| 摘要 |
PROBLEM TO BE SOLVED: To provide an offset cancel circuit capable of canceling an offset of a DAC (Digital to Analog Converter), without incurring increase in the size of a chip or the number of terminals. SOLUTION: The offset cancel circuit is a means for canceling an offset of a digital to analog converter 3 which converts a digital input signal DI into an analog output voltage AO. The circuit comprises a comparator 7 comparing the analog output voltage AO with a predetermined bias voltage BIAS to generate a comparison result signal SBO, a first computation unit 8 for generating a feedback signal phO according to the digital input signal DI and the comparison result signal SBO, an integrator 10 for integrating the feedback signal phO to generate an integration result signal (Σ(A×phO) in Figure 1), and a second computation unit 11 for applying feedback to the digital input signal DI according to the integration result signal to output a corrected digital input signal DI' to the digital to analog converter 3. COPYRIGHT: (C)2009,JPO&INPIT
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