For half-bridge drivers, a floating bias supply referenced to the switch node is required to turn on the high-side transistor. This bias supply is typically created with a bootstrap circuit using a resistor, diode, and capacitor. For more information about the bootstrap circuit and component selection guidance, see Bootstrap Circuitry Selection for Half-Bridge Configurations. Gate drivers with an integrated bootstrap diode can simplify a driver design and save cost and board space by removing the need for external bootstrap diode and resistor components. Figure 2-6 shows an example of the LM2105 gate driver with an integrated bootstrap diode.

Figure 2-6 LM2105 Block Diagram with Integrated Bootstrap Diode