| 摘要 |
A programmable gain amplifier includes an OP amplifier, N decayed capacitor(s), (N+1) adjusting capacitor modules, switches, a switch control module, and a feedback switch. First terminals of adjusting capacitors of the capacitor modules are connected together. One capacitor module is connected to an input terminal of the OP amplifier, and neighboring two of the capacitor modules are connected together through one of the decayed capacitor(s). Each switch controlled by the switch control module has a common terminal connected to a second terminal of the capacitor so as to couple the capacitor to an input signal, a reference voltage, or an output terminal of the OP amplifier. The feedback switch is connected between the output terminal and the first input terminal, and turns on in a first phase. The adjusting capacitor can be connected to the output terminal to serve as the feedback capacitance through control of the switches in a second phase, which does not overlap with the first phase.
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