1. US20220085825 - POWER SUPPLY DRIVE CIRCUIT

A power supply drive circuit includes a primary-side power supply drive circuit and a secondary-side power supply circuit. The primary-side power supply drive circuit has a digital-to-analog converter for executing soft-start control of a primary-side power supply circuit with a predetermined step amount. The primary-side power supply circuit generates a predetermined primary-side voltage from a power supply voltage. The secondary-side power supply drive circuit drives a secondary-side power supply circuit that lowers the predetermined primary-side voltage to generate a predetermined secondary-side voltage. The digital-to-analog converter further sets a step amount for an output of the digital-to-analog converter to be smaller than the predetermined step amount based on a condition that the output is in a vicinity of the predetermined secondary side voltage.