Technical parameters

Input voltage : 24VAC

Output voltage : min 0VDC – max 30VDC

Output current : min 0A – max 4.5A (output voltage ripple 0.01% 0-25VDC)

Output current : min 0A – 0.5A (output voltage ripple 0.01% 0-30VDC)

Two types of regulation - Analog with potentiometers see schematic components in red box, components in green box is not populated or Digital with DAC (MCP4725) see schematic components in green box, components in red box is not populated.

Voltage ripple in CV mode 20V 4A load - Vrms-2mV, Peak to Peak 8.5mV

Voltage ripple in CC mode 20V 4A limited load - Vrms-8.5mV, Peak to Peak 23mV

Calibration measure board, ADC (Attiny45)

If use Analog regulation

After programming the MCU, within 5 seconds, turn off the power supply: set the current and voltage control potentiometers to the center position and turn on the power supply.

Pull the potentiometer for voltage control to the zero position and turn off the source, wait until the green and red LEDs go out, and then turn on the source (offset_error calibration and zero current value calibration will be performed).

Using a multimeter, set the output value to 29.0V as accurately as possible, measure the voltage at the output using a multimeter, the voltage on the display will probably not match. Turn off the source again, wait until the green and red LEDs go out, and then turn on the source (gain_error calibration is performed).

Calibration is performed only once, re-calibration is only possible after reprogramming the MCU.

If use Digital regulation

Turn on the source and with the "A" button - set 5VDC, with the "B" button - set 0.5A

For current and voltage - offset_error calibration, press the "C" button - the source will go into CC mode and perform calibration. Wait about 5 seconds.

Next with the button "B" - set 0.5A.

To calibrate the voltage - gain_error, press the "D" button, measure the voltage at the output with a multimeter, enter value the measured voltage rounded to one decimal place using the keyboard and confirm with the "#" button.

Calibration can be performed again at any time.