| 摘要 |
PURPOSE:To stabilize and secure operation even at a low power voltage by providing an arithmetic feedback circuit which outputs a current bearing a fixed relation to the oerating current of PP-connected transistors and then keeps this current constant. CONSTITUTION:The output of signal source 11 is supplied to output circuit 16 composed of PP-connected ransistors TRQ7 and TRQ8 via pre-amplifying circuit 13 and driving circuit 14. Then, the operating crrent of TRQ7 is detected by TRQ9 and arithmetic feeback circuit 18 composed of TRQ11 and Q12 generates current IF, bearing the relation of IFproportional (I1.I2)<1/2> to operating currents I1 and I2, of TRQ1 and Q2, which is fed back to amplifying circuit 13 to keep current IF constant. Thus, the operation can be stabilized and secured even at a low power voltage. Additionally, idle currents of TRQ1 and Q2 can easily be set. |
