TLV9154: Burn-test problem check

Jenny Chen

Part Number: TLV9154

Hi team,

The customer encountered an issue during the burn-in test.
Test conditions:
Ambient temperature: 45°C
Input: 300 Vac / 50 Hz
Output: 48 V / 90 A
After approximately 30 minutes of burn-in, high-frequency noise was observed on the OPA output. This noise interferes with the control loop and causes a momentary increase in output power, which then triggers OCP protection.
The issue typically occurs after nearly 30 minutes of burn-in, at which point the IC temperature may rise above 90°C. We have also confirmed that the IC Vcc voltage remains stable at 3.3 V during the event.
From the waveform, it appears that a sudden rise in the OPA output may be causing the control malfunction. Since this phenomenon only occurs at high temperature, we suspect that the OPA may be entering thermal protection due to overheating.
We would like to ask:
1. What could possibly cause this type of waveform behavior?
2. For this condition, are there any recommended thermal improvement solutions? (ex: are there any internal thermal pin for this device?)

Waveform channels:
Ch1: DAC (represents Vout feedback = OPA output)
Ch2: Iout
Ch3: Vout
Ch4: Iout feedback (OPA output)

Thank you.

3 days ago

+1 Chris Featherstone 3 days ago

TI__Mastermind 27615 points

Hi Jenny,

It is difficult to determine the root cause with the information provided. Based on the burn-in conditions described, one possibility is that the device's thermal protection may be activating, particularly if there are significant output current demands on the TLV9154.

Are you able to share additional information such as:

Schematic
What is the output current that is being demanded from the TLV9154
What is the supply condition of the TLV9154
Any other relevant details would be appreciated.

Note that the device has thermal protection and if it is indeed kicking in, you may see unexpected behavior. When thermal protection engages, the output stage can momentarily disable. This loss of drive may appear as unexpected transitions in a control loop system. See the excerpt from the datasheet below.

Best Regards,

Chris Featherstone

0 Jenny Chen 2 days ago in reply to Chris Featherstone

TI__Expert 4850 points

Hi Chris,

Could you please clarify why you believe the device is entering thermal protection?

Based on the schematic, are there any optimization suggestions to prevent this issue?

We’d like to check if any recommend methods to reduce temperature? we want to try to control the thermal first time see if the issue can be resolved.

Vout feedback

Iout feedback

Thank you.

BR,

Jenny

+1 Chris Featherstone 2 days ago in reply to Jenny Chen

TI__Mastermind 27615 points

Hi Jenny,

When I click on the images they are very low resolution and I can't make out the component values.

Jenny Chen said:
Could you please clarify why you believe the device is entering thermal protection?

You mentioned that this is a burn in test. While a temperature of 45 degrees C is within our recommended operating temperature range you also mentioned very high levels of current. Specifically:

Input: 300 Vac / 50 Hz
Output: 48 V / 90 A

For this reason I would like to know the following:

What is the output current that is being demanded from the TLV9154
What is the input voltage to the TLV9154
What is the supply condition of the TLV9154
Any other relevant details would be appreciated.

This will help us understand if there is a power demand issue that is causing the die temperature to increase beyond the normal operating temperature.

If you can re-upload the schematic in a higher resolution that would also help us.

Best Regards,

Chris Featherstone

0 Jenny Chen 1 day ago in reply to Chris Featherstone

TI__Expert 4850 points

Hi Chris,

Understood. Have send your schematic via mail.

What is the output current that is being demanded from the TLV9154 -> less than 1mA since only for signal (DC)
What is the input voltage to the TLV9154 -> Vcc=3.3V, th3 highest signal voltage is 3.3V as well
What is the supply condition of the TLV9154 -> LDO

Please help to look into the issue.

Thanks a lot!

Jenny

0 Chris Featherstone 1 day ago in reply to Jenny Chen

TI__Mastermind 27615 points

Hi Jenny,

Jenny Chen said:
The issue typically occurs after nearly 30 minutes of burn-in, at which point the IC temperature may rise above 90°C.

Jenny Chen said:
From the waveform, it appears that a sudden rise in the OPA output may be causing the control malfunction. Since this phenomenon only occurs at high temperature, we suspect that the OPA may be entering thermal protection due to overheating.

Jenny Chen said:
Ambient temperature: 45°C
Input: 300 Vac / 50 Hz
Output: 48 V / 90 A

If the output current demand of the TLV9154 is less than 1mA and the supply is stable at 3.3V then I don't see how the die temperature is rising to 90 degrees C unless there is something unrelated to the OPA that is demanding a high amount of current on either its input or output.

Question:

Is there anything in the circuit that is unexpectedly demanding high levels of current from the TLV9154?
Is it possible that something in the circuit is causing an electrical overstress event onto the TLV9154?
There are two circuits that were provided. Has the problem been isolated to one of the circuits? I suspect the Vout feedback circuit. See below.

Jenny Chen said:
We’d like to check if any recommend methods to reduce temperature? we want to try to control the thermal first time see if the issue can be resolved.

I have simulated both circuits in Tina Ti. I see 3dB of gain peaking in the circuit. This potentially means that there could be a stability issue. It may be marginally stable at room temperature and then at hot it may go unstable. Or it is unstable and getting hot from being unstable.