1、working principle： Due to the built-in power switch with a large current, 34063 can control the switch current to 1.5A. The internal circuit includes a reference voltage source oscillator, a converter, a logic control circuit, and a switching transistor. Reference voltage source is a bandgap reference with temperature compensation. The oscillation frequency of the oscillator is determined by the external timing capacitor of the 3 pin. The switching transistor is composed of a reverse input terminal of the comparator and a logic control circuit connected with the oscillator, and is provided with a ON, and is composed of a next pulse which is synchronized with the output of the oscillator to be OFF. 2、Function Description: This module is mainly to achieve DC 5V boost to DC 12V； 3、Description of each function module: