Multiple output power supply

• US 8,564,155 B2
• Filed: 05/06/2010
• Issued: 10/22/2013
• Est. Priority Date: 05/06/2009
• Status: Active Grant

• Current Assignee: Polar Semiconductor, LLC (Sanken Electric Co., Ltd.)
• Original Assignee: Polar Semiconductor, Inc. (Sanken Electric Company Limited)
• Inventors: Wibben, Josh
• Primary Examiner(s): KAPLAN, HAL IRA
• Application Number:
  US12/800,094
• Publication Number:
  US 20100283322A1
• Time in Patent Office: 1,265 Days
• Field of Search: None
• US Class Current: 307/31
• CPC Class Codes: H02M 1/009 having two or more independently controlled outputs for DC-DC converter with intermediate AC H02M3/33561
• CPC Class Codes: H02M 3/158 including plural semiconductor devices as final control devices for a single load
• CPC Class Codes: H05B 45/327 Burst dimming
• CPC Class Codes: H05B 45/3725 Switched mode power supply [SMPS]
• CPC Class Codes: H05B 45/375 using buck topology
• CPC Class Codes: H05B 45/38 using boost topology
• CPC Class Codes: H05B 45/382 with galvanic isolation between input and output
• CPC Class Codes: H05B 45/385 using flyback topology
• CPC Class Codes: H05B 45/39 Circuits containing inverter bridges
• CPC Class Codes: H05B 45/46 having LEDs disposed in parallel lines

Abstract

A method is provided for supplying power to multiple output channels. Channel control signals are monitored to determine a state for each of the output channels. Each channel control signal is associated with one of the output channels. The energy in a storage element is directed to output channels according to the state of the channel control signals.

Claims

1. A method for supplying energy to multiple output channels, the method comprising:

storing energy from an energy source in a storage element of a current supplying circuit;

monitoring a plurality of channel control signals to determine a state for each of the output channels where each channel control signal is associated with one of the multiple output channels; and

operating a plurality of channel switches, each associated with one of the multiple output channels, to direct a current from the energy stored in the storage element from a common node to the output channels which have states that require energy one output channel at a time.

2. The method of claim 1 further comprising storing energy from the energy source in the storage element while directing the current from the energy stored in the storage element to one of the output channels that has a state that requires energy.

3. The method of claim 2 wherein directing the current from the energy stored in the storage element to the output channel comprises directing a controlled current to the output channel based on the state of the channel control signal associated with the output channel.

4. The method of claim 2 wherein the storage element is an inductor.

5. The method of claim 4 wherein directing the current from the energy stored in the inductor comprises using a power supply topology selected from the group consisting of:

a boost mode single inductor multiple output (SIMO) power supply, a flyback SIMO power supply, a forward SIMO power supply, buck SIMO power supply, a buck-boost SIMO power supply, and a single ended primary inductor converter (SEPIC).

6. The method of claim 1 wherein monitoring the plurality of channel control signals includes monitoring a plurality of channel enable signals to determine if an output channel requires energy, where each channel enable signal is associated with one of the multiple output channels.

7. The method of claim 1 wherein monitoring a plurality of channel control signals includes monitoring a plurality of analog dimming magnitude inputs.

8. The method of claim 1 wherein monitoring the plurality of channel control signals includes a method of monitoring a channel control signal selected from the group consisting of:

reading a digital serial interface, reading a pulse width modulation interface, reading a digital input interface, reading an analog input interface, and reading commands from a pre-programmed internal controller.

9. The method of claim 1 wherein at least one of the multiple output channels comprises a string of LEDs.

10. The method of claim 9 wherein the channel control signals comprise pulse width modulation commands for dimming the string of LEDs.

11. The method of claim 1 further comprising storing energy in the storage element once for each output channel that has a state that requires energy.

12. The method of claim 11 further comprising:

directing current from all of the energy in the storage element to at least one of the output channels until it is empty; and

waiting for an idle period where the storage element remains empty before storing energy in the storage element for a next output channel that has a state that requires energy.

13. The method of claim 11 further comprising:

maintaining energy in the storage element during a freewheel period before storing energy in the storage element for a next output channel that has a state that requires energy.

14. The method of claim 1 further comprising storing energy in the storage element once for all output channels that have states that require energy.

