Power management

Power management forum

State
Locked Locked
Replies 4 replies
Subscribers 63 subscribers
Views 257 views
Users 0 members are here

Support feedback

Options

Options

Related

TPS61500: As Backlight for 5 LCd's

Jonas Botzenhardt

Prodigy 10 points

Part Number: TPS61500

Hi, TI Support Team

I want to drive 5 LCDs (EA TFT020-23AI), that require 24V, 20mA each. I have the circuit from the datasheet and I get about 24V, so far so good. But on LED+ there are synchronously with Fs noises of 2.5V. These fluctuations cross-talk on the SPI communication and interfere with the writing to the LCDs.

What can I do to reduce these fluctuations?

Thanks

over 2 years ago

0 Patrick Yao over 2 years ago

TI__Mastermind 34780 points

Hi Jonas,

Could you please capture the waveform of SW node?

BR

Patrick

0 Jonas Botzenhardt over 2 years ago in reply to Patrick Yao

Prodigy 10 points

Hi Patrick

Thanks for youre response.

Here is the waveform on the SW Pin. Hopefully it helps you.

Thanks Jonas

0 Patrick Yao over 2 years ago in reply to Jonas Botzenhardt

TI__Mastermind 34780 points

Hi Jonas,

I'm on a biz trip and will reply to your questions this Friday. Sorry for the inconvenience and thanks for your patience.

BR

Patrick

0 Patrick Yao over 2 years ago in reply to Jonas Botzenhardt

TI__Mastermind 34780 points

Hi Jonas,

Sorry for the late reply.

In your previous post you said that the LCD voltage is 24V typical, but the SW waveform shows that peak voltage over 30V. Have you checked this yet?

And could you please send me your layout for double check?

BR

Patrick