Microchip has made available a pure sine wave uninterruptible power supply (UPS) reference design, based on it's microcontroller family dsPIC33F "GS" series of digital-power Digital Signal Controllers (DSCs)
This compact design features the use of small transformer, smart battery charging, efficiency of 85%, lower noise, USB interface and lesser BOM cost. All the circuit diagram, schematic, other documents, source code/software for microcontroller and PCB gerber file can be downloaded from site at: http://www.microchip.com/offlineups.
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 steps up 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 lead-acid battery from the AC line power.
The reference design also features an LCD display panel, for communication with the external world.
"This reference design jumpstarts our customers' advanced UPS designs and brings the benefits of digital power to their products quickly," said Sumit Mitra, vice president of Microchip's High Performance Microcontroller Division. "It uses the flexible dsPIC33F "GS" series of DSCs, which enables easy customization and configuration through simple modifications to the control software."
Key design specifications are,
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
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 are also provided