Backup power supply for electronic system and operation method thereof

A backup power supply of an electronic system comprises:

• a battery string configured to provide a power to the electronic system;
• a fuse coupled to the battery string;
• a battery monitoring protection unit coupled to the battery string and the fuse to monitor and protect the backup power supply;
• and
• a micro-controller processing unit coupled to the battery monitoring protection unit and the electronic system,
• wherein
• the micro-controller processing unit estimates a reading voltage error and a resistance of the fuse;
• the micro-controller processing unit reads a real-time battery discharging current;
• the micro-controller processing unit reads and calculates a voltage difference between two terminals of the fuse;
• the micro-controller processing unit determines whether to send a fuse replacement message to the electronic system according to the voltage difference between the two terminals of the fuse, the reading voltage error, the resistance of the fuse and the real-time battery discharging current,
• wherein when the micro-controller processing unit estimates the reading voltage error and the resistance of the fuse, the micro-controller processing unit performs:
• setting a first discharging current;
• measuring a first voltage difference between the two terminals of the fuse, wherein the first voltage difference between the two terminals of the fuse comprises the reading voltage error;
• setting a second discharging current;
• measuring a second voltage difference between the two terminals of the fuse, wherein the second voltage difference between the two terminals of the fuse comprises the reading voltage error;
• and
• estimating the reading voltage error and the resistance of the fuse according to the first voltage difference between the two terminals, the second voltage difference between the two terminals, the first discharging current and the second discharging current.