LED tube lamp
A circuit board configuration adapted to carry electronic components of a power supply module is provided. The circuit board configuration comprises: a first circuit board, having a first plane configured to dispose and connect a part of the electronic components; and a second circuit board, electrically connected to the first circuit board and having a second plane configured to dispose and connect another part of the electronic components, wherein at least one of the first and the second circuit boards is disposed, perpendicular to an axial direction of the lamp tube, in an interior space formed by the lamp tube and at least one of the two end caps, so that the a direction normal to the first and the second planes is substantially parallel to the axial direction of the lamp tube.
1. A circuit board configuration adapted to carry electronic components of a power supply module, wherein the power supply module is disposed in an LED tube lamp having a lamp tube and two end caps connected to respective ends of the lamp tube, and the circuit board configuration comprises:
a first circuit board, having a first plane configured on which to dispose and connect a part of the electronic components; and
a second circuit board, electrically connected to the first circuit board and having a second plane configured on which to dispose and connect another part of the electronic components,
wherein at least one of the first and the second circuit boards disposed, perpendicular to an axial direction of the lamp tube, in an interior space formed by the lamp tube and in at least one of the two end caps, so that a first direction normal to the first and the second planes is substantial parallel to the axial direction of the lamp tube, and
wherein the part of the electronic components disposed on the first circuit board comprises:
an impedance detection controller, configured to perform, before the LED tube lamp is lighted up, an impedance detection to determine whether the LED tube lamp is electrically connected to a foreign external impedance in series.
2. The circuit board configuration according to claim 1 , wherein at least one of the first and the second circuit boards is arranged toward to an end wall of the at least one of the end caps, along the axial direction.
3. The circuit board configuration according to claim 1 , wherein the first and the second circuit boards are bonded together by wires.
4. The circuit board configuration according to claim 1 , wherein at least one of the first and the second circuit boards is a disk-shaped circuit board having a disk-shaped structure.
5. The circuit board configuration according to claim 4 , wherein a maximum outer diameter of the disk-shaped circuit board is smaller than an inner diameter of the corresponding end cap.
6. The circuit board configuration according to claim 1 , wherein the impedance detection controller causes at least one transient variation to an operating current of the LED tube lamp for detecting an equivalent impedance and limits the operating current of the LED tube lamp to not exceed 5 MIU in root-mean-square (RMS) when the LED tube lamp is electrically connected to the foreign external impedance in series.
7. The circuit board configuration according to claim 6 , wherein a duration of each transient variation does not exceed 1 millisecond when the impedance detection controller performs the impedance detection.
8. The circuit board configuration according to claim 6 , wherein the impedance detection controller causes at least two transient variations within a first detection period when the LED tube lamp is electrically connected to the foreign external impedance in series, a duration of each transient variation does not exceed 1 millisecond, and the time difference between adjacent transient variations is in a range of between plus and minus 15% of 75 milliseconds.
9. The circuit board configuration according to claim 8 , wherein the impedance detection controller causes, after the first detection period, at least two transient variations within a second detection period, and wherein there is a time interval between the first detection period and the second detection period.
10. The circuit board configuration according to claim 9 , wherein the time interval is in a range of 0.5 seconds to 2 seconds.
11. The circuit board configuration according to claim 6 , wherein the impedance detection controller is activated to perform the impedance detection when the LED tube lamp receives an external driving signal, and triggers the transient variation during a falling time of the external driving signal.
12. The circuit board configuration according to claim 11 , wherein the impedance detection controller triggers the transient variation when the external driving signal reaches a first voltage level or a first phase during the falling time.
13. The circuit board configuration according to claim 6 , wherein the impedance detection controller is activated to perform the impedance detection when the LED tube lamp receives an external driving signal, and triggers the transient variation during a rising time of the external driving signal.
14. The circuit board configuration according to claim 13 , wherein the impedance detection controller triggers the transient variation when the external driving signal reaches a first voltage level or a first phase during the rising time.
15. The circuit board configuration according to claim 1 , wherein the other part of the electronic components is disposed on the second circuit board and comprises:
a rectifying circuit, configured to rectify an external driving signal received by the LED tube lamp; and
a filtering circuit, configured to filter a signal received from the rectifying circuit,
wherein the impedance detection controller has a first terminal electrically connected to an output of the rectifying circuit and a second terminal electrically connected to an input of the filtering circuit.
16. The circuit board configuration according to claim 15 , wherein the other part of the electronic components disposed on the second circuit board further comprises:
a driving circuit, configured to generate a driving current for driving an LED module of the LED tube lamp, wherein the driving circuit is electrically connected to the second terminal of the impedance detection controller via the filtering circuit.
17. The circuit board configuration according to claim 15 , wherein the impedance detection controller is configured to receive a first signal reflecting a voltage level of the output of the rectifying circuit by a third terminal.
18. The circuit board configuration according to claim 15 , wherein the impedance detection controller is configured to receive a first signal reflecting a voltage level of the external driving signal by a third terminal.
19. The circuit board configuration according to claim 18 , wherein the other part of the electronic components disposed on the second circuit board further comprises:
a first diode, having an anode electrically connected to a first input of the rectifying circuit, and a cathode electrically connected to the third terminal of the impedance detection controller; and
a second diode, having an anode electrically connected to a second input of the rectifying circuit, and a cathode electrically connected to the cathode of the first diode.
20. The circuit board configuration according to claim 1 , wherein the other part of the electronic components is disposed on the second circuit board and comprises:
a ballast detection circuit, electrically connected to the impedance detection controller, and configured to detect a signal feature of an external driving signal received by the LED tube lamp and determine whether the external driving signal is provided by an electronic ballast or directly by a power grid.
21. The circuit board configuration according to claim 20 , wherein when the external driving signal is provided by an electronic ballast, the ballast detection circuit bypasses at least one component of the impedance detection controller to block the impedance detection.
22. The circuit board configuration according to claim wherein the first circuit board has a male plug and the second circuit board has a female plug configured to connect to the male plug.
23. A circuit board configuration adapted to carry electronic components of a power supply module, wherein the power supply module is disposed in an LED tube lamp having a lamp tube and two end caps connected to respective ends of the lamp tube, and the circuit board configuration comprises:
a first circuit board, having a first plane configured on which to dispose and connect a part of the electronic components; and
a second circuit board, electrically connected to the first circuit board and having a second plane configured on which to dispose and connect another part of the electronic components,
wherein at least one of the first and the second circuit boards is disposed, perpendicular to an axial direction of the lamp tube, in an interior space formed by the lamp tube and in at least one of the two end caps, so that a first direction normal to the first and the second planes is substantially parallel to the axial direction of the lamp tube, and
wherein the first circuit board has a male plug and the second circuit board has a female plug configured to connect to the male plug.