I have a led module with Vin = 12V.

I have made a simple flasher/blinker with 555 and transistor.
But when I connect to the led module, the led module voltage is decreased
for about 0.7V.

So my questions are :
Does anyone have a flasher circuit that does not decrease the led module voltage ?
(the led module have no voltage regulator chip).

I cannot use relay because it's too slow.