1.What is offline UPS?

Offline UPS, also known as UPS backup power supply, has a small volume and is often used for temporary power supply, household electricity, personal computer hosts, and other occasions where frequency and voltage are stable and power requirements are low. The offline UPS is usually in the battery charging state, but in the event of a power outage, the inverter will urgently switch to the working state, converting the DC power provided by the battery into stable AC power output. 

Offline UPS has the basic and important UPS functions, such as automatic voltage regulation and power outage protection. The AC output from offline UPS inverter is square wave, not pure sine wave. However, due to its advantages of simple structure, low cost, and high reliability, it is widely used in fields such as microcomputers, peripheral devices, POS machines, etc.

2.The functions and characteristics of offline UPS

Function Description:

1. Synchronize conversion between mains power and UPS.
2. Offline UPS adjusts the output voltage through PWM closed-loop control.
3. Battery charging, intelligent adjustment.
4. Communicate with PC computer through serial port.

Characteristics Description:

1. Simple structure, small volume, light weight, and lower cost.
2. The conversion efficiency of offline UPS power supply is high.
3. Having a comprehensive self-protection system.For example, emergency warning for low battery voltage, over-current and short circuit protection, discharge end protection, etc.
4. When the mains power is normal, UPS has no solution to the mains power and directly outputs it to the load, offline UPS has poor attenuation ability against mains noise and spikes.

Offline UPS is a type of power supply that directly supplies power to the load under normal circumstances. When the power is cut off, it is powered by UPS and converted into AC power supply through battery energy storage to supply the load. When the mains power is interrupted and converted to UPS power supply, there is a switching time, so the precision system cannot use offline UPS.