Timeline for Linear regulator that regulates even with negative current?
Current License: CC BY-SA 3.0
13 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| May 8, 2019 at 8:13 | vote | accept | mic_e | ||
| Apr 25, 2018 at 0:35 | comment | added | Vince Patron | You basically want a two-quadrant power supply. Does it have to be linear? There are switch-mode power modules made by Linear Technology that are easy to use and do exactly this. I've used them to make battery emulators for phone testing, wherein the phone can discharge or charge the fake battery. The easy to use modules can do 3 Amps. They have controllers to do even much higher current. | |
| S Apr 24, 2018 at 19:41 | history | suggested | jsotola | CC BY-SA 3.0 |
resized schematics
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| Apr 24, 2018 at 17:26 | review | Suggested edits | |||
| S Apr 24, 2018 at 19:41 | |||||
| Apr 24, 2018 at 10:13 | history | tweeted | twitter.com/StackElectronix/status/988722631674384389 | ||
| Apr 24, 2018 at 2:33 | comment | added | The Photon | What problem are you actually trying to solve? If you keep an absolutely constant voltage on the capacitor then it never sinks or sources current itself, and it does not affect whatever other circuits are connected to it. So why not just remove the capacitor, and supply a fixed voltage to the rest of the circuit with whatever kind of regulator circuit is appropriate? | |
| Apr 24, 2018 at 1:04 | answer | added | Henry Crun | timeline score: 1 | |
| Apr 23, 2018 at 21:45 | answer | added | bobflux | timeline score: 5 | |
| Apr 23, 2018 at 21:35 | comment | added | brhans | If you add a resistor between your opamp and the cap then the voltage follower should work without becoming unstable. | |
| Apr 23, 2018 at 21:19 | comment | added | TonyM | @Bimpelrekkie, the vast majority (by volume sold) of linear regulators use pass transistors and therefore can't sink current, so OP is not wrong there. Your 'an LDO' would be a rarer case and it only sank a modest current anyway. | |
| Apr 23, 2018 at 21:04 | comment | added | Ale..chenski | Stability of LDO with regard to details of load capacitance is/was always a concern. So there are no differences. If one needs to regulate voltage both ways, the last circuit is the only valid one. Stability needs to be worked out of course. | |
| Apr 23, 2018 at 20:53 | comment | added | Bimpelrekkie | OpAmp outputs are not stable when connected to capacitive loads; therefore this doesn't work. I disagree as that depends on the opamp. Make the opamp a trans impedance amplifier (OTA, voltage to current amplifier) so that the output impedance (of the OTA) // C1 are the dominant pole and you can make this stable. Also: LDO outputs can't sink current I disagree as it depends on the LDO, I have worked on an LDO which could sink (a modest) current. You make a lot of (wrong) assumptions about the behavior of these circuits and dismiss them for the wrong reasons. | |
| Apr 23, 2018 at 20:45 | history | asked | mic_e | CC BY-SA 3.0 |