LED tube lamp compatible with different ballasts providing external driving signal

A light-emitting diode (LED) tube lamp, comprising:

• a lamp tube having at least a pin at a first end of the lamp tube and at least a pin at a second end of the lamp tube, for receiving an external driving signal;
• a light strip disposed in the lamp tube, comprising an LED module for emitting light;
• a rectifying circuit for rectifying the external driving signal to produce a rectified signal;
• a filtering circuit coupled to the rectifying circuit, for filtering the rectified signal in order to drive the LED module;
• a current-limiting element for receiving the external driving signal input at one or more of the pins, the current-limiting element coupled to one or more of the pins, and coupled to the rectifying circuit;
• and
• a ballast interface circuit coupled to or in the rectifying circuit, and coupled to the current-limiting element, for the LED tube lamp to be compatible with a ballast providing the external driving signal, wherein the ballast interface circuit has a first terminal and a second terminal and is configured to determine whether the external driving signal comes from a ballast, according to a state of a property of the external driving signal, or according to a state of a property of a detection signal transmitted through the first terminal and the second terminal upon the external driving signal being input to the LED tube lamp,
• wherein the ballast interface circuit comprises a ballast-compatible circuit comprising a switch and a control circuit configured to control the switch;
• the switch is coupled to the first terminal and the second terminal;
• and the control circuit is configured to detect a state of a property of the external driving signal or the rectified signal, and to control current conduction or cutoff of the switch according to the detection result, and
• wherein when the external driving signal is a relatively low frequency AC signal or DC signal, the switch is configured to be cut off with the external driving signal flowing through the current-limiting element to provide power for emitting light by the LED module.

A light-emitting diode (LED) tube lamp, comprising:

• a lamp tube having at least a pin at a first end of the lamp tube and at least a pin at a second end of the lamp tube, for receiving an external driving signal;
• a light strip disposed in the lamp tube, comprising an LED module for emitting light;
• a rectifying circuit for rectifying the external driving signal to produce a rectified signal;
• a filtering circuit coupled to the rectifying circuit, for filtering the rectified signal in order to drive the LED module;
• a current-limiting element for receiving the external driving signal input at one or more of the pins, the current-limiting element coupled to one or more of the pins, and coupled to the rectifying circuit;
• and
• a ballast interface circuit coupled to or in the rectifying circuit, and coupled to the current-limiting element, for the LED tube lamp to be compatible with a ballast providing the external driving signal, wherein the ballast interface circuit has a first terminal and a second terminal and is configured to determine whether the external driving signal comes from a ballast, according to a state of a property of the external driving signal, or according to a state of a property of a detection signal transmitted through the first terminal and the second terminal upon the external driving signal being input to the LED tube lamp,
• wherein the ballast interface circuit comprises a ballast-compatible circuit comprising a switch and a control circuit configured to control the switch;
• the switch is coupled to the first terminal and the second terminal;
• and the control circuit is configured to detect a state of a property of the external driving signal or the rectified signal, and to control current conduction or cutoff of the switch according to the detection result, and
• wherein the property of the external driving signal or the rectified signal is frequency or voltage, and when the frequency or voltage is below a defined level, the switch is configured to be turned off with the external driving signal flowing through the current-limiting element to provide power for emitting light by the LED module.

A light-emitting diode (LED) tube lamp, comprising:

• a lamp tube having at least a pin at a first end of the lamp tube and at least a pin at a second end of the lamp tube, for receiving an external driving signal;
• a light strip disposed in the lamp tube, comprising an LED module for emitting light;
• a rectifying circuit for rectifying the external driving signal to produce a rectified signal;
• a filtering circuit coupled to the rectifying circuit, for filtering the rectified signal in order to drive the LED module;
• a current-limiting element for receiving the external driving signal input at one or more of the pins, the current-limiting element coupled to one or more of the pins, and coupled to the rectifying circuit;
• and
• a ballast interface circuit coupled to or in the rectifying circuit, and coupled to the current-limiting element, for the LED tube lamp to be compatible with a ballast providing the external driving signal, wherein the ballast interface circuit comprises a detection circuit, and a switch circuit coupled to a first terminal and a second terminal;
• and upon the external driving signal being input to the LED tube lamp, the detection circuit is configured to detect a state of a property of the external driving signal, the rectified signal, or a detection signal transmitted through the first terminal and the second terminal, and to conduct or cut off the switch circuit according to the detection result,
• wherein the property of the external driving signal is a frequency of the external driving signal;
• when the external driving signal is in a first frequency range, the switch circuit is configured to be turned off to allow the external driving signal to flow through a circuit connected in parallel with the switch circuit or an external circuit outside the detection circuit;
• and when the external driving signal is in a second frequency range, the switch circuit is configured to be turned on to allow transmission of the external driving signal bypassing the circuit connected in parallel with the switch circuit, or the external circuit.

A light-emitting diode (LED) tube lamp, comprising:

• a lamp tube having at least a pin at a first end of the lamp tube and at least a pin at a second end of the lamp tube, for receiving an external driving signal;
• a light strip disposed in the lamp tube, comprising an LED module for emitting light;
• a rectifying circuit for rectifying the external driving signal to produce a rectified signal;
• a filtering circuit coupled to the rectifying circuit, for filtering the rectified signal in order to drive the LED module;
• a current-limiting element for receiving the external driving signal input at one or more of the pins, the current-limiting element coupled to one or more of the pins, and coupled to the rectifying circuit;
• and
• a ballast interface circuit coupled to or in the rectifying circuit, and coupled to the current-limiting element, for the LED tube lamp to be compatible with a ballast providing the external driving signal, wherein the ballast interface circuit comprises a detection circuit, and a switch circuit coupled to a first terminal and a second terminal;
• and upon the external driving signal being input to the LED tube lamp, the detection circuit is configured to detect a state of a property of the external driving signal, the rectified signal, or a detection signal transmitted through the first terminal and the second terminal, and to conduct or cut off the switch circuit according to the detection result,
• wherein when the external driving signal is a relatively low frequency AC signal or DC signal, the switch circuit is configured to be turned off with the external driving signal flowing through the current-limiting element to provide power for emitting light by the LED module.

A light-emitting diode (LED) tube lamp, comprising:

• a lamp tube having at least a pin at a first end of the lamp tube and at least a pin at a second end of the lamp tube, for receiving an external driving signal;
• a light strip disposed in the lamp tube, comprising an LED module for emitting light;
• a rectifying circuit for rectifying the external driving signal to produce a rectified signal;
• a filtering circuit coupled to the rectifying circuit, for filtering the rectified signal in order to drive the LED module;
• a current-limiting element for receiving the external driving signal input at one or more of the pins, the current-limiting element coupled to one or more of the pins, and coupled to the rectifying circuit;
• and
• a ballast interface circuit coupled to or in the rectifying circuit, and coupled to the current-limiting element, for the LED tube lamp to be compatible with a ballast providing the external driving signal, wherein the ballast interface circuit comprises a detection circuit, and a switch circuit coupled to a first terminal and a second terminal;
• and upon the external driving signal being input to the LED tube lamp, the detection circuit is configured to detect a state of a property of the external driving signal, the rectified signal, or a detection signal transmitted through the first terminal and the second terminal, and to conduct or cut off the switch circuit according to the detection result,
• wherein the property of the external driving signal or the rectified signal is frequency or voltage, and when the frequency or voltage is below a defined level, the switch circuit is configured to be turned off with the external driving signal flowing through the current-limiting element to provide power for emitting light by the LED module.