| 摘要 |
PROBLEM TO BE SOLVED: To provide a low pass filter circuit and a power supply device whose noise removal capability is high, and whose output is stably and quickly started.SOLUTION: A low pass filter circuit includes: a capacitive element connected to an output terminal; and a resistance circuit connected between an input terminal and an output terminal. The resistance circuit includes: a first MOS transistor connected between the input terminal and the output terminal; and an amplifier whose input terminal is connected to a first input terminal, and whose output terminal is connected to a second input terminal, and to whose output terminal the gate of the first MOS transistor is connected for controlling the time constant of the low pass filter circuit.SELECTED DRAWING: Figure 1 |
