Current supply for luminescent diodes

• US 8,207,689 B2
• Filed: 03/04/2010
• Issued: 06/26/2012
• Est. Priority Date: 07/04/2002
• Status: Active Grant

• Current Assignee: Tridonic AG (Zumtobel Group AG), Tridonic Jennersdorf GMBH (Zumtobel Group AG)
• Original Assignee: Tridonic AG (Zumtobel Group AG), Tridonic Jennersdorf GMBH (Zumtobel Group AG)
• Inventors: Tobler, Felix, Zimmermann, Michael, Tasch, Stefan
• Primary Examiner(s): Owens, Douglas W
• Assistant Examiner(s): A, Minh D
• Application Number:
  US12/717,824
• Publication Number:
  US 20100213853A1
• Time in Patent Office: 845 Days
• Field of Search: 315/307, 315/291, 315/224, 315/244, 315/200.R, 315/209.R, 315/248, 362/464, 362/465, 362/466, 362467-468
• US Class Current: 315/307
• CPC Class Codes: H05B 45/10 Controlling the intensity of the light
• CPC Class Codes: H05B 45/36 Circuits for reducing or suppressing harmonics, ripples or electromagnetic interferences [EMI]
• CPC Class Codes: H05B 45/375 using buck topology
• CPC Class Codes: H05B 45/382 with galvanic isolation between input and output
• CPC Class Codes: H05B 45/56 involving measures to prevent abnormal temperature of the LEDs
• CPC Class Codes: Y02B 20/30 Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

Abstract

The present invention is based on a regulation circuit (200a, 200b) for making available a constant current supply on the basis of a transformer principle, in which there flows through the luminescent diodes (D1, . . . , DN) a triangular a.c. current (I_D) varying periodically around a d.c. current value. With this method it is afforded by means of a circuitry provision that both the charging and also the discharging current (I_L1) of an inductive reactance (X_L1) connected in series to the luminescent diodes (D1, . . . , DN), functioning as a storage choke (L1) for filtering of mains harmonics, flows as diode current (I_D) through the luminescent diodes (D1, . . . , DN). The advantage of this method consists in a significant reduction of the overall power loss (P_{V, ges}) of the LED illumination module (100). According to one exemplary embodiment of the invention the ceramic circuit board (102) of the LED illumination module (100) in accordance with the invention has a direct mains current supply (104, 108), which for protection from mechanical damage is accommodated in a transparent housing (106) having a highly transparent polymer mass (110) serving as optically active lens surface.

Claims

1. An LED module comprising one or more LED(s) mounted on a circuit board and fed with alternating current via current supply mains, wherein at least one LED of the one or more LED(s) is a blue LED which produces white light by means of a color conversion layer arranged above the at least one LED, and the LED module is accommodated in a transparent housing and the LED module comprises a current supply circuit for providing a constant current supply, wherein the current supply circuit is arranged on a side of the circuit board opposite to the one or more LED(s), and wherein the current supply circuit comprises (a) at least one inductive reactance being provided in series to the one or more LED(s), (b) at least one switching stage for switching between a charging process and a discharging process occurring in the at least one inductive reactance by respectively exceeding or falling below threshold values of respective control voltages, (c) one free-running current path being provided in parallel to the one or more LED(s) and the at least one inductive reactance for at least a part of the discharging current that is released to the one or more LED(s) by the at least one inductive reactance when the at least one switching stage is blocked, and (d) a free-running diode being arranged in the free-running current path and being provided antiparallel to the one or more LED(s) and the at least one inductive reactance, wherein the current supply circuit further comprises a first detector for detecting a diode current flowing through the one or more LED(s) during the discharging process occurring in the at least one inductive reactance.

2. The LED module according to claim 1, wherein the at least one inductive reactance is connected as a storage choke.

3. The LED module according to claim 1, the module comprising a plug and/or socket for connection to an AC current mains.

4. The LED module according to claim 1, wherein at least one of the one or more LED(s) is an unhoused LED die molded in a polymer mass.

5. The LED module according to claim 4, wherein the polymer mass is highly transparent.

6. The LED module according to claim 1, wherein the LED module comprises at least two LEDs, of the one or more LED(s), being arranged in series.

7. The LED module according to claim 1, wherein the circuit board is a thermally well conducting circuit board.

8. The LED module according to claim 7, wherein the circuit board is a ceramic circuit board.

9. The LED module according to claim 1, wherein the one or more LED(s) are arranged on the circuit board by means of a chip-on-board technology.

10. LED module according to claim 1, wherein Fresnel lenses in the form of a lens plate for the attainment of a bundled homogenous light distribution in a region of main emission directions are positioned centrally above each of the one or more LED(s) within the transparent housing and are laterally adhered thereto.

11. The LED module according to claim 1, wherein the housing can be contacted with the aid of at least one of a plug, a socket and a connection cable led out of the housing to a side of the housing.

12. The LED module according to claim 1, wherein a reflector is mounted around the one or more LED(s).

13. The LED module according to claim 12, wherein the reflector is made of plastics.

14. The LED module according to claim 13, wherein the plastics have a highly reflective inner side surface.

15. The LED module according to claim 1, wherein the current supply circuit further comprises a second detector for detecting the diode current flowing through the one or more LED(s) during the charging process occurring in the at least one inductive reactance.

16. The LED module according to claim 15, wherein the second detector is settable for dimming the one or more LED(s).

17. The LED module according to claim 1, wherein the current supply circuit further comprises a Zener diode as a voltage limiter tapped off at output terminals of an opto-coupler diode, level or potential offset stage for stabilizing a control voltage of a first electronically controllable semiconductor power transistor.

18. The LED module according to claim 1, wherein the current supply circuit further comprises a time dependent controller for switching over between the charging process and the discharging process occurring in the at least one inductive reactance.

19. The LED module according to claim 1, wherein at least one LED of the one or more LED(s) is dimmable.

20. The LED module according to claim 19, wherein for dimming the at least one dimmable LED, the LED module is arranged to receive radio or infrared signals.

21. The LED module according to claim 19, wherein for dimming the at least one dimmable LED, the LED module comprises a microcontroller arranged for receiving signals from a bus.

22. An LED module comprising one or more LED(s) mounted on a circuit board and fed with alternating current via current supply mains, wherein at least one LED of the one or more LED(s) is a blue LED which produces white light by means of a color conversion layer arranged above the at least one LED, and the LED module is accommodated in a transparent housing and the LED module comprises a current supply circuit for providing a constant current supply, wherein the current supply circuit is arranged on a side of the circuit board opposite to the one or more LED(s), and wherein the current supply circuit comprises (a) at least one inductive reactance being provided in series to the one or more LED(s), (b) at least one switching stage for switching between a charging process and a discharging process occurring in the at least one inductive reactance by respectively exceeding or falling below threshold values of respective control voltages, and (c) one free-running current path being provided in parallel to the one or more LED(s) and the at least one inductive reactance for at least a part of the discharging current that is released to the one or more LED(s) by the at least one inductive reactance when the at least one switching stage is blocked, wherein the current supply circuit further comprises a detector for detecting a diode current flowing through the one or more LED(s) during the discharging process occurring in the at least one inductive reactance.

23. The LED module according to claim 22, further comprising a free-running diode being arranged in the free-running current path.