Overtemperature detection of power semiconductor components

US4730228A · kind A · utility

Assignee

• Siemens Aktiengesellschaft · DE

Inventors

• Josef Einzinger · Spalt, DE
• Christine Fellinger · Unterhaching, DE
• Ludwig Leipold · Munich, DE
• Jenoe Tihanyi · Tauberbischofsheim, DE
• Roland Weber · Munich, DE

Key dates

• Filing date: Jul 16, 1986
• Grant date: Mar 8, 1988
• Expiry date: Jul 16, 2006

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S323/907
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

The temperature of the power semiconductor component is sensed by a bipolar transistor. The bipolar transistor is in series with a depletion mode MOSFET whose gate and source electrodes are connected together. The drain electrode is also connected to a threshold element. Normally, the FET has low impedance, so that at the input of the threshold element source potential, e.g. ground potential, is present. With current rising as a function of temperature, the current through the FET is limited to a constant, essentially temperature-independent value, and the potential at the input of the threshold element rises steeply. This condition is detected as an overtemperature signal.