TP5100 module fails when connecting and disconnecting under load.

[arlaneenalra]

I've seen the TP5100 module release the magic smoke (literally though with very little visible damage) on a few occasions when connecting power to the PSU board, especially when it's under load (i.e. the system is booted).

The TP5100 modules I've seen are common and all seem to have the same configuration. (See https://www.jotrin.com/technology/details/tp5100-lithium-battery-charger-module for the common configuration).

By default, the come configured for 2A charging (with to 0.1ohm resistors in parallel to get 0.05ohm). This configuration seems to be the absolute maximum of the board. It's possible there's a transient on connection that pulls damages the chip or that something is over currenting the chip.

See: http://toppwr.com/uploadfile/file/20230304/6402f53e7e8d9.pdf

A couple of theories:

• The 2A charge rate runs too close to the boards maximum and a transient during charger insertion overloads it.
• There could be an input voltage dip when the charger is plugged in due to the load on the 15v converter and the start up current of the charging unit. The 1400HD power brick is rated for 12V@2.2A, it's possible the input voltage to the switching unit in the TP5100 drops when connected under load and over currents the module.

Possible fix:

• Pull one of the 0.1ohm resistors to drop the charging current down to 1A instead of the 2A it ships with.

[arlaneenalra]

Charging current alone is not the answer. I had a module setup for 1A toast itself when I turned flipped the power switch while the unit was plugged in charging. It started buzzing and quickly overheated .. not sure what's going on.

[arlaneenalra]

Further evidence that this module is basically junk https://secondlifestorage.com/index.php?threads/we-have-ignition-tp5100-fiery-fail.10753/ ... from what I can tell, it's missing filtering capacitors and seems to be known to just straight up fail when running anywhere close to 12v input .. hmm.

There seems to be evidence that at least some variants actually have a top voltage limit of 10v instead of 12v https://secondlifestorage.com/index.php?threads/we-have-ignition-tp5100-fiery-fail.10753/

https://secondlifestorage.com/index.php?threads/we-have-ignition-tp5100-fiery-fail.10753/post-87233

Most datasheets say 18-20V max, but the one I bought (from LCSC) says 10V (https://datasheet.lcsc.com/lcsc/221...Extension-Microelectronics-TP5100_C379389.pdf) Maybe Top Power ASIC revised the chip and upped the specs, or it's the same chip, but limited the VIN due to failures. I emailed the manufacturer, but maybe someone here knows?

[arlaneenalra]

Looks like the addition of a 330uF capacitor might actually solve the issue. https://www.reddit.com/r/PCB/comments/1gy4iw2/comment/lyowm1n/ When switching you get a voltage spike the external supply that can jump to +20v. Well above the absolute maximums of the TP5100 chip. Based on the document linked in that comment, this can be made worse by ceramic capacitors on the charging module. Attaching a 330uF electrolytic to the input seems to be enough to prevent the chip from going boom. At least in the units I've got. I'm also reducing the charging current by removing one of the 0.1ohm resistors just to be on the safe side. The whole external supply can only handle 2.2a and this module is supposed to be able to draw 2a on it's own, reducing the charging current should pull it back into a safe range for the external brick. (at least on the HD variant).