Operating circuit for energizing a lamp, LED converter, and method for operating an operating circuit

Patent metadata

Field	Value
Publication number	US-9924571-B2
Application number	US-201515503091-A
Country	US
Kind code	B2
Filing date	Oct 19, 2015
Priority date	Oct 17, 2014
Publication date	Mar 20, 2018
Grant date	Mar 20, 2018

Abstract

An operating circuit for energizing a lamp ( 5 ) comprising at least one light emitting diode ( 6 ) has a primary side ( 11 ) and a secondary side ( 12 ) that is electrically isolated from the primary side. The operating circuit comprises a clocked converter ( 14 ) that has a primary coil and a secondary coil ( 18 ). The operating circuit further comprises a detection device ( 20 ) for determining an output voltage (V out ) of the operating circuit; the detection device ( 20 ) comprises an inductor ( 21 ) which is located on the primary side ( 11 ) of the operating circuit and which is inductively coupled to the secondary coil ( 18 ).

First claim

What is claimed is:

1. An operating circuit for powering a lamp ( 5 ), which comprises at least one light emitting diode ( 6 ), wherein the operating circuit has a primary side ( 11 ) and a secondary side ( 12 ) galvanically isolated therefrom, and wherein the operating circuit comprises:
a clocked converter ( 14 ), which comprises a primary coil ( 17 ) and a secondary coil ( 18 );
a detection device ( 20 ) for measuring a voltage (V sns ) on the secondary side of the operating circuit, wherein the detection device ( 20 ) comprises an inductor ( 21 ) disposed on the primary side ( 11 ) of the operating circuit, which is inductively coupled to the secondary coil ( 18 ) of the clocked converter ( 14 );
a control device ( 19 ) that receives a signal representing the measured voltage (V_sns) on the secondary side of the operating circuit and controls switching of the clocked converter ( 14 ) to adjust an output voltage (Vout) at an output of the operating circuit for the lamp; and
wherein the control device ( 19 ) is configured to determine the output voltage (V out ) as a function of a maximum value ( 71 ) of the measured voltage at the inductor ( 21 ) and a voltage correction value ( 74 ) that is a function of the output current.

2. The operating circuit according to claim 1 wherein a diode ( 51 , 52 ) is provided between the secondary coil ( 18 ) and the output ( 55 ) of the operating circuit, wherein the voltage correction value ( 74 ) is a product of the output current (I out ) and a differential resistor resistance of the diode.

3. The operating circuit according to claim 1 , further comprising a current transformer ( 61 , 62 , 63 ) for measuring the output current (I out ).

4. The operating circuit according to claim 3 further comprising a current measuring circuit having an active rectifier ( 64 ) controlled by the control device ( 19 ).

5. The operating circuit according to claim 1 , wherein the operating circuit is configured to switch, in a clocked manner, at least one controllable switch ( 41 , 42 ) of the converter ( 14 ), as a function of the determined output voltage (V out ).

6. The operating circuit according to claim 1 , wherein the operating circuit is configured for a power regulation and/or a power limitation of an output power of the operating circuit, as a function of the determined output voltage (V out ).

7. The operating circuit according to claim 1 , wherein the inductor ( 21 ) differs from the primary coil ( 17 ).

8. The operating circuit according to claim 1 , wherein the converter ( 14 ) is a primary side, clocked LLC resonance converter ( 14 ) having a half-bridge activation.

9. A method for operating an operating circuit for powering a lamp ( 5 ), which comprises at least one light emitting diode ( 6 ), wherein the operating circuit has a primary side ( 11 ) and a secondary side ( 12 ), galvanically isolated therefrom, and wherein the method comprises:
a clocked switching of at least one controllable switch of a converter ( 14 ), which comprises a primary coil ( 17 ) and a secondary coil ( 18 ), and
determining an output voltage (V out ) of the operating circuit as a function of a voltage at an inductor ( 21 ) and as a function of an output current (I out ) of the operating circuit, wherein the inductor ( 21 ) is disposed on the primary side ( 11 ) and is inductively coupled to the secondary coil ( 18 )
wherein the output voltage (V out ) is determined as a function of a maximum value ( 71 ) of the voltage at the inductor ( 21 ) and a voltage correction value ( 74 ) that is a function of the output current.

10. The method according to claim 9 , wherein the inductor ( 21 ) differs from the primary coil ( 17 ).

11. The method according to claim 9 wherein a diode ( 51 , 52 ) is provided between the secondary coil ( 18 ) and an output ( 55 ) of the operating circuit and the voltage correction value ( 74 ) is a product of the output current (I out ) and a differential resistance of the diode.

12. The method according to claim 9 wherein the output current is measured with a current transformer ( 61 , 62 , 63 ) and a signal from the transformer is processed through at least an active rectifier ( 64 ).

Assignees

• Tridonic Gmbh & Co Kg

Inventors

• Duenser Mathias

Classifications

• H05B45/14

  using electrical feedback from LEDs or from LED modules · CPC title

• H05B45/37

  Converter circuits · CPC title

• H05B45/395

  Linear regulators · CPC title

• H05B45/60

  Circuit arrangements for operating LEDs comprising organic material, e.g. for operating organic light-emitting diodes [OLED] or polymer light-emitting diodes [PLED] · CPC title

• H02M3/33523 Primary

  with galvanic isolation between input and output of both the power stage and the feedback loop · CPC title