Method and circuit for monitoring the functioning of a sensor bridge

US6040779A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Georg Pfaff · Schifferstadt, DE
• Herbert Keller · Pulheim, DE

Key dates

• Filing date: Feb 24, 1999
• Grant date: Mar 21, 2000
• Expiry date: Feb 24, 2019

Classification

• Technology area (CPC G): Physics
• CPC primary: G01R35/00
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

Monitoring of the function of a symmetrical sensor bridge circuit is performed in that the signal from the positive or negative half-bridge is subtracted from half the bridge supply voltage (V.sub.s /2) in a summing member (2) and is subsequently amplified by an amplifier (3) in such a way that it corresponds to the full bridge signal (V.sub.in). The full bridge signal (V.sub.in) is compared with the amplified difference signal in a comparator (5). If the difference signal deviates in an unacceptable manner from the full bridge signal, the comparator switches an alarm signal on the output signal (6) of the sensor, so that this output signal is placed into a range which lies outside of the normal operational range of the sensor.