SM3320-BATT-EV(#2): 12V, 9A Charger, 15 ~ 45Vin

The SolarMagic™ SM72442 MPPT digital controller and SM72295 photovoltaic full bridge drivers are designed to control high efficiency DC/DC conversion used in photovoltaic applications. This application note will detail the usage of those devices in a battery charging application.

The RD-189 reference design is meant to provide support for a wide variety of implementations, however, unless otherwise noted, this reference design system is shown charging a 12V commercial automotive lead acid battery.

If the battery voltage is very low, a slow charge current is applied and limited until the voltage rises above a pre-set threshold value Vt. The full charge current is then applied. Once full charge is detected on the voltage of the battery, the system switches to a floating charge and maintains the battery voltage at a fixed threshold. At any time, the system will run in MPPT mode if the available power is lower than the power required to achieve voltage or current regulation.

• 12V Lead Acid Battery
  

• Vin range = 15V to 45V Vmp (50V Voc)
  

• Max Input Current: Isc = 11A
  

• MPPT algorithm for optimized photovoltaic applications
  

• Up to 9A charging current
  

• Reverse current protection
  

• Trickle charge and fast charge mode
  

• Up to 98% converter efficiency
  

• 14.2V max charge voltage, 13.5V floating voltage
  

• Output voltage set-points can be re programmed