Patent ID: 7461281

Claim:
A capacitive load driving circuit, comprising: an error amplification circuit, including input terminals, that amplifies a difference between an external input signal provided to one input terminal and a negative feedback signal provided from the following negative feedback circuit to the other input terminal; a modulation circuit that pulse-modulates the signal outputted from the error amplification circuit; a power switching circuit that switches between a power supply voltage and a ground potential or between a positive power supply voltage and a negative power supply voltage; a gate driving circuit that generates a gate driving signal to switch-control a switching element configuring the power switching circuit, from a modulated signal outputted from the modulation circuit; a low-pass filter, connected to an output side of the power switching circuit, that removes switching carrier components included in an output signal of the power switching circuit; an output transformer that boosts an output signal of the low-pass filter and that has a primary winding connected to an output terminal of the low-pass filter; a capacitive load connected in parallel with a secondary winding of the output transformer; and a negative feedback circuit, that performs negative feedback from the output terminal of the low-pass filter, to provide the negative feedback signal to the input terminal of the error amplification circuit.