ST AN3290 Application Note Design Reference for Dual Output SMPS Applied to Power Line Modem Utilizing ALTAIR04-900 Primary Controller
Summary
This application note provides a detailed design and technical evaluation for building a double-output Switched-Mode Power Supply (SMPS) specifically for power line communication systems. The solution utilizes the ALTAIR04-900 controller, featuring primary sensing to simplify circuit design by eliminating secondary voltage references or optocouplers. The document covers comprehensive testing data, including efficiency measurements, operational waveforms across various mains voltages, and detailed reports on protection features like overload and brownout detection. This resource is ideal for engineers designing robust, high-reliability low-voltage power supplies used in modem applications.
Page 1 Text Content
AN3290
Application Note
Reference design for double output SMPS for power line modem applications using ALTAIR04-900 primary controller
Introduction This application note introduces a new “all-primary sensing” switching regulator ALTAIR04- 900, used to build an innovative solution to supply a power line communication. A demonstration board, implementing a wide-range double-output power supply, has been developed and the results of its bench evaluation are reported in this document. The board uses the new ALTAIR04-900, a quasi-resonant (QR) current-mode controller IC specifically designed for QR ZVS (zero voltage switching at switch turn-on) flyback converters, which combines a high-performance low-voltage PWM controller chip and a typical 16 RDSon, 900 V, avalanche-rugged power MOSFET in the same package. The device is capable of providing constant output voltage regulation using primary-sensing constant voltage loop (CV loop). This eliminates the need for the optocoupler and the secondary voltage reference while still maintaining quite accurate regulation. Also, using the primary constant current loop (CC loop), it is possible to set the maximum deliverable output current without any secondary components or current sensor.
April 2011 Doc ID 18038 Rev 1 1/34
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Page Summary Contents For ST AN3290 Application Note Design Reference for Dual Output SMPS Applied to Power Line Modem Utilizing ALTAIR04-900 Primary Controller
Manual Details
| Brand | Dual |
|---|---|
| Pages | 34 |
| File Size | 3.14 MB |
| Published | June 01, 2026 |
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Frequently Asked Questions
What primary benefit does using primary sensing offer?
It uses a constant voltage loop (CV loop) for regulation, eliminating the need for optocouplers and secondary voltage references.
What protective features are included in this design board?
Protection includes overload/short-circuit protection, auxiliary winding disconnection (brownout), and secondary winding short-circuit detection.
How can I set a maximum output current limit?
The primary constant current loop (CC loop) allows setting the limit without requiring external current sensors or components.
Does this converter support wide input voltage ranges?
Yes, performance measurements are provided covering operation across various VAC inputs, such as 85 VAC to 264 VAC.