SYSTEM FOR DRIVING A LAMP

• US 20120032604A1
• Filed: 04/16/2010
• Published: 02/09/2012
• Est. Priority Date: 04/21/2009
• Status: Active Grant

• Current Assignee: Philips Lighting BV (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Hontele, Bertrand Johan Edward
• Granted Patent: US 8,847,519 B2
• Time in Patent Office: Days
• US Class Current: 315/201
• CPC Class Codes: H05B 45/14 using electrical feedback from LEDs or from LED modules
• CPC Class Codes: H05B 45/3725 Switched mode power supply [SMPS]

Abstract

A driver (10) for driving a LED (2) comprises:

• • an ACDC converter (5) receiving AC mains voltage and generating DC output current;
  • a chopper (6) receiving the DC output current and provide a regularly interrupted output current;
  • a clock generator (20) generating a clock signal (S_CL);
  • a controller (50) receiving a user input signal (S_U) indicating a dimming level, receiving the clock signal, receiving a mains signal (S_M) representing the actual phase of the mains voltage, and generating a control signal (S_C) for the chopper.

The chopper is responsive to the controller'"'"'s control signal as regards the switching moments of the output current.

The controller calculates the required duty cycle on the basis of the user input signal.

The controller synchronizes its control signal with the mains signal.

The controller sets an arbitrary value for the phase difference of the output control signal with respect to the input mains signal.

Claims

1. Illumination system comprising a plurality of LEDs with associated driver, each driver:

a power input for receiving AC mains voltage;

current source means for receiving the AC mains voltage and designed to provide a regularly interrupted output current having a current interruption frequency and a variable duty cycle;

a lamp output for connecting a light source;

a clock generator for generating a clock signal;

a controller, having a user input for receiving a user input signal indicating a desired dimming level, having a clock input coupled for receiving the clock signal from the clock generator, having a mains input coupled for receiving a mains signal representing the actual phase of the mains voltage at input, and having a control output for generating a control signal for the current source means;

wherein the current source means are responsive to the controller'"'"'s control signal as regards the switching moments of the output current;

wherein the controller is designed to calculate the required duty cycle on the basis of the user input signal;

and wherein the controller is designed to synchronize its control signal with the mains signal received at its mains input, wherein each controller is configured to set an arbitrary value for the phase difference of its output control signal with respect to the input mains signal.

3. The illumination system according to claim 1, wherein the controller configured to calculate the current interruption frequency at an arbitrary suitable value within a predetermined frequency range.

4. The illumination system according to claim 1, wherein the current source means comprise:

an ADC converter for receiving the AC mains voltage and designed to generate a DC output current;

a controllable chopper for receiving the DC output current from the ACDC converter and designed to provide a regularly interrupted output current having a variable duty cycle.

7. The illumination system of claim 3, wherein the predetermined frequency range is from 300 Hz to 3000 Hz.

8. The illumination system of claim 1, wherein the controller is configured calculate the current interruption frequency at a fixed predetermined frequency.

2. (canceled)

5-6. -6. (canceled)