TPS55340EVM-017: Regulating load current

Justinas

Part Number: TPS55340EVM-017
Other Parts Discussed in Thread: TPS55340, TPS61500

Hello everyone,

I'm here with few questions. How can I regulate TPS55340 EVM-017 load current while keeping Vin constant? I want to regulate the intesity of light from diodes strip. And can I change those diodes, in order not to burn them while testing, with a transistor base connected to evm and a LED connected with emmiter to watch whether current is flowing. Keeping trasnsistor's gain in mind.

Best regards,

Justinas

over 8 years ago

0 Youhao Xi over 8 years ago

TI__Guru* 78735 points

It seems you want to create a current source. You need to put the LED in series with a load sense resistor, and use that that sense resistor voltage as the feedback voltage. The controller will regulate that feedback voltage, which means the load current. If your LED current is high, the TPS55340 can would not appear to be the right choice, because the FB voltage is 1.23V, implying a big power losses at the load current sense. You may consider the Boost LED drivers. Check TI website for various products.

0 Helen chen over 8 years ago

TI__Mastermind 40080 points

Could you please specify the Vin range, LED voltage, Current to us?

0 Helen chen over 8 years ago

TI__Mastermind 40080 points

You can check TPS61500, this part is for LED driver applicaiton, but this but not belong to our team.

0 Justinas over 8 years ago in reply to Helen chen

Prodigy 120 points

Thank you for your answers. I'm willing to use input from 5V to 12V. LEDs will be 24V and drawing around 0.6A of current. I want to dim them using this module, because that's the only option i've got for now.

Best regards,

Justinas

0 Helen chen over 8 years ago in reply to Justinas

TI__Mastermind 40080 points

TPS61500 can support 24V/0.5A output. 0.6A output is not enough.

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TPS55340EVM-017: Regulating load current