Timeline for Inexpensive circuit architecture for power supply voltage adjustment?
Current License: CC BY-SA 3.0
16 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Jul 28, 2016 at 2:16 | comment | added | user4718 | @pjc, those cost a lot more than digital rheostats. not really helpful. | |
| Jul 27, 2016 at 11:26 | comment | added | pjc50 | You could build around a programmable converter IC: linear.com/products/digitally_programmable_regulators - or you could just build your own programmable buck from a microcontroller. | |
| Jul 27, 2016 at 11:04 | answer | added | Peter Smith | timeline score: 2 | |
| Jul 27, 2016 at 5:22 | answer | added | markrages | timeline score: 2 | |
| Jul 27, 2016 at 4:51 | comment | added | markrages | Off topic, but you should try to use digital pots as potentiometers rather than rheostats. So you would replace both divider resistors with the digital pot. This reduces the influence of the typically abysmal wiper resistance and overall tolerance specs. | |
| Jul 27, 2016 at 0:52 | comment | added | user4718 | @ThreePhaseEel, in my particular case it's a monolithic buck+switch IC with an 0.6v onboard reference. Sadly I do not have access to the error amp or really anything else useful; it's a real black box that way. All they give you is a "power good" flag which is nothing more than a +/-5% comparator. | |
| Jul 26, 2016 at 23:58 | answer | added | esoterik | timeline score: 0 | |
| Jul 26, 2016 at 23:53 | answer | added | Whit3rd | timeline score: 0 | |
| Jul 26, 2016 at 23:28 | comment | added | ThreePhaseEel | I presume that you're working with a converter/controller with a fixed onboard reference, correct? Or can you gain access to the error amp reference input and/or the error amp output? | |
| Jul 26, 2016 at 23:18 | comment | added | user4718 | @Ignacio, using the FET gate as a capacitor as the integrator? I'd thought of using capacitors to integrate PWMs but this is for a buck converter which (at this early prototyping stage) has really awful EMI emissions (those get cleaned up once everything else works). I'm a bit nervous about having any nodes that aren't strongly driven lying around. | |
| Jul 26, 2016 at 23:14 | comment | added | The Photon | @IgnacioVazquez-Abrams, Are you answering from experience? I haven't tried it (and I have a similar design problem on my plate to OP's), but I'd be concerned about the smoothing filter adding delay in the control loop. | |
| Jul 26, 2016 at 23:06 | answer | added | Russell McMahon♦ | timeline score: 1 | |
| Jul 26, 2016 at 23:03 | history | edited | user4718 | CC BY-SA 3.0 |
added 20 characters in body
|
| Jul 26, 2016 at 22:59 | comment | added | Ignacio Vazquez-Abrams | Smoothed PWM and a FET? | |
| Jul 26, 2016 at 22:52 | history | edited | user4718 | CC BY-SA 3.0 |
added 589 characters in body
|
| Jul 26, 2016 at 22:46 | history | asked | user4718 | CC BY-SA 3.0 |