Patent ID: 6825726
Filing Date: 2004-11-30
Classification: H03F

Abstract:
A power amplifier for receiving a first input signal at a first input terminal and for producing a first output signal at a first output terminal, said first output signal corresponding to said first input signal, a first signal amplifier being coupled to the first input terminal to receive the first input signal and coupled to the first output terminal to provide the first output signal, the first signal amplifier having a first power terminal for receiving a total power signal and said power amplifier having a first power supply circuit comprising:(a) a first input signal compensation block coupled to the first input terminal to receive the first input signal and to provide a compensated input signal corresponding to the first input signal, wherein the compensated input signal defines a target power level; (b) a power signal compensation block for receiving the total power signal and for providing a compensated power signal corresponding to the total power signal; (c) a summer coupled to the first input signal compensation block and to the power signal compensation block for providing an error signal corresponding to a difference between the target power level and a power level of the total power signal; (d) a control circuit coupled to the summer for receiving the error signal and for providing a first control signal and a second control signal in response to the error signal, wherein the first control signal corresponds to a target main power signal level and the second control signal corresponds to a target transient power signal level; (e) a transient detect block coupled to the first input signal compensation block for providing a transient signal to identify a transient condition when a rate of change in a slew rate of the compensated input signal exceeds a selected transient threshold; (f) a main power supply for providing a main power signal at the first power terminal in response to the first control signal; and (g) a selectively engageable transient power supply for providing a transient power signal at the first power terminal in response to the second control signal and the transient signal, wherein the transient power supply is engaged when the transient signal indicates that a transient condition exists; wherein the control circuit provides the first and second control signals such that the target main power signal level is equal to or higher than the target transient power signal level and wherein the magnitude of the total power signal is generally equal to the higher of the magnitude of the main power signal or the magnitude of the transient power signal.