Title:
TEMPERATURE SENSOR CIRCUIT
Document Type and Number:
Japanese Patent JPH02269922
Kind Code:
A
Abstract:
PURPOSE:To eliminate the need for an A/D converter and to reduce the cost by outputting temperature which is measured by a sensor directly as a frequency signal. CONSTITUTION:The sensor circuit is provided with an astable multivibrator MV1 which has a constant current source as a load and charges and discharges a capacitor to determine its oscillation frequency, a bias circuit BAS1 which determines the level of a charging signal for charging the capacitor through the constant current source, and a temperature element which is provided as a circuit element of the bias circuit BAS1 and generates the charging signal corresponding to measured temperature. Then the temperature element of the bias circuit BAS1 varies the charging signal applied to the capacitor of the astable multivibrator MV1 to output an oscillation frequency corresponding to the measured temperature. Consequently, the need for an A/D converter in the circuit is eliminated and the cost is reducible.
Inventors:
YAMAGATA MICHIAKI
ANDO YUKIKIYO
ANDO YUKIKIYO
Application Number:
JP9238889A
Publication Date:
November 05, 1990
Filing Date:
April 12, 1989
Export Citation:
Assignee:
YOKOGAWA ELECTRIC CORP
International Classes:
G01K7/00; G01K7/24; (IPC1-7): G01K7/00; G01K7/24