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Hello all,
I'm having major issues with the TPS25923 in a simple, no external MOSFET configuration, for the purposes of protecting an ADC circuit's power input.
I take in 5V and run it through the eFuse out to the TPS6209733 3.3V power regulator, and at first was getting no power through the fuse at all. Below is my schematic.
I identified the problem as being with 'R14' - I had taken the documentation too literally and set the resistor to 0, which was passing no voltage to the EN_UVLO and therefore the fuse was shutdown permanently. After replacing the resistor with a 430k, to produce a undervoltage limit of about 4.6V (by my calculations) the eFuse is now passing current, but instead my scope trace comes out like this (yellow is input power, blue is output):
In the interest of time, I need to eliminate any still-standing issues with my original design, can anybody see any other mistakes I've made that could result in unusual behavior such as this?
If not, could this behavior be indicative of a fault further down the chain from my included schematic, such as a poorly fabricated section of the PCB/short circuit?
To me, my inexperienced impression is that the eFuse is repeatedly going into shutdown for some reason due to the way the power line signal behaves, but that's not backed by anything solid.
Thanks in advance,
Louis
Hi Rakesh,
I've made the alteration of adding a 470pF to pin 1 and now the eFuse is passing no current at all.
The max load on the 3V3 line is roughly 200mA, purely used for logic level conversion of certain IO.
The voltage threshold is actually set higher than 4.4V, as per my original post, to 4.6V.
Do you need any additional information or schematics?
Many thanks,
Louis