TPS54200: TPS54200DDCR Performance problem

yingjiao LI

Part Number: TPS54200

Debug between led+ and led-, using a 200Ω resistor

The pwm uses 3.3v direct power supply, and the lamp series uses a resistor instead, but the fb pin voltage is always 100mv

Could you please help confirm the cause

Thank you.

6 months ago

0 Steven Li 6 months ago

TI__Genius 16630 points

Hi Yingjiao,

May I understand what is your power-on sequence of VIN and PWM 3.3V direct power supply?

Best Regards,

Steven

0 yingjiao LI 6 months ago in reply to Steven Li

Intellectual 975 points

As shown in the schematic diagram, vin is 24v input, pwm is powered on by 3.3v alone, and the output is connected to two strings of led, each string has seven led, it is supposed that the fb pin feedback voltage is 200mv under the condition of 3.3v pwm, but the actual measured value is 100mv, and the power is powered on after pwm

Below are the led parameters I used

0 Steven Li 6 months ago in reply to yingjiao LI

TI__Genius 16630 points

Hi Yingjiao,

Please try first powering on the VIN, and then PWM 3.3V direct power supply and see if this helps.

Best Regards,

Steven

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TPS54200: TPS54200DDCR Performance problem