Author Topic: Negative high voltage low drop-out linear regulator  (Read 1247 times)

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Offline dk-001Topic starter

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Negative high voltage low drop-out linear regulator
« on: June 04, 2020, 04:48:54 am »
Hi,

In my project I need a negative high voltage (-55V -- -60V) low-dropout voltage regulator. TPS7A33 https://www.ti.com/product/TPS7A33 is an example but it can go down to -36V. (it would have been great if MAX17651 had its negative version.)

I've searched digikey but came empty handed. I would appreciate if there are any suggestions.

Thanks.
 

Online moffy

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Re: Negative high voltage low drop-out linear regulator
« Reply #1 on: June 04, 2020, 06:36:07 am »
Why do you need a low drop out regulator at such high voltages? Normally you can tolerate the 1.5-2.5v normal drop out voltage.
 

Offline ycui7

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Re: Negative high voltage low drop-out linear regulator
« Reply #2 on: June 05, 2020, 02:41:52 am »
There are two options.

1. build your own linear regulator with pass transistor and voltage regulation circuitry. An example can be found in uA723's datasheet. There is a floating negative circuit that supposed to give you negative high voltage output. However, it did not work for me, as the resistor's value did not work as datasheet specified, also some parts are obsoleted.

2. Take a 3 terminal regulator, like LM137, with normal voltage range, add some zener protection between input, output and FB pins to limit voltage differential to below 37V. The 3 terminal regulator is a floating regulator, it does not care what the real voltage is, but only care the voltage between the 3 pin, as long you keep the relative voltage below 37V, you are fine. The addition of zener diode make sure the voltage differential does not exceed 37V. This configuration is much simpler than #1 and worked for me.


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