Digital Pure Sine Wave Uninterruptible Power Supply Reference Design

The Pure Sine Wave Uninterruptible Power Supply (UPS) Reference Design, from Microchip Technology, is based on the dsPIC33F “GS” series of digital-power Digital Signal Controllers (DSCs). The UPS reference design demonstrates how digital-power techniques enable easy modifications through software, the use of smaller magnetics, intelligent battery charging, higher efficiency, compact designs, lower audible and electrical noise via a purer sine-wave output, USB communication and a lower overall bill-of-materials cost. All of the documentation, software, and Gerber files needed to build the reference design can be downloaded for free.

Microchip Digital Pure Sine Wave Uninterruptible Power Supply Reference Design

Pure Sine Wave UPS Reference Design Specifications

  • Input Range AC
    • 85 to 135V ,60 HZ +/-3
    • 145 to 280V ,50 HZ +/-3
  • Output Voltage AC
    • 110V @ 60 Hz +/-3
    • 220V @ 50 Hz +/-3
  • DC Input
    • 36V (12 VDC x3)
    • Lead Acid Battery
  • Adjustable Charging Current
  • Efficiency >85%
  • Pure Sine Wave Output With THD <5%
  • Rating
    • 1000 VA Steady-State Output Power
    • 1350 VA Peak Power (Surge)
  • Mains to Battery Transfer Time <10ms
  • Supports Crest Factor of 3:1
  • Fault Indications

Microchip’s UPS Reference Design utilizes high-frequency switching techniques to implement three optimized digital power-conversion stages. The Push-Pull DC/DC Converter stage boosts the battery voltage to drive the inverter stage. The Full-Bridge Inverter stage creates Pure Sine Wave AC power to the load. Finally, the Flyback Switch-Mode Charger charges the battery from the AC line power.

The dsPIC33F “GS” series of digital-power DSCs from Microchip is the heart of this Offline UPS reference design. The dsPIC33F controls all critical operations of the system, as well as the housekeeping operations. Fast and reliable switchover from mains to inverter, and vice-versa, is done intelligently to ensure that power to the load is transferred without surges and sags. The reference design also features USB connectivity and an LCD panel, for communication with the external world.

More information: Microchip Digital Pure Sine Wave UPS Reference Design