Designing SMPS Controllers with the Infineon TDA16831

The quest for efficient, reliable, and cost-effective power conