| 摘要 |
PURPOSE:To compare the quantity of two kinds of voltages with high accuracy by applying positive feedback connection to two inverters via a capacitor and a switch and adding further a common mode rejection circuit. CONSTITUTION:When phi1, phi2 go to L and switches SW1, SW2 only are turned on, the mode is selected to the amplifier mode and a difference between a reference voltage VREF and analog input voltages Va1, Va2 is amplified respectively by the inverters 201, 202. When the theta1 goes to L and the phi2 goes to H and switches SW7, SW8 are turned on, the mode enters the positive feedback mode and a positive feedback loop is formed between the input and output of the inverters 201, 202 via capacitors 221, 222. Then the quantity of the voltages Va1, Va2 is discriminated. Further, current sources 231, 232, 241, 242 act like common mode rejection circuits to cope with a common mode noise expected to be superimposed on the inverter input in the common mode. Thus, the quantity of two kinds of voltages is compared with high accuracy. |
