METHOD AND APPARATUS FOR SUPPLYING POWER

• US 20080211468A1
• Filed: 03/03/2007
• Published: 09/04/2008
• Est. Priority Date: 03/03/2007
• Status: Active Grant

• Current Assignee: Innovage LLC (Innovage)
• Original Assignee: Innovage LLC (Innovage)
• Inventors: Sadwick, Laurence P., Mojarradi, Mohammad M., Hwu, Ruey-Jen
• Granted Patent: US 7,782,644 B2
• Time in Patent Office: Days
• US Class Current: 323/272
• CPC Class Codes: H02M 3/335 using semiconductor devices only
• CPC Class Codes: H02M 7/12 using discharge tubes with control electrode or semiconductor devices with control electrode

Abstract

A power supply includes a power source having at least one power source output, and a plurality of drivers connected to the at least one power source output. At least one of the plurality of drivers includes a bridge network having a first switch, a second switch and a bridge network output. The first switch is connected between the at least one power source output and the bridge network output. The second switch is connected between the bridge network output and a ground. The bridge network further includes at least one control input connected to the second switch to direct electrical current from the at least one power source output either substantially through the bridge network output or through the second switch to ground.

Claims

1. A power supply, comprising:

a power source having at least one power source output; and

a plurality of drivers connected to said at least one power source output, at least one of said plurality of drivers comprising;

a bridge network comprising a first switch, a second switch and a bridge network output, said first switch connected between said at least one power source output and said bridge network output, said second switch connected between said bridge network output and a voltage reference node, said bridge network further comprising at least one control input connected to said second switch to direct electrical current from said at least one power source output either substantially through said bridge network output or through said second switch to said voltage reference node.

2. The power supply of claim 1, said voltage reference node comprising a ground.

3. The power supply of claim 1, said at least one of said plurality of drivers further comprising a current mirror connected to said at least one control input and a reference current source connected to said current mirror, wherein an electrical current through said second switch is proportionally controlled by a reference current from said reference current source, said at least one of said plurality of drivers further comprising a stealer switch connected between said at least one control input and said voltage reference node to digitally control said third switch.

4. The power supply of claim 3, further comprising a pulse width modulated control signal connected to said stealer switch.

5. The power supply of claim 1, wherein said bridge network is a full bridge network further comprising a third switch, a fourth switch and a second bridge network output, said third switch connected between said at least one power source output and said second bridge network output, said fourth switch connected between said second bridge network output and said voltage reference node, said bridge network further comprising at least one second control input connected to said fourth switch.

6. The power supply of claim 5, said power source comprising an alternating current source, said at least one of said plurality of drivers being envelope-driven driver wherein a waveform at said bridge network output tracks a waveform of said alternating current source.

7. The power supply of claim 6, said at least one power source output comprising first and second power source outputs, each 180 degrees out of phase from the other, wherein said first power source output is connected to said first switch and said second power source output is connected to said third switch.

8. The power supply of claim 1, said first and second switches each comprising a stack of switches, thereby dividing a potential across said first and second switches into a number of lower potentials across each switch in said stacks of switches.

9. The power supply of claim 1, further comprising a current detector connected between said second switch and said voltage reference node.

10. A method of driving current to an output, comprising:

generating an envelope waveform;

amplifying a voltage of said envelope waveform to generate a high voltage envelope and supplying said high voltage envelope to a bridge network driver;

switching a control input on said bridge network driver to either drive said high voltage envelope through said bridge network driver to said output or to turn off said output and direct a portion of said high voltage envelope to a voltage reference node through said bridge network driver, wherein said control input is operated by a lower voltage than said high voltage envelope.

11. The method of claim 10, said high voltage envelope having a voltage higher than about 100 volts and said lower voltage having a voltage lower than about 100 volts.

12. The method of claim 10, said voltage reference node comprising a ground.

13. The method of claim 10, wherein said control input is switched with a pulse width modulated signal to vary a duty cycle of said high voltage envelope being driven to said output.

14. The method of claim 10, said bridge network driver comprising a full bridge network, said method further comprising controlling a current level through said output by applying at least one reference current to said bridge network driver through at least one current mirror.

15. The method of claim 14, wherein said control input controls a first half of said full bridge network driver, said method further comprising switching a second control input to control a second half of said full bridge network, wherein current flows between said output from said first half and an output from said second half only when said one of said control input and said second control input is on and another is off.

