Velocity Research developed a customized 1800W Universal Input AC to DC power supply with integrated power measurement, automatic fan control, and multiple voltage rails from the ground (pun) up. This project included thermal simulation of the case heatsink, highly integrated mechanical and electrical design, and construction of 6 finished devices.

The hottest component of the design was simulated at load to determine if the heat-sinking provided by the chassis would be sufficient. We discovered that with a properly sized fan we could maintain an acceptable temperature, however we wanted the fan to design in some intelligence about when it turned on. Simulations were compared to thermal images on the physical device with good agreement.

Because the power supply only needs to supply high power for short bursts, a simple RTD device and comparator with hysteresis was sufficient to protect the supply at high power, and limit noise at low power while keeping development costs low. The temperature curve is in yellow, and the fan control signal is in blue below showing proper turn on and turn off, as well as cooling efficacy. When the temperature reaches an adjustable set point, the fan will turn on until the temperature has come back down. This method was chosen over a regular proportional fan speed to keep noise down in the client’s application.

In addition to the thermal management system, the power supply includes integrated voltage and current measurements that can be read by a host microcontroller allowing power calculations and allowing the host controller to know what kind of power is available from the AC source. 

The chassis, cover, and PCB were modeled in 3D together to ensure a proper fit. Given the tight space requirements, a very compact design was necessary.

Our client was provided realistic images and simulation throughout the design process and physical measurement and verification of correct operation on the final products. The design successfully met or exceeded all requirements and was delivered on time and on budget. Design support was also provided after integration with the rest of their project.