| 摘要 |
PROBLEM TO BE SOLVED: To precisely calibrate a DC offset and a duty in a simple circuit.SOLUTION: An amplification circuit 1 comprises: a preamplifier section for amplifying differential input signals to generate differential output signals; an input switching section 2 for setting the differential input signals at the same voltage level of reference voltage signals in the process of calibration; a PWM conversion section 5 for pulse-width-modulating the differential output signals to generate differential PWM signals on the basis of results of comparison of the differential output signals with a sawtooth or triangular reference signal; a calibration section 6 for generating an offset adjustment signal in accordance with a phase difference of the differential PWM signals in the process of calibration; and a power amplifier section 8 for power-amplifying the differential PWM signals to generate differential final output signals. In the process of calibration, the preamplifier section 4 adjusts voltage levels of the differential output signals on the basis of the offset adjustment signal so as to reduce a potential difference of the differential output signals. |
