LED tube lamp and power supply module applicable thereto
A power supply module is applicable to an LED tube lamp adapted to install on a lamp socket, and having electric shock protection function, the LED tube lamp including a lamp tube; two end caps, each having a first external connection terminal, and each coupled to a respective end of the lamp tube, the first connection terminals of the two end caps for receiving an external signal; and an LED module configured for emitting light. The power supply module includes: a rectifying circuit, coupled to the first external connection terminals of the end caps and the LED module, for rectifying a received signal to produce a rectified signal; a filtering circuit, coupled to the rectifying circuit and the LED module, for filtering the rectified signal to produce a filtered signal; a switch circuit configured to be switched according to a control signal; an electric shock protection controller coupled to the switch circuit, for detecting whether an electric shock risk has occurred, and configured to turn the switch circuit on or off according to the detection result; and impedance devices, which impedance devices and at least one electric component of the electric shock protection controller form a detection path. The electric shock protection controller is configured to cause a current to be conducted in the detection path for generating the detection result.
1. A light-emitting diode (LED) tube lamp adapted to install on a lamp socket and having electric shock protection function protecting a user from electric shock when installing the LED tube lamp into the lamp socket, the LED tube lamp comprising:
a lamp tube;
two end caps, each having a first external connection terminal, and each coupled to a respective end of the lamp tube, the first connection terminals of the two end caps for receiving an external signal;
a rectifying circuit, coupled to the first external connection terminals of the end caps, for rectifying a received signal to produce a rectified signal;
a filtering circuit, coupled to the rectifying circuit, for filtering the rectified signal to produce a filtered signal;
an LED module coupled to the rectifying circuit and the filtering circuit and configured for emitting light;
an electric shock protection controller, configured to determine whether to limit a current on a power loop formed between the first external connection terminals to less than a predefined value according to a detection result;
a switch circuit serially connected to the power loop and configured to be switched according to a control signal; and
impedance devices, which impedance devices and at least one electric component of the electric shock protection controller form a detection path,
wherein the electric shock protection controller is configured to cause a current to be conducted in the detection path for detecting an installation state between the LED tube lamp and the lamp socket and generating the detection result.
2. The LED tube lamp according to claim 1 , wherein detecting the installation state is for detecting whether an electric shock risk has occurred, and the electric shock protection controller is configured to turn the switch circuit on or off according to the detection result.
3. The LED tube lamp according to claim 1 , configured such that a driving voltage is provided to the electric shock protection controller when power is provided to at least one of the two end caps of the LED tube lamp, and the electric shock protection controller starts to work when the driving voltage reaches a defined logic level.
4. The LED tube lamp according to claim 1 , wherein:
the impedance devices include a first resistor having a first end connected to the power loop and a second resistor having a first end connected to a ground terminal; and
the electric shock protection controller includes a transistor having a first terminal connected to a second end of the first resistor, a second terminal coupled to a second end of the second resistor, and a control terminal, wherein the detection path includes the resistors and the transistor.
5. The LED tube lamp according to claim 1 , wherein the electric shock protection controller includes a control circuit configured to produce the control signal according to a detection result signal indicating the installation state, and a detection determining circuit coupled to the control circuit and configured to detect a signal feature on the detection path and produce the detection result signal.
6. The LED tube lamp according to claim 5 , wherein:
the impedance devices include a first resistor having a first end connected to the power loop and a second resistor having a second end connected to a ground terminal; and
the electric shock protection controller includes a transistor having a first terminal connected to a second end of the first resistor via a first node, a second terminal coupled to a second end of the second resistor via a second node, and a control terminal for receiving a detection control signal,
wherein the detection determining circuit detects the signal feature on at least one of the first and the second nodes.
7. The LED tube lamp according to claim 6 , wherein the detection control signal is a pulse signal whose pulse width is between 10 us to 1 ms.
8. The LED tube lamp according to claim 6 , wherein the electric shock protection controller includes a detection pulse generating module for generating the detection control signal, and the detection control signal comprises at least two pulses for performing two detections.
9. The LED tube lamp according to claim 8 , wherein at least one of the pulses is not generated when the logic level of the external signal is substantially zero.
