Led tube lamp with overcurrent and/or overvoltage protection capabilities

Patent metadata

Field	Value
Publication number	US-2016198535-A1
Application number	US-201615054137-A
Country	US
Kind code	A1
Filing date	Feb 26, 2016
Priority date	Sep 28, 2014
Publication date	Jul 7, 2016
Grant date	—

Abstract

A light-emitting diode (LED) tube lamp with overcurrent and/or overvoltage protection capabilities includes a lamp tube, a first rectifying circuit, a filtering circuit, an LED lighting module, and a protection circuit. The lamp tube has pins for receiving an external driving signal. The first rectifying circuit is for rectifying the external driving signal to produce a rectified signal. The filtering circuit is for filtering the rectified signal to produce a filtered signal. The LED lighting module includes an LED module, wherein the LED lighting module is configured to receive the filtered signal to produce a driving signal, and the LED module is for receiving the driving signal for emitting light. The protection circuit is configured to determine whether to enter a protection state, wherein upon entering the protection state, the protection circuit works to limit or restrain the level of the filtered signal.

First claim

What is claimed is:

1 . An LED tube lamp with overcurrent and/or overvoltage protection capabilities, comprising:
a lamp tube, having a first pin and a second pin for receiving an external driving signal; a first rectifying circuit, coupled to the first and second pins, for rectifying the external driving signal to produce a rectified signal; a filtering circuit, coupled to the first rectifying circuit, for filtering the rectified signal to produce a filtered signal, the filtering circuit having a first filtering output terminal and a second filtering output terminal; an LED lighting module, coupled to the filtering circuit and including an LED module, the LED lighting module configured to receive the filtered signal and produce a driving signal, and the LED module for receiving the driving signal for emitting light; and a protection circuit, coupled to the filtering circuit, and configured to determine whether to enter a protection state, wherein:
the protection circuit is configured such that, upon entering the protection state, the protection circuit limits or restrains a level of the filtered signal;
the protection circuit includes a voltage clamping circuit and a voltage division circuit;
the voltage clamping circuit is coupled to the first filtering output terminal and the second filtering output terminal, and the voltage division circuit is coupled to the voltage clamping circuit and the second filtering output terminal; and
the voltage division circuit is also coupled to a positive terminal of the LED module to detect a voltage of the LED module, and is configured to receive a current detection signal, which represents a magnitude of current through the LED module.

2 . The LED tube lamp according to claim 1 , wherein when a current of the LED module is within a normal range but the voltage at the positive terminal of the LED module exceeds an overvoltage value, the voltage division circuit causes the voltage clamping circuit to enter a conducting state between the first filtering output terminal and the second filtering output terminal, causing the protection circuit to be in the protection state in which the voltage between the first filtering output terminal and the second filtering output terminal is restrained or clamped down on.

3 . The LED tube lamp according to claim 1 , wherein when a current of the LED module is within a normal range but the voltage at the positive terminal of the LED module is below an overvoltage value, the voltage division circuit causes the voltage clamping circuit to be in a cutoff state between the first filtering output terminal and the second filtering output terminal, causing the protection circuit to not be in the protection state.

4 . The LED tube lamp according to claim 1 , wherein the protection circuit further comprises a capacitor, and the voltage clamping circuit comprises a thyristor and a symmetrical trigger diode; the thyristor has a first terminal connected to the first filtering output terminal, a second terminal connected to the second filtering output terminal, and a control terminal connected to a first terminal of the symmetrical trigger diode; the symmetrical trigger diode has a second terminal connected to an end of the capacitor, which has another end connected to the second filtering output terminal; and the voltage division circuit is connected to the second terminal of the symmetrical trigger diode.

5 . The LED tube lamp according to claim 4 , wherein the thyristor comprises a bidirectional triode thyristor or a silicon controlled rectifier.

6 . The LED tube lamp according to claim 4 , wherein the voltage division circuit comprises a first electronic switch, a second electronic switch, a first resistor, a second resistor, a third resistor, and a fourth resistor, wherein the third resistor has an end connected to the second terminal of the symmetrical trigger diode and another end connected to the second filtering output terminal; the first resistor has an end connected to the second terminal of the symmetrical trigger diode and another end connected to the first electronic switch, which is connected to the second filtering output terminal; the second resistor has an end connected to the second terminal of the symmetrical trigger diode and another end connected to the second electronic switch and first electronic switch; the second electronic switch is connected to the second filtering output terminal and is configured to receive the current detection signal; and the fourth resistor has an end connected to the second terminal of the symmetrical trigger diode and another end connected to the positive terminal of the LED module.

7 . The LED tube lamp according to claim 6 , wherein the resistance of the first resistor is smaller than that of the second resistor, and when a current of the LED module is within a normal range but the voltage at the positive terminal of the LED module exceeds an overvoltage value, the second electronic switch enters a cutoff state and the first electronic switch enters a conducting state, causing the thyristor to enter a cutoff state by an electric potential at the second terminal of the symmetrical trigger diode, thus causing the protection circuit to be in the protection state to restrain or clamp down on the level of the filtered signal between the first filtering output terminal and the second filtering output terminal.

8 . The LED tube lamp according to claim 6 , wherein the resistance of the first resistor is smaller than that of the second resistor, and when a current of the LED module is within a normal range but the voltage at the positive terminal of the LED module is below an overvoltage value, the second electronic switch enters a cutoff state and the first electronic switch enters a conducting state, causing the thyristor to enter a cutoff state by an electric potential at the second terminal of the symmetrical trigger diode, thus causing the protection circuit to not be in the protection state.

9 . An LED tube lamp with overcurrent and/or overvoltage protection capabilities, comprising:
a lamp tube, having a first pin and a second pin for receiving an external driving signal; a first rectifying circuit, coupled to the first and second pins, for rectifying the external driving signal to produce a rectified signal; a filtering circuit, coupled to the first rectifying circuit, for filtering the rectified signal to produce a filtered signal; an LED driving circuit, coupled to the filtering circuit and an LED module, the LED driving circuit being configured to receive the filtered signal to produce a driving signal, and the LED module for receiving the driving signal for emitting light; and a protection circuit, coupled to the filtering circuit, and configured to determine whether to enter a protection state, wherein upon entering the protection state, the protection circuit limits or restrains a voltage and/or current level of the filtered signal.

10 . The LED tube lamp according to claim 9 , wherein the filtering circuit has a first filtering output terminal and a second filtering output terminal, and the protection circuit includes a voltage clamping circuit and a voltage division circuit; the voltage clamping circuit is coupled to the first filtering output terminal and the second filtering output terminal, and the voltage division circuit is coupled to the voltage clamping circuit, the second filtering output terminal, and a biasing voltage source; wherein the voltage division circuit is configured to receive a current detection signal, which represents a magnitude of current through the LED module.

11 . The LED tube lamp according to claim 10 , wherein when the LED lamp is

Assignees

• Jiaxing Super Lighting Electric Appliance Co Ltd

Inventors

• Ye Qifeng
• Zhang Yueqiang
• Hu Hechen
• Xiong Aiming

Classifications

• H05K1/118 Primary

  specially for flexible printed circuits, e.g. using folded portions · CPC title

• H05B45/50

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

• H05B45/40

  Details of LED load circuits · CPC title

• F21V29/83

  the elements having apertures, ducts or channels, e.g. heat radiation holes · CPC title

• H05K2201/10106

  Light emitting diode [LED] · CPC title