Light-emitting device

Patent metadata

Field	Value
Publication number	US-10791601-B2
Application number	US-201916353526-A
Country	US
Kind code	B2
Filing date	Mar 14, 2019
Priority date	Mar 14, 2018
Publication date	Sep 29, 2020
Grant date	Sep 29, 2020

Abstract

A light-emitting device has a stabilizing-current circuit, a current source having a high electron mobility transistor, and a light source electrically connected to the stabilizing-current circuit and the current source.

First claim

What is claimed is:

1. A light-emitting device, comprising:
a light source having a first terminal and a second terminal;
a stabilizing-current circuit connected with the first terminal, the stabilizing-current circuit including:
a high electron mobility transistor;
a capacitor; and
a Zener diode having an anode connected with the capacitor, the Zener diode and the capacitor are connected with the high electron mobility transistor in parallel; and

a current source connected with the second terminal, and having a second transistor connected with the light source.

2. The light-emitting device of claim 1 , wherein the light source includes a filament connected with the stabilizing-current circuit and the current source in series.

3. The light-emitting device of claim 1 , further comprising a filter connected with the stabilizing-current circuit.

4. The light-emitting device of claim 1 , further comprising a bleeder circuit connected with the stabilizing-current circuit and the light source.

5. The light-emitting device of claim 4 , wherein the bleeder circuit is connected with the stabilizing-current circuit and the light source in parallel, and is connected with the current source in series.

6. The light-emitting device of claim 4 , wherein the bleeder circuit is connected with the light source through the current source.

7. The light-emitting device of claim 6 , wherein the bleeder circuit is connected with the stabilizing-current circuit, the light source and the current source in parallel.

8. A light-emitting device, comprising:
a first current source activated under a first voltage;
a stabilizing-current circuit activated under a second voltage, and electrically connected with the first current source, the stabilizing-current circuit including:
a capacitor;
a Zener diode, with an anode connected to the capacitor; and
a first resistor and a second resistor connected in series, wherein the first resistor and the second resistor are connected with the Zener diode and the capacitor in parallel;

a second current source electrically connected with the first current source; and
a light source activated under a third voltage, and electrically connected with the stabilizing-current circuit and the second current source, wherein the first voltage is lower than the third voltage and the third voltage is lower than the second voltage.

9. The light-emitting device of claim 8 , wherein the second current source includes two high electron mobility transistors connected in parallel.

10. The light-emitting device of claim 9 , wherein the first current source is connected with the stabilizing-current circuit, the light source and the second current source in parallel.

11. The light-emitting device of claim 8 , wherein the stabilizing-current circuit further includes a high electron mobility transistor connected with the Zener diode and the capacitor in parallel.

12. The light-emitting device of claim 8 , further comprising a filter connected with second current source in series.

13. The light-emitting device of claim 12 , wherein the first current source is connected with the filter and the second current source in parallel.

14. The light-emitting device of claim 8 , wherein the first current source is connected with the second current source in series.

15. The light-emitting device of claim 8 , wherein the first current source is closed when the light source is activated.

Assignees

• Epistar Corp

Inventors

• Chang Chao-Kai
• Wang Chen-Yu
• Wu Chang-Hseih
• Kuo Jai-Tai

Classifications

• H05B45/10

  Controlling the intensity of the light · CPC title

• H05B45/00

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

• H05B45/22

  using optical feedback · CPC title

• H05B45/48 Primary

  having LEDs organised in strings and incorporating parallel shunting devices · CPC title

• H05B45/37 Primary

  Converter circuits · CPC title