SY20745RBC - SMBus Controlled 1-4 Cell Battery Charger Controller Supporting Boost Mode


  • Input Voltage Range 4.5V to 25V
  • SMBus Controlled Synchronous Buck Controller with 615kHz, 750kHz and 885kHz Programmable Switching Frequency
  • SMBus Controls
     -Battery Charge Voltage (1.024V – 19.2V) 
     -Battery Charge Current (128mA – 8.128A)
     -Adapter Input Current Limit (128mA – 8.064A)
  • ±0.5% Battery Charge Voltage Accuracy
  • ±3% Battery Charge Current Accuracy
  • ±3% Adapter Input Current Limit Accuracy
  • ±2% 20x Input Current or Charge Current Amplifier Output Accuracy
  • Internal Charge Pumps for AC Blocking NFETs and BAT NFET
  • Integrated Loop Compensation
  • Internal Soft Start
  • Programmable Adapter Detection and Indicator Support Air-line Adapter
  • Support 1, 2, 3 and 4 Cells Battery Pack
  • Support Boost Mode 
  • Battery LEARN Function and  Programmable Battery Depletion Threshold
  • Cycle-by-cycle Peak Current Limit
  • Battery Over Voltage Protection and Short Protection
  • Inductor and MOSFET Short Circuit Protection
  • Thermal Shutdown with Hysteresis
  • 0.65mA(0.8mA Max) Adapter Standby Quiescent Current
  • 5μA Off-state Battery Discharge Current
  • Package QFN 3.5x3.5-20

Typical Application


The SY20745 is a high efficient, multi-cell battery charger controller supporting Boost mode. It allows the battery to discharge energy to the system when the system power demand is higher than the input capacity temporarily.
Three internal DACs are used as the reference of the charge voltage, the charge current, and the input current limit. They can be programmed by the system using SMBus. 
The SY20745 can charge 1, 2, 3 and 4 cells battery pack and is available in QFN3.5x3.5-20 package to allow the small PCB footprint.


  • Notebook and Sub-notebook
  • Battery Charger Cradle
  • Portable Equipment with Rechargeable Battery
  • Battery Back-up Systems