invention provides a power supply arrangement for a microcomputer comprising regulator means for supplying a regulated main voltage or a regulated standby voltage to a microcomputer, and a monitoring integrated circuit having a plurality of circuit elements which is connected to the microcomputer for sending a resetting signal to the microcomputer. A circuit element of the monitoring integrated circuit has an output connected to a control input of the regulator means via a threshold circuit. The monitoring integrated circuit is arranged to generate, in response to a resetting signal after a predetermined time delay, a control signal for switching the regulator means when the microcomputer has reached a defined state for switching to a standby mode. The advantage of the above-described arrangement is that an existing circuit can be utilized without any redesign of the circuit itself.
In more detail, the voltage regulator means has a control input for receiving an "on" signal to switch the voltage regulator means to supply the regulated main power to the microcomputer, but when the "on" signal is not present at the control input the regulated standby power is supplied. The "on" signal is delivered by means for providing the "on" signal which include an ignition switch so that, when the ignition switch is switched, the "on" signal is provided at the control input and the voltage regulator means delivers the main power to the microcomputer. The monitoring integrated circuit provides a resetting signal in response to the "on" signal which is also provided to it at a monitoring input. A time delay network including a capacitor and resistors is provided connected to the control input and to the monitoring integrated circuit. This time delay network provides a time interval during which the "on" signal is maintained at the control input of the voltage regulator means after switching the ignition switch to provide the standby power.
BRIEF DESCRIPTI
REFERENCES:
patent: 4122359 (1978-10-01), Breikss
patent: 4250858 (1981-02-01), Jeenicke et al.
patent: 4279020 (1981-07-01), Christian et al.
patent: 4327298 (1982-04-01), Burgin
patent: 4433390 (1984-02-01), Carp et al.
patent: 4502446 (1985-03-01), Kanegae et al.
patent: 4512019 (1985-04-01), Bodig et al.
patent: 4541050 (1985-09-01), Honda et al.
patent: 4558416 (1985-12-01), Pauwels et al.
patent: 4580220 (1986-04-01), Braun et al.
patent: 4629907 (1986-12-01), Kosak
patent: 4638465 (1987-01-01), Rosini et al.
patent: 4651286 (1987-03-01), Fukai et al.
patent: 4653003 (1987-03-01), Kirstein
patent: 4750040 (1988-06-01), Hakamada
patent: 4777626 (1988-10-01), Matsushita et al.
patent: 4817049 (1989-03-01), Bates et al.
patent: 4827149 (1989-05-01), Yabe
patent: 4843592 (1989-06-01), Tsuaki et al.
patent: 4864998 (1989-09-01), Onishi
patent: 4878196 (1989-10-01), Rose
patent: 4924399 (1990-05-01), Kaiser et al.
patent: 4959786 (1990-09-01), Glowczewski et al.
patent: 4977537 (1990-12-01), Dias et al.
patent: 4992951 (1991-02-01), Glowczewski et al.
patent: 5023527 (1991-06-01), Erdman et al.
Davis George
MacDonald Allen R.
Robert & Bosch GmbH
Striker Michael J.
LandOfFree
Apparatus for controlled switching of a microcomputer to standby does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus for controlled switching of a microcomputer to standby, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus for controlled switching of a microcomputer to standby will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2390739