EEVblog Electronics Community Forum

Electronics => Projects, Designs, and Technical Stuff => Topic started by: envisionelec on April 11, 2019, 01:08:23 pm

Title: High Praise for the TI TPS6204X in a fault condition
Post by: envisionelec on April 11, 2019, 01:08:23 pm

A recent hand-built prototype turned up on my desk with "low voltage rails" tagged on it. It uses a 1.8V and 3.3V buck regulator formed by a pair of TPS6204X ICs. The rails were at 1.6V and 3.0V, respectively...odd, especially considering these are both fixed voltage devices. A quick FLIR image of the board showed some rapid heating of the two switcher ICs and local bypass tantalum capacitors. On further investigation, I found both SMD inductors were each turned 90 degrees on their pads, effectively sending the SW node straight into the bypass cap. What I found curious and quite impressive is that the devices held the rail voltage at a safe level in spite of this failure.

What are some unexpected but "happy" failures you've experienced?

Title: Re: High Praise for the TI TPS6204X in a fault condition
Post by: OwO on April 11, 2019, 01:25:08 pm

I'm only surprised that the buck IC didn't blow up like other TI power management chips tend to do :-DD

All the cheap buck ICs with integrated MOSFET have cycle-by-cycle current limiting and would have been fine as well, these use analog circuitry which can respond fast to overcurrent and overtemperature while the TI chips tend to just be a MCU and power transistors slapped onto the same die.