SEMICONDUCTOR INTEGRATED CIRCUIT

摘要

PURPOSE:To secure the stability of a semiconductor integrated circuit at the time of negative feedback, by providing a serial circuit of a capacity and resistance in parallel with an earthing point at the signal point between the next- stage amplifier having a high-output resistance and an output buffer having a high-input impedance. CONSTITUTION:A serial circuit of a capacity 4 for phase compensation and resistance 5 for phase compensation is connected in parallel between the signal point 9 between the next stage amplifier 2 and output buffer 3 and earthing point 10. From the pole of a transfer function which is determined by the time constant between the capacity and resistance shunted from the high-output resistance of the amplifier 12, a gain damping characteristic of -6dB/Oct and phase delaying characteristic are obtained. In addition, a phase advancing characteristic is obtained at the zero point on the left-half plane of the transfer function determined by the time constant between the shunted capacity and resistance and the phase delaying quantity in the vicinity of a unit gain frequency is extremely improved. Therefore, high stability can be maintained even when the negative feedback quantity to be added to an operational amplifier is increased.