Patent ID: 7541956

Claim:
A variable input gain apparatus of an inverter system, the variable input gain apparatus processing an analog input voltage signal and delivering the processed signal to the inverter system, the variable input gain apparatus comprising: a comparator unit for receiving the analog input voltage signal and compared with at least one threshold voltage value to determine a voltage range of the analog input voltage signal; an amplifier unit for receiving and amplifying the analog input voltage signal; a feedback-controlling gain unit electrically connected with the comparator unit and the amplifier unit, the feedback-controlling gain unit adjusting a voltage gain of the amplifier unit according to the voltage range of the analog input voltage signal; and an analog-to-digital converter unit electrically connected with the amplifier unit and converting an analog signal outputted from the amplifier unit into a digital count; wherein the comparator unit outputs an indicating signal to indicate the voltage range of the analog input voltage signal.