Finnegan, Henderson, Farabow, Garrett & Dunner
Constant-voltage circuit with a diode and MOS transistors operating in the saturation region
 A constant-voltage circuit in which a diode and an MOS transistor are connected in series between power supply terminals between which a battery power source is connected. The MOS transistor is biased to operate in the saturation region. The forward voltage drop across the diode is kept substantially constant independent of variations in battery voltage and temperature. This constant-voltage circuit may preferably be used in a battery checker circuit for detecting the end of battery life. 
Tokyo Shibaura Electric Co., Ltd.
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G01R G05F G05F
inventional inventional inventional
Takeshi Yasoji Tetsuya
Hitotsuyanagi Suzuki Iida