Method and circuit arrangement for operating light-emitting means, with beat avoidance

Patent metadata

Field	Value
Publication number	US-9155144-B2
Application number	US-201214368279-A
Country	US
Kind code	B2
Filing date	Dec 20, 2012
Priority date	Dec 23, 2011
Publication date	Oct 6, 2015
Grant date	Oct 6, 2015

Abstract

The invention relates to an operating circuit for illuminants, in particular one or more LED sections ( 17 ), comprising an actively clocked PFC circuit ( 11 ), which can be supplied by an AC voltage (U AC ) and optionally also a DC voltage (U DC ) and the output voltage of which is directly or indirectly supplied through the illuminant ( 17 ) to a unit ( 19 ) for generating a PWM-modulated current. The operating circuit also has a control unit ( 16 ) that detects a residual ripple in the voltage (U PFC ) in the supply chain before ( 18 a ), in ( 18 b ) or after ( 18 c ) the PFC circuit ( 11 ) and causes the frequency of the PWM modulation of the current through the illuminant ( 17 ) to be selected as a function of the frequency of the residual ripple.

First claim

What is claimed is:

1. An operating circuit for light-emitting means comprising:
an actively clocked power factor correction (PFC) circuit ( 11 ) which can be supplied originating from an AC voltage (U AC ) and optionally also a DC voltage (U DC ), the output voltage (U PFC ) of said PFC circuit being supplied directly or indirectly to a unit ( 19 ) for generating a pulse width modulation (PWM)-modulated current through the light-emitting means ( 17 ),
a control unit ( 16 ), which detects a residual ripple in the voltage (U PFC ) in the supply chain upstream of, in or downstream of the PFC circuit ( 11 ) and initiates that a frequency of the PWM modulation of the current through the light-emitting means ( 17 ) is selected depending on a frequency of the residual ripple, wherein the control unit ( 16 ) is further configured to implement detection of an AC voltage (UAC) and a DC voltage (UDC) and to thereby distinguish between a normal operating mode and an emergency operating mode.

2. The operating circuit as claimed in claim 1 , wherein the control unit ( 16 ) determines the frequency of the PWM modulation such that the frequency of the PWM modulation is an integral multiple of the frequency of the AC voltage (U AC ).

3. The operating circuit as claimed in claim 2 , wherein the control unit ( 16 ) determines the frequency of the PWM modulation such that the frequency of the PWM modulation differs by at least 20 Hz from a frequency of a control loop of the PFC circuit and integral multiples of the frequency of the control loop of the PFC circuit ( 11 ).

4. The operating circuit as claimed in claim 1 , wherein the control unit ( 16 ) determines the frequency of the PWM such that the frequency of the PWM modulation is the frequency of a control loop of the PFC circuit ( 11 ).

5. The operating circuit as claimed in claim 4 , wherein the control unit ( 16 ) determines the frequency of the PWM modulation such that the frequency of the PWM modulation differs by at least 20 Hz from integral multiples of the frequency of the AC voltage (U AC ).

6. The operating circuit as claimed in claim 1 , wherein the control unit ( 16 ) is connected to a control input of the PFC circuit ( 11 ), said control input makes it possible to set the frequency of a control loop of the PFC circuit ( 11 ), the control unit ( 16 ) determines the frequency of the PWM modulation and the frequency of the control loop of the PFC circuit ( 11 ) such that the frequency of the PWM modulation corresponds to the frequency of the control loop of the PFC circuit ( 11 ) and/or the frequency of the PWM modulation and the frequency of the control loop of the PFC circuit ( 11 ) differs by at least 20 Hz from integral multiples of the frequency of the AC voltage (U AC ).

7. An operating circuit for light-emitting means comprising:
an actively clocked power factor correction (PFC) circuit ( 11 ) which is suppliable originating from an AC voltage (U AC ) and optionally also a DC voltage (U DC ) and whose output voltage (U PFC ) is supplied directly or indirectly to a unit ( 19 ) for generating a pulse width modulation (PWM)-modulated current through the light-emitting means ( 17 ),
a control unit ( 16 ), which detects a residual ripple in the voltage (U PFC ) in the supply chain upstream of, in or downstream of the PFC circuit ( 11 ) and is configured in such a way that a PWM frequency and a frequency of the residual ripple do not generate any beats in the range of below 20 Hz, wherein the control unit ( 16 ) is further configured to implement detection of an AC voltage (UAC) and a DC voltage (UDC) and to thereby distinguish between a normal operating mode and an emergency operating mode.

8. A system comprising an operating circuit as claimed in claim 1 and a light-emitting means load ( 17 ).

9. A method for operating light-emitting means, the method comprising:
performing actively clocked power factor correction (PFC) originating from an AC voltage (U AC ) or a DC voltage (U DC ),
using an output voltage (U PFC ) of the power factor correction directly or indirectly for generating a pulse width modulation (PWM)-modulated current through the light-emitting means ( 17 ),
detecting a residual ripple in the voltage (U PFC ) in the supply chain upstream of, in or downstream of the power factor correction, and
selecting a frequency of the PWM modulation of the current through the light-emitting means ( 17 ) depending on a frequency of the residual ripple, wherein detection of an AC voltage (UAC) and a DC voltage (UDC) is implemented, and a distinction is thereby drawn between a normal operating mode and an emergency operating mode.

10. The method as claimed in claim 9 , wherein the frequency of the PWM modulation is determined such that the frequency is an integral multiple of the frequency of the AC voltage (U AC ).

11. The method as claimed in claim 10 , wherein the frequency of the PWM modulation is determined such that the frequency differs by at least 20 Hz from a frequency of the control loop of the power factor correction and integral multiples of the frequency of the control loop of the power factor correction.

12. The method as claimed in claim 9 , wherein the frequency of the PWM modulation is determined such that the frequency is the frequency of the clocking of the power factor correction.

13. The method as claimed in claim 12 , wherein the frequency of the PWM modulation is determined such that the frequency differs by at least 20 Hz from integral multiples of the frequency of the AC voltage (U AC ).

14. The method as claimed in claim 9 , wherein the frequency of the PWM modulation and the frequency of the clocking of the power factor correction are determined such that the frequency of the PWM modulation corresponds to the frequency of the control loop of the power factor correction and/or the frequency of the PWM modulation and the frequency of the control loop of the power factor correction differs by at least 20 Hz from integral multiples of the frequency of the AC voltage (U AC ).

Assignees

• Tridonic Gmbh & Co Kg

Inventors

• Mitterbacher Andre
• Mayrhofer Markus

Classifications

• H02M1/4225 Primary

  using a non-isolated boost converter · CPC title

• H05B45/10

  Controlling the intensity of the light · CPC title

• H02M3/156

  with automatic control of output voltage or current, e.g. switching regulators · CPC title

• H05B45/50 Primary

  responsive to malfunctions or undesirable behaviour of LEDs; responsive to LED life; Protective circuits · CPC title

• H05B33/0887

  Electricity · mapped topic