Modulated supply stage with feedback to switched supply

Abstract

There is disclosed a voltage supply stage comprising: a selection means for selecting one of a plurality of power supply voltages in dependence on a reference signal representing a desired power supply voltage; a combining means for combining the selected power supply voltage with a correction signal to generate an adjusted power supply voltage; and an adjusting means adapted to generate the correction signal in dependence on the reference signal and the adjusted power supply voltage, wherein the selection means is arranged to select the one of the plurality of supply voltages further in dependence on a signal derived from one of the inputs to the combining means.

What is claimed is: 
     
         1 - 48 . (canceled) 
     
     
         49 . A voltage supply stage comprising:
 a controller for receiving an input signal and a plurality of power supply voltages, and for selecting one of the plurality of power supply voltages in dependence on the reference signal;   a combiner for combining the selected power supply voltage with a correction signal to generate an adjusted power supply voltage; and   a correction stage adapted to generate the correction signal in dependence on a reference signal representing a desired power supply voltage and the adjusted power supply voltage, wherein the controller is arranged to select the one of the plurality of supply voltages further in dependence on a signal derived from one of the inputs to the combiner,   wherein the reference signal provided to the controller is adapted to control current flow in the combiner due to the selected power supply voltage and thereby control current flow in the correction stage.   
     
     
         50 . The voltage supply stage of  claim 49  wherein the current flow in the combiner due to the selected power supply voltage is increased in order to reduce the current flow in the correction stage. 
     
     
         51 . The voltage supply stage of  claim 50  wherein the current flow in the combiner due to the selected power supply voltage is maximised in order to minimise the current flow in the correction stage. 
     
     
         52 . The voltage supply stage of  claim 49  further comprising a reference adjustment stage for adjusting the reference signal. 
     
     
         53 . The voltage supply stage of  claim 49  wherein the selection means is further arranged to select the one of the plurality of supply voltages further in dependence on the correction signal. 
     
     
         54 . The voltage supply stage according to  claim 49  wherein the reference adjustment stage is adapted to include a correlator for determining the current flow in the inductor and for providing a control signal to modify coefficients of a differentiator in dependence thereon, the differentiator being arranged to receive the reference signal and generate a differentiated version thereof. 
     
     
         55 . The voltage supply stage according to  claim 54 , wherein the differentiator is arranged to receive as an input the amplitude adjusted reference signal generate a differentiated amplitude adjusted reference signal, the reference adjustment stage further comprising a summer for summing the amplitude adjusted reference signal with the differentiated amplitude adjusted reference signal to form the modified reference signal. 
     
     
         56 . A voltage supply stage comprising:
 a controller for receiving an input signal and a plurality of power supply voltages, and for selecting one of the plurality of power supply voltages as a selected supply voltage in dependence on the reference signal;   a combiner for combining the selected power supply voltage with a correction signal to generate an adjusted power supply voltage; and   a correction stage adapted to generate the correction signal in dependence on a reference signal representing a desired power supply voltage and the adjusted power supply voltage, wherein the controller is arranged to select the one of the plurality of supply voltages further in dependence on a signal derived from one of the inputs to the combiner,   wherein the amplitude of the reference signal is adjusted in dependence upon a difference between the amplitude of the reference signal and an amplitude of a selected supply voltage.   
     
     
         57 . The voltage supply stage of  claim 56  further comprising a reference adjustment stage comprising an amplitude adjustment stage for adjusting the reference signal to provide a modified reference signal. 
     
     
         58 . The voltage supply stage of  claim 56  wherein the selection means is further arranged to select the one of the plurality of supply voltages further in dependence on the correction signal. 
     
     
         59 . The voltage supply stage according to  claim 56  wherein the amplitude adjustment stage includes:
 a correlator for determining the amplitude error between the reference signal and the selected supply voltage; and 
 an amplitude adjustment block for modifying the reference signal in dependence on said error. 
 
     
     
         60 . A tracking modulated power supply stage for a mobile wireless device including a voltage supply stage according to  claim 56 . 
     
     
         61 . A voltage supply stage comprising:
 a controller for receiving an input signal and a plurality of power supply voltages, and for selecting one of a plurality of power supply voltages as a selected supply voltage in dependence on the reference signal;   a combiner for combining the selected power supply voltage with a correction signal to generate an adjusted power supply voltage;   a correction stage adapted to generate the correction signal in dependence on a reference signal representing a desired power supply voltage and the adjusted power supply voltage; and   a stage for controlling the current flowing in the combiner due to the selected power supply voltage to thereby control the current required to flow in the correction stage,   wherein the amplitude of the reference signal is adjusted in dependence on a difference between the amplitude of the reference signal and an amplitude of the selected supply voltage.   
     
     
         62 . The voltage supply stage of  claim 61  wherein the current flow in the combiner due to the selected power supply voltage is increased in order to reduce the current flow in the correction stage. 
     
     
         63 . The voltage supply stage of  claim 61  wherein the current flow in the combiner due to the selected power supply voltage is maximised in order to minimise the current flow in the correction stage. 
     
     
         64 . The voltage supply stage of  claim 61  further comprising an amplitude adjustment stage for adjusting the reference signal to provide the adjusted reference signal. 
     
     
         65 . The voltage supply stage of  claim 61  wherein the selection means is further arranged to select the one of the plurality of supply voltages further in dependence on the correction signal.