Ratio metric output type heat generation resistor type air flow indicator and heat generation resistor type air flow indicator and engine control control equipment

摘要

PROBLEM TO BE SOLVED: To make the accuracy of a radiometric output characteristic higher, by adding the output signal of a proportional circuit and the output signal of a multiplying circuit to each other so as to be the output of a ratiometeric circuit, and reducing the ratio of the error of the multiplying circuit to the error of the whole ratiometeric circuit. ;SOLUTION: The retiometric circuit 4 is constituted of an internal-reference power- supply circuit 5, a multiplying circuit 6, a proportional circuit 8, and an addition circuit 9. The internal-reference power-supply circuit 5 generates an internal-reference voltage VINT as a first reference voltage signal. A differential amplifier 6a at the multiplying circuit 6 detects a voltage VD as the difference between an external- reference voltage VREF as a second reference voltage signal and the internal-reference voltage VINT. A multiplier 6b outputs a voltage Vm as the product of the voltage VD multiplied by the output voltage Vin of an output-characteristics adjusting circuit 3. The addition circuit 9 adds the output voltage Vm to a voltage Vp which is constant-multiplies the output voltage Vin and which is output by the proportional circuit 8, and an output voltage Vout which expresses the air flow rate of a flowmeter is obtained.;COPYRIGHT: (C)1998,JPO