Patent ID: 6420931
Filing Date: 2002-07-16
Classification: H03F

Abstract:
An amplifier output circuit for receiving a differential input signal and producing a single-ended output signal indicative of the input signal, said output circuit comprising:a level shifting circuit configured to receive the differential input signal having first and second components, said level shifting circuit defining a first current path disposed intermediate first and second power supply rails and controlled by the first component of the differential input signal and a second current path disposed intermediate the first and second power supply rails and controlled by the second component of the differential input signal, first and second transistors connected in series with the first and second current paths, respectively, with the first and second transistors being disposed intermediate the respective current paths and a same one of the power supply rails; a driver stage having a first input coupled to the first current path at a node intermediate the first transistor and the power supply rail other than the same one of the power supply rails and a second input coupled to the second current path at a node intermediate the second transistor and the power supply rail other than the same one of the power supply rails and a first output indicative of a voltage level on the first current path and a second output indicative of a voltage level on the second current path; a common mode feedback circuit configured to alter current flow in the first and second current paths in response to the voltage level on the first current path and the voltage level on the second current path; and an output stage including a third transistor coupled between the first supply rail and an amplifier output where the single-ended output signal is produced and having a base coupled to the driver stage first output and a fourth transistor coupled between the second supply rail and the amplifier output and having a base coupled to the driver stage second output.