Auto-Sensing Switching Regulator to Drive A Light Source Through A Current Regulator

• US 20120068626A1
• Filed: 09/22/2010
• Published: 03/22/2012
• Est. Priority Date: 09/22/2010
• Status: Active Grant

• Current Assignee: ABL IP Holding LLC (Acuity Brands, Inc.)
• Original Assignee: OSRAM Sylvania Inc. (Ams-Osram AG)
• Inventors: Antony, Biju, Lekatsas, Nicholas
• Granted Patent: US 8,531,131 B2
• Time in Patent Office: Days
• US Class Current: 315/307
• 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 45/385 using flyback topology
• CPC Class Codes: Y02B 20/30 Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

Abstract

An auto-sensing switching regulator, and systems and methods including same, is disclosed. The auto-sensing switching regulator includes a switching regulator and a controller coupled thereto. The controller is configured to provide a control signal to the switching regulator to increase the output voltage while receiving a current sense signal representative of a current output of the switching regulator, and to provide the control signal in response to the current sense signal to set the output voltage at a set value corresponding to a value at which the current output stops increasing with an increase in the output voltage. A system to drive a light source includes a current regulator configured to provide a constant current output to the light source and an auto-sensing switching regulator coupled to the current regulator, and configured to receive an input voltage from a voltage supply and provide an output voltage to the current regulator.

Claims

1. A system to drive a light source, the system comprising:

a current regulator configured to provide a constant current output to the light source; and

an auto-sensing switching regulator coupled to the current regulator, and configured to receive an input voltage from a voltage supply and provide an output voltage to the current regulator, the auto-sensing switching regulator comprising;

a switching regulator; and

a controller coupled to the switching regulator, the controller being configured to provide a control signal to the switching regulator to increase the output voltage while receiving a current sense signal representative of a current output of the switching regulator, the controller being configured to provide the control signal in response to the current sense signal to set the output voltage at a set value corresponding to a value at which the current output stops increasing with an increase in the output voltage.

2. A system according to claim 1, wherein the controller is further configured to provide the control signal to reduce the output voltage from the set value and then increase the output voltage while receiving the signal representative of the current output, the controller being configured to provide the control signal to set the output voltage at a second set value corresponding to a second value at which the current output stops increasing with an increase in the output voltage.

3. A system according to claim 1, wherein the set value is the same as the value at which the current output stops increasing with an increase in the output voltage.

4. A system according to claim 1, wherein the set value is a different value than the value at which the current output stops increasing with an increase in the output voltage.

5. A system according to claim 1, wherein the set value is approximately equal to a forward voltage drop from an output of the auto-sensing switching regulator through the light source.

6. A system according to claim 1, wherein the controller is configured to receive a voltage sense signal representative of the voltage output, and wherein the controller is configured to provide the control signal to set the output voltage at the set value in response to the current sense signal and the voltage sense signal.

7. A system according to claim 6, wherein the controller is configured to store a value of the voltage sense signal corresponding to a value at which the current sense signal stops increasing with increasing values of the voltage sense signal, and wherein the set value is a voltage value corresponding to the stored value of the voltage sense signal.

8. A system according to claim 1, wherein the light source comprises at least one solid state light source.

9. An auto-sensing switching regulator to receive a voltage input from a voltage supply and to provide an output voltage to a current regulator configured to provide a constant current output to a light source, the auto-sensing switching regulator comprising:

a switching regulator; and

a controller coupled to the switching regulator, the controller being configured to provide a control signal to the switching regulator to increase the output voltage while receiving a current sense signal representative of a current output of the switching regulator, the controller being configured to provide the control signal in response to the current sense signal to set the output voltage at a set value corresponding to a value at which the current output stops increasing with an increase in the output voltage.

10. An auto-sensing switching regulator according to claim 9, wherein the controller is further configured to provide the control signal to reduce the output voltage from the set value and then increase the output voltage while receiving the signal representative of the current output, the controller being configured to provide the control signal to set the output voltage at a second set value corresponding to a second value at which the current output stops increasing with an increase in the output voltage.

11. An auto-sensing switching regulator according to claim 9, wherein the set value is the same as the value at which the current output stops increasing with an increase in the output voltage.

12. An auto-sensing switching regulator according to claim 9, wherein the set value is a different value than the value at which the current output stops increasing with an increase in the output voltage.

13. An auto-sensing switching regulator according to claim 9, wherein the set value is approximately equal to a forward voltage drop from an output of the auto-sensing switching regulator through the light source.

14. An auto-sensing switching regulator according to claim 9, wherein the controller is configured to receive a voltage sense signal representative of the voltage output, and wherein the controller is configured to provide the control signal to set the output voltage at the set value in response to the current sense signal and the voltage sense signal.

15. An auto-sensing switching regulator according to claim 14, wherein the controller is configured to store a value of the voltage sense signal corresponding to a value at which the current sense signal stops increasing with increasing values of the voltage sense signal, and wherein the set value is a voltage value corresponding to the stored value of the voltage sense signal.

16. A method of improving efficiency of a system including a current regulator to drive a light source, the method comprising:

monitoring a current output to the current regulator while increasing an output voltage to the current regulator; and

setting the output voltage at a set value corresponding to a value at which the current output stops increasing with an increase in the output voltage.

17. A method according to claim 16, the method further comprising:

reducing the output voltage from the set value and then increasing the output voltage while monitoring the current output; and

setting the output voltage at a second set value corresponding to a second value at which the current output stops increasing with an increase in the output voltage.

18. A method according to claim 16, wherein the set value is the same as the value at which the current output stops increasing with an increase in the output voltage.

19. A method according to claim 16, wherein the set value is a different value than the value at which the current output stops increasing with an increase in the output voltage.

20. A method according to claim 16, wherein the set value is approximately equal to a forward voltage drop from an output of the auto-sensing switching regulator through the light source.