Texas Instruments' LM5170-Q1 controller provides the essential high voltage and precision elements of a dual-channel bidirectional converter for automotive 48 V and 12 V dual battery systems. It regulates the average current flowing between the high voltage and low voltage ports in the direction designated by the DIR input signal. The current regulation level is programmed through analog or digital PWM inputs.

Dual-channel differential current sense amplifiers and dedicated channel current monitors achieve typical current accuracy of 1%. Robust 5 A half-bridge gate drivers are capable of driving parallel MOSFET switches delivering 500 W or more per channel. The diode emulation mode of the synchronous rectifiers prevents negative currents but also enables discontinuous mode operation for improved efficiency with light loads. Versatile protection features include cycle-by-cycle current limiting, overvoltage protection at both HV and LV ports, MOSFET failure detection, and overtemperature protection.

An innovative average current mode control scheme maintains constant loop gain allowing a single R-C network to compensate both buck and boost conversion. The oscillator is adjustable up to 500 kHz and can synchronize to an external clock. Multiphase parallel operation is achieved by connecting two LM5170-Q1 controllers for 3- or 4-phase operation, or by synchronizing multiple controllers to phase-shifted clocks for a higher number of phases. A low state on the UVLO pin disables the LM5170-Q1 in a low current shutdown mode.

The LM5170EVM-BIDIR is a high performance dual-phase bidirectional converter ideal for 48 V to 12 V dual battery system applications.  The two phases operate in 180-degree interleaved operation, and they evenly share a max DC current of up to 60 A.  When DIR is set to "1," the power flows from the 48 V port to the 12 V port, and the 12 V port voltage is regulated at about 14.5 V.  When DIR is set to "0," the power flows from the 12 V port to the 48 V port, 48 V port voltage is regulated at about 50.5 V.  The EVM also includes various jumpers to flexibly and conveniently configure the circuit to fit for many different use cases, including the capable of being controlled by MCU, high power unidirectional buck or boost converters, etc.