SRK2001TR

The SRK2001 controller implements a control scheme specific for secondary side synchronous rectification in LLC resonant converters that use a transformer with center tap secondary winding for full wave rectification. It provides two high current gate drive outputs, each capable of driving one or more N-channel power MOSFETs. Each gate driver is controlled separately and an interlock logic circuit prevents the two synchronous rectifier MOSFETs from conducting simultaneously. The control scheme in this IC provides for each synchronous rectifier being switched on as the corresponding half-winding starts conducting and switched off as its current goes to zero. The innovative turn-on logic with adaptive masking time and the adaptive turn-off logic allows maximizing the conduction time of the SR MOSFETs eliminating the need of the parasitic inductance compensation circuit. The low consumption mode of the device allows to meet the most stringent requirement for converter power consumption in light-load/no load conditions. A noticeable feature is the very low external component count required.

Applications

• AC-DC adapters
• All-in-one PC
• High-end flat panel TV
• 80(+85+) compliant ATX SMPS
• 90(+92+) compliant SERVER SMPS
• Industrial SMPS

Key features

• Secondary side synchronous rectification controller optimized for LLC resonant converter
• Dual gate driver for N-channel MOSFETs
• Adaptive turn-off logic
• Turn-on logic with adaptive masking time
• Auto-compensation of parasitic inductance
• Low consumption mode: 50 μA quiescent current
• VCC operating voltage range 4.5 to 32 V
• High voltage drain-to-source Kelvin sensing for each SR MOSFET
• Operating frequency up to 500 kHz
• 35 ns total delay at turn-off
• Protection against current reversal
• Safe management of load transient, light-load and startup conditions
• Intelligent automatic sleep mode at light-load with user programmable enter/exit load levels, with soft transitions and function disable
• Programmable exit load levels from burst mode
• Compatible with standard level MOSFETs
• SSOP10 package