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LED Driver ICs Forum Discussions

User20728
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First question asked
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How to reduce LED current inaccuracy when using analog dimming with TLD5097EP, TLD5098EP and TLD5099EP?
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1 Solution
fausto_borg
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Moderator 10 likes received 10 sign-ins 5 solutions authored
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Hello Robert,

to dim the LED current you have to change the voltage on the SET pin.
To do that, a resistor divider from IVCC is the good choice.
the first idea that came to my mind is to use just a trimmer
4910.attach

It has the drawback that for more than 2/3 of trimmer turns the LED light is not dimmed.
Otherwise you can use two resistors to generate the desired voltage to be applied to SET pin. The circuit here below shows this option
4911.attach

If you want to dim the LED current online, R2 can be changed with a trimmer
4912.attach

you can find more information on the application notes and datasheets of LITIX Power devices

View solution in original post

4 Replies
j_oehmen
Moderator
Moderator 10 replies posted 5 replies posted 10 questions asked
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When pin IVCC is connected to SET by a resistor divider (see the application information section in the datasheet) , the IVCC capacitor has to be as close as possible to the IVCC pin. Otherwise the IVCC signal may become noisy. This noise may then be visible at the SET pin and therefore changing the output current unintentionally.
See https://www.infineon.com/cms/en/product/power/lighting-ics/litix-automotive-led-driver-ic/litix-powe... for more datasheets and application notes on our boost controllers
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User21078
Level 1
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Can you dim an LED with a resistor?
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henrylmosley
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First reply posted First like given Welcome!
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You need to use a more sensitive resistor to get a more accurate result and maybe become a bit more patient. I usually recommend consulting a professional who can even advise you by online video chat, but I think the solution suggested above will also work for you. Be sure to change the voltage on the SET pin to reduce the LED current.

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fausto_borg
Moderator
Moderator 10 likes received 10 sign-ins 5 solutions authored
Moderator
Hello Robert,

to dim the LED current you have to change the voltage on the SET pin.
To do that, a resistor divider from IVCC is the good choice.
the first idea that came to my mind is to use just a trimmer
4910.attach

It has the drawback that for more than 2/3 of trimmer turns the LED light is not dimmed.
Otherwise you can use two resistors to generate the desired voltage to be applied to SET pin. The circuit here below shows this option
4911.attach

If you want to dim the LED current online, R2 can be changed with a trimmer
4912.attach

you can find more information on the application notes and datasheets of LITIX Power devices