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Monitoring Temperature of Semiconductor Chips by Multiplexed Sensing of Current and Voltage of Off Chip Driver Emitted Follower Circuits Using Microprocessor

IP.com Disclosure Number: IPCOM000036785D
Original Publication Date: 1989-Oct-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 2 page(s) / 31K

Publishing Venue

IBM

Related People

Kostenko, WP: AUTHOR

Abstract

Each chip that is to be monitored for temperature has a temperaturesensing transistor that has its emitter terminal connected to an output point of the chip in the conventional configuration of an off-chip driver. The collector terminal of each temperature sensing transistor is connected to a common potential point, and the base terminal is connected to a separate selection circuit that turns on one of these transistors at a time. All of the emitter terminals are connected on a common line to a circuit that measures the emitter current and the voltage between the emitter and the collector potential point. The current and voltage measurements are digitized and sent to a microprocessor.

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Monitoring Temperature of Semiconductor Chips by Multiplexed Sensing of Current and Voltage of Off Chip Driver Emitted Follower Circuits Using Microprocessor

Each chip that is to be monitored for temperature has a temperaturesensing transistor that has its emitter terminal connected to an output point of the chip in the conventional configuration of an off-chip driver. The collector terminal of each temperature sensing transistor is connected to a common potential point, and the base terminal is connected to a separate selection circuit that turns on one of these transistors at a time. All of the emitter terminals are connected on a common line to a circuit that measures the emitter current and the voltage between the emitter and the collector potential point. The current and voltage measurements are digitized and sent to a microprocessor. The microprocessor controls the selection circuit to turn on a selected transistor and it calculates the junction temperature of the transistor from the current and voltage measurements.

The drawing shows chips 2, the temperature-sensing transistors 3, the selection circuit 4, the microprocessor 5, and the measuring circuit 6. In circuit 6 the emitter current is measured as a voltage drop across a resistor 7, and these signals are digitized by an analogto-digital (A/D) converter 8. An A/D converter 9 provides an input to the microprocessor. The microprocessor controls a variable voltage source 10 and a variable current source 1...