This reference design is an industry-first digital hybrid hysteretic control (HHC) solution, targeting server PSU applications with 12-V to 54-V output. This reference design shows the HHC control advantages by UCD3138, in a 400-V to 12-V 1-kW LLC power stage. This design achieves 8-kHz peak loop bandwidth. It holds less than 500-mV peak-to-peak deviation under 0% and 100% load translation with 2.5 A/us, and less than 800-mV peak-to-peak deviation under 0% and 150% load translation with 2.5 A/us.
Features
- High load transient performance
- Monotonic startup with any load condition
- Burst mode for power saving in light load
- Integrated SR control for secondary MOSFET
- Low audio susceptibility suppressing input voltage ripple
- Configurable deadtime