Wenderoth, Lind and Ponack, L.L.P.
Current sensing circuit with automatic offset compensation
 The current sensing circuit with automatic offset compensation is provided with a current sensing resistor, a difference amplifier which inputs this current sensing resistor voltage at its voltage measuring input terminal and inputs a reference voltage at its reference voltage terminal, and a measuring circuit which determines the current flowing in the current sensing resistor from the difference amplifier output voltage. The current sensing circuit adds a small bias voltage to the current sensing resistor voltage and inputs it to the voltage measuring input terminal to increase difference amplifier output voltage. The measuring circuit measures difference amplifier output voltage and compensates the reference voltage input to the difference amplifier reference voltage terminal to compensate difference amplifier output to 0V when current sensing resistor current is zero. 
Sanyo Electric Co., Ltd.
G G
G01R G01R
inventional inventional
Masato
Sano