16. The method of claim 14, further comprising measuring a current level through said full bridge network.

17. The method of claim 14, said controlling said current level comprising applying a first reference current to a first side of said full bridge network through a first current mirror and applying a second reference current to a to second side of said full bridge network through a second current mirror.

18. The method of claim 10, said bridge network driver comprising a half bridge network, said method further comprising controlling a current level through said output by applying a reference current to through a current mirror placed in series with a load connected to said output.

19. The method of claim 10, further comprising switching a plurality of control inputs to drive said high voltage envelope through a respective plurality of bridge network drivers.

20. A power supply comprising a power source and at least one bridge network driver, said at least one bridge network driver comprising:

a first transistor having an input connected to an output of said power source, an output connected to a driver output, and a control input connected to said power source output through a first resistor;

a diode connected at an anode to said first transistor output and at a cathode to said first transistor control input; and

a second transistor connected at an input to said diode cathode, at an output to a voltage reference node, and to a control signal at a control input.

21. The power supply of claim 20, said voltage reference node comprising a ground.

22. The power supply of claim 20, said power source comprising:

an oscillator;

a power source transistor having a control input connected to an output of said oscillator;

a transformer having a first winding connected between a power input and a voltage reference node, said power source transistor being connected in series between said power input and said ground with said first winding, said transformer having a second winding connected to said power source output.

23. The power supply of claim 22, said oscillator being selected from the group consisting of a 555 timer, a crystal, a phase locked loop, a logic oscillator, an operational amplifier oscillator, a Wein bridge, and a bridge oscillator.

24. The power supply of claim 22, said power source transistor being connected between said first winding and said power input to pull said first winding up to a potential of said power input, said power source further comprising a second power source transistor connected between said voltage reference node and a node between said first winding and said power source transistor to pull said first winding down to a potential of said voltage reference node, said power source further comprising an inverter having an input connected to said oscillator output and an output connected to said power source transistor control input and to a control input of said second power source transistor so that said power source transistor control input is connected to said oscillator output through said inverter.

25. The power supply of claim 22, said power source further comprising a full bridge rectifier connected across output terminals of said second winding.

26. The power supply of claim 22, said power source further comprising a direct current voltage supply connected in series with said second winding.

27. The power supply of claim 22, said power source further comprising a pulse width modulator to vary a duty cycle of said power source output.

28. The power supply of claim 22, said power source further comprising at least one diode having an anode connected to said second winding and a cathode connected to said power source output.

29. The power supply of claim 20, said diode comprising a Zener diode having a reverse breakdown voltage larger than the threshold of the first transistor.

30. The power supply of claim 20, said diode comprising a diode-connected transistor.

31. The power supply of claim 20, said bridge network driver further comprising at least one stacked transistor connected between said first transistor and said power source output, and at least one second stacked transistor connected between said second transistor and said diode cathode, said bridge network driver further comprising a gate resistor network connected in series between said power source output and said voltage reference node, said at least one stacked transistor and said at least one second stacked transistor having control inputs connected to nodes between resistors in said gate resistor network.

32. The power supply of claim 20, said at least one bridge network driver further comprising a second resistor connected between said second transistor output and said voltage reference node.

33. The power supply of claim 32, further comprising a current monitor connected to a node between said second transistor and said second resistor.

34. The power supply of claim 20, further comprising a voltage divider connected between said driver output and said voltage reference node and a current monitor connected to a midpoint in said voltage divider.

35. The power supply of claim 20, further comprising a second driver output and a current monitor connected between said second driver output and said voltage reference node, wherein a load may be connected between said driver output and said second driver output.

36. The power supply of claim 20, further comprising a current mirror transistor having an input connected to a reference current source, an output connected to said voltage reference node through a third resistor, and a control input connected to said second transistor control input and to said current mirror transistor input.

37. The power supply of claim 36, further comprising a stealer transistor having an input connected to said second transistor control input, an output connected to said voltage reference node and a control input connected to a digital control signal

38. The power supply of claim 20, wherein said bridge network driver comprises a full bridge network, said bridge network driver having a first half and a second half, said second half being a mirror image of said first half, said first half comprising at least said first and second transistors, said diode and said first resistor.

39. The power supply of claim 20, further comprising a second diode having an anode connected to a node between said diode cathode, said first transistor control input and said first resistor, said second diode having a cathode connected to said second transistor input.

40. The power supply of claim 32, further comprising a negative voltage protection diode connected between each of said at least one second stacked transistor.

41. The power supply of claim 40, further comprising a voltage divider network connected to nodes adjacent said at least one negative voltage protection diodes.