Automotive 5.6V to 40V, 1.2A buck converter with 3 LDOs

The TPS65300-Q1 power supply is a combination of a single switch-mode buck power supply and three linear regulators. This device is a monolithic high-voltage switching regulator with an integrated 1.2-A peak current switch, 45-V power MOSFET, and one low-voltage linear regulator and two voltage-regulator controllers.

The device has a voltage supervisor which monitors the output of the switch-mode power supply, the 3.3-V linear regulator, and the 1.234-V linear regulator. An external timing capacitor is used to set the power-on delay and the release of the reset output nRST. This reset output is also used to indicate if the switch-mode supply, the 3.3-V linear regulator supply, or the 1.234-V linear regulator supply is outside the set limits. The 5-V regulator tracks the 3.3-V linear regulator within the specified limits.

The TPS65300-Q1 device has a switching frequency range from 2 MHz to 3 MHz, allowing the use of low-profile inductors and low-value input and output ceramic capacitors. External loop compensation gives the user the flexibility to optimize the converter response for the appropriate operating conditions.

This device has built-in protection features such as soft start on IGNEN ON or enables cycle, pulse-by-pulse current-limit, thermal sensing, and shutdown because of excessive power dissipation.