Linear solid-state lighting with galvanic isolation
A linear light-emitting diode (LED)-based solid-state lamp comprising an LED driving circuit, LED arrays, at least one pair of electrical contacts, and a controller, is used to replace a fluorescent tube or a conventional LED tube lamp in an existing lamp fixture. The controller and the at least one pair of electrical contacts are configured to perform galvanic isolation between the controller and the LED driving circuit connecting with LED arrays. Thus an overall through-lamp electric shock current can be limited only from the controller, eliminating a substantial electric shock current flow through the LED driving circuit and subsequently the LED arrays. The scheme can effectively reduce a risk of electric shock and an internal fire hazard to users during relamping or maintenance.
1. A linear light-emitting diode (LED) tube lamp, comprising:
a housing having two ends;
at least one light-emitting diode printed circuit board (LED PCB) disposed between the two ends of the housing, the at least one LED PCB having LED arrays fixed thereon, the LED arrays having two inputs;
an LED driving circuit connecting to the LED arrays on the at least one LED PCB, the LED driving circuit having two inputs;
two lamp bases respectively connected to the two ends of the housing, each lamp base comprising at least one electrical conductor connecting to a lamp fixture socket;
at least one pair of electrical contacts; and
a controller receiving power from a rectified direct current (DC) voltage, the controller comprising an isolation module configured to perform galvanic isolation between the controller and the LED driving circuit connecting to the LED arrays,
wherein:
when the at least one pair of electrical contacts are not electrically connected, a through-lamp electric shock current does not flow through the LED arrays; and
when the at least one electrical conductor in each lamp base is inserted into the lamp fixture socket, the at least one pair of electrical contacts are actuated to deliver electrical power from the at least one electrical conductor in each lamp base to the LED arrays.
2. The linear LED tube lamp of claim 1 , wherein the isolation module comprises an opto-coupler or an opto-isolator.
3. The linear LED tube lamp of claim 1 , wherein the at least one pair of electrical contacts comprise electrical terminals of at least one triac.
4. The linear LED tube lamp of claim 1 , wherein the at least one pair of electrical contacts comprise electrical terminals of at least one electronic switch comprising a metal-oxide-semiconductor field-effect transistor (MOSFET), a transistor, a back-to-back thyristor, a silicon-controlled rectifier (SCR), or a combination thereof.
5. The linear LED tube lamp of claim 1 , wherein the controller further comprises a wireless receiver configured to receive a signal and to control the at least one pair of electrical contacts.
6. The linear LED tube lamp of claim 5 , wherein the wireless receiver comprises a radio receiver, an infrared receiver, an audio receiver, or an internet-based receiver controllable by a smart phone.
7. The linear LED tube lamp of claim 1 , wherein the controller comprises a hardwired receiver configured to receive a signal and to control the at least one pair of electrical contacts.
8. The linear LED tube lamp of claim 7 , wherein the hardwired receiver operates based on a protocol of RS232, RS485, DMX512, Universal Serial Bus (USB), or Digital Addressable Lighting Interface (DALI).