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LED Driver ICs Forum Discussions

User20728
Level 1
First question asked
Level 1
Hello all,

I'm new in this forum and I hope someone will help me on this topic...

I'm realizing a display backlight with TLD5099EP. In the datasheet I'm not able to find the contrast ratio the device is able to manage.
Is there anybody that can share to me this value?
What about the other devices in the family?

Thank you in advance.

Have a nice day,

Jacky
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1 Solution
fausto_borg
Moderator
Moderator 10 likes received 10 sign-ins 5 solutions authored
Moderator
Hi Jacky,

nice to meet you in this forum.

The dimming ratio (called also contrast ratio) is the ratio between the PWM period and the minimum duty time manageable by the DC-DC.

In order to perform dimming without color shift, digital dimming has to be used.

The minimum PWM frequency to avoid flickering is 50 Hz (--> 20 ms period time). The minimum duty time for TLD5099EP is tPWMI,H = 6 us. Then the contrast ratio is 20*10-3/(6*10-6):1 --> 3333:1

See the section "Enable and dimming function" in the datasheet of TLD5099EP

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fausto_borg
Moderator
Moderator 10 likes received 10 sign-ins 5 solutions authored
Moderator
Hi Jacky,

nice to meet you in this forum.

The dimming ratio (called also contrast ratio) is the ratio between the PWM period and the minimum duty time manageable by the DC-DC.

In order to perform dimming without color shift, digital dimming has to be used.

The minimum PWM frequency to avoid flickering is 50 Hz (--> 20 ms period time). The minimum duty time for TLD5099EP is tPWMI,H = 6 us. Then the contrast ratio is 20*10-3/(6*10-6):1 --> 3333:1

See the section "Enable and dimming function" in the datasheet of TLD5099EP