DIY 0-30V 7.5A Darth Vader Power Supply

If you're interested in the Darth Vader power supply, why not follow this guide to DIY a 0-30V 7.5A Darth Vader power supply board?

Start by drilling holes with a 0.8mm corn mill bit and enlarging them. This avoids the hassle of changing drill bits. Next, switch to a 20-degree 0.2mm flat-bottomed pointed tool for engraving.

Almost done with the machining.

Since the tool path was optimized, there's no need for copper stripping. Just cut directly. After machining, give it a wash.

The soldering process isn’t detailed here, as it mostly involves assembly. The choke inductor and Schottky diodes were salvaged from a computer power supply, and the MOSFETs were taken from an electric bike controller. Here's the finished product:

If you don't have a 3.6K resistor, you can use a 3.3K instead. This will increase the frequency from the original 32.51kHz to 35.46kHz. There are no 9V/12V/24V voltage regulators.

The 24V and 12V regulators are used together to power the TL494. The 24V regulator prevents the Q4 base voltage from becoming too high and saturating. The 12V and 24V regulators serve the same function, acting as clamps. Two 5V regulators can be used in series to replace the 12V regulator. This reduces the TIP41 Vce and diode voltage drop, resulting in a measured TL494 supply voltage of 8.8V (just enough, as the minimum operating voltage for the TL494 is 8V).

Two 5V regulators can also replace the 9V regulator. If you don't have a 1K potentiometer, you can use a 20K one instead. The maximum input voltage of 24V can only be adjusted to 15V. The MOSFET gate drive voltage is 4.3V. By replacing the potentiometer with a smaller one and adding a 10K resistor in series, the voltage can rise to 19V. The MOSFET gate drive voltage will reach 10V. To further increase the output voltage, you’ll need to adjust the duty cycle of the 494 output.

In constant voltage mode, the output is 5V.

Without changing any parameters, the highest output voltage is 14.84V.

The T12 soldering iron core test load. If you don’t have a 0.01Ω resistor, you can use a 0.22Ω one instead. The maximum output current is 3.6A in constant current mode with a 1.58V output voltage.

At 5V, with the T12 soldering iron core, the current is 501mA and the voltage drops to 4.56V, entering constant current mode.

Note: The power supply has not been adjusted to its optimal working state (0-30V), and it exhibits ripple, making it unsuitable for highly precise applications. You may need to adjust and test it yourself.

Update: After changing the power sampling resistor, the output is now stable at 30V. The schematic is as follows: