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MAX17578 Production
The Himalaya series of voltage regulator ICs, power modules, and chargers enable cooler, smaller, and simpler power-supply solutions. The MAX17577 and...
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MAX17578 on Analog.com

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MAX17578 output drop down

moned

on Nov 26, 2025

Category: Hardware

Product Number: MAX17578

Hi,
In order to create a negative 12V for dual opamp, I used the MAX17578, with the proposed schemtic in the DS:

On start-up I have a 200mA current drawn on -12V, and a stabilised current 20mA. However, the output voltage does not regulate, and stuck a ~-0,8V.
Any ideas of the problem ?
Thanks a lot,

Mo"

tonie

on Nov 27, 2025 5:28 AM
0
Hello, have you tried without load during start up? You can further measure the EN/UVLO voltage if it is above the threshold to enable to part. Measure VCC as well. Are other boards acting the same? Based on your schematic, i don't see any issue. This might be assembly related issue.
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moned
on Dec 1, 2025 4:29 AM
0
Hi Tonies, thanks for your follow-up.
I tried different scenarios, and it seems to be an inrush current problem:
With pure resistive load, no problem for startup and stabilisation (0.6A). But with my board (only 3 OPA593, with 0.6A in-rush current on lab PSU), the -12V function doesn't even start.
I've tried ith a MX17577 with fixed frequency, tried with a longer soft-start, but no better results.
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tonie

on Dec 2, 2025 8:53 AM
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Have you tried increasing the current limit on the lab power supply? You can explore adjusting the soft-start capacitor to further help control the inrush during start-up.
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moned
on Dec 2, 2025 10:33 AM
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on Lab PSU, I have no problem to use my board, and I only measure a 0,6A in-rush current (<10mA).
with the MAX17578, even with buffing the soft start to 1s (CSS to 5µF), it doesn't want to start up.
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tonie

on Dec 4, 2025 5:46 AM
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Hello, what about smallest SS capacitor? You can also add big input capacitor and try to change the output capacitor either parallel to increase the value or use lower value than the original. The controller is expected to hiccup mode as well. On my understanding the output is not recovering during start up?
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moned
on Dec 4, 2025 9:31 AM
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Hi Tonies,

I also tried with decresing SS capacitor, but with same behaviour. I also tried to play with IN/OUT capacitors, with same effect. For Output capacitor, i'll also be perturbed by my load afterwards.
indeed, the output is not recovering during start(up, the hiccup mode doesn't seems to launch.
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tonie

on Dec 8, 2025 4:02 AM
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As it works with resistive load, can you try adding a pre-load maybe 10K ohms?
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MAX17578 output drop down