High efficiency variable voltage supply

Abstract

There is disclosed a power supply stage ( 202 ), comprising: generating means for generating a power supply voltage from a high efficiency variable voltage supply ( 204 ) in dependence on a reference signal; adjusting means for receiving the generated power supply voltage ( 220 ), and adapted to provide an adjusted selected power supply voltage tracking the reference signal ( 216 ) in dependence thereon.

1 . A power supply stage, comprising: generating means for generating a power supply voltage from a high efficiency variable voltage supply in dependence on a reference signal; and adjusting means for receiving the generated power supply voltage, and adapted to provide an adjusted generated power supply voltage tracking the reference signal in dependence thereon.  
   
   
       2 . A power supply stage according to  claim 1  wherein the output efficiency of the high efficiency variable voltage supply is greater than 0.7.  
   
   
       3 . A power supply stage according to  claim 1 , further comprising a lower efficiency voltage supply for supplying the adjusting means.  
   
   
       4 . A power supply stage according to  claim 1  wherein the output efficiency of the adjusting means is greater than 0.4.  
   
   
       5 . A power supply stage according to  claim 1  in which the reference signal comprises an input waveform representing a desired supply voltage level.  
   
   
       6 . A power supply voltage according to  claim 1  in which the high efficiency variable supply generates an intermediate supply voltage level.  
   
   
       7 . A power supply voltage according to  claim 6  in which the adjusting means includes a correction element for generating an error level representing an error between a desired voltage supply level and an output supply voltage level.  
   
   
       8 . A power supply stage according to  claim 7  wherein the power supply stage is adapted to maximise the efficiency of the high efficiency variable voltage supply, whilst maintaining a low peak-to-average ratio for the error level.  
   
   
       9 . A power supply stage according to  claim 7  wherein the power supply stage is adapted to maximise the efficiency of the high efficiency variable voltage supply, whilst maintaining a low slew rate for the error level.  
   
   
       10 . A power supply stage according to  claim 8  wherein a ratio of peak error signal to peak output signal is maintained at less than 0.7  
   
   
       11 . A power supply stage according to  claim 9  wherein a ratio for peak error signal slew rate to peak output signal slew rate is less than 1.5.  
   
   
       12 . A power supply voltage according to  claim 7  in which the error level is generated in dependence on the supply voltage level fed back from an output of the supply voltage stage.  
   
   
       13 . A power supply voltage according to  claim 7  in which the error level is generated in dependence on a prediction of the supply voltage level at an output of the supply voltage stage.  
   
   
       14 . A power supply voltage according to  claim 13  in which the prediction of the supply voltage level is at least partly determined in dependence on the intermediate supply voltage level.  
   
   
       15 . A power supply voltage according to  claim 7  in which the adjusting means includes a combiner for combining the error level with an intermediate supply voltage level to generate the output supply voltage level.  
   
   
       16 . A power supply stage according to  claim 15  in which the combiner is adapted to sink energy, source energy, or sink energy and source energy, in dependence on the error level.  
   
   
       17 . A power supply stage according to  claim 16  wherein the combiner is adapted to sink energy from, source energy to, or sink energy from and source energy to, the output of the high efficiency variable voltage supply.  
   
   
       18 . A power supply according to  claim 7  in which the intermediate supply power is greater than an error power.  
   
   
       19 . A power supply according to  claim 18  in which the ratio of the error power to the intermediate supply power is much less than 1.  
   
   
       20 . A power supply according to  claim 18  in which the ratio of the error power to the intermediate supply power is less than 0.4.  
   
   
       21 . A power supply according to  claim 7  in which the power associated with the signal providing the intermediate supply voltage level is greater than the power associated with the signal providing the error level.  
   
   
       22 . A power supply amplifier according to  claim 7  in which the correction element is configured to receive a continuous supply modulation.  
   
   
       23 . A power supply amplifier according to  claim 7  in which the correction element is configured to receive a supply switched between pluralities of supplies.  
   
   
       24 . A power supply according to  claim 23  in which the correction element is a linear Class-G of Class-H amplifier having multiple power supplies.  
   
   
       25 . A power supply according to  claim 1  in which there is further provided a feedback from the high efficiency variable voltage supply to the generating means.  
   
   
       26 . A power supply according to  claim 1  wherein there is further provided a feedback from an output of the power supply stage to the generating means.  
   
   
       27 . A power supply according to  claim 1  wherein the generating means includes tracking means.  
   
   
       28 . A power supply stage having an output supply voltage level, comprising: a variable voltage supply, adapted to generate an intermediate supply voltage level in dependence on an input waveform representing a desired output supply voltage level; a correction element, adapted to generate an error level representing an error between the actual output supply voltage level and the desired supply voltage level; and a combiner for combining the error level and the intermediate supply voltage level to provide the output voltage supply level.  
   
