CHARGING AN INPUT CAPACITOR OF A LOAD CONTROL DEVICE

• US 20140265897A1
• Filed: 03/14/2013
• Published: 09/18/2014
• Est. Priority Date: 03/14/2013
• Status: Active Grant

• Current Assignee: Lutron Technology Company LLC
• Original Assignee: Lutron Electronics Company Incorporated (Lutron Electronics)
• Inventors: Taipale, Mark, Blakeley, Matthew Robert, MacAdam, Russell L., Ross, Johnathan Paul
• Granted Patent: US 9,955,547 B2
• Time in Patent Office: Days
• US Class Current: 315/200.R
• CPC Class Codes: H02J 13/00004 characterised by the power network being locally controlled
• CPC Class Codes: H02J 13/00009 using pulsed signals
• CPC Class Codes: H02J 2310/12 The local stationary network supplying a household or a building
• CPC Class Codes: H05B 45/10 Controlling the intensity of the light
• CPC Class Codes: H05B 47/10 Controlling the light source
• CPC Class Codes: H05B 47/105 in response to determined parameters
• CPC Class Codes: H05B 47/11 by determining the brightness or colour temperature of ambient light
• CPC Class Codes: H05B 47/115 by determining the presence or movement of objects or living beings
• CPC Class Codes: H05B 47/165 following a pre-assigned programmed sequence; Logic control [LC]
• CPC Class Codes: H05B 47/18 via data-bus transmission
• CPC Class Codes: H05B 47/185 via power line carrier transmission
• CPC Class Codes: H05B 47/19 via wireless transmission
• CPC Class Codes: Y02B 20/40 Control techniques providing energy savings, e.g. smart controller or presence detection
• CPC Class Codes: Y02B 70/30 Systems integrating technologies related to power network operation and communication or information technologies for improving the carbon footprint of the management of residential or tertiary loads, i.e. smart grids as climate change mitigation technology in the buildings sector, including also the last stages of power distribution and the control, monitoring or operating management systems at local level
• CPC Class Codes: Y02B 90/20 Smart grids as enabling technology in buildings sector smart grids supporting the management or operation of end-user stationary applications in general, or like technologies with no associated climate change mitigation effect Y04S20/00
• CPC Class Codes: Y04S 20/246 the system involving the remote operation of lamps or lighting equipment
• CPC Class Codes: Y04S 40/121 using the power network as support for the transmission

Abstract

A load control device for controlling the amount of power delivered to an electrical load may include a rectifier circuit configured to receive a phase-control voltage and produce a rectified voltage. A power converter may be configured to receive the rectified voltage at an input and generate a bus voltage. An input capacitor may be coupled across the input of the power converter. The input capacitor may be adapted to charge when the magnitude of the phase control voltage is approximately zero volts. The power converter may be configured to operate in a boost mode, such that the magnitude of the bus voltage is greater than a peak magnitude of the input voltage. The power converter may be configured to operate in a buck mode to charge the input capacitor from the bus voltage when the magnitude of the phase-control voltage is approximately zero volts.

Claims

1. A load control device for controlling the amount of power delivered to an electrical load, the load control device comprising:

a rectifier circuit configured to receive a phase-control voltage and produce a rectified voltage;

a power converter configured to receive the rectified voltage at an input and generate a bus voltage; and

an input capacitor coupled across the input of the power converter;

wherein the input capacitor is adapted to charge when the magnitude of the phase-control voltage is approximately zero volts.

2. The load control device of claim 1, further comprising:

a power supply coupled to the input capacitor for charging the input capacitor when the magnitude of the phase-control voltage is approximately zero volts.

3. The load control device of claim 2, wherein the power supply is further configured to charge a supply capacitor to generate a supply voltage.

4. The load control device of claim 3, wherein the power supply is configured to cease charging the input capacitor when the magnitude of the rectified voltage across the input capacitor exceeds a predetermined threshold, and to charge the supply capacitor until the magnitude of the phase-control voltage is approximately zero volts at the end of the present half-cycle of the phase-control voltage.

5. The load control device of claim 4, wherein the power supply comprises a buck converter and a buck control circuit for controlling the operation of the buck converter.

