| 摘要 |
PROBLEM TO BE SOLVED: To provide a digital amplifier which has a simple and inexpensive configuration and can drive a speaker with arbitrary high voltage and attain complete digitalization in a small LSI (large scale integrated circuit). SOLUTION: An arithmetic circuit 1 operates a difference between an input signal vi and a feedback signal Fb. A PWM (pulse width modulation) circuit 2 converts an output of the arithmetic circuit 1 into a pulse width modulated signal. A waveform conversion circuit 3 consists of a switch transistor that is subjected to on/off control by an output of the PWM circuit 2, a coil inserted with the switch transistor in series and a capacitor charged by induced current of the coil, and converts the output of the PWM circuit 2 into a high voltage analog signal to supply the high voltage analog signal to a load 4. In addition, an amplifier 5 amplifies the output of the PWM circuit 2 and returns the amplified output to the arithmetic circuit 1 as the feedback signal Fb. COPYRIGHT: (C)2006,JPO&NCIPI |
