SGM40571

The SGM40571 is a 1A linear battery charger that it can charge single-cell Li-Ion or Li-polymer battery in a wide input voltage range from smart wall adapter or USB device. The high input voltage range with input over-voltage protection supports charging by an unregulated adapter. 

This chip indeed allows the simultaneous connection of the system and battery to the output port. To ensure that the battery is fully charged within the 12-hour safety timer, the average system load must be carefully managed. 

The charging process involves three stages: 

1. Pre-charge stage: A small pre-charge current activates the low-voltage battery to enable constant-current fast charging.
2. Constant-current stage: the battery is charged at a constant-current.
3. Constant-voltage stage: the battery is charged at a constant-voltage until it reaches full-charge. 

Additionally, the SGM40571 includes the internal thermal regulation and the over-temperature protection (OTP) to ensure safe charging. 

The SGM40571 allows the charging process to be customized with the external resistors:

• Fast charge current: set by an external resistor.
• Pre-charge current and termination current: adjustable by changing external resistor. 

Additionally, the SGM40571 integrates JEITA control to optimize charging based on the battery temperature, which can be monitored by using an NTC resistor.