Temperature detection circuit

• US 7,795,950 B2
• Filed: 02/15/2008
• Issued: 09/14/2010
• Est. Priority Date: 02/17/2007
• Status: Expired due to Fees

• Current Assignee: Ablic Inc. (Minebea Mitsumi, Inc.)
• Original Assignee: Seiko Instruments Incorporated (Seiko Group)
• Inventors: Igarashi, Atsushi
• Primary Examiner(s): Nguyen; Hai L
• Application Number:
  US12/070,211
• Publication Number:
  US 20080198899A1
• Time in Patent Office: 942 Days
• Field of Search: 327/512, 327/513, 327/532, 327/551, 327/552, 361/56
• US Class Current: 327/513
• CPC Class Codes: G01K 15/00 Testing or calibrating of thermometers
• CPC Class Codes: G01K 15/007 Testing
• CPC Class Codes: G01K 7/01 using semiconducting elements having PN junctions G01K7/02, G01K7/16, G01K7/30 take precedence
• CPC Class Codes: G01K 7/16 using resistive elements resistive elements per se H01C, H01L

Abstract

A temperature detection circuit has a temperature sensor circuit whose output voltage changes with a variation in temperature. A reference voltage circuit generates a reference voltage. A comparator has an output terminal and compares an output voltage from the temperature sensor circuit with the reference voltage to generate one of a temperature detection signal and a temperature non-detection signal, the comparator having an output terminal. An operation preventing circuit is connected with the output terminal of the comparator such that immediately after activation of a power supply to the temperature detection circuit, the comparator generates the temperature non-detection signal.

Claims

1. A temperature detection circuit, comprising:

a temperature sensor circuit whose output voltage changes with a variation in temperature;

a reference voltage circuit that generates a reference voltage;

a comparator that compares an output voltage from the temperature sensor circuit with the reference voltage to generate one of a temperature detection signal and a temperature non-detection signal, the comparator having an output terminal;

a positive power supply terminal, a negative power supply terminal, and an output terminal connected to the output terminal of the comparator; and

an erroneous operation preventing circuit that is connected with the output terminal of the comparator such that immediately after activation of a power supply to the temperature detection circuit, the comparator generates the temperature non-detection signal, the erroneous operation preventing circuit having a first terminal connected with the positive power supply terminal and a second terminal connected with the output terminal of the temperature detection circuit, wherein the erroneous operation preventing circuit controls the comparator such that immediately after activation of the power supply, when the output voltage of the temperature sensor circuit or the reference voltage of the reference voltage circuit is insufficient, the positive power supply terminal is short-circuited with the output terminal of the temperature detection circuit to cause the temperature non-detection signal to be forcedly outputted from the output terminal of the temperature detection circuit.