UCC28750数据手册TI中文资料规格书

描述 Description

UCC28750 is a highly-integrated current-mode, continuous-conduction-capable, PWM controller optimized for high performance, low standby power, and cost effective offline flyback converter applications using an opto-coupler. During light-load conditions the device enters frequency foldback and burst modes, improving light-load efficiency. The burst-mode algorithm used in UCC28750 controls the minimum effective switching frequency to prevent audible noise during light-load conditions. Frequency dithering improves EMI performance, and is active in normal, frequency foldback, and power boost operations.

UCC28750 provides protection features that enable a robust converter design with minimal external components. Output over-power protection (OPP) and cycle-by-cycle over-current limit protect the load and power-stage components from electrical stress. Over-voltage and under-voltage lockout (OVLO and UVLO) prevent switching in unwanted input conditions. The FLT pin provides line brown-out sensing and protection, or external over-temperature and over-voltage protection, depending on the device variant. The FLT pin is also used to disable the device through external control by pulling the pin to ground, regardless of the device variant.

特性 Features

• Stable continuous conduction mode (CCM) operation with internal slope compensation
• Fixed-frequency operation of 65kHz or 100kHz
• Secondary-side regulation (SSR) with opto-coupler
• Frequency foldback and burst mode for improved light-load efficiency
• Frequency dithering for improved EMI performance
• Gate source/sink capability: 300mA/500mA
• Internal 4ms soft-start
• Robust protection features:
• Over-voltage and Under-voltage lockout
• Output over-power protection (OPP)
• Output short-circuit (OSC) protection
• Output over-voltage (OVP) protection
• Cycle-by-cycle peak over-current limit
• External over-temperature, over-voltage protection (OTP, OVP) and brownout detection on FLT pin
• Internal thermal shutdown