Voltage-controlled control device capable of accurate control characteristics without increasing the number of interface lines

摘要

In the control voltage generator, the pulse density modulation signal or the pulse width modulation signal is generated in accordance with the digital control signal and supplied to the averaging circuit for averaging. The power supply voltage is supplied from the first power supply to the first buffer circuit. Then, the averaged signal is supplied to the control voltage generating circuit to generate the target control voltage. When the control voltage is generated, an output voltage equal to the output voltage of the first buffer circuit is generated by the second buffer circuit. According to the output voltage output from the second buffer circuit, the operation control circuit supplies the power supply voltage to the first voltage generation circuit so that the control voltage generation circuit can operate. Further, the control voltage generating circuit uses the output voltage supplied from the second buffer circuit as a reference voltage to adjust the control voltage. Consequently, depending on the voltage of the output voltage supplied in the second buffer circuit, ON / OFF of the control voltage generating circuit can be controlled, and the reference voltage used for adjusting the control voltage can be further supplied.