DC/DC converter with adaptive drive voltage supply

Abstract

A circuit comprises a first input for receiving a supply voltage and a second input for receiving a sensed current signal from an output of a DC to DC converter. The circuit also includes an output voltage for providing an adjustable drive voltage to a drive circuit. The circuit additionally includes circuitry for adjusting the drive voltage responsive to supply voltage and the sensed current signal.

What is claimed is: 
     
       1. A DC to DC converter circuit, comprising:
 a power stage for generating a regulated DC output voltage responsive to drive signals; 
 a driver circuit for generating the drive signals for power transistors in the power stage responsive to an adjustable supply voltage and drive control signals; 
 a controller for generating the drive control signals to the driver circuit responsive to a sensed current signal at least the regulated DC output voltage; 
 a current sensor for generating the a sensed current signal responsive to a sensed current in the power stage; 
 an adaptive drive voltage supply responsive to a supply voltage, the sensed current signal and a switching frequency of the power transistors in the power stage for generating the adjustable supply voltage. 
 
     
     
       2. The DC to DC converter circuit of  claim 1 , wherein the current sensor senses a load current of the power stage. 
     
     
       3. The DC to DC converter circuit of  claim 2 , wherein the adaptive drive voltage supply varies the adjustable supply voltage responsive to the sensed load current to improve an efficiency of the DC to DC converter circuit over a wide range of load currents. 
     
     
       4. The DC to DC converter circuit of  claim 1 , wherein the adaptive drive voltage supply adjusts the adjustable supply voltage responsive to a digital control signal. 
     
     
       5. The DC to DC converter circuit of the  claim 1 , wherein the adaptive drive voltage supply comprises a linear voltage regulator responsive to the supply voltage and the sensed current signal to linearly adjust the adjustable supply voltage between a first voltage responsive to a first sensed current signal and a second voltage responsive to a second sensed current signal. 
     
     
       6. The DC to DC converter circuit of  claim 1 , wherein the adaptive drive voltage supply comprises a switching voltage regulator responsive to the supply voltage and the sensed current signal to adjust the adjustable supply voltage. 
     
     
       7. The DC to DC converter circuit of  claim 1 , wherein the adaptive drive voltage supply comprises a plurality of adaptive drive voltage supplies, each of the plurality of adaptive drive voltage supplies providing a different adjustable supply voltage for a portion of the power transistors of the power stage. 
     
     
       8. A DC to DC converter circuit, comprising:
 a power stage for generating a regulated DC output voltage responsive to drive signals; 
 a driver circuit for generating the drive signals for power transistors in the power stage responsive to an adjustable supply voltage and drive control signals; 
 a controller for generating the drive control signals to the driver circuit responsive to a sensed current signal at least the regulated DC output voltage; 
 a current sensor for generating the a sensed current signal responsive to a sensed current in the power stage; 
 an adaptive drive voltage supply responsive to a supply voltage and the sensed current signal for generating the adjustable supply voltage, wherein the adaptive drive voltage supply comprises a plurality of adaptive drive voltage supplies, each of the plurality of adaptive drive voltage supplies providing a different adjustable supply voltage for a portion of the power transistors of the power stage. 
 
     
     
       9. The DC to DC converter circuit of  claim 8 , wherein the adaptive drive voltage supply adjusts the adjustable supply voltage responsive to a digital control signal. 
     
     
       10. The DC to DC converter circuit of  claim 8 , wherein the current sensor senses a load current of the power stage. 
     
     
       11. The DC to DC converter circuit of  claim 10 , wherein the adaptive drive voltage supply varies the adjustable supply voltage responsive to the sensed load current to improve an efficiency of the DC to DC converter circuit over a wide range of load currents. 
     
     
       12. The DC to DC converter circuit of  claim 8 , wherein the adaptive drive voltage supply is further responsive to a switching frequency of the power transistors in the power stage. 
     
     
       13. The DC to DC converter circuit of the  claim 8 , wherein the adaptive drive voltage supply comprises a linear voltage regulator responsive to the supply voltage and the sensed current signal to linearly adjust the adjustable supply voltage between a first voltage responsive to a first sensed current signal and a second voltage responsive to a second sensed current signal. 
     
     
       14. The DC to DC converter circuit of  claim 8 , wherein the adaptive drive voltage supply comprises a switching voltage regulator responsive to the supply voltage and the sensed current signal to adjust the adjustable supply voltage. 
     
     
       15. A DC to DC converter circuit, comprising:
 a power stage for generating a regulated DC output voltage responsive to drive signals; 
 a driver circuit for generating the drive signals for power transistors in the power stage responsive to an adjustable supply voltage and drive control signals; 
 a controller for generating the drive control signals to the driver circuit responsive to a sensed current signal at least the regulated DC output voltage; 
 a current sensor for generating the a sensed current signal responsive to a sensed current in the power stage; 
 an adaptive drive voltage supply responsive to a supply voltage and the sensed current signal for generating the adjustable supply voltage, wherein the adaptive drive voltage supply adjusts the adjustable supply voltage responsive to a digital control signal. 
 
     
     
       16. The DC to DC converter circuit of  claim 15 , wherein the current sensor senses a load current of the power stage. 
     
     
       17. The DC to DC converter circuit of the  claim 16 , wherein the adaptive drive voltage supply comprises a linear voltage regulator responsive to the supply voltage and the sensed current signal to linearly adjust the adjustable supply voltage between a first voltage responsive to a first sensed current signal and a second voltage responsive to a second sensed current signal. 
     
     
       18. The DC to DC converter circuit of  claim 16 , wherein the adaptive drive voltage supply varies the adjustable supply voltage responsive to the sensed load current to improve an efficiency of the DC to DC converter circuit over a wide range of load currents. 
     
     
       19. The DC to DC converter circuit of  claim 16 , wherein the adaptive drive voltage supply is further responsive to a switching frequency of the power transistors in the power stage.