TI TIDA-01168 Bidirectional Automotive 12V (48V) Power System Reference Design

TI's TIDA-01168 is a four-phase bidirectional automotive 12V/48V power system reference design, using two LM5170-Q1 current controllers and TMS320F28027F microcontroller (MCU), 12V input voltage range 6V-18V, 48V input voltage range 24V-54V, with reverse polarity, over-current and over-voltage and over-temperature protection, multi-phase upgrade options, output power 2kW, efficiency 97%, mainly used in 12V/48V automotive power distribution, supercapacitor or battery backup power converter. This article introduces the main features of LM5170-Q1, block diagram, 60A two-phase 48V/12V bidirectional converter application circuit and reference design TIDA-01168 main features and system indicators, block diagram, circuit diagram, bill of materials and PCB design.

The LM5170-Q1 controller provides the necessary high-precision dual-channel bidirectional conversion elements for automotive 48V and 12Vdual battery systems. It regulates the average current between the high-voltage and low-voltage ports in the direction specified by the DIR input. The current regulation level is programmedthrough either analog or digital PWM inputs.

Dual-channel differential current sense amplifiers and dedicated channel current monitors achieve 1% typical current accuracy. Robust 5-A half-bridge gatedrivers are capable of driving parallel MOSFET switches delivering 500 W or more per channel. Diode emulation mode of the synchronous rectifiersprevents negative current and also enables discontinuous mode operation for improved efficiency at light loads. Versatile protection features include cycle-by-cycle current limiting, high-voltage and low-voltage ports, and MOSFET fault detection for overtemperature protection.

An innovative average current mode control schememaintains constant closed loop gain allowing a single R-C network to compensate for both buck and boostconversion. The oscillator is adjustable to 500 kHz and can be synchronized to an external clock. Multiphaseparallel operation is achieved by connecting two LM5170-Q1 controllers for 3 and 4 operation, or synchronizing multiple controllers with phase-shiftedclocks for a higher number of phases. A low state on the UVLO pin disables the LM5170-Q1 at low

Current shutdown mode.

LM5170-Q1 key features:

1• Compliant with AEC-Q100 automotive applications:

-Equipment temperature level 1: 40 degrees to

+ 125 degrees room temperature working range

– ESD level classification of device HBM2

– Device CDM ESD classification level C4B

• 100-V high voltage ports and ports with a maximum rating of 65-V LV

• 1% accurate bidirectional current regulation

• 1% accurate channel current monitoring

• 5-peak half-bridge gate driver

• Programmable or adaptive dead time control

• Programmable oscillator frequency with optionalsynchronization external clock

• Independent channel enable control input

• Current control input for analog and digital channels

• Programmable cycle-by-cycle peak current limit

• Overvoltage protection for high and low voltage ports

• Diode simulation to prevent negative current

•Programmable soft-start timer

•MOSFET fault detection start-up and circuit breaker control

Multiphase operation phase increase or decrease

LM5170-Q1 Applications:

• Dual battery system for cars

• Super Cap or Battery Backup Power Converter

• Stacked buck or boost converters

Figure 1. LM5170-Q1 functional block diagram

Figure 2. LM5170-Q1 simplified application circuit diagram

Figure 3. LM5170-Q1 application circuit: 60A dual-phase 48V/12V bidirectional converter

Reference Design TIDA-01168

The TIDA-01168 reference design is a four-phase, bidirectional DC-DC converter development platform for 12 V/48 V automotive systems. The system uses two LM5170-Q1 current controllers and a TMS320F28027F microcontroller (MCU) for power stage control. The LM5170-Q1 system uses average current feedback to control the current while the C2000™ MCU provides voltage feedback. This control scheme eliminates the phase current balancing typical of multiphase converters. LM5170-Q1-based systems allow for a high level of integration, which reduces printed circuit board (PCB) area, simplifies design, and speeds up development.