6. The load control device of claim 5, wherein the power supply further comprises a feedback circuit operable to provide a feedback signal to the buck control circuit, the buck control circuit controlling the operation of the buck converter to charge the input capacitor when the magnitude of the phase-control voltage is approximately zero volts until the magnitude of the rectified voltage exceeds the predetermined threshold, and to charge the supply capacitor after the magnitude of the rectified voltage exceeds the predetermined threshold until the magnitude of the phase-control voltage is approximately zero volts at the end of the present half-cycle of the phase-control voltage.

7. The load control device of claim 6, wherein the magnitude of the feedback signal is representative of the magnitude of the supply voltage when the buck control circuit is charging the supply capacitor, and the magnitude of the feedback signal is representative of the magnitude of the rectified voltage when the buck control circuit is charging the input capacitor.

8. The load control device of claim 6, wherein the magnitude of the feedback signal is approximately equal the supply voltage when the buck control circuit is charging the supply capacitor, and the magnitude of the feedback signal is less than the magnitude of the supply voltage when the buck control circuit is charging the input capacitor.

9. The load control device of claim 2, further comprising:

a second power supply configured to charge a supply capacitor to generate a supply voltage.

10. The load control device of claim 1, wherein the power converter is configured to operate in a boost mode, such that the magnitude of the bus voltage is greater than a peak magnitude of the rectified voltage.

11. The load control device of claim 10, wherein the power converter is configured to operate in a buck mode to charge the input capacitor from the bus voltage when the magnitude of the phase-control voltage is approximately zero volts.

12. The load control device of claim 11, wherein the power converter is configured to operate in the boost mode when the magnitude of the phase-control voltage is greater than a predetermined threshold.

13. The load control device of claim 1, wherein the electrical load comprises a gas discharge lamp, and the load control device comprises an electronic ballast.

14. The load control device of claim 1, wherein the electrical load comprises an LED light source, and the load control device comprises an LED driver.

15. A load control device for controlling the amount of power delivered to an electrical load in response to a phase-control voltage, the load control device comprising:

a power converter configured to receive an input voltage at an input and generate a bus voltage, the power converter configured to operate in a boost mode, such that the magnitude of the bus voltage is greater than a peak magnitude of the input voltage; and

an input capacitor coupled across the input of the power converter;

wherein the power converter is configured to operate in a buck mode to charge the input capacitor from the bus voltage when the magnitude of the phase-control voltage is approximately zero volts.

16. The load control device of claim 15, wherein the power converter is configured to operate in the boost mode when the magnitude of the phase-control voltage is greater than a predetermined threshold.

17. A load control device for controlling the amount of power delivered to an electrical load in response to a phase-control voltage, the load control device comprising:

a power converter configured to receive an input voltage at an input and generate a bus voltage;

an input capacitor coupled across the input of the power converter; and

a power supply configured to receive the bus voltage and charge a supply capacitor to generate a supply voltage, the power supply further configured to charge the input capacitor when the magnitude of the phase-control voltage is approximately zero volts.

18. The load control device of claim 17, wherein the power supply is configured to cease charging the input capacitor when the magnitude of the input voltage exceeds a predetermined threshold, and to charge the supply capacitor until the magnitude of the phase-control voltage is approximately zero volts at the end of the present half-cycle of the phase-control voltage.

19. The load control device of claim 18, wherein the power supply comprises a buck converter and a buck control circuit for controlling the operation of the buck converter.

20. The load control device of claim 19, wherein the power supply further comprises a feedback circuit operable to provide a feedback signal to the buck control circuit, the buck control circuit controlling the operation of the buck converter to charge the input capacitor when the magnitude of the phase-control voltage is approximately zero volts until the magnitude of the input voltage exceeds the predetermined threshold, and to charge the supply capacitor after the magnitude of the input voltage exceeds the predetermined threshold until the magnitude of the phase-control voltage is approximately zero volts at the end of the present half-cycle of the phase-control voltage.

21. The load control device of claim 20, wherein the magnitude of the feedback signal is representative of the magnitude of the supply voltage when the buck control circuit is charging the supply capacitor, and the magnitude of the feedback signal is representative of the magnitude of the input voltage when the buck control circuit is charging the input capacitor.

22. The load control device of claim 20, wherein the magnitude of the feedback signal is approximately equal the supply voltage when the buck control circuit is charging the supply capacitor, and the magnitude of the feedback signal is less than the magnitude of the supply voltage when the buck control circuit is charging the input capacitor.