AUXILIARY POWER SUPPLY FOR LIGHTING DRIVER CIRCUITRY

• US 20140361623A1
• Filed: 01/21/2013
• Published: 12/11/2014
• Est. Priority Date: 01/20/2012
• Status: Active Grant

• Current Assignee: OSRAM Sylvania Inc. (Ams-Osram AG)
• Original Assignee: OSRAM Sylvania Inc. (Ams-Osram AG)
• Inventors: Siessegger, Bernhard, Coleman, Colin
• Granted Patent: US 9,859,812 B2
• Time in Patent Office: Days
• US Class Current: 307/64
• CPC Class Codes: G01R 31/2635 Testing light-emitting diodes, laser diodes or photodiodes
• CPC Class Codes: G01R 31/40 Testing power supplies testing photovoltaic devices H02S50/10
• CPC Class Codes: G01R 31/44 Testing lamps
• CPC Class Codes: G01R 31/64 Testing of capacitors
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48227 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 25/167 comprising optoelectronic devices, e.g. LED, photodiodes
• CPC Class Codes: H01L 27/156 two-dimensional arrays
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/12032 Schottky diode
• CPC Class Codes: H01L 2924/12044 OLED
• CPC Class Codes: H01L 2924/1301 Thyristor
• CPC Class Codes: H01L 2924/13033 TRIAC - Triode for Alternating Current - A bidirectional switching device containing two thyristor structures with common gate contact
• CPC Class Codes: H01L 2924/1305 Bipolar Junction Transistor [BJT]
• CPC Class Codes: H01L 2924/13091 Metal-Oxide-Semiconductor Field-Effect Transistor [MOSFET]
• CPC Class Codes: H01L 33/62 Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls
• CPC Class Codes: H02M 1/0006 Arrangements for supplying an adequate voltage to the control circuit of converters
• CPC Class Codes: H02M 1/0045 : Converters combining the concepts of switch-mode regulation and linear regulation, e.g. linear pre-regulator to switching converter, linear and switching converter in parallel, same converter or same transistor operating either in linear or switching mode
• CPC Class Codes: H02M 1/15 : using active elements
• CPC Class Codes: H02M 1/4208 : Arrangements for improving power factor of AC input
• CPC Class Codes: H02M 1/4258 : using a single converter stage both for correction of AC input power factor and generation of a regulated and galvanically isolated DC output voltage H02M1/4241 takes precedence
• CPC Class Codes: H02M 1/44 : Circuits or arrangements for compensating for electromagnetic interference in converters or inverters
• CPC Class Codes: H02M 3/156 : with automatic control of output voltage or current, e.g. switching regulators
• CPC Class Codes: H02M 3/335 : using semiconductor devices only
• CPC Class Codes: H02M 7/06 : using discharge tubes without control electrode or semiconductor devices without control electrode
• CPC Class Codes: H02S 50/00 : Monitoring or testing of PV systems, e.g. load balancing or fault identification
• CPC Class Codes: H05B 45/00 : Circuit arrangements for operating light-emitting diodes [LED]
• CPC Class Codes: H05B 45/10 : Controlling the intensity of the light
• CPC Class Codes: H05B 45/20 : Controlling the colour of the light
• CPC Class Codes: H05B 45/37 : Converter circuits
• CPC Class Codes: H05B 45/395 : Linear regulators
• CPC Class Codes: H05B 45/40 : Details of LED load circuits
• CPC Class Codes: H05B 45/48 : having LEDs organised in strings and incorporating parallel shunting devices
• CPC Class Codes: H05B 45/58 : involving end of life detection of LEDs
• CPC Class Codes: Y02B 20/30 : Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]
• CPC Class Codes: Y02B 70/10 : Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
• CPC Class Codes: Y02E 10/50 : Photovoltaic [PV] energy

Abstract

Techniques for supplying auxiliary power to lighting driver circuitry are disclosed. An auxiliary power supply can be used, for example, to provide auxiliary power to a current source that drives an LED string. In some embodiments, the LED string is effectively used as a series resistor to charge a capacitor that provides the auxiliary voltage V_aux. As soon as the capacitor is charged to a given threshold, the LED string can be disconnected from the capacitor and the current through the LED string bypasses the auxiliary supply circuit. Thus, the current source provides a current through the LED string, which in turn may be selectively fed to the auxiliary power supply to provide auxiliary power back to the current source or to provide auxiliary power to other circuitry.

