DK3704A

This synchronous rectification controller IC, paired with external power transistors, replaces Schottky diodes to achieve rectification, significantly improving system efficiency. It is suitable for QR flyback, active clamp flyback (ACF), asymmetric half-bridge (AHB), and other topologies. The device incorporates multiple efficiency-enhancing features: a fast comparator with short propagation delay reduces switching losses, a high gate drive voltage minimizes MOSFET conduction losses, and a built-in standby mode further reduces standby power consumption. The IC is self-powered from the output voltage, eliminating additional supply losses. A built-in adaptive slope false-turn-on prevention algorithm simplifies design with no external parameter adjustment required, and distinguishes between normal turn-on cycles and resonance to prevent false turn-on when the system operates in discontinuous mode. The IC is available in a SOT23-6 package.

Applications

• USB charger
• Adapter
• LED driver

Key features

• Suitable for flyback QR, active clamp flyback ACF, and asymmetric half-bridge AHB applications
• Low supply loss, powered by system output
• Built-in adaptive cross-conduction prevention algorithm
• Supports 500KHz switching frequency
• Standby mode with low standby current
• Simplified peripheral circuitry