Patent ID: 9705462
Date: 2017-07-11
CPC Classifications: G01K,H03F,H03G

Claim:
1. A sensor signal output circuit for use with a temperature sensor, comprising: a buffer amplifier which amplifies and outputs an output signal of the temperature sensor; an operational amplifier which has an inverting input terminal, a non-inverting input terminal, and an output terminal, an output voltage of the buffer amplifier being inputted to the inverting input terminal through a resistor, a reference voltage divided by an offset adjusting resistor being inputted to the non-inverting input terminal, and a gain adjusting resistor being provided between the inverting input terminal and the output terminal; an oscillator which generates a triangular wave signal with a predetermined amplitude; a comparator which compares the triangular wave signal with an output voltage of the operational amplifier and generates a PWM signal with a pulse width corresponding to the output voltage of the operational amplifier; an offset adjusting unit which adjusts the offset adjusting resistor to make the output voltage of the buffer amplifier at a first temperature equivalent to the voltage at the inverting input terminal of the operational amplifier; an amplitude adjusting unit which adjusts the amplitude of the triangular wave signal to make the pulse width of the PWM signal equivalent to a defined first pulse width at the first temperature after the offset adjusting resistor has been set; and a gain adjusting unit which adjusts the gain adjusting resistor to make the pulse width of the PWM signal equivalent to a defined second pulse width at a second temperature that different from the first temperature after the amplitude of the triangular wave signal has been set.