Voltage regulator... proportional?

jpanhalt

Joined Jan 18, 2008
11,087
Here is what I was talking about simulated with a linear regulator:
upload_2019-9-2_14-32-24.png

I am not really happy with that. I varied the input from 14.4V to 12V. Load is approximately 500 mA. V(adjust) varies by the same percentage, but V(output) only reduces to about 87% instead of 83%. At 500 mA, it will generate quite a bit of heat (14.4V - 5V = 9.4V @0.5 A = 4.7 W). (NB: The load resistor shown (10 ohm) is wrong. I just grabbed the wrong image. Simulation is the same with a 30 ohm resistor.)

I would still recommend a switching regulator, but I don't have that device in my files to simulate. Most important, the voltage feedback regulation in the TPS63070 mentioned above is a bit different than what the linear regulator does, so the method used to make the output reflect the input voltage may be different.
 
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