Electronic Component Solutions

Highly Integrated Battery Charger IC Use Case: Battery Backup Systems

Battery backup systems used in applications such as solar-powered outdoor cameras, lighting, and small cell systems like 4G/5G access points need multi-cell battery chargers for power. The traditional solution for multi-cell battery chargers is composed of several discrete power MOSFETs and multiple auxiliary components. In traditional discrete solutions, designers need at least two power MOSFETs for the charger’s DC/DC converter, one power MOSFET to prevent battery power from flowing back to the input, and another MOSFET if power path functionality from the battery is needed. Control loops that include sensing circuits, compensating circuits, PWM generators, and drivers are essential. Furthermore, the system needs circuits that offer protection, indications for the input source or any changes in operating conditions, and other functions. These discrete components result in a complicated design process, lack of flexible programmability, large board size, and high BOM costs. The MP2759 is a highly integrated switching charger designed for charging applications with 1-cell to 6-cell series Li-ion, Li-polymer, and LiFePO4 battery packs. This IC integrates three power MOSFETs — plus programmable analog control circuits — into a 3mmx3mm package, and can operate reliably and safely with very few external components.

The MP2759 switches to battery power if the power supply goes away, and it supports up to 40V protection on the input, compared to only 28V in many other solutions. Additional features include:

  • Programmable Input Current Limit Regulation
  • Programmable Battery Charging Temperature Range
  • Battery Thermal Monitor and Protection with JEITA Profile
  • Up to 36V Operation Input Voltage and 40V Protection
  • Up to 3A Programmable Charge Current
  • Up to 6 Cell Series with 3.6V/4.0V/4.1V/4.15V/4.2V/4.35V/4.4V Battery Regulation Voltage for Each Cell
  • Input Minimum Voltage Regulation for MPPT
  • Support OR Selection Power-Path Management to Allow Instant-On with a Low Battery
  • 0.5% Battery Regulation Voltage Accuracy
  • 450kHz or 700kHz Switching Frequency
  • Integrated Reverse Blocking FET and Buck Switching FETs
  • Internal Loop Compensation
  • Charge Operation Indicator
  • Input Status Indicator
  • Battery Over-Voltage Protection
  • Charging Safety Timer
  • Die Over-Temperature Protection