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Continuously Adjustable Power Supply Overcurrent Protection Circuit

IP.com Disclosure Number: IPCOM000061308D
Original Publication Date: 1986-Jul-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Radcliffe, JK: AUTHOR

Abstract

An automatic multi-level overcurrent protection circuit is shown in the IBM Technical Disclosure Bulletin 28, 1054 (August 1985). The circuit shown in the above publication adjusts the overcurrent trip point of a power supply dependent upon the number of cards or circuits drawing current from the power supply. The resolution of the circuit shown in that publication can be improved and the cost of the circuit can be reduced by use of the following type of circuit: Establish a constant voltage on the current set line (i.e., mode 16A in the above publication) by means of any commonly accepted voltage feedback technique. Provide a current sense resistor in series with the voltage source of the feedback circuit in order to monitor the current into the current set line.

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Continuously Adjustable Power Supply Overcurrent Protection Circuit

An automatic multi-level overcurrent protection circuit is shown in the IBM Technical Disclosure Bulletin 28, 1054 (August 1985). The circuit shown in the above publication adjusts the overcurrent trip point of a power supply dependent upon the number of cards or circuits drawing current from the power supply. The resolution of the circuit shown in that publication can be improved and the cost of the circuit can be reduced by use of the following type of circuit: Establish a constant voltage on the current set line (i.e., mode 16A in the above publication) by means of any commonly accepted voltage feedback technique. Provide a current sense resistor in series with the voltage source of the feedback circuit in order to monitor the current into the current set line. The current in the current set line will be proportional to the load conductance between the current set line and ground. This current will cause a voltage drop across the sense resistor, making this voltage proportional to the load conductance. This voltage may then be compared to the signal from the current detection circuit by a comparison circuit. This constitutes an adjustable overcurrent trip point.

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