TPS923652: TPS923652: TPS923652 may be damaged during use

DK Purchaser

Prodigy 10 points

Part Number: TPS923652

It is designed to drive a 24V 0.4A high-brightness screen.

The frequency is set at 400KHZ, and the MCU is used to send a 10KHZ PWM signal to the ADIM PIN as analog dimming.

During the testing process, TPS923652 was occasionally damaged.

We designed it in mid-2024. In the latest data manual, we found that CSN and CSP have a set of RC.

Datasheet says it is optional and is for noise filtering purpose.

However, we didn't reserve a position for R, so we came up with an alternative solution. We pulled down a set of R+C to ground at the SW end. The resistance of R is 10 ohms, and the capacitance of C is 4.7nF. So far, no damage has occurred during testing. Could this also solve the damage issue?Or is there any risk associated with this RC?

5 个月前

0 Eirwen 5 个月前

TI__Mastermind 41555 points

Hello, we have received your case and the investigation will take some time. Thank you for your patience.

0 Eirwen 5 个月前回复 Eirwen

TI__Mastermind 41555 points

Could you pls share me the schematic before and after? May I know the input voltage? I suppose 24V is VLED(LED forward voltage)

When the damage happen, do you have waveform of VIN, SW, and ILED? Is this just happen occasionally or can be reproduced?

0 DK Purchaser 5 个月前

Prodigy 10 points

Hi Eirwen,this is our schematic diagram. The input voltage is 12V, the output voltage is 39v when there is no load.When no load connect,the output voltage is 24v.

When the damage happen, the VIN,SW and VLED are all 12V. The issue may still reoccurs after replacing the IC.

0 DK Purchaser 5 个月前回复 Eirwen

Prodigy 10 points

The following three waveforms represent the waveform of the SW backend under no load, the waveform of the SW backend under load, and the waveform of the SW backend after adding RC.

0 Eirwen 5 个月前回复 DK Purchaser

TI__Mastermind 41555 points

Let me review the schematic and get back to you soon. Thank you!

0 Eirwen 4 个月前回复 Eirwen

TI__Mastermind 41555 points

Yes, Rflt and Cflt are required for robustness.

DK Purchaser 说：
In the latest data manual, we found that CSN and CSP have a set of RC.

The function of Rflt/Cflt and RC snubber are different. It will be good to add RC snubber which can help to suppress excessive switching spikes and ringing.

DK Purchaser 说：
However, we didn't reserve a position for R, so we came up with an alternative solution. We pulled down a set of R+C to ground at the SW end.

From the waveform shared, it looks good and seems like it's not the waveform when the issue happen. For the recommendation, both Rflt/Cflt and RC snubber are suggested in order to improve the robustness.

DK Purchaser 说：
So far, no damage has occurred during testing. Could this also solve the damage issue?Or is there any risk associated with this RC?

Thank you!

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TPS923652: TPS923652: TPS923652 may be damaged during use