TPS61028, TPS61025 Question

Toshio Ushikubo

Other Parts Discussed in Thread: TPS61028

Hello,

Please answer following question from customer.

Q1:

In case of VBAT is supplied form battery and battery is discharged, start-up rush current may cause battery voltage decrease to UVLO voltage and converter will shut down. After shut down battery voltage will rise (because of no load) and converter start again. And converter may continue to recycle shutdown and start.

Please advise if abnormal current that cause problem or damage will flow while above situation.

Q2:

Please advise the deglitch time of UVLO.

Best Regards.

over 9 years ago

0 Jasper Li over 9 years ago

TI__Mastermind 46905 points

it look like the batter is too week to start up the TPS61028. this doesn't damage the device, but you may to find other solution. may i know the VIN, VOUT, IOUT condition, which kind of battery is using?
you can also refer to this application note about reducing the input inrush current "www.ti.com/.../getliterature.tsp

0 Toshio Ushikubo over 9 years ago in reply to Jasper Li

Mastermind 9620 points

Hello Jasper-san,

Thank you for your answer.

I will ask customer if lower input voltage device (ex. TPS6120x) is suitable or not.
But could you continue to answer additional question.

Q3
Please advise if reverse current from VOUT to SW will flow or not and device may be damaged or not when input voltage is 0V and 1V is remaining at output capacitor.

Best Regards.

0 Jasper Li over 9 years ago in reply to Toshio Ushikubo

TI__Mastermind 46905 points

No. it is OK that VIN=0, and some voltage at VOUT pin

0 Toshio Ushikubo over 9 years ago in reply to Jasper Li

Mastermind 9620 points

Hello Jasper-san,

Please answer additional question.

Customer wants to add 100kohm and 1uF RC low-pass filter between input voltage and EN terminal to delay the start timing.
Could you please advise if EN terminal has any restriction of rise and fall time.

Best Regards.

0 Jasper Li over 9 years ago in reply to Toshio Ushikubo

TI__Mastermind 46905 points

The EN pin is just logic input pin. it would not have restriction on the rising and falling time.

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TPS61028, TPS61025 Question