SRK2001ATR

The SRK2001A 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 directly driving 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 driver high-level voltage is clamped to 11V in order to avoid providing excessive gate charge to SR MOSFETs, in case the device is supplied at higher VCC voltages. 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 turn-on logic with adaptive masking time (up to 10% of clock cycle) and innovative adaptive turn-off logic allow 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 and 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 V to 32 V
• High voltage drain-to-source Kelvin sensing for each SR MOSFET
• Operating frequency up to 500 kHz
• Programmable exit load levels from burst mode
• SSOP10 package