SY20751BTYC - High Integrated Bi-Direction Power Regulator For Single-Cell Battery Power Bank Application


  • Maximum 18V Input Voltage Rating
  • Build in Low Rdson Power Path NFETs and Power Switches
  • Programmable Boost Switching Frequency
  • Maximum 3A Charge Current
  • Maximum 3A Boost Output Current
  • 4.2V/4.35V/4.4V Selectable Cell Voltage
  • +/-0.5% Battery Cell Voltage Tolerance
  • 4 LEDs Battery Level Indicator
  • Trickle Current / Constant Current / Constant Voltage Charge Mode
  • Adaptive Input Current Limit
  • Input Voltage UVLO and OVP
  • Output Divider Mode, DCP Mode Handshaking
  • Boost Auto Start When Portable Device Inserts
  • Boost Auto Shutdown with Light Load
  • Boost Cycle-by-cycle Peak Current Limit
  • Boost Programmable Output Current Limit Boost Output Short Circuit Protection
  • Thermal Shutdown Protection
  • Compact Package: QFN4×4-26

Typical Application


The SY20751B is a 4.5-5.7V input bi-directional regulator which is designed for single cell Li-Ion battery power bank application. Advanced bi-directional energy flow control with automatic input power source detection is adopted to achieve battery charge mode and battery power supply mode alternately. If the external power supply is present, the SY20751B will run in battery charge mode with fully protection function. If the external power supply is absent, the SY20751B will run in battery power supply mode with output current capability up to 3A. 
The SY20751B has integrated reverse blocking switches to prevent current leaking from the system side or battery side to the input side. The high side switch protects the battery from high discharge current and short circuits at SYS point.
The SY20751B also provides the KEY control and LEDs status indication. 
The SY20751B is available in QFN4x4 package to minimize the PCB layout size.


  • Power Bank
  • Portable Internet Devices