| 摘要 |
PURPOSE: A signal processing circuit for a pressure sensor is provided to control an offset voltage and a span, and to compensate for an offset voltage and a temperature of the span, by constituting the signal processing circuit using ion implantation resistors with different temperature coefficients. CONSTITUTION: A pressure sensor(100) comprises resistors(RS1,RS2,RS3,RS4), and a signal processing circuit(200) two operational amplifiers(OP1,OP2) and resistors(R1,Rd,Ra,Rb,Rc,Rg,R16). Output voltages(Vin1,Vin2) of the pressure sensor are connected to non-inverting input terminals of the operational amplifiers respectively. Then, The output voltage(Vin1) indicates a voltage of a contact point between the resistor Rs2 and the resistor Rs4, and the output voltage(Vin2) indicates a voltage of a contact point between the resistor Rs1 and the resistor Rs3. One end of the resistor(R1) is connected to a power supply voltage(Vcc), and another end is connected to one end of the resistor(Rd), and another end of the resistor(Rd) is connected to the ground. A voltage(Vref) between the resistor R1 and Rd corresponds to an offset voltage, and these resistors(R1,Rd) are for controlling the offset voltage. The resistors(Ra,Rb) are for controlling a gain of the operational amplifier(OP1), and the resistors(Rc,R16) are for controlling a gain of the operational amplifier(OP2). And, the resistor(Rg) controls a span and a temperature coefficient of the span.
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