Vermes
Advanced Member level 4
It is a 3-channel laboratory power supply with a total capacity of about 110W. It has two pulse stabilized channels with continuous voltage 0-13V, a constant current limit threshold 4A and USB channel linearly stabilized with two 5V sockets and indicator light, so that the total current consumption from the USB sockets exceeds 700mA (it is only a indicating, not current limiting). All the channels are fully galvanically isolated from each other, so you can combine the outputs in parallel or in series. Then you get 0-13V/8A or 0-26V/4A.
Pulse stabilization was applied to two power channels to minimize the power loss as heat. Linear stabilizer was selected for the USB channel, because weak currents flow and too much heat will not be given off, so the choice was LM7805. To cool the whole device with only one heat sink (better control of heat), pads and insulating sleeves were used. The fan is activated at a temperature of approximately 45 degrees Celsius and its work is signalled by the indicator.
The whole was divided to a few modules: auxiliary power supply board (5V for the voltmeter, USB and the temperature control system and 12V for the fan), voltmeter board (AVT2270 kit) and channels boards.
All the protections are fully electronic and reversible. There is no fuse. When testing, both power channels were shorted and loaded with the USB, and the only effect was the illumination of the short circuit indicators, switching the power supply to the current mode and more frequent switching the fan.
The power supply is very stable. Turn the power switch, activate one of the channels by pressing “ON”, set the voltage with no load and after connecting the receiver consuming less than 4A, the voltage does not drop up to 0,1V. Decreasing the voltage after exceeding the 4A is caused by the current limitation.
Schema:
Link to original thread (useful attachment) – Zasilacz 3-kanałowy 110W 2x0-13V/4A 5V/700mA stab. impulsowo
