FOLLOW
1 Reviews   |   583 Views   |   1 Followers

Controller for a Phase Cut Dimmable LED Driver

Patent

US9883560

Owner

OSRAM GmbH

Filing Date

September 25, 2015

Priority Date

September 25, 2015

Portfolio

Lighting - OSRAM

Intro

A particular challenge with regard to LED lamp drivers is using them with a phase cut dimmer. A phase cut dimmer cuts off a portion of each cycle of the alternating current from the main voltage supply. The invention uses a control algorithm that measures phase cut and zero crossing angles of the input mains waveform, and to maintain constant LED current commensurate with a user-set dimming level.

Claims

1. A method for control of a phase cut dimmer for lighting systems, the method comprising: receiving, at a controller of a lighting driver circuit, a ...
  1. A method for control of a phase cut dimmer for lighting systems, the method comprising: receiving, at a controller of a lighting driver circuit, a representation of an input voltage waveform having a phase cut angle (φcut) and a waveform zero angle (φzero), as well as a known frequency; acquiring, by the controller, data representative of a period of the waveform; determining, by the controller, a plurality of Fourier series coefficients associated with the waveform; extracting, by the controller, the phase cut angle (φcut) and the waveform zero angle (φzero) based on the coefficients; determining, by the controller, a current for one or more light emitting diodes (LEDs) based on at least one of the phase cut angle (φcut) and the waveform zero angle (φzero); and adjusting, by the controller, a duty cycle of a pulse width modulation (PWM) signal to provide the determined current to the one or more LEDs.
  2. The method of claim 1 wherein determining a plurality of Fourier series coefficients associated with the period comprises determining the two lowest order Fourier series coefficients (0th and 1st) associated with the waveform.
  3. The method of claim 1, further comprising: storing the data representative of the waveform period.
  4. The method of claim 1 wherein acquiring data representative of a period of the waveform comprise acquiring data representative of one period of the waveform.
  5. The method of claim 1 wherein extracting the phase cut angle (φcut) and the waveform zero angle (φzero) based on the coefficients comprises extracting the phase cut angle (φcut) and the waveform zero angle (φzero) through inversion of an analytical representation of the coefficients, the inversion comprising: determining the values of cos(φcut) and sin(φcut); and determining the value of the waveform zero angle φzero based on cos(φcut) and sin(φcut).
  6. FURTHER CLAIMS IN PATENT DOCUMENT 
read more

Abstract

A control scheme for a dimmable lighting driver is provided. The control scheme may operate with a phase cut type dimmer (leading or trailing edge). I...
A control scheme for a dimmable lighting driver is provided. The control scheme may operate with a phase cut type dimmer (leading or trailing edge). In an embodiment, the control scheme is programmed or otherwise configured into a controller as a control algorithm. The control algorithm is configured to measure phase cut and zero crossing angles of the input mains waveform, and to subsequently maintain constant LED current commensurate with a user-set dimming level, with no flicker. The control algorithm may be implemented in software, such as a firmware-based routine executable by one or more controllers of a given driver. The one or more controllers may be, for example, an existing general purpose controller of the given driver, or a dedicated dimming controller. Numerous configurations will be apparent in light of this disclosure.
read more
Write Review

Here are the reviews from the crowd!

Rating categories
WOW!
GOTCHA!
DEAL!
Where should the donation go to?
Timsta
June 18, 2018

I would like to see the hardwear at a much bigger scale.

LIKE       COMMENT


Rate the patent & write your own review!

Rating categories
WOW!
GOTCHA!
DEAL!
Where should our donation go to?
Your review
Write about potential applications
Write about potentially interested companies
Choose a name

Convinced about the patent? Contact us!

Your bid
Your e-mail
Your message