National Semiconductor Corporation

Gary E Sheehan

Jun Wan

Peter R Holloway

A circuit in an integrated circuit for measuring temperature dependent voltages of a temperature sensing element includes a voltage generator circuit providing the temperature dependent voltages, a first sampling switch and a second sampling switch. The voltage generator circuit includes a temperature sensing element being excited by a first switched current and a second switched current. The first and second sampling switches sample a first voltage and a second voltage at the temperature sensing element while the temperature sensing element is being excited by the second current and the first current, respectively. Each of the first and second sampling switches includes a boosted switch circuit incorporating a pedestal voltage compensation circuit. The sampled first and second voltages are coupled to be stored on capacitors external to the integrated circuit. The difference between the first voltage and the second voltage is measured to determine the temperature of the integrated circuit.

Synchronized delta-VBE measurement system

A method for measuring a temperature of an integrated circuit is disclosed. The integrated circuit includes a temperature sensing element being excited by a first switched current and a second switched current. The method includes coupling a first capacitor to the temperature sensing element through a first switch and coupling a second capacitor to the temperature sensing element through a second switch. The first and second capacitors are external to the integrated circuit. The method further includes charging the first capacitor through the first switch to a first voltage when the temperature sensing element is being excited by the first switched current, charging the second capacitor through the second switch to a second voltage when the temperature sensing element is being excited by the second switched current, and measuring a difference between the first voltage and the second voltage to determine the temperature of the integrated circuit.

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Londonderry, NH, United States of America

Gary E Sheehan