Tubular device for fitting to a tubular light fitting
A tubular solid state lighting device has a pin safety circuit electrically connected to connection pins of the one end. The pin safety circuit comprises two protection components, of different types. In one set of examples, there is an electrically controlled isolation switch and an electronic switch which functions as a high voltage isolation barrier. The switch provides full galvanic contact separation, whereas the isolation barrier provides current protection if the isolation switch is not functional. In another set of examples, there is a mechanically controlled isolation switch and an electrical or electronic isolation barrier. This provides two levels of protection, but requiring only a single manual operation by the installer of the lighting device. It avoids end-of-life protection circuitry being triggered during the installation of the lighting device.
1. A tubular solid state lighting device for receiving a high frequency signal, comprising:
a tubular housing having an elongate axis and first and second opposite ends, each end comprising two projecting electrical connection pins;
a safety circuit electrically coupled between connection pins of the first end and connection pins of the second end,
wherein the safety circuit comprises:
an electrically or mechanically controlled isolation switch providing a clearance distance;
a triac connected in series with the switch; and
a triac gate control circuit, wherein the triac gate control circuit comprises a high frequency detection startup circuit and wherein the high frequency detection startup circuit comprises an RC filter circuit for closing the triac when a high frequency voltage is present across terminals of the triac.
2. The tubular solid state lighting device as claimed in claim 1 further comprising:
a rectifier circuit, wherein the pins of the second end are electrically connected to the rectifier circuit;
a lighting driver circuit powered by the output of the rectifier circuit; and
a solid state lighting arrangement.
3. The tubular solid state lighting device as claimed in claim 1 , wherein the pins of the first end are electrically connected to the safety circuit through a first filament emulation circuit comprising a series resistor arrangement, and the pins of the second end are electrically connected to the rectifier circuit through a second filament emulation circuit comprising a series resistor arrangement.
4. The tubular solid state lighting device as claimed in claim 1 , wherein the electrically controlled isolation switch comprises an electrical relay.
5. The tubular solid state lighting device as claimed in claim 1 , wherein the triac comprises a three or four quadrant triac.
6. The tubular solid state lighting device as claimed in claim 1 , wherein the triac gate control circuit further comprises a voltage supply and a gate resistor.
7. The tubular solid state lighting device as claimed in claim 3 , wherein the high voltage isolation barrier comprises a thyristor between the rectifier and the LED driver.
8. The tubular solid state lighting device as claimed in claim 1 , wherein the solid state lighting arrangement comprises an LED arrangement and the lighting driver circuit comprises an LED driver.
9. A lighting fixture comprising:
an electronic fluorescent lighting ballast; and
the tubular solid state lighting device as claimed in claim 1 fitted to the fluorescent lighting ballast.