Abstract: A system for detecting and controlling an abnormal state of an electrical signal, includes: an abnormality decision part determining whether or not an electrical signal detected from a power line is abnormal by using the electrical signal and generating a control signal for controlling ON/OFF of N switches included in a leakage breaker. The system for detecting and controlling the abnormal state of the electrical signal is capable of controlling an operation of the leakage breaker by using voltage and current signals detected from the power line through which commercial power is supplied and functioning as a black box when an accident occurs such as a fire, etc.

Abstract: In accordance with a startup circuit, a capacitive sensor amplification device having the startup circuit, and a startup method for the amplification device, a startup time can be shortened by connecting the high impedance resistor of an amplifier to a predetermined voltage source during startup. The capacitive sensor amplification device includes an amplification unit for amplifying a signal input to the amplification device; and a startup circuit for improving a startup time of the amplification unit, wherein the startup circuit includes a comparator for receiving an output of the amplification unit as a first comparison signal, receiving a preset reference voltage as a second comparison signal, comparing the comparison signals with each other, and outputting a comparison result; and a switch for selecting and outputting one of a first voltage and a second voltage depending on the output of the comparator.

Abstract: In accordance with a startup circuit, a capacitive sensor amplification device having the startup circuit, and a startup method for the amplification device, a startup time can be shortened by connecting the high impedance resistor of an amplifier to a predetermined voltage source during startup. The capacitive sensor amplification device includes an amplification unit for amplifying a signal input to the amplification device; and a startup circuit for improving a startup time of the amplification unit, wherein the startup circuit includes a comparator for receiving an output of the amplification unit as a first comparison signal, receiving a preset reference voltage as a second comparison signal, comparing the comparison signals with each other, and outputting a comparison result; and a switch for selecting and outputting one of a first voltage and a second voltage depending on the output of the comparator.

Abstract: 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.

Abstract: The present invention provides 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 (Bias) for applying a bias voltage to an input signal when the input signal is output from a microphone condenser. An impedance unit (Z) 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 (40) 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.