DC1830B-C: 20 ~ 60Vin, 5A 4-Cell LiFePO4, Solar Charger with Maximum Power Point Control

Demonstration circuit 1830B - C is a battery charger controller and PowerPath manager with maximum power point control (MPPC) featuring the LTC4000-1. MPPC extracts near maximum power from high impedance sources such as solar panels, wind turbines or fuel cells. MPPC is achieved by means of an input voltage regulation control loop. This board should be connected to a front-end DC/DC power supply for a complete charger solution.

The DC1830B is customizable to handle a wide variety of applications with output voltages from 3V to 30V and output currents up to 6.5A with the PFETs supplied, and up to 60V and/or 13A with higher voltage rating and/or added PFETs. The reference design provided with DC1830B is targeted at 4-cell LiFePO4 (14.6V/5A) applications. Other voltages can be set by changing ROFB2 and RBFB2.

The desired nominal voltage can be accurately trimmed by using trim resistors ROFBX and RBFBX. For example, for 14.4V battery float voltage, change ROFB2 and RBFB2 to 86.6k, and add 7.5M at ROFBX and RBFBX for greater setpoint accuracy. Other parameters can be adjusted to suit specific applications with guidance provided in the LTC4000-1 data sheet.

The DC1830B-C provides a solution complete with both battery charger control and PowerPath management. It includes a second PFET (Q2) between VOUT-SYS and BAT to provide "instant-on" functionality which keeps VOUT-SYS within a narrow range regardless of battery voltage, and disconnects the battery when it is fully charged and power is available from the front-end DC/DC converter. Thermal regulation circuitry is also provided to limit the temperature of both PFETs.