SWITCHED-MODE DC/DC CONVERTER HAVING A BOOTSTRAPPED HIGH-SIDE DRIVER

摘要

A gate driver (103) for a high-side NMOS power transistor (Mhs) in a DC/DC boost converter (100) includes first and second switches (102, 104) coupled in series between an output pin (P1) and the gate of the high-side transistor. A third switch (106) is coupled between the gate and a switch-node (SW) between the high-side and low-side transistors (Mhs, Mls), the switch node also being coupled to an input pin (P3). Fourth and fifth switches 108, 110) are coupled in series between the output pin and a clamp pin (P4). Sixth and seventh switches (112, 114) are coupled in series between the output pin and a ground pin (P2). First and second bootstrap capacitors (C1, C2) have respective first terminals coupled to a first node (105) between the first and second switches. The first capacitor has a second terminal coupled to a node (107) between the fourth and fifth switches; the second capacitor has a second terminal coupled to a node (109) between the sixth and seventh switches.