Texas Instruments UCC28740DR | Demoboard PMP30191

Description

The UCC28740 isolated-flyback power-supply controller provides Constant-Voltage (CV) using an optical coupler to improve transient response to large-load steps. Constant-Current (CC) regulation is accomplished through Primary-Side Regulation (PSR) techniques. This device processes information from opto-coupled feedback and an auxiliary flyback winding for precise high-performance control of output voltage and current.An internal 700-V startup switch, dynamically controlled operating states, and a tailored modulation profile support ultra-low standby power without sacrificing startup time or output transient response.Control algorithms in the UCC28740 allow operating efficiencies to meet or exceed applicable standards. The drive output interfaces to a MOSFET power switch. Discontinuous conduction mode (DCM) with valley-switching reduces switching losses. Modulation of switching frequency and primary current-peak amplitude (FM and AM) keeps the conversion efficiency high across the entire load and line ranges.The controller has a maximum switching frequency of 100 kHz and always maintains control of the peak-primary current in the transformer. Protection features keep primary and secondary component stresses in check. A minimum switching frequency of 170 Hz facilitates the achievement of less than 10-mW no-load power.

Features

Less than 10-mW No-Load Power CapabilityOptocoupled Feedback for CV, andPrimary-Side Regulation (PSR) for CCEnables ±1% Voltage Regulation and ±5% Current Regulation Across Line and Load700-V Startup Switch100-kHz Maximum Switching Frequency Enables High-Power-Density Charger DesignsResonant-Ring Valley-Switching Operation for Highest Overall EfficiencyFrequency Dithering to Ease EMI ComplianceClamped Gate-Drive Output for MOSFETOvervoltage, Low-Line, and Overcurrent Protection FunctionsSOIC-7 Package

More information

• Datasheet
• IC product information