| 摘要 |
PURPOSE:To integrate the entire circuit in a chip by constituting a pseudo current source with a positive power supply with the use of a resistor inserted between the positive power supply and an emitter of a cascode transistor(TR) of common base connection and compensating the phase with a capacitor of a less capacitance. CONSTITUTION:A differential amplifier 1 consists of differential input TRs Q1, Q2 and a couple of cascode TRs Q3,Q4 whose emitters connect to collectors 3, 5 of the TRs Q1, Q2. Moreover, the differential amplifier 1 has resistors R3,R4 inserted respectively between the power supply Vcc and collectors of the TRs Q1, Q2. The resistors R3,R4 constitute the current source with the 2nd power supply Vcc. Thus, the current source is integrated in one and same chip with the differential amplifier 1 and a problem of difficulty in the circuit integration when the current source is formed by using PNP TRs is solved. |
