Current project : Fan controller for GWInstek PSU - Page 1
Forum section: electronics / projects

author: Rolo
author_rank: Regular Contributor
timestamp: February 15, 2019, 12:28:49 pm
content: Would like to share my current project, a fan controller for my GWinstek GPD-4303S. It's a nice power supply, 4 outputs on a small footprint. It has a 80mm fan with temparature dependend speed, but the idle speed is still noisy. I'm using this PSU mostly for low currents so it rarely get's hot. I have the service manual and the factory solution is a 80mm fan with build in speed regulator, connected to two 10K thermistors in parallel next to the heatsinks. The power for the fan is tapped from an auxiliary powerstage. I measured 7.5V DC on this power line. The original fan is a 12V model so it's never going to run on full speed.The new fan is a Noctua NF A8 5V PWM. I have choosen the 5V model so I can use the full range for this fan, that's from 450 RPM to 2200 RPM. I made a controller using an Atmel ATtiny85 microcontroller, it has a piezo buzzer that gives an alarm when the fan is not rotating and when the connection to the thermistors is lost. It also goes into full speed when the thermistors are disconnected. It keeps the fan idle at ~500 RPM and ramps it up when the heatsinks get warm, using the original thermistors.The prototype is running now and the PSU is very quit now, you can not hear it when it's cold. I designed a PCB for it and that is being produced at the moment, hoping to receive them in two weeks. The PCB will be mounted on two M3 holes on the heatsink with nylon spacers.Will post an update when the PCB is ready and mounted in the PSU. Made some pictures :https://photos.app.goo.gl/PwR7xQRYDCEqW4uR6If you have any questions or want more details please ask.

author: Rolo
author_rank: Regular Contributor
timestamp: March 01, 2019, 06:32:57 am
content: Update on project: The PCB's have arrived. I have assembled the board and it's working. The controller is now build into the PSU and I'm very happy with the result. I have some more boards laying arround (can't order one PCB) so if any other owner of this type of PSU wants one, let me know. I think it wil also work for the 3 channel model.I have added some pictures to the album where you can see the controller in the PSU.

author: coromonadalix
author_rank: Super Contributor
timestamp: March 01, 2019, 11:13:37 am
content: nice project congrats for your design

author: coromonadalix
author_rank: Super Contributor
timestamp: March 02, 2019, 11:50:18 am
content: Can the fan curve response be changed

author: HighVoltage
author_rank: Super Contributor
timestamp: March 02, 2019, 12:04:49 pm
content: A lot of PSUs and many other instruments could benefit from your fan controller.Nice project!

author: Rolo
author_rank: Regular Contributor
timestamp: March 02, 2019, 12:11:38 pm
content: Quote from: coromonadalix on March 02, 2019, 11:50:18 amYes, in the software. I read the analog value from the varistors, depending on that value I send a PMW signal to the fan, that sets the speed of the fan.The mapping is done in a min/max window, all readings less then min gives the idle speed, all readings more then max gives the full speed.