Claims

1. A lighting driver circuit, comprising:

a current source configured to control a current through at least one lighting element; and

an auxiliary power supply configured to selectively receive the current so as to charge the auxiliary power supply with the current and provide auxiliary power to a secondary circuit.

2. The lighting driver circuit of claim 1, wherein the secondary circuit comprises at least one of the current source, driver control circuitry, and/or a motor.

3. The lighting driver circuit of claim 1 wherein the auxiliary power supply comprises:

a capacitor;

at least one diode whose anode is connected to receive the current and whose cathode is connected to the capacitor; and

a first switch connected to the anode of the diode, and when the first switch is closed it prevents the auxiliary power supply from receiving the current.

4. The lighting driver circuit of claim 3, further comprising a linear voltage regulator connected between the cathode of the diode and the secondary circuit.

5. The lighting driver circuit of claim 3, further comprising a controller configured to control the first switch based on the voltage at the cathode of the diode.

6. The lighting driver circuit of claim 5, wherein the first switch is a normally-off switch, and the controller is configured to close the first switch when the voltage on the cathode of the diode reaches an upper threshold voltage value, and to open the first switch when the voltage on the cathode of the diode falls below a lower threshold voltage value.

7. The lighting driver circuit of claim 5, further comprising a second switch located between the capacitor and the secondary circuit.

8. The lighting driver circuit of claim 7, wherein the second switch is a normally-off switch, and the controller is configured to close the second switch when the voltage on the cathode of the diode reaches an upper threshold voltage value.

9. The lighting driver circuit of claim 8, wherein the second switch is configured to remain closed throughout remaining circuit operation time after the upper threshold voltage value is reached.

10. The lighting driver circuit of claim 1, wherein the current source comprises at least one of a boost converter and/or a buck converter.

11. The lighting driver circuit of claim 1, further comprising at least one lighting element, wherein the at least one lighting element comprises an LED string.

12. The lighting driver circuit of claim 1, further comprising at least one lighting element, wherein the at least one lighting element comprises a plurality of LEDs, and further comprising at least one normally-off switch connected in parallel to sub-groups of the LEDs.

13. A method of creating auxiliary power in a lighting circuit, comprising:

controlling a current through at least one lighting element with a current source;

selectively directing the current through the at least one lighting element to an auxiliary power supply so as to charge the auxiliary power supply with the current; and

providing auxiliary power to a secondary circuit from the auxiliary power supply.

14. The method of claim 13, wherein selectively directing the current comprises directing the current through a diode to a node connecting the cathode of the diode with a capacitor and an auxiliary power input of the secondary circuit.

15. The method of claim 14, further comprising reducing voltage ripple between the cathode of the diode and the secondary circuit using at least one linear voltage regulator.

16. The method of claim 14, wherein selectively directing the current comprises controlling a first switch to prevent the auxiliary power supply from receiving the current when the voltage on the capacitor reaches an upper threshold voltage, and allowing the auxiliary power supply to receive the current when the voltage on the capacitor falls below a lower threshold voltage.

17. The method of claim 16, wherein selectively directing the current further comprises charging the capacitor upon startup by maintaining open a second switch, located between the capacitor and the secondary circuit, until the voltage on the capacitor reaches the upper threshold voltage, and closing the second switch when the upper threshold voltage is reached.

18. The method of claim 16, wherein the first switch is synchronized with the voltage at the input of the current source.

19. The method of claim 16, wherein the condition of the first switch is communicated to control circuitry of the lighting driver circuit.

20. The method of claim 19, wherein the control circuitry of the lighting driver circuit takes the voltage drop across the auxiliary power supply into consideration when controlling the lighting driver.

21-25. -25. (canceled)