Dynamic control circuit

Patent metadata

Field	Value
Publication number	US-10225898-B2
Application number	US-201515320067-A
Country	US
Kind code	B2
Filing date	Jun 8, 2015
Priority date	Jun 17, 2014
Publication date	Mar 5, 2019
Grant date	Mar 5, 2019

Abstract

The invention describes a dynamic control circuit ( 1 ) realized for connection in series with an LED arrangement ( 2 ), characterized by a first switching element (Q 1 ) realized to provide a path for the LED current (I LED ), and a monitoring arrangement (M) realized to control the first switching element (Q 1 ) according to the level of the LED current (I LED ) SO that the dynamic control circuit ( 1 ) presents a series impedance (Z dyn ), which series impedance (Z dyn ) gradually increases in response to a decreasing LED current (I LED ) through the LED arrangement ( 2 ). The invention also describes a dimmable lighting arrangement ( 10 ) comprising an LED arrangement ( 2 ); a driver ( 3 ) realized to provide an input voltage (V in ) and an input current (I LED ) to the LED arrangement ( 2 ); and such a dynamic control circuit ( 1 ) connected in series with the LED arrangement ( 2 ). The invention further describes retrofit LED light-bulb ( 100 ); and a method of driving an LED arrangement.

First claim

The invention claimed is:

1. A dynamic control circuit realized for connection in series with a Light Emitting Diode (LED) arrangement, characterized by a first switching element realized to provide a path for the LED current, and a monitoring arrangement realized to control the first switching element according to the level of the LED current so that the dynamic control circuit presents a series impedance which increases in response to a decreasing LED current through the LED arrangement, wherein the series impedance is inversely non-linearly proportional to the LED current.

2. The dynamic control circuit according to claim 1 , wherein the monitoring arrangement comprises a second switching element arranged to generate a control signal to control the operation of the first switching element.

3. The dynamic control circuit according to claim 1 , wherein the monitoring arrangement comprises a filter circuit portion arranged to filter the control signal of the first switching element.

4. The dynamic control circuit according to claim 1 , wherein the dynamic control circuit comprises only discrete components arranged to operate on a voltage supplied at the output of the LED arrangement.

5. The dynamic control circuit according to claim 1 , wherein the components of the dynamic control circuit are chosen on the basis of a desired series impedance at specific LED current levels.

6. The dynamic control circuit according to claim 1 , wherein the first switching element comprises a bipolar junction transistor.

7. The dynamic control circuit according to claim 1 , realized to present a series impedance of at least 10.00, for a phase-cut angle less than 45° and at most 0.10, for a phase-cut angle greater than 135°.

8. A dimmable lighting arrangement comprising:
an LED arrangement;
a driver realized to provide an input current to the LED arrangement; and
a dynamic control circuit according to claim 1 connected in series with the LED arrangement.

9. The lighting arrangement according to 8 , comprising a bleeder circuit arrangement realized to bleed a portion of the input current according to a voltage at the output of the LED arrangement.

10. The lighting arrangement according to 9 , wherein the bleeder circuit arrangement comprises an NPN bipolar junction transistor whose base is connected to an output of the LED arrangement.

11. The lighting arrangement according to claim 8 , wherein the driver comprises a switched-mode power supply.

12. The lighting arrangement according to claim 8 , comprising a buffer capacitor connected across the outputs of the driver.

13. A retrofit LED light-bulb, comprising:
a housing with a GU10 socket connector for connecting to a dimmable power supply; an LED arrangement comprising a number of LEDs mounted on a circuit board in the housing; and
a dynamic control circuit according to claim 1 connected in series with the LED arrangement.

14. A method of driving an LED arrangement, comprising the steps of:
connecting a dynamic control circuit in series with the LED arrangement, the dynamic control circuit comprising a switching element;
providing an LED current to the LED arrangement, wherein the switching element is arranged to provide a path for the LED current; and
operating the switching element of the dynamic control circuit to affect an increase in its series impedance in response to a decrease in LED current through the LED arrangement, wherein the series impedance is inversely non-linearly proportional to the LED current.

15. The dynamic control circuit according to claim 1 , realized to present a series impedance of at least 1000.00 for a phase-cut angle less than 45° and to present a series impedance of at most 100.00 for a phase-cut angle greater than 135°.

Assignees

• Philips Lighting Holding Bv

Inventors

• Arulandu Kumar
• Malyna Dmytro Viktorovych
• Kurt Ralph

Classifications

• H05B45/44 Primary

  with an active control inside an LED matrix · CPC title

• F21K9/238

  Arrangement or mounting of circuit elements integrated in the light source · CPC title

• H05B33/0815

  Electricity · mapped topic

• Y02B20/383

  Cross-Sectional Technologies · mapped topic

• H05B33/0851

  Electricity · mapped topic