adamjohnson
- Oct 14, 2016
- 6
- Joined
- Oct 14, 2016
- Messages
- 6
Hello all,
I was wondering if its ok to use a voltage divider to drop voltage and feed that to the Vin of a linear regulator lm2940 for example. IE: Voltage divide from 14.5 down to 9v then go from 9v to 5v with the LM2940. I'm going to go out and assume that this a janky way of getting a
linear regulator to work with out over heating it.
I'm wanting to draw at most 100ma and right now doing it 14.5v to 5v its getting up to 170f at room temperature of 71f yikes..! I know a lot of that comes from shedding voltage difference in heat.
I also have a second question if i reduce my current pull down to 10ma the LM2940 gets around 105f is that pretty safe for a automotive environment.
I'm confined to a package and can't get a heat sink really in there to help with the regulator.
I could possible lay it down and solder it to the board if that would help for longevity.
I appreciate any help, kind of been something I have been trying to figure out. I was originally using a buck converter but it didn't have revers polarity protection, or load dump protections like the LM2940 does So I went that route as anything else buck converter wise was way way over price point I was trying to stay in.
I'm also open to suggestions.
I was wondering if its ok to use a voltage divider to drop voltage and feed that to the Vin of a linear regulator lm2940 for example. IE: Voltage divide from 14.5 down to 9v then go from 9v to 5v with the LM2940. I'm going to go out and assume that this a janky way of getting a
linear regulator to work with out over heating it.
I'm wanting to draw at most 100ma and right now doing it 14.5v to 5v its getting up to 170f at room temperature of 71f yikes..! I know a lot of that comes from shedding voltage difference in heat.
I also have a second question if i reduce my current pull down to 10ma the LM2940 gets around 105f is that pretty safe for a automotive environment.
I'm confined to a package and can't get a heat sink really in there to help with the regulator.
I could possible lay it down and solder it to the board if that would help for longevity.
I appreciate any help, kind of been something I have been trying to figure out. I was originally using a buck converter but it didn't have revers polarity protection, or load dump protections like the LM2940 does So I went that route as anything else buck converter wise was way way over price point I was trying to stay in.
I'm also open to suggestions.