2.2-MHz wide-VIN, synchronous boost controller with output voltage tracking

The LM51231-Q1 device is a wide input range

synchronous boost controller that employs peak current mode control. The device’s wide input

range supports automotive cold-crank and load dump. The minimum input voltage can be as low

as 0.8V when BIAS is equal to or greater than 3.8V. The output voltage can be dynamically

programmed by using the tracking function. Bypass mode operation is automatically entered

when VSUPPLY > VLOAD, eliminating the body diode drop of the

high-side MOSFET. The switching frequency is dynamically programmed with an external

resistor from 100kHz to 2.2MHz. Switching at 2.2MHz minimizes AM band interference and

allows a small solution size and fast transient response.

The device has built-in protection features

such as peak current limit, which is constant over VSUPPLY, overvoltage

protection, and thermal shutdown. External clock synchronization, programmable spread

spectrum modulation, and a lead-less package with minimal parasitic, help to reduce EMI and

avoid cross talk. Additional features include line UVLO, FPWM, diode emulation, DCR inductor

current sensing, programmable soft start, and a power-good indicator