DC-DC CONVERTER WITH LOW-POWER AND LOW-VOLTAGE STARTUP

摘要

PROBLEM TO BE SOLVED: To provide a DC-DC converter with low-power and low-voltage startup.SOLUTION: A DC-DC converter (1) with low-power and low-voltage startup includes: an inductor (3) connected to an input voltage source (2); a switch (11) connected to the inductor and controlled by a control device (10); and a diode (12) connected to a connection node of the inductor and the switch for supplying an output voltage (Vout). The control device includes an oscillator and a monostable element to which power is supplied by an input voltage (Vin). The oscillator supplies an oscillation signal (OSC) having a switching cycle term T of the switch. A monostable element (103) is controlled by the oscillation signal and determines a conduction term Tn of the switch (11) and during the conduction term Tn, an increased current (IL) flows through the inductor (3). Input impedance of the DC-DC converter is increased in the case where the input voltage (Vin) drops lower than a first voltage threshold and a duty cycle d=Tn/T is decreased.SELECTED DRAWING: Figure 1