I'm presently considering building a half-bridge converter, which means I have a transistor that's not tied to circuit common. To drive it, I'll need some voltage supply referenced to its source. This is a common problem with many switching topologies.
I'm aware of two general ways to power such a driver: a magnetically isolated DC/DC converter, or a bootstrap. But magnetic isolators still see some capacitive coupling across the isolation barrier, which can cause problems in the control circuit. And bootstrap converters can have EMI issues and only work if you switch a lower transistor often enough to recharge them.
All this is very vague in my head. Are there other ways of powering a high-side transistor drive? Are there other design considerations between the means I've mentioned?