| 摘要 |
PROBLEM TO BE SOLVED: To provide a reference voltage generating circuit setting an output voltage at high speed by charging the capacitance of a low-pass filter for reducing noise at high speed. SOLUTION: The reference voltage generating circuit is provided with: a reference voltage source 1 for generating a DC voltage to be reference; the low-pass filter 2 connected to the output of the reference voltage source; a first voltage buffer circuit 10 where the output of the reference voltage source is connected to the input terminal and the output of the low-pass filter is connected to the output terminal and voltage gain is the 1 time; and a hysterisis comparator 11 where the output of the reference voltage source is connected to one input terminal and the output of the low-pass filter is connected to the other input terminal. The output impedance of the first voltage buffer circuit is controlled by the output signal of the hysterisis comparator during a period when a voltage difference between the output of the reference voltage source and the output of the low-pass filter exceeds a prescribed value in starting. The low-pass filter is rapidly charged by the low impedance in starting, thereby a setting time is shortened. COPYRIGHT: (C)2010,JPO&INPIT
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