Cantor Colburn LLP
Digital condenser microphone having preamplifier with variable input impedance and method of controlling variable input impedance of preamplifier
Provided are a digital condenser microphone having a preamplifier with variable input impedance and a method of controlling the variable input impedance of the preamplifier. The preamplifier includes a bias terminal for applying a bias voltage to an input signal when the input signal is output from a microphone condenser. An impedance unit includes at least one variable input impedance element which is connected to the bias terminal and to which the bias voltage is applied via the bias terminal. An operational amplifier receives the input signal, converts the input signal into an output signal, and outputs the output signal. A control block determines whether a DC voltage level of the output signal output from the operational amplifier has reached a reference value, and controls a total impedance of the impedance unit based on a result of the determination.
CESIGN CO., LTD.
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Soo-Hyoung Justin Jungsup
Lee Kim