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13 Threads found on White Led Drive
So for Ic=330mA max and T=63%3.3V=RC and 99%Vin=5xRC ** How long will it take to power up your Cap to say drive a 1W white led which as a threshold of 2.85V at say 10% of Imax or 10%*330mA and an ESR of ~1/Pmax =1 Then your Cap has an ESR of ?? How long would expect to run the led with an added Rs=1Ω If (...)
Your input rectifier capacitance ratio is too high and attenuates the RF!! 100mW*50=V^2, V=2.2V which enough to drive a Red HB led with a Vf of 2.2V and threshold of ~1.85V , while a Blue or white led has a Vth of 2.85 and Vf=~3~3.2V use a 10R series in each led and draw 50mW from your excess power via (...)
Two series power white leds will work fine directly across two 3.6v 14500 only when Charger is OFF. They will be much dimmer at 3V per led which is when the SoC of LiPo drops to 0. MOSFET switch must be much less than ESR of led's which is around 1 Ohm @ 1Watt. So choose <<100 mOhm. with logic level drive.
The white leds in your ebay link have a voltage of from 3.4V to 3.6V and says their current MUST be limited to 20mA By Your Circuit. They will burn out instantly if you feed them 5V. They are bright probably because the case focusses the light into a very narrow beam. The led strips need to have the connectors they sell. Many solar garden (...)
What kind of led you are using? Considering white led's you usually drive them with constant current to avoid violating the Absolute Maximum Current Rating and compromising the reliability and to obtain predictable and matched luminous intensity. you need some sort of voltage/current regulators. Like this one... - - - (...)
There is a type of oscillator popularized by the name 'joule thief', which can extract juice from a battery that is drained below 1V, and drive a bright white led (which requires 3.6V). Its name is blocking oscillator. It's made from a handwound transformer using a small core. Typical operating frequency is 10kHz to 100 kHz. Try a web (...)
if it is white led, check for 3V drop with ohm meter Anode is the +side. The call them either Cathode Row or Anode Row. If "Cathode Row" then drive Cathodes with low side drivers and Anode Columns with high side driver. If "Anode Row" then drive Anode Rows with high side (...)
Buy a boost converter type driver with an analog control input. Higher-color (and white) leds need more than 3V forward to light.
Hellow. I need to have an exilent circuit to drive white led from 6V or 12V battery. Application can be varried from one led to 100 leds. Please help. Regards Vicky What is your led rating?
This should answer your question: "Why drive white leds with Constant Current?" Regards, IanP
PLEASE TELL ME THAT WHY WE REQUIRE A led driveR FOR white ledS, AS IF RED, GREEN ,BLUE, YELLOW ledS DOES NOT REQUIRE ANY DRIVING CIRCUIT Not all leds requier a drive circuit because of the current they require. It also depends on the circuit in the first place (if the (...)
Now I want to drive about 8 white leds in series and the current through them is 330mA, so the total power is above 8wat, I want a step up architecture, but it seems that this kind of product doesn't exsit. I doubt if this IC is available?
In the recently, the white led is popular. The driver of white led is designed by many company. What is the most popular driver of white led? Try this link