15. A method for supplying energy to multiple output channels comprising:

monitoring a plurality of channel control signals to determine a state for each of the output channels;

connecting a single energy storage element to each output channel at a common node to provide a current to each output channel one channel at a time; and

delivering the current from the single energy storage element from the common node to the output channels according to each output channel'"'"'s associated channel control signal.

16. The method of claim 15 wherein connecting the single energy storage element to each output channel comprises connecting the single energy storage element to each output channel independently.

17. The method of claim 15 further comprising charging the single energy storage element once for all of the output channels and providing the current to each output channel by discharging the single energy storage element to the output channels according to their associated channel control signals one channel at a time.

18. The method of claim 17 further comprising providing the current to each output channel by discharging the single energy storage element completely before charging the single energy storage element for a next output channel.

19. The method of claim 17 further comprising maintaining a charge in the single energy storage element during a freewheel period between discharging the single energy storage element to the output channels.

20. The method of claim 15 further comprising charging the single energy storage element once for each output channel that has an associated channel control signal that indicates energy is required and providing the current by discharging the single energy storage element to the output channel.

21. The method of claim 20 further comprising discharging the single energy storage element completely before a next charging cycle.

22. The method of claim 20 further comprising maintaining a charge in the single energy storage element during a freewheel period before a next charging cycle.

23. The method of claim 15 wherein the single energy storage element is an inductor.

24. The method of claim 15 further comprising:

monitoring a second plurality of channel control signals to determine a state for a second plurality of the output channels;

connecting a second energy storage element to each of the second plurality of output channels at a second common node to provide a second current to each of the second plurality of output channels one channel at a time; and

delivering the second current from the second energy storage element from the second common node to the output channels according to each output channel'"'"'s associated channel control signal.

25. The method of claim 15 wherein delivering the current from the single energy storage element further comprises delivering energy from an energy source to the output channels according to each output channel'"'"'s associated control signal.

26. The method of claim 15 wherein at least one of the output channels comprises a string of LEDs.

27. The method of claim 26 wherein the channel control signals comprise pulse width modulation commands for dimming the string of LEDs.

28. A circuit for supplying energy to multiple output channels comprising:

a current supplying circuit having an output connected to a common node and including a switch for controlling energy in a storage element;

a plurality of channel switches for directing a current from the energy in the storage element from the common node to an output channel associated with a respective channel switch;

a plurality of channel control inputs each associated with an output channel indicating a state for the output channel; and

a controller adapted to receive the plurality of channel control inputs and operate the switch and the plurality of channel switches to independently deliver the current to the output channels associated with channel control inputs according to the state of the output channel.

29. The circuit of claim 28 where the state indicates an on/off condition for the output channel.

30. The circuit of claim 28 where the state indicates an amount of current to be delivered to the output channel.

31. The circuit of claim 28 wherein the channel control inputs are channel enable inputs and the controller is adapted to receive the plurality of channel enable inputs and operate the switch and the plurality of channel switches to deliver the current from the energy in the storage element to the output channels associated with channel enable inputs that indicate that the output channel is enabled.

32. The circuit of claim 28 wherein the channel control inputs are analog dimming magnitude inputs and the controller is adapted to receive the analog dimming magnitude inputs and operate the switch and the plurality of channel switches to deliver the current from the energy in the storage element to the output channels according to an analog dimming magnitude indicated by the analog dimming magnitude inputs.

33. The circuit of claim 28 wherein the storage element is an inductor.

34. The circuit of claim 28 further comprising a power supply topology that includes the inductor selected from the group consisting of:

a boost mode SIMO power supply, a flyback SIMO power supply, a forward SIMO power supply, a buck SIMO power supply, a buck-boost mode SIMO power supply, and a single ended primary inductor converter (SEPIC).

35. The circuit of claim 28 wherein the plurality of channel control inputs is selected from the group consisting of:

a digital serial interface, a PWM interface, a digital input interface an analog input interface, and a pre-programmed internal controller interface.

36. The circuit of claim 28 further comprising a freewheel switch operated by the controller and adapted to sustain the energy in the storage element.

37. The circuit of claim 28 wherein at least one of the multiple output channels comprises a string of LEDs.

38. The circuit of claim 37 wherein the channel control inputs receive pulse width modulation commands used to dim the string of LEDs.

39. The circuit of claim 28 wherein the controller is adapted to operate the switch and the plurality of channel switches to deliver the current from the energy stored in the storage element and energy from an energy source to the output channels according to the state of the output channels.