Driver for switch and a method of driving the same

1. A driver for a switch, comprising:

switching circuitry having a driver switch referenced to a voltage level and configured to provide a drive signal to a control terminal of said switch referenced to another voltage level and subject to a control voltage limit; and

a comparator and a combinatorial logic gate configured to:

disable conduction of said driver switch when a voltage at said control terminal passes a threshold voltage to limit said drive signal within said control voltage limit of said switch, wherein said control voltage limit of said switch is less than a difference between said another voltage level and said voltage level, and

enable conduction of said driver switch to pull down said control terminal of said switch.

2. The driver as recited in claim 1 wherein said threshold voltage is referenced to said another voltage level.

3. The driver as recited in claim 1 wherein said switching circuitry is configured to turn on said switch in response to a high control signal.

4. The driver as recited in claim 1 wherein said drive signal is a function of a signal to control a duty cycle of said switch and said driver further comprises an operational amplifier and level translator configured to reference said signal to control said duty cycle of said switch to said another voltage.

5. The driver as recited in claim 1 wherein said comparator and said combinatorial logic gate are configured to disable conduction of said driver switch when said voltage at said control terminal of said switch is less than said threshold voltage.

6. The driver as recited in claim 1 wherein said switching circuitry includes another driver switch configured to provide a drive signal to another switch series-coupled with said switch, said drive signal for said another switch being provided with sufficient dead time to prevent a shoot-through current from said switches.

7. The driver as recited in claim 1 wherein said combinatorial logic gate is an AND gate or a NOR gate.

8. A method of driving a switch, comprising:

providing a drive signal to a control terminal of said switch with switching circuitry having a driver switch referenced to a voltage level, said switch being referenced to another voltage level and subject to a control voltage limit;

disabling conduction of said driver switch with a comparator and a combinatorial logic gate when a voltage at said control terminal passes a threshold voltage to limit said drive signal within said control voltage limit of said switch, wherein said control voltage limit of said switch is less than a difference between said another voltage level and said voltage level; and

enabling conduction of said driver switch with said comparator and combinatorial logic to pull down said control terminal of said switch.

9. The method as recited in claim 8 wherein said threshold voltage is referenced to said another voltage level.

10. The method as recited in claim 8 further comprising turning on said switch in response to a high control signal.

11. The method as recited in claim 8 wherein said drive signal is a function of a signal to control a duty cycle of said switch and said method further comprises referencing said signal to control said duty cycle of said switch to said another voltage.

12. The method as recited in claim 8 further comprising disabling conduction of said driver switch with said comparator and combinatorial logic when said voltage at said control terminal of said switch is less than said threshold voltage.

13. The method as recited in claim 8 wherein said switching circuitry includes another driver switch that provides a drive signal to another switch series-coupled with said switch, said drive signal for said another switch being provided with sufficient dead time to prevent a shoot-through current from said switches.

14. The method as recited in claim 8 wherein said combinatorial logic gate is an AND gate or a NOR gate.

15. A power converter couplable to a source of electrical power adapted to provide an input voltage thereto, comprising:

a power train including a power switch, referenced to said input voltage and subject to a control voltage limit, configured to conduct for a duty cycle and provide a regulated output characteristic at an output of said power converter;

a controller configured to provide a signal to control said duty cycle of said power switch; and

a driver configured to provide a drive signal as a function of said signal to control said duty cycle of said power switch, including:

switching circuitry having a driver switch referenced to a voltage level different from said input voltage level and configured to provide said drive signal to a control terminal of said power switch, and

a comparator and a combinatorial logic gate configured to:

disable conduction of said driver switch when a voltage at said control terminal passes a threshold voltage to limit said drive signal within said control voltage limit of said switch, wherein said control voltage limit of said switch is less than a difference between said input voltage level and said voltage level, and

enable conduction of said driver switch to pull down said control terminal of said power switch.

16. The power converter as recited in claim 15 wherein said combinatorial logic gate is an AND gate or a NOR gate.

17. The power converter as recited in claim 15 wherein said switching circuitry is configured to turn on said power switch in response to a high control signal.

18. The power converter as recited in claim 15 wherein said driver further includes an operational amplifier and level translator configured to reference said signal to control said duty cycle of said switch to said input voltage.

19. The power converter as recited in claim 15 wherein said comparator and said combinatorial logic gate are configured to disable conduction of said driver switch when said voltage at said control terminal of said power switch is less than said threshold voltage.

20. The power converter as recited in claim 15 wherein said switching circuitry includes another driver switch configured to provide a drive signal to another power switch series-coupled with said power switch, said drive signal for said another power switch being provided with sufficient dead time to prevent a shoot-through current from said power switches.