DC component cancellation circuit

Abstract

A pulse width detection circuit for accurately detecting a pulse width from an input signal. The detection circuit includes a first filter circuit for receiving the input signal and generating a first processed signal. The first processed signal includes a first component having an AC component of the input signal and a second component having a low frequency component or a DC component of the input signal. A second filter circuit is electrically connected to the first filter circuit. The second filter circuit includes a high pass filter for receiving the first processed signal and generating a second processed signal. A binary conversion circuit is electrically connected to the second filter circuit to receive the second processed signal and generate the binary signal.

1 - 16 . (canceled).  
     
     
         17 . A DC component cancellation circuit connected to an input terminal and an output terminal of an amplifier that amplifies an input signal and generates an amplified signal, wherein the cancellation circuit eliminates an offset voltage included in the input signal, the cancellation circuit comprising: 
 a voltage holding circuit for receiving the amplified signal and holding a peak voltage of the amplified signal; and    a feedback amplifier connected to the voltage holding circuit, wherein the feedback amplifier compares the held peak voltage with a reference voltage and generates a feedback signal to eliminate the offset voltage, the feedback signal being provided to the input terminal of the first amplifier.    
     
     
         18 . The DC component cancellation circuit according to  claim 17 , wherein the amplifier converts current of the input signal to voltage to generate a voltage signal, which is the amplified signal, and generates a reference signal having the reference voltage, and wherein the feedback amplifier compares a peak voltage of the voltage signal with the reference voltage.