LED retrofit lamp

Patent metadata

Field	Value
Publication number	US-9480123-B2
Application number	US-201414903389-A
Country	US
Kind code	B2
Filing date	Aug 18, 2014
Priority date	Aug 29, 2013
Publication date	Oct 25, 2016
Grant date	Oct 25, 2016

Abstract

The present invention relates to an LED retrofit lamp adapted for operation with an alternating current. The LED lamp comprises an LED unit, first and second switching devices (e.g., first and second relays), a startup voltage supply unit ( 1010 ) coupled in parallel to the first switching device, an ignition detection unit ( 1020 ) coupled in parallel to the second switching device, and a switch drive unit ( 1030 ) for setting the first and second switching devices to a conducting state. If one of the first and second switching devices is shorted either no startup supply voltage or no detection signal is provided, such that the failure is indicated externally to a user.

First claim

The invention claimed is:

1. An LED retrofit lamp adapted for operation with an alternating current, comprising:
an LED unit;
a first switching device, and a second switching device; said first switching device, said second switching device, and said LED unit being connected in series;
a startup voltage supply unit connected to a capacitor forming a parallel connection with said first switching device; said startup voltage supply unit adapted to generate a startup supply voltage if the first switching device is in a non-conducting state;
an ignition detection unit connected to a capacitor forming a parallel connection with said second switching device, said ignition detection unit adapted to generate a detection signal if the second switching device is in a non-conducting state; and
a switch drive unit adapted to provide said startup supply voltage to said first and second switching devices, in response to said detection signal, wherein said first and second switching devices are adapted to assume a conducting state upon receipt of said startup supply voltage.

2. The LED retrofit lamp according to claim 1 , wherein said LED retrofit lamp further comprises a mains current line; said first switching device, said second switching device, and said LED unit being connected in series along said mains current line, said ignition detection unit adapted to generate said detection signal in response to detecting an ignition voltage on said mains current line.

3. The LED retrofit lamp according to claim 1 , wherein said LED unit further comprises a steady-state voltage supply unit; said steady-state voltage supply unit being adapted to generate a steady-state supply voltage, wherein said steady-state voltage supply unit is further adapted to derive a steady-state supply voltage for said first and second switching devices from a mains current line of said LED retrofit lamp.

4. The LED retrofit lamp according to claim 3 , wherein said steady-state voltage supply unit is further adapted to set said first and second switching devices at least temporarily to a non-conducting state in response to the power reduction on a mains current line of said LED lamp.

5. The LED retrofit lamp according to claim 3 , said steady-state voltage supply unit being adapted to provide said steady-state supply voltage to the first and second switching devices, wherein said steady-state voltage supply unit is connected between said first and second switching devices.

6. The LED retrofit lamp according to claim 5 , wherein said steady-state voltage supply unit comprises a shunt supply circuit adapted to tap energy from the mains current line of said LED retrofit lamp during a steady-state mode of operation.

7. The LED retrofit lamp according to claim 6 , wherein said shunt supply circuit comprises at least one of:
a full diode bridge and a shunt switch;
an active full bridge comprising at least two diodes and at least two MOSFETs; and
an asymmetrical half-bridge.

8. The LED retrofit lamp according to claim 1 , wherein said first switching device comprises a first relay, and wherein said second switching device comprises a second relay.

9. The LED retrofit lamp according to claim 8 , wherein the first relay comprises a first coil, and wherein the second relay comprises a second coil; wherein the first and second coils are connected to receive said startup supply voltage from said switch drive unit, wherein said first and second relays change from a non-conducting state to a conducting state upon receipt of said startup supply voltage from said switch drive unit.

10. The LED retrofit lamp according to claim 1 , wherein said first and second switching devices are adapted to assume said conducting state if said startup supply voltage is above a minimum threshold voltage.

11. The LED retrofit lamp according to claim 1 , wherein the LED lamp is adapted for operation with an electrical ballast, and wherein said ignition voltage on said mains current line corresponds to an HF signal from said electrical ballast.

12. The LED retrofit lamp according to claim 11 , wherein said ignition detection unit is adapted to detect the HF signal from said electrical ballast.

13. The LED retrofit lamp according to claim 1 , wherein, if said first switching device is in a conducting state, said startup voltage supply unit is bypassed by the first switching device, and wherein, if said second switching device is in a conducting state, said ignition detection unit is bypassed by the second switching device.

14. A method of operating an LED retrofit lamp with an alternating current; said method comprises the steps of:
generating a startup supply voltage if a first switching device, which is included in the LED retrofit lamp, is in a non-conducting state;
generating a detection signal if a second switching device, which is included in the LED retrofit lamp, is in a non-conducting state, wherein the first and second switching devices are connected in series with an LED unit in the LED retrofit lamp; and
in response to said detection signal, providing said startup supply voltage to said first and second switching devices, wherein said first and second switching devices are adapted to assume a conducting state upon receipt of said startup supply voltage.

Assignees

• Koninklijke Philips Nv

Inventors

• Van Dijk Bernhard Christiaan
• Tao Haimin
• Su Borong

Classifications

• H05B45/50 Primary

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

• H05B33/0884 Primary

  Electricity · mapped topic

• H05B45/00

  Circuit arrangements for operating light-emitting diodes [LED] · CPC title

• H05B47/26

  Circuit arrangements for protecting against earth faults · CPC title

• Y02B20/30

  Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED] · CPC title