SRK2001L

SRK2001 Adaptive synchronous rectification controller for LLC resonant converter Datasheet - production data  80+/85+ compliant ATX SMPS  90+/92+ compliant SERVER SMPS  Industrial SMPS SSOP10 Description 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 and logic level MOSFETs: SRK2001 and SRK2001L 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. Table 1. Ordering codes  SSOP10 package Applications  AC-DC adapters  All-in -one PC Package Packing Tube SSOP10  High-end flat panel TV May 2015 This is information on a product in full production. DocID027367 Rev 3 Tape and reel Standard gate MOSFETs Logic gate MOSFETs SRK2001 SRK2001L SRK2001TR SRK2001LTR 1/22 www.st.com Contents SRK2001 Contents 1 Block diagrams and pin connections . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2 Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3 Typical application schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 4 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 5 Operation description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 5.1 Drain voltage sensing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 5.2 Turn-on . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 5.3 Turn-off . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11 5.4 ZCD comparator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 5.5 Gate drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 5.6 Intelligent automatic sleep mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 5.7 EN and PROG pins: function and usage . . . . . . . . . . . . . . . . . . . . . . . . . 14 5.8 6 5.7.1 Automatic sleep mode function enabled . . . . . . . . . . . . . . . . . . . . . . . . 15 5.7.2 Automatic sleep mode function disabled . . . . . . . . . . . . . . . . . . . . . . . . 16 Layout guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 SSOP10 package information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 7 2/22 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 DocID027367 Rev 3 SRK2001 1 Block diagrams and pin connections Block diagrams and pin connections Figure 1. Internal block diagram '96 696 89/2 +9 &/$03 $1' 6:,7&+ 9%86 9&& 32:(5 0$1$*(0(17 *1' '96 696 7,0(56 &203$5$7256 (1 21 =&' 2)) $'& $'$37,9( 21 ±7,0( 352* $'$37,9( 2))± 7,0( &. &21752//2*,& *' *' '5,9(5 '5,9(5 $0 Figure 2. Typical system block diagram 3)&35( 5(*8/$725237,21$/ //&5(621$17+$/) %5,'*(:,7+6