Data Brief SZ1105 (Silanna)

SZ1105 Flyback PWM Controller with Integrated Active Clamp Circuit Features Product Description
▪ Integrated UHV Active Clamp FET, Active Clamp The SZ1105 is an Active Clamp Flyback (ACF) PWM Driver and Startup Regulator Controller that integrates an adaptive digital PWM ▪ Capable of Over 93% Efficiency controller and the following Ultra High-Voltage (UHV) ▪ Flat Efficiency Across Universal (90 - 265 Vac) components: active clamp FET, active clamp driver and a startup regulator. Input Voltage and Load ▪ Tight Switching Frequency Regulation for The device provides ease-of-design of a simple flyback Improved Input EMI Filter Utilization controller with all the benefits of an ACF design, including ▪ Up to 140 kHz Switching Frequency Operation recycling of the leakage inductance energy of the flyback ▪ transformer and limiting the primary FET drain voltage OptiMode™ Cycle-by-Cycle Adaptive Digital spike during the turn-off events. Employing Silanna’s Control OptiModeTM digital control architecture, the SZ1105 ▪ Quasi-Resonant (QR), Valley Mode Switching adjusts the device’s mode of operation on a cycle-by-cycle (VMS) for low EMI basis to maintain high efficiency, low EMI, fast dynamic ▪ Multi-Mode Operation (Burst Mode, QR, VMS) load regulation and other key power supply parameters in ▪ Self-Tuning Valley Detection response to varying line voltage and load. ▪ OTP, OVP, OCP, OPP and OSCP Protections Furthermore, the switching frequency is confined within a ▪ <50 mW No Load Power Consumption tight frequency band for simplified EMI filtering. In addition, ▪ Up to 65 W Output Power adaptive digital control of the active clamp operation ▪ 16-pin SOIC Package enables near ZVS turn-on of the primary FET and clamps

the drain voltage during the turn-off, thus further improving efficiency and reducing EMI.
Applications
Unlike conventional ACF designs, tight tolerances of the ▪ High Power Density USB-PD AC/DC Power clamp capacitor and leakage inductance values are not Supplies required for proper operation of the circuit in high volume ▪ High Efficiency USB-PD Power Adapters production. Moreover, a small 3.3 nF clamp capacitor is sufficient to realize the benefits of ACF operation. The SZ1105 is well suited for high efficiency and high-power
Application Diagram
density USB-PD AC/DC power adapters, providing up to V 65 W output power. BULK Primary The SZ1105 is available in a space saving 16-pin SOIC Primary FET package. V5OUT BOOT_CL SW GATE ISNS Auxiliary V10 CLAMP CLMP_S SZ1105 VAUX_S VBULK_S TEMP V5OUT DGND GND FB
Figure 1: Active Clamp Flyback Controller Figure 2: Device Package Image
Silanna Semiconductor Proprietary and Confidential Page 1 Patents: www.SilannaSemi.com/patents Document 10854 Ver. 3.0