Patent ID: 7973588

Claim:
An analog insulation multiplexer, comprising: a first switching element for generating a drive control signal by switching in accordance with an external signal; a drive insulation transformer for receiving the drive control signal on a primary side via a first resistor and for delivering an insulated drive control signal from a secondary side; a second switching element for chopping an analog signal input in accordance with the insulated drive control signal so as to generate a chopped analog signal; and an analog signal insulation transformer for receiving the chopped analog signal on a primary side and for delivering an insulated chopped analog signal on a secondary side, wherein one side of a second resistor is connected to the first resistor in parallel on the primary side of the drive insulation transformer, a cathode side of a diode is connected to an opposite side of the second resistor, one side of a capacitor is connected to an anode side of the diode, and an opposite side of the capacitor is connected to a ground, and thereby a series circuit of the second resistor, the diode, and the capacitor is provided, and the one side of the capacitor is connected to a power supply via a third resistor for charging the capacitor, and thereby, when the first switching element is turned on, a drive voltage of the drive insulation transformer is made a constant voltage promptly, and after that, the drive voltage is increased at a predetermined time constant.