TPS2116: Voltage Drop During TPS2116 Power Path Switching

Conor

Part Number: TPS2116
Other Parts Discussed in Thread: TIDA-01638

Tool/software:

Hi,

We are currently evaluating the TPS2116 in a power path switching application and would appreciate your technical guidance on the following issue.

【Configuration】

VIN1: VCC_5V
VIN2: VBUS
Cout: 10uF

【Issue】
When switching from VIN1 to VIN2 or from VIN2 to VIN1, we observe a momentary voltage drop of approximately 1V at VOUT.
We are aiming to reduce this voltage drop to within 200mV. However, increasing Cout beyond 10uF did not yield significant improvement.

【Questions】

Is this behavior expected based on the TPS2116's internal operation?
Are there any recommended measures to limit the voltage drop to under 200mV?

Conor

10 months ago

0 Kunal Goel 10 months ago

TI__Guru* 79151 points

Hi Conor,

Please let me check and get back.

Regards

Kunal Goel

+1 Kunal Goel 10 months ago in reply to Kunal Goel

TI__Guru* 79151 points

Hi Conor,

1. Within switchover response time voltage drop is a function of load cap and load current.

2. Maybe you can increase switchover threshold of VIN.

0 Conor 10 months ago in reply to Kunal Goel

Guru 14080 points

Hi Kunal,

The relationship between Vdip and Cout is also specifically described in Chapter 2.2.3 "Output Voltage Dip and Fast Switchover" of TI's "TIDA-01638 Application Report".

TIDA-01638 Application Report: Seamless Switchover for Backup Power Reference Design
https://www.ti.com.cn/cn/lit/ug/tidue50/tidue50.pdf

Based on this formula, in order to keep Vdip at about 0.2V, an output capacitor of about 50µF or more may be required in the current usage environment. Is it okay to consider adding Cout using this formula as a guide?

The background to the question is that this "Seamless Switchover for Backup Power Reference Design" is written for the TSP2121, so I am wondering if the same calculation is applicable to the TPS2116.

Thanks,

Conor

0 Kunal Goel 10 months ago in reply to Conor

TI__Guru* 79151 points

We just need to adjust formula with response time of tps2116.

I am on leave this week. Please expect delay in response

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TPS2116: Voltage Drop During TPS2116 Power Path Switching