ZVS Full Bridge PWM Controller

The ISL6551 is a zero voltage switching (ZVS) full-bridge PWM controller designed for isolated power systems. This part implements a unique control algorithm for fixed-frequency ZVS current mode control, yielding high efficiency with low EMI. The two lower drivers are PWM controlled on the trailing edge and employ resonant delay while the two upper drivers are driven at a fixed 50% duty cycle.

FEATUREs
• High speed PWM (up to 1MHz) for ZVS full bridge control
• Current mode control compatible
• High current high-side and low-side totem-pole drivers
• Adjustable resonant delay for ZVS
• 10MHz error amplifier bandwidth
• Programmable soft-start
• Precision bandgap reference
• Latching shutdown input
• Non-latching enable input
• Adjustable leading edge blanking
• Adjustable dead time control
• Adjustable ramp for slope compensation
• Fast short-circuit protection (hiccup mode)
• Adjustable cycle-by-cycle peak current limiting
• Drive signals to implement synchronous rectification
• VDD undervoltage lockout
• Current share support
• ±5% “in regulation” indication
• Pb-free (RoHS compliant)

APPLICATIONs
• Full-bridge and push-pull converters
• Power supplies for off-line and Telecom/Datacom
• Power supplies for high end microprocessors and servers