Patent ID: 7852128

Claim:
A driving circuit for a capacitive load, the driving circuit comprising: a driving signal generating unit that generates a driving signal for driving the capacitive load by using a driving transistor pair including two transistors connected complementarily; and a power source voltage generating unit that generates a high-voltage power source voltage that is higher than the voltage of the driving signal and a low-voltage power source voltage that is lower than the voltage of the driving signal and applies the high-voltage power source voltage and the low-voltage power source voltage to the collectors of the driving transistors, wherein the power source voltage generating unit is configured by a power source transistor pair including two transistors connected complementarily and a capacitor of which low-voltage terminal is connected to an output side of the power source transistor pair, and wherein the low-voltage power source voltage is generated in an output side of the power-source transistor pair as a voltage that is in a voltage region lower than that of the driving signal and follows the driving signal and is output from a low-voltage terminal of the capacitor by supplying a control signal having a waveform following the driving signal to an input side of the power source transistor pair, and the high-voltage power source voltage is output from a high-voltage terminal of the capacitor as a voltage that is acquired from adding a charged voltage of the capacitor to the low-voltage power source voltage, is in a voltage region higher than that of the driving signal, and follows the driving signal.