Put HVLED815pf to sleep, is possible?

fabioeb · ‎2013-04-17

Posted on April 17, 2013 at 11:53

Hello, I've prototyped a led driver built around

an HVLED815PF, it's woking nicely.

Now I'd like to add an integrated day/night

switch to the lamp, with minimal components.

Is it possible to put the HVLED815 in some

sort of sleep-mode or standby, with minimal

power consumption from th supply

(while the rectified mains is still on the drain)?

Or I have to disconnect the circuit form

the mains supply?

The lamp is a 10W led lamp, powered from 230V mains,

high power factor circuit, not dimmable, built adapting the

AN4129 schematic and component values.

Thanks,

Fabio Eboli

#hvled815 #led

fabioeb · ‎2013-04-22

Posted on April 23, 2013 at 00:10

Hello, I reply to myself and come back with

one solution and more questions, maybe this can be

helpful to somebody else.

The solution it to change the output voltage, changing the

divider ratio to DMG pin trough a transistor.

This changes the maximum output voltage allowed.

Putting the max voltage value below the leds forward voltage,

shuts down the psu and makes it work in burst-mode.

But I'm still not satisfied, the driver still takes approx

4mA of current from mains. Observing

the collector, I see that it checks the voltage, pulsing

the drain each 500uS, as per datasheet. After 40-60mS

it restarts and recovers the voltage lost on the output capacitors.

The secondary has a bleeder resistor, now the problem is:

how could I reduce the power taken from mains?

If I raise the value of output bleeder resistor, probably I will

slow down the restarting rate, reducing the power

dissipated on the resistor, but the leds keep glowing.

Is this due to excessive leackage inductance on the

ferrite core?

If I reduce the output resistor, I can make the leds

shut down, but the psu will take more current from

mains.

Any ideas is welcome... ST engineers, are you around here? ;)

Thanks.