| 摘要 |
PURPOSE:To obtain an amplifier circuit which can work even with the power supply voltage of a low level by providing a pair of differential transistors (TR), a constant current source which subtracts the same bias current from the current outputs of both differential TRs and a current subtractor circuit which performs the current subtraction processing of both current outputs including said bias current. CONSTITUTION:The subtraction is not carried out directly between both collector currents of a pair of differential TRs 11 and 12 by a current mirror circuit consisting of the TRs complementary to said paired TRs. Instead the same bias current (collector currents of TRs 14 and 15) is subtracted from both collector currents of the TRs 11 and 12. The result of said subtraction is subtracted by a current mirror circuit consisting of the TRs similar to the TRs 11 and 12. Thus both bias currents are eliminated with each other, and the difference between both collector currents of the TRs 11 and 12 is delivered to an output terminal. Such an amplifier circuit can work even with the input terminal voltage set at 0. |
