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SY7638 Sample Application
General Description

SY7638 is a single-chip IC specially designed for charging/discharging applications of small-capacity lithium batteries, integrating a switch charger with charging current of 0.5A (customizable 0.25A/1A), a synchronous boost output with maximum discharge current of 1.2A, and a power MOS. The integrated battery status detection, LED Driver and KEY function provide a simple and easy-to-use solution for the application of small-capacity lithium batteries (lithium ion or lithium polymer). including constant charging current, LED battery display, KEY function and automatic load identification. SY7638 is available in a SOP8 package.

Features

Standby power loss: 75uA

Switch charger with 0.5A default charging current, 0.25A/1A customizable

90% discharging efficiency @1A

Switch frequency for charger: 1MHz

Charging in three stages: trickle current mode, constant current mode and constant voltage mode

Adaptive adapter for adjusting charging current

Adjustable charging current based on temperature

10%ICC charge Termination curren,automatic recharge

Preset 4.2V floating charge voltage with ±1% accuracy

5.05V synchronous boost output

Switch frequency for discharge: 1MHz

93% discharging efficiency

7mA discharge cut-off current

Over-current, short-circuit, over-voltage and over-temperature protections of discharging module

LED Driver, charge/discharge indication and abnormality indication by 4 LEDs by default, customizable 1*LED, 2*LED and 2*LED turn light

Customizable KEY function and automatic load identification (default): click KEY for battery fuel gauge display and to activate the discharging module; automatic load identification; long press KEY to shut down output

Customizable version:

(1) Click KEY for battery gauge display and to activate/deactivate the discharging module; without automatic load identification function;

(2) Click KEY for battery gauge display and to activate/deactivate the discharging module; with automatic load identification function.

Typical Application Circuit Diagram
Applications

Charge/discharge applications of small-capacity lithium batteries