Zero Standby PSR Flyback Controller with CVCC and Wake-Up Monitoring

Rapid load step response with smallest output capacitors - tight regulation window avoids downstream system restart due to UV protection.
 

The UCC28730 isolated-flyback power supply controller provides Constant-Voltage (CV) and Constant-Current (CC) output regulation without the use of an optical coupler, and signal detection to improve transient response to large load steps. A minimum switching frequency of 30Hz facilitates achieving less than 5mW of no-load power. This device processes information from the primary power switch and an auxiliary flyback winding for precise control of output voltage and current.

The monitoring works with a secondary-side alarm device such as the UCC24650 to deliver rapid response to heavy load steps using minimal output capacitance. An internal 700V start-up switch, dynamically- controlled operating states and a tailored modulation profile support ultra-low stand-by power without sacrificing start-up time or output transient response.

Control algorithms in the UCC28730 allow operating efficiencies to meet or exceed applicable standards. Discontinuous conduction mode (DCM) operation with valley-switching reduces switching losses. Modulation of the switching frequency and primary current peak amplitude (FM and AM) keeps the conversion efficiency high across the entire load and line ranges.

  • Enables (<5 mW) standby consumption
  • Smart detection enables smallest output capacitance
  • Primary-side regulation (PSR) eliminates opto-coupler
  • ±5% voltage regulation and current regulation across line and load
  • 700 V start-up switch
  • 83 kHz maximum switching frequency enables low stand-by power charger designs
  • Resonant-ring valley-switching operation for highest overall efficiency
  • Frequency-dither to ease EMI compliance
  • Clamped gate-drive output for MOSFET
  • Over-voltage, low-line, and over-current protection functions
  • Programmable cable compensation
  • SOIC-7 Package
Applications

  • Clothes washer & dryer microwave ovens
  • Multimedia
  • Smartphone
  • Refrigerators & freezers

Datasheet

 
 
29 de abril de 2015