TLV700: Reverse current issue

Zhee Loong Woon

Part Number: TLV700

Hi TI,

When doing reverse current check, I found that the Vo > Vin +0.3V for few ms. Thus, I probe the output current to check any reverse current issue.

Question:

1. Is the red box showing reverse current happened once Vo > Vin + 0.3V? If no, what is the correct way to check reverse current?

2. Datasheet shows that external limiting to 5% of the rated output current is recommended. Mean we have to make sure the reverse current spike < 0.05 x 200mA = 10mA during LDO shutting down? Any timing spec?

3. Any proposal for the external limiting current circuit?

4. Is there any risk based on the above waveform as the inrush current is +/-60mA which is ~30% of rated output current?

over 1 year ago

0 Erin Thibeault over 1 year ago

TI__Expert 6570 points

Hi Zhee,

1. Does this condition occur as you are shutting down the device?

2. We recommend limiting reverse current conditions like this per datasheet recommendations. I will check to see if there is a recommended time limit for overcurrent.

3. See this app note for recommendations design recommendations regarding reverse current: LDO Basics: Preventing Reverse Current

4. Ideally, reverse current should not exceed Iout max +5%. Continuous reverse current, or overcurrent conditions could degrade device performance overtime. If this condition is brief, it may not impact performance.

BR,

Erin

0 Zhee Loong Woon over 1 year ago in reply to Erin Thibeault

Prodigy 50 points

Hi Erin,

1. Does this condition occur as you are shutting down the device?

ZL: Yes.

2. & 4. Ideally, reverse current should not exceed Iout max +5%. Continuous reverse current, or overcurrent conditions could degrade device performance overtime. If this condition is brief, it may not impact performance.

ZL: Sorry, I am little bit confuse on the reverse current spec. It should be 5% of the Iout max or 105% of the Iout max?

0 Erin Thibeault over 1 year ago in reply to Zhee Loong Woon

TI__Expert 6570 points

Hi Zhee Loong,

1. This is a reverse current condition.

2. Apologies for the confusion here. Maximum Iout spec is 105% of recommended value for Iout max.

BR,

Erin

0 Zhee Loong Woon over 1 year ago in reply to Erin Thibeault

Prodigy 50 points

Hi Erin,

As a conclusion, there is no risk for the condition of TLV700 with reverse current +/-60mA which is 30% of Iout spec(200mA max), because the max reverse current spec is 105% (210mA max). Correct?

0 Zhee Loong Woon over 1 year ago in reply to Zhee Loong Woon

Prodigy 50 points

Hi Erin,

Any update?

0 Erin Thibeault over 1 year ago in reply to Zhee Loong Woon

TI__Expert 6570 points

Hi Zhee Loong,

Thanks for your patience here. You are correct, there is no risk for the condition of TLV700 with reverse current +/-60mA which is 30% of Iout spec(200mA max), because the max reverse current spec is 105% (210mA max).

BR,

Erin

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TLV700: Reverse current issue