Reference design for a 250 Watt ATX Power Supply



The Power supply comes under the 80 plus certification standard.

The power supply is an integrated part of the power source for any Computing Device.

The ATX power Supplies came into existence after the development of ATX( Advance technology Extended ) motherboards in 1995. These motherboards required a source with fewer impurities to power it up as all the accessories were directly interfaced with the motherboard.


The reference design is based on the development of an ATX based power supply. The power supply should work as a constant and high current source which makes it different from normal rectifier based circuits. Some parameters which play an important role while designing a Power Supply for an application are –

  • Voltage and current requirement of the device to be powered by the supply.
  • The operating input and output voltage of the circuit.
  • Number of Channels needed from the circuit. When an ATX supply is designed, it generally has 3 broad channels for 12V, 5V and 3.3 V supply voltages.
  • The efficiency and Power factor of the circuit.
  • The total output power of the circuit with isolated and non-isolated components.

These are some of the design parameters which should be followed during the selection and schematic design of a circuit for Power Supply.

Some of the feature of the Referenced Design for Power Supply are –

  • The input operating voltage ranges from 90 Volts to 264 Volts.
  • The maximum current dissipation of the design is 13 amperes.
  • The total output power of the circuit is 253 watts.
  • The number of channels for output voltages is 5 channels. These are 12V,-12V,+5V,+3.3V and 0V.
  • The power supply is equipped with overtemperature and over-voltage protection. The feature of input or output short protection is also there in the circuit.
  • The output efficiency is above 88% with a power factor of 0.92.
Powerbox's Peak Load Power Supply For Medical Laser Applications

All these features make it an effective option for computing-based applications. All the documents related to design are provided by On Semiconductors and are included with the reference design which can be downloaded here.




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