Constant-voltage, constant-current controller with primary-side regulation for bipolar power devices
Product details
Parameters
Package | Pins | Size
Features
- < 10-mW No-Load Power
- Primary-Side Regulation (PSR) Eliminates Opto-
Coupler - ±5% Voltage and Current Regulation Across Line
and Load - 700-V Start-Up Switch
- 80-kHz Maximum Switching Frequency Enables
High-Power Density Charger Designs - Quasi-Resonant Valley-Switching Operation for
Highest Overall Efficiency - Wide VDD Range Allows Small Bias Capacitor
- Dynamic BJT Drive
- Overvoltage, Low-Line, and Overcurrent
Protection Functions - Programmable Cable Compensation
- SOIC-7 Package
Description
The UCC28720 flyback power supply controller provides isolated-output Constant-Voltage (CV) and Constant-Current (CC) output regulation without the use of an optical coupler. The devices process information from the primary power switch and an auxiliary flyback winding for precise control of output voltage and current.
An internal 700-V start-up switch, dynamically-controlled operating states and a tailored modulation profile support ultra-low standby power without sacrificing start-up time or output transient response.
Control algorithms in the UCC28720 allow operating efficiencies to meet or exceed applicable standards. The output drive interfaces to a bipolar transistor 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 80 kHz and always maintains control of the peak-primary current in the transformer. Protection features help keep primary and secondary component stresses in check. The UCC28720 allows compensation for voltage drop in the cable to be programmed with an external resistor.
Technical documentation
| Type | Title | Date | |
|---|---|---|---|
| * | Datasheet | UCC28720 Constant-Voltage, Constant-Current Controller With Primary-Side Regulation datasheet (Rev. B) | Sep. 30, 2015 |
| Application note | Minimize Standby Consumption for UCC287XX Family | Aug. 01, 2019 | |
| Application note | Maximum Output Power and Thermal Considerations for UCC28720 and UCC28722 | Dec. 06, 2017 | |
| Application note | Troubleshooting TI PSR controllers | Oct. 03, 2016 | |
| Technical articles | Slim down your flyback; lose that excess snubber | Feb. 15, 2016 | |
| White paper | Control Challenges for Low Power AC/DC Converters | Oct. 02, 2015 | |
| White paper | Control Challenges for Low Power AC/DC Converters (PPT) | Oct. 02, 2015 | |
| Technical articles | Designing multiple output converters with primary side sensing | Aug. 04, 2015 | |
| Application note | 5-W USB Flyback Design Example Using the UCC28722 | Jan. 08, 2014 | |
| Technical articles | Isolated power supplies – Is analog dead? | Sep. 24, 2013 | |
| User guide | Using the UCC28720EVM-212 (Rev. A) | Sep. 20, 2013 |
Design & development
For additional terms or required resources, click any title below to view the detail page where available.Hardware development
Description
Features
- <10mW no load power
- Primary Side Regulation (PSR) eliminates opto-coupler
- +/- 5% Voltage & Current Regulation
- Quasi-resonant valley switching operation for highest overall efficiency
- Wide VDD range (35V) allows small bias capacitor
- Drive Output for low cost Bipolar
- Protection Functions: Over Voltage, Low (...)
Design tools & simulation
Reference designs
CAD/CAE symbols
| Package | Pins | Download |
|---|---|---|
| SOIC (D) | 7 | View options |
Ordering & quality
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