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SY5501 Sample Application
General Description

SY5501 is a chip specially designed for True Wireless Stereo (TWS) application, which provides a perfect solution for battery charging, protection, and power line communication isolation. 
The device is integrated with a linear charger management, a discharging protection module, and a single signal line for data bidirectional transmission (charging cradle and ear buds). 
The I2C interface is used for charging management and controlling different operating functions. 
The maximum charging current of SY5501 can be adjusted by external resistors. SY5501 supports constant charging ICC and floating charging voltage VFLOAT, 
which the gears of both can be adjusted by I2C interface. The device is integrated with NTC temperature detection and protection module, which can charge and discharge the battery more safely. 
SY5501 also supports battery discharge protection and shipmode function, which can achieve the low power consumption requirements for the earbuds system.
SY5501 integrates private control instructions, which can be control by the charge cradle and the control instructions are sent from VIN, 
realizing the operations of power on/off and resetting the earbuds. SY5501 also supports the intelligent recognition of earbuds in cradle/out of cradle status, and actively informs the earbuds MCU. 
The multiple functions all inside SY5501 helps customer shorten the product development period. The tiny package of QFN14-1.6mmx1.6mm is suitable for space limited design like bluetooth earbuds application.

Features

VBAT standby current: 1uA

Standby current in shipmode: 300nA

Input voltage withstand up to 12V

Input VIN OVP protection of 6V and OCP protection of 450mA

External resistance adjustment of charging current at ICH pin, with 10~300mA of the adjustment charging current and supporting of 8 levels of percentage charging current adjustment

Battery 4.2V/4.35V/4.4V/4.45V adjustable charging float voltage, accuracy of ±0.5%

Trickle charging current and shut down charging current can be adjusted separately in two levels

Automatic rechargeable

Active recharging with multiple adjustable levels of recharging voltage

NTC detection and JEITA configurable temperature range protection is available

Over-voltage protection ( OVP ), over-temperature protection ( OTP ), and time out protection

Discharge battery under voltage protection, over current protection ( OCP ) and short circuit protection ( SCP )

Bidirectional communication with communication direction automatically switching and up to 3Mbps

Private control instructions integrated, and the controlling of SY5501 through VIN terminal by the cradle is available

auto detection of earbuds in cradle/out of cradle status integrated, supporting of sending the reset signal when earbuds enter the cradle and the wake-up signal when earbuds out of the cradle to the earbuds MCU

Support I2C controlling and status reading, interruption signal output is also supported

Typical Application Circuit Diagram
Applications

Charging management of Bluetooth earbuds