| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a technique capable of generating a drive signal having a voltage exceeding a supply voltage and of generating a stable drive signal independent of ambient temperature and manufacturing variations of components. <P>SOLUTION: A drive waveform signal on which a drive signal to be applied to a capacitive load is based is pulse-modulated to generate a modulated signal, and the resultant modulated signal is power-amplified and then passed through a smoothing filter, which demodulates the drive signal. The resultant drive signal is negatively fed back to suppress a resonance peak of the smoothing filter. The peak is not completely suppressed but a gain is kept at a fixed value or greater (for example, 2 or greater) in a relatively wide frequency band, so that a drive signal having a voltage exceeding a supply voltage can be stably generated. <P>COPYRIGHT: (C)2012,JPO&INPIT |
