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Richtek

The RT7781S is a high-performance current mode PWM controller featuring Richtek’s proprietary PowerZero technology. The PowerZero offers an excellent green power solution, particularly under light-load and no-load conditions. The integrated high-voltage device enables a fast start-up function without the need for external start-up resistors. Additionally, It includes brown-in and brown-out detection.The RT7781S provides comprehensive protection functions, including internal Over-Temperature Protection (OTP) and VDD Overvoltage Protection (OVP). It also features Secondary Rectifier Short-Circuit Protection (SRSP) and Current Sensing pin (CS) open-circuit protection. These protections simplify and enhance the reliability of power supply unit designs.The recommended junction temperature range is -40°C to 125°C, and the ambient temperature range is -40°C to 85°C.

应用

  • Notebook Adapters
  • Switching AC-DC Adapters with Low No-Load Input Power
  • TV and Monitor Applications
  • Open Frame Power Supply
主要规格
RT7781S
Status Active
Feedback Regulation Mode SSR
Switching Frequency_Normal (kHz) 65
Peak load Application No
HV Start-up Yes(w/i X-CAP discharge)
CCM/Valley Multi-mode CCM/Hard Switching Multi-Mode
Programmable Burst/Green-mode No
Brown-in/out Yes (AC Side)
OVP OVP
External OTP No
UVLO ON (V) 16.5
UVLO OFF (V) 9
VDD OVP (V) 27
Features Current Mode Control;Cycle-by-Cycle Current Limit;OCP;OVP
Package Type SOP-7
Outline Dimension, Footprint, Drawing Download
关键特性
  • PowerZero Technology
    - Integrated 700V Start-Up Device
    - Brown-In and Brown-Out Detection
  • Low No-Load Input Power (<50mW)
  • Driver Capability: 400mA/-400mA
  • ACD Pin for TV Applications
  • Frequency Jittering Function
  • Soft Driving for Reducing EMI Noise
  • VDD Overvoltage Protection
  • Internal Over-Temperature Protection
  • Secondary Rectifier Short-Circuit Protection
  • CS Pin Open-Circuit Protection
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