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IC manufacturers ON Semiconductor

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ON Semiconductor FAN501A

Offline DCM / CCM Flyback PWM Controller for Charger Applications


TopologyFlyback Converter
Input voltage30 V
Switching frequency85-140 kHz
IC revisionA


The advanced PWM controller, FAN501A, simplifies isolated power supply design that requires CC regulation of the output. The output current is precisely estimated with only the information in the primary side of the transformer and controlled with an internal compensation circuit, removing the output current-sensing loss and eliminating external CC control circuitry. With an extremely low operating current (250 µA), Burst Mode maximizes light-load efficiency, allowing conformance to worldwide Standby Mode efficiency guidelines. Compared with a conventional approach using external control circuit in the secondary side for CC regulation, the FAN501A can reduce total cost, component count, size, and weight; while increasing efficiency, productivity, and system reliability.


WSaver® Technology Provides Ultra-Low Standby Power Consumption for Energy Star’s 5-Star Level (<30 mW)Constant-Current (CC) Control without Secondary-Side Feedback Circuitry for Discontinuous Conduction Mode (DCM) and Continuous Conduction Mode (CCM)Dual-Frequency Function Changes Switching Frequency (140 kHz / 85 kHz) According to Input Voltage to Maximize Transformer Utilization and Improve EfficiencyHigh Power Density and High Conversion Efficiency in CCM Compact Charger ApplicationsFrequency Hopping to Reduce EMI NoiseHigh-Voltage StartupPrecise Maximum Output Power Limit by CC Regulation through External Resistor AdjustmentPeak-Current-Mode Control with Slope Compensation to Avoid Sub-Harmonic OscillationProgrammable Over-Temperature Protection with Latch Mode through External NTC ResistorTwo-Level UVLO Reduces Input Power in Output Short SituationVS Over-Voltage Protection with Latch ModeVDD Over-Voltage Protection with Auto RestartAvailable in MLP 4 X 3 Package

Typical applications

  • Ac-DC Adapters for Portable Devices or Battery Chargers that Require CV/ccControl.
  • Battery Chargers for Smart Phones, Feature Phones and Tablet PCs.