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Optically Coupled Power Supplies

IP.com Disclosure Number: IPCOM000073438D
Original Publication Date: 1970-Dec-01
Included in the Prior Art Database: 2005-Feb-22
Document File: 2 page(s) / 33K

Publishing Venue

IBM

Related People

Lemke, LT: AUTHOR [+2]

Abstract

In many instances, such as in computer-systems, there are several power supplies and it is necessary to turn these power supplies ON and OFF in a particular sequence, with electrical isolation between the supplies. When switch SW1 is closed, power supply 1 provides power to utilization device 10 and also energizes light source 11 which can be a light emitting diode. The light from 11 energizes phototransistor 12. The output signal from 12 enables power supply 2 to provide power to utilization device 10 and to turn-on light source 13. Phototransistor 14 is responsive to the light from 13 and enables power supply 3 to provide power to 10.

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Optically Coupled Power Supplies

In many instances, such as in computer-systems, there are several power supplies and it is necessary to turn these power supplies ON and OFF in a particular sequence, with electrical isolation between the supplies. When switch SW1 is closed, power supply 1 provides power to utilization device 10 and also energizes light source 11 which can be a light emitting diode. The light from 11 energizes phototransistor 12. The output signal from 12 enables power supply 2 to provide power to utilization device 10 and to turn-on light source 13. Phototransistor 14 is responsive to the light from 13 and enables power supply 3 to provide power to 10.

This arrangement provides turn-on and turn-off sequencing of power supplies with electrical isolation between them. It also provides a fail-safe shutdown sequencing should one of the power supplies fail. The turn-on and turn-off times of the power supplies can be varied by including simple capacitor charging and discharging networks around each source.

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