Green mode PFC/Flyback-PWM Controller
SG6905—Green Mode PFC/Flyback-PWM Controller
October 2008
SG6905 Green Mode PFC/Flyback-PWM Controller
Features
Int...
Description
SG6905—Green Mode PFC/Flyback-PWM Controller
October 2008
SG6905 Green Mode PFC/Flyback-PWM Controller
Features
Interleaved PFC/PWM Switching Green Mode PWM Operation Low Startup and Operating Current Innovative Switching-Charge Multiplier-Divider Average-Current-Mode Control for PFC PFC Over-Voltage and Under-Voltage Protections PFC Remote On/Off Control PFC and PWM Feedback Open-Loop Protection Cycle-by-Cycle Current Limiting for PFC/PWM Slope Compensation for PWM Constant Power Limit for PWM Power-On Sequence Control Brownout Protection Over-Temperature Protection
Applications
Switching Power Suppliers with Active PFC High-Power Adaptors LCD TV Applications
Description
The highly integrated SG6905 is specially designed for power supplies consisting of boost PFC and flyback PWM. It requires very few external components to achieve green-mode operation and versatile protections. It is available in 20-pin SOP package.
The proprietary interleave-switching feature synchronizes the PFC and PWM stages and reduces switching noise. At light loads, the switching frequency is continuously decreased to reduce power consumption.
For PFC stage, the proprietary multi-vector control scheme provides a fast transient response in a lowbandwidth PFC loop, in which the overshoot and undershoot of the PFC voltage are clamped. If the feedback loop is broken, the SG6905 shuts off PFC to prevent extra-high voltage on output.
For the flyback PWM, the synchronize...
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