Re: Clamping to Linear regulators
- From: Jim Thompson <To-Email-Use-The-Envelope-Icon@xxxxxxxxxxxxxxx>
- Date: Tue, 02 May 2006 09:51:14 -0700
On Tue, 02 May 2006 09:44:03 -0700, Tim Wescott <tim@xxxxxxxxxxxxxxxx>
wrote:
AJ wrote:
Hi,Most power supply type regulators (i.e. 3-terminal ones) are 1-quadrant
I have a 3.3V linear regulator that I want to use to clamp 24V to via a 100K
resistor and a diode. Im pretty sure this is ok but just wanted to double
check. Does anyone have any feedback?
devices -- they supply current in one direction from a voltage at one
polarity. If you just had a 3-terminal regulator, a 24V supply and your
resistor the voltage at the output of your regulator would rise,
possibly not to 24V but probably well above 3.3V.
If you just want a shunt regulator look for a 'precision zener'. These
are IC's that behave like zener diodes, but with much better regulation.
If you don't mind wasting a bit of power in your system make sure that
you're drawing more current from 3.3V than the maximum that can be
delivered from your '24V' rail and resistor, possibly with a simple load
resistor on the regulator output.
Try a TL431
...Jim Thompson
--
| James E.Thompson, P.E. | mens |
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| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |
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- From: AJ
- Re: Clamping to Linear regulators
- From: Tim Wescott
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