| 摘要 |
PURPOSE:To obtain a reciprocal function generating circuit of simple constitution, by turning on and off analog switches by the output of a comparator having hysteresis and charging and discharging smoothing circuits. CONSTITUTION:A constant source voltage Vr1 is inputted to the uninverted input terminal of a comparing circuit 63 having hysteresis of a voltage DELTAVe1, and the output voltage Vc1 of the smoothing circuit 61 is applied to the inverted input terminal. When Vc1<Vr1, the circuit 63 generates a high-level output to turn on analog switches SW64a and SW64c, and while the capacitor of the circuit 61 is charged with an input voltage V1, the capacitor C2 of a smoothing circuit 62 is charged with a constant voltage Vr2. When the C1 is charged until Vc1>Vr1, the output of the circuit 63 drops to a low level, and while the SWs 64a and 64c are turned off, SWs 64b and 64d are turned on to discharge the C1 and C2. When Vc1<Vr1, the C1 is charged again and the Vc1 pulsates with width DELTAVe1, so that the circuit 63 outputs a pulse signal 63a in inverse proportion to the input voltage with a duty factor T0/T1=Vr1/V1. The circuit 62, on the other hand, outputs a voltage in inverse proportion to the input voltage of an output voltage V0=Vr1XVr2/V1. |
