| 摘要 |
PURPOSE:To set the voltage change time linearly and to decrease its variance by providing an input/output comparison circuit applying operating processing to the voltage difference of input/output, a time constant setting circuit, an integration circuit and a correction circuit. CONSTITUTION:A signal at an input terminal 15 and a D/A converter 39 is inputted to the input/output comparison circuit A employing an operational amplifier 9 as its major component, the operation processing of the input/output voltage difference and its output is inputted to a time constant setting circuit B. The circuit B consists of digital switches 30, 31 a reference oscillator 32 and a programmable frequency divider 33, and an updown counter 38 of an integration circuit C is changed according to the time constant decided by the frequency divider 33 depending on the value set to the switches 30, 31. In this case, the change time of one step of the counter 38 is a period of an output clock of the oscillator 32, the changing time constant of the voltage outputted at an output terminal 8 is set linearly and its variance is decreased according to the accuracy of the oscillator 32. Further, a correction circuit D makes the change in the output signal continuously as an analog output.
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