10. The LED tube lamp according to claim 6 , wherein the signal level of a voltage on the detection path is determined by voltage division among the resistors, the transistor, and an impedance of a human body.
11. The LED tube lamp according to claim 5 , wherein the control circuit pulls a control terminal of the switch circuit to a high level when a voltage on the detection path is higher than a reference voltage, and pulls the control terminal of the switch circuit to a low level when the voltage on the detection path is lower than the reference voltage.
12. The LED tube lamp according to claim 1 , wherein the LED module is configured to be driven based on a driving signal for emitting light, and the LED tube lamp further comprises a driving circuit coupled to the filtering circuit and the LED module, for performing power conversion and producing the driving signal.
13. The LED tube lamp according to claim 1 , wherein the electric shock protection controller, the switch circuit, and the impedance devices are part of an installation detection module for detecting an installation state between the LED tube lamp and the lamp socket.
14. A power supply module applicable to an LED tube lamp adapted to install on a lamp socket, and having electric shock protection function, the LED tube lamp including a lamp tube; two end caps, each having a first external connection terminal, and each coupled to a respective end of the lamp tube, the first connection terminals of the two end caps for receiving an external signal; and an LED module configured for emitting light, the power supply module comprising:
a rectifying circuit, coupled to the first external connection terminals of the end caps and the LED module, for rectifying a received signal to produce a rectified signal;
a filtering circuit, coupled to the rectifying circuit and the LED module, for filtering the rectified signal to produce a filtered signal;
a switch circuit configured to be switched according to a control signal;
an electric shock protection controller coupled to the switch circuit, for detecting whether an electric shock risk has occurred, and configured to turn the switch circuit on or off according to the detection result; and
impedance devices, which impedance devices and at least one electric component of the electric shock protection controller form a detection path,
wherein the electric shock protection controller is configured to cause a current to be conducted in the detection path for generating the detection result.
15. The power supply module according to claim 14 , wherein the LED module is configured to be driven based on a driving signal for emitting light, and the power supply module further comprises a driving circuit coupled to the filtering circuit and the LED module, for performing power conversion and producing the driving signal.
16. The power supply module according to claim 14 , wherein the electric shock protection controller includes a control circuit configured to produce a control signal according to a detection result signal indicating the installation state, and further comprising a detection determining circuit coupled to the control circuit and configured to detect a signal feature on the detection path and produce the detection result signal.
17. The power supply module according to claim 16 , wherein the impedance devices include a first resistor having a first end connected to the rectifying circuit; and a second resistor having a first end connected to a ground terminal; and the electric shock protection controller includes:
a transistor, having a first terminal connected to a second end of the first resistor via a first node, a second terminal coupled to a second end of the second resistor via a second node, and a control terminal for receiving a detection control signal,
wherein the detection determining circuit detects the signal feature on at least one of the first and the second nodes.
18. The power supply module according to claim 17 , wherein the detection control signal is a pulse signal whose pulse width is between 10 us to 1 ms.
19. The power supply module according to claim 17 , wherein the electric shock protection controller includes a detection pulse generating module for generating the detection control signal, and the detection control signal comprises at least two pulses for performing two detections.
20. The power supply module according to claim 19 , wherein at least one of the pulses is not generated when the logic level of the external signal is substantially zero.
21. The power supply module according to claim 17 , wherein the signal level of a voltage on the detection path is determined by voltage division among the resistors, the transistor, and an impedance of a human body.
22. The power supply module according to claim 16 , wherein the control circuit pulls a control terminal of the switch circuit to a high level when a voltage on the detection path is higher than a reference voltage, and pulls the control terminal of the switch circuit to a low level when the voltage on the detection path is lower than the reference voltage.
23. The power supply module according to claim 14 , configured such that a driving voltage is provided to the electric shock protection controller when power is provided to at least one of the two end caps of the LED tube lamp, and the electric shock protection controller starts to work when the driving voltage reaches a defined logic level.
24. The power supply module according to claim 14 , wherein the electric shock protection controller, the switch circuit, and the impedance devices are part of an installation detection module for detecting whether an electric shock risk has occurred.