I want use TPS26625 as protection of power supply for 24mA current loop. Schematic is on next picture. I have problem with short protection. I have load 10mA and start-up is correct (pic1). If I connect short on output (connect VOUT to GND) and disconnect short after it, thou output is still power off. Auto retry don’t start(pic2).
Start-up (pic1)
yellow - Vin, blue - Vout, pink - Iout
Short (pic2)
yellow - Vin, blue - Vout, pink - Iout
Thanks for help.
Hi,
Firstly, I use direct wire connection (red on schematic). In second case, I used mechanical switch with two resistor (its green one). Both solution has same result, auto-retry not work.
On VIN I haven’t any overshoot, on output I use TVS in schematic and no undershoot present on VOUT.
Marking:
The part is from TI samples.
I have two prototype board and both has same problem.
And there is answer for point 5:
I think all is correct: overvotage is 25.44V and undervotage is 22.12V
Hi Jan,
1. What I meant is in your design OVLO rising is 25.44V. That means when VIN goes above 25.44V eFuse is cut off. Now again to turn on eFuse VIN should go below OVLO falling threshold which is 23.265V in your case. Bur since your typical application voltage is 24V so once your system enters into overvoltage and if VIN does not go below 23.265V device will not turn on back.
2. I am thinking if VIN is jumping above 25.44V during short , it show as max as 26V and then not going below 23.265 could cause part to latch.
3. Also can you share your layout for review?
4. To look for undershoot and overshoot you should probe close to VIN and VOUT pin and observe at zoomed in scale. VOUT scale you can reduce to something 2V/div.
Regards
Kunal Goel
