A High-Voltage DC–DC Buck Converter With Dynamic Level Shifter for Bootstrapped High-Side Gate Driver and Diode Emulator

摘要

Considering the propagation delay, dV(SW)/dt immunity, and power dissipation issues in the bootstrapped high-side gate driver design, amonolithic high-voltage dc-dc buck converter with a high-speed dynamic level shifter and improved gate drive buffer is presented in this article. With the introduction of instantaneous dynamic current, the propagation delay of the level shifter is reduced to 1.13 ns for the high-side switch. The dV(SW)/dt immunity is enhanced by a dynamic current compensation during positive slewing and a diode voltage clamp during negative slewing. The average current consumption of the level shifter is only 8.45 mu A at a switching frequency of 1 MHz. The proposed gate drive buffer eliminates the shoot-through current with the use of dead-time control. The compact level shifter and buffer are also used to drive an integrated p-channel MOSFET transistor serving as a bootstrap diode emulator. Experimental results show that the fabricated converter with the proposed scheme regulates well with an 18V input, 1.05V output, and 2 A load current. Also, high efficiency of up to 93% is achieved.