Automotive buck converter with auto-sourced LDO regulator provides a flexible design

The Texas Instruments TPS65320D-Q1 device is a combination of a high-VIN DC-DC step-down converter, referred to as the buck regulator, with an adjustable switch-mode frequency from 100kHz to 2.5MHz, and a high-VIN 280mA low-dropout (LDO) regulator. The input range is 3.6V to 36V for the buck regulator and 3V to 36V for the LDO regulator. The buck regulator includes an integrated high-side MOSFET. The LDO regulator offers a low-input supply current of 45µA typical in no-load, also has an integrated MOSFET with an active-low, push-pull reset output pin. The input supply of the LDO regulator auto-source from the output of the buck regulator when it is in operation. Low-voltage tracking option enables the device to track the input supply during cold-crank conditions. The buck regulator offers a flexible design to fit system requirements. The external loop compensation circuit enables optimisation of the converter response for the relevant operating conditions. A low-ripple pulse-skip mode decreases the no-load input-supply current to maximum 140µA. The regulator has built-in protection features such as current-limit, soft start, thermal sensing and shutdown due to excessive power dissipation. Moreover, the device includes an internal UVLO function that turns off it off when the supply voltage is too low.