illustrate:

• Uninterruptible power supply powered by a single-cell lithium-ion battery, input 5V (MIN 1.5A), output 5V (MAX 2.4A).

Features:

1. It adopts a five-in-one dedicated chip with overshoot, over-discharge, high temperature and over-current/short circuit protection and three-light status display (external power indicator, charging indicator, boost indicator).
2. Input undervoltage, maximum input current, maximum charging current, and maximum output current can be set individually by resistors; trickle charging time and charging time can be set by separate capacitors; battery charging voltage can be set to 4.2/4.35V optionally.
3. It has a fixed priority. When an external power supply is present, the output and charging are provided by the external power supply. When the output load is too large, priority is given to load power supply.
4. The system has low power consumption, the overall quiescent current is ≤30uA (sleep mode is set), plug and play, no switch button required (mode setting related pins can also be used to control).
5. Supports 2000-20000mAh single-cell lithium battery (4.2V cut-off voltage).

Notice:

• This circuit is only the core part, the USB input and output needs to be designed separately.
• The design uses a 29 74 100 aluminum profile shell, and the battery uses three 606070 or two 906070 lithium polymer batteries.
• The circuit is still in the experimental stage, all parameters are calculated parameters, and the stability and safety need to be verified.
• Any economic losses caused by using this circuit shall be borne by the user, and the circuit designer does not bear any legal responsibility.