发布时间:2022-12-15 16:10:24 作者: 来源:

η-BalanceTM Current Mode PWM Controller@65KHz


   Less than 75mW Standby Power

   Programmable OLP Debounce Time

   Proprietary η-BalanceTM Control to Boost Light Load Efficiency

   Proprietary “Zero OCP/OPP Recovery Gap” Control

   Proprietary “Audio Noise Free OCP Compensation”

   Dmax up to 80%

   Fixed 65KHz Switching Frequency

   Built-in Frequency Shuffling

   Built-in Soft Start Function

   Frequency Reduction and Burst Mode Control for Energy Saving

   Built-in Synchronous Slope Compensation

   Cycle-by-Cycle Current Limiting

   Built-in Leading Edge Blanking (LEB)

   Current Mode Control

   Pin Floating Protection

   Very Low Startup Current

   Audio Noise Free Operation




Offline AC/DC Flyback Converter for

   AC/DC Adaptors

   Open-frame SMPS

   Laptop Charger


SF5533P is a high performance, high efficiency, highly integrated current mode PWM controller for offline flyback converter applications. The OLP debounce time can be programmed in SF5533P.

In SF5533P, PWM switching frequency with shuffling is fixed 65KHz and is trimmed to tight range. When the output power demands decrease, the IC decreases switching frequency based on the proprietaryη-BalanceTM control to boost power conversion efficiency at the light load. When output power falls below a given value, the IC enters into burst mode and can achieve less than 75mW no load power.

The IC can achieve “Zero OCP/OPP Recovery Gap” using SiFirst’s proprietary control algorithm. SF5533P also has built in proprietary “Audio Noise Free OCP Compensation”, which can achieve constant power limiting and can achieve audio noise operation at heavy loading when line input is around 90VAC.

SF5533P integrates functions and protections of Under Voltage Lockout (UVLO), VDD Over Voltage Protection (OVP), Cycle-by-cycle Current Limiting (OCP), Pins Floating Protection, Over Load Protection (OLP), Gate Clamping, RT Pin Short-to-GND Protection, Leading Edge Blanking (LEB), Soft Start, etc.

SF5533P is available in SOT23-6 package.

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