Patent ID: 7388422

Claim:
A high side charge pump circuit for supplying voltage to a high side switch drive circuit, wherein the high side charge pump circuit is used together with a low side switch drive voltage-raising circuit for supplying output voltage to a bridge drive circuit, the high side charge pump circuit comprising: a first switching device; a capacitor having a first terminal supplied with input voltage via the first switching device; a second switching device connected to the first terminal of the capacitor and to an output terminal of the high side charge pump circuit; a third switching device for selectively grounding the capacitor or supplying the input voltage to the capacitor synchronously with the supply of the input voltage to the first switching device or synchronously with stopping of the supply of the input voltage to the first switching device; a supply section, connected to the first terminal of the capacitor, for supplying the output voltage of the low side switch drive voltage-raising circuit to the capacitor; and a charge pump control circuit for controlling the first and third switching devices; wherein when the input voltage is higher than the output voltage of the low side switch drive voltage-raising circuit, the charge pump control circuit controls the first and third switching devices based on the input voltage so that the capacitor is charged to a voltage obtained by subtracting a voltage drop that occurs in the second switching device from the output voltage of the low side switch drive voltage-raising circuit.