   
       29 . A power supply stage according to  claim 28  in which the variable voltage supply includes a high efficiency supply stage and the correction element includes a lower efficiency supply stage.  
   
   
       30 . A power supply stage according to  claim 28  in which the variable voltage supply includes a supply stage for generating an output signal having an efficiency greater than 0.7, and the correction element includes a supply stage for generating an output signal having an efficiency greater than 0.4.  
   
   
       31 . A power supply stage according to  claim 30  wherein the output signal of the correction element has a lower efficiency than an output signal of the supply stage.  
   
   
       32 . A power supply stage according to  claim 28  wherein the intermediate supply voltage has an intermediate power level and the error level has an error power level, the intermediate supply voltage level being much greater than the error level.  
   
   
       33 . A power supply stage according to  claim 32  wherein the ratio of the error level to the intermediate supply voltage level is less than 0.4.  
   
   
       34 . A power supply stage according to  claim 29  wherein the efficiency of the variable voltage supply is maximised, whilst jointly minimising the peak-to-average ratio of the error level and the slew rate of the error level.  
   
   
       35 . A power supply stage according to  claim 34  wherein a ratio of peak error signal to peak output signal is maintained at less than 0.7, and wherein a ratio for peak error signal slew rate to peak output signal slew rate is maintained at less than 1.5.  
   
   
       36 . A power supply stage according to  claim 1  wherein the output of the stage provides a power supply to a radio frequency amplifier.  
   
   
       37 . A method of controlling a power supply stage, comprising: generating a power supply voltage from a high efficiency variable voltage supply in dependence on a reference signal; receiving the generated power supply voltage, and adjusting the generated power supply voltage by tracking the reference signal in dependence thereon.  
   
   
       38 . A method of controlling a power supply stage according to  claim 37  wherein the output efficiency of the high efficiency variable voltage supply is maintained as greater than 0.7.  
   
   
       39 . A method of controlling a power supply stage according to  claim 38 , further comprising providing a lower efficiency voltage supply for supplying the adjusting means.  
   
   
       40 . A method of controlling a power supply stage according to  claim 39  wherein the output efficiency of the adjusting means is maintained as greater than 0.4.  
   
   
       41 . A method of controlling a power supply stage according to  claim 37  further comprising providing, as the reference signal, an input waveform representing a desired supply voltage level.  
   
   
       42 . A method of controlling a power supply voltage according to  claim 37  comprising generating an intermediate supply voltage level.  
   
   
       43 . A method of controlling a power supply voltage according to  claim 42  comprising generating an error level representing an error between a desired voltage supply level and an output supply voltage level.  
   
   
       44 . A method according to  claim 43  including the steps of: maximising the efficiency of the high efficiency variable voltage supply; and maintaining a low peak-to-average ratio for the error level.  
   
   
       45 . A method according to  claim 43  including the steps of: maximising the efficiency of the high efficiency variable voltage supply; and maintaining a low slew rate for the error level.  
   
   
       46 . A method according to  claim 44  wherein a ratio of peak error signal to peak output signal is maintained at less than 0.7  
   
   
       47 . A method according to  claim 45  wherein a ratio for peak error signal slew rate to peak output signal slew rate is less than 1.5.  
   
   
       48 . A method of controlling a power supply voltage according to  claim 43  further comprising combining the error level with the intermediate supply voltage level to generate the output supply voltage level.  
   
   
       49 . A method according to  claim 48  in which the combining step comprises one of sinking energy, sourcing energy, or sinking energy and sourcing energy, in dependence on the error level.  
   
   
       50 . A method according to  claim 49  wherein the combining step comprises sinking energy from, sourcing energy to, or sinking energy from and sourcing energy to, the output of the high efficiency variable voltage supply.  
   
   
       51 . A method of controlling a power supply according to  claim 43  in which intermediate supply power is maintained greater than error power.  
   
   
       52 . A method of controlling a power supply according to  claim 51  comprising maintaining the ratio of the error power to the intermediate supply power as much less than 1.  
   
   
       53 . A method of controlling a power supply according to  claim 51  in which the ratio of the error power to the intermediate supply power is maintained as less than 0.4.  
   
   
       54 . A method of controlling a power supply according to  claim 43  further comprising maintaining the power associated with the signal providing the intermediate supply voltage level as greater than the power associated with the signal providing the error level.  
   
   
       55 . A method of controlling a power supply stage having an output supply voltage level, comprising: generating an intermediate supply voltage level in dependence on an input waveform representing a desired output supply voltage level; generating an error level representing an error between an actual output supply voltage level the desired supply voltage level; and combining the error level and the intermediate supply voltage level to provide the output voltage supply level.