The UCC24636 SR is a compact, 6-pin secondary-side synchronous rectifier MOSFET controller and driver for high efficiency Flyback converters operating in Discontinuous (DCM) and Transition mode (TM). Unlike traditional SR controllers which measure the SR MOSFET drain voltage, UCC24636 implements a volt-second balance control method to determine the turn off transition of the SR MOSFET; hence, SR conduction time is independent of the MOSFET RDSON, parasitic inductance or ringing allowing flexibility to designers in component slelction and PCB layout. This control method enables maximum SR conduction time and highest rectifier efficiency for a given MOSFET.
●The controller has built in intelligence to detect converter no load operation and automatically enters standby mode. While in standby mode, it disables the SR MOSFET and lowers its bias supply current to 110µA to further reduce overall system standby power consumption. The wide VDD operating range for the controller allows direct bias from the converter output for fixed or variable output voltage designs. This eliminates the need for an auxilliary winding on the main transformer, which simplifies the circuit design and reduces the cost.
● Secondary-Side SR Controller Optimized for
●5-V to 24-V Output Discontinuous/Transition Mode
●Only Flyback Converters
● Volt-Second Balance Control Enables Highest
●Rectifier Efficiency
● Compatible with PSR and SSR Flyback
●Controllers
● Ultra Low 110-µA Standby Current Consumption
● Auto-Detect Standby Mode Disables SR Switching
●for Lower No-Load
●Power Consumption
● SR Turn-Off Independent of RDSON and Parasitic
●Inductance
● Operating Frequency Up to 130 kHz
● Wide VDD Range from 3.6 V to 28 V
● Adaptive Gate Drive Clamp
● Open and Short Pin Fault Protection
