Power Design Tip 43: A Circuit Design That Can Replace an Integrated MOSFET Driver

One-piece inductor

description:

In Power Supply Design Tip 42, we discussed the emitter tracker used in the MOSFET gate drive circuit and learned that the drive current in the 2A range can be achieved with a small SOT-23 transistor. In this design tip, let's take a look at self-driven rectifiers and discuss when discrete drivers are needed to protect the synchronous rectifier gate from excessive voltage. Ideally, you can use a power transformer to drive the synchronous rectifier directly, but due to the wide input voltage variation, the transformer voltage can become so high that it can damage the synchronous rectifier.