Reed Smith LLP
Logic circuit
The power supply-voltage dependency of a current source current is reduced and the power supply voltage is lowered. The invention includes an emitter-coupled logic circuit 118 and a reference-voltage generating circuit 119 for generating a reference voltage VCSC for controlling a drain current (=current source current ICS) of a constant current-supplying n-type MOS transistor 110. The emitter-coupled logic circuit 118 comprises a current switch made up of a pair of emitter-coupled bipolar transistors 106 and 107, a constant current-supplying n-type MOS transistor 110 that is connected in series with the current switch, and resistor means 108 and 109 connected in series with the bipolar transistors 106 and 107 individually for obtaining an output voltage. The reference-voltage generating circuit 119 comprises an n-type MOS transistor 111, a bipolar transistor 112 which determines the drain voltage of the n-type MOS transistor 111, and a control circuit 120 for controlling the drain current of the n-type MOS transistor 111. 
Hitachi, Ltd.
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H03F H03K H03K
inventional inventional inventional
Akio Atsushi Masahito Tatsuhiro Hiroki
Koyama Itoh Sonehara Aida Yamashita