Regulated Power Supply with Stability at 3A

Figure 1 

The circuit was designed to build a stable power supply the will provide a regulated voltage from 40 V to 70 V in a 3 A current.

• 2N3055 – a complementary Silicon Epitaxial-Base planar NPN transistor mounted in Jedec TO-3 metal case for use as power transistor
• BD243 – an epitaxial-base Silicon NPN transistor intended for wide variety of high speed switching and power amplifier applications such as series and shunt regulators, and driver and output stages of high-fidelity amplifiers
• BC303 – a PNP silicon planar epitaxial transistor used for AF drivers & outputs, for AF medium power amplifiers, and for switching applications up to 1 A

There are times when some applications are requiring a regulated power supply that has relatively high output voltage and stability. All of these features are being attained in the design of this circuit. The voltage output of the circuit can range from 40 V up to 60 V while carrying a current of 3 A while providing stabilization. The construction of the circuit is very simple since the components used were available easily in the market. The only thing that matters is how the connection will be ensured.

During the operation, when the circuit is delivering 50 V up to 60 V, the transistor Q1 will be hot enough and would require a large heatsink. For voltage output higher than 50 V up to 70 V, the stability of the circuit may be found unsatisfactory. This is the reason why the ideal output voltage of the circuit is 45 V up to 60 V. In order to alter the output voltage from 40 V up to 70 V, a 470 Ohms potentiometer RV1 is used for the adjustments. However, the potentiometer may also be replaced by two constant resistors with suitable values when the circuit adjustment has been done. This is due to the fact that the use of a potentiometer may lead to a 3 V of over voltage.

As a reminder, the positive output of the circuit should be connected at point A while the 0 V output should be connected at point B. The 0 V reference should not be connected to the ground for the circuit to function properly.

The use of this 3 A power supply with an average of 50 V circuit may be found on various applications that normally requires this rating. Since this type of circuit is easily built, it is being utilized in industrial, educational, clinical, and laboratory facilities. It may come with different additional features such as reduced ripple & noise, overload protection, and short circuit & high current protection.

Source:users.otenet.gr/~athsam/power_supply_50V_3A.htm