LTC7872

The evaluation board EVAL-LTC7872-AZ is a high power, high efficiency, four-phase bidirectional converter featuring the LTC7872 and LTC7060. The terminals labeled V_HIGH and V_LOW are either inputs or outputs depending on the direction of power flow. When the switch SW1 is set to the BUCK position, V_LOW provides a 14V output and V_HIGH is the input with a range of 30V to 75V with a maximum load current of 120A. When the switch SW1 is in the BOOST position, V_HIGH provides a 48V output and V_LOW is the input with a range of 10V to 14V with a maximum load current of 34A at a 14V input voltage. The maximum I_LOW current is 120A in both directions. The maximum output power is 1.7kW when operating as a buck within the input voltage range. When operating as a boost, the maximum output power is 1.6kW when the input voltage is 14V. External airflow is required when operating at maximum power in either direction of power flow. The MOSFETs in each phase are driven by the LTC7060 half-bridge driver.

The inductor current for each phase is sensed with a low 1mΩ sense resistor using a highly accurate AC/DC current-sensing architecture with low power dissipation. The LTC7872’s constant-current loop provides a DC current limit for the current flowing in or out of the V_LOW terminal depending on the state of the BUCK pin. This current can be programmed with the SETCUR pin and monitored with the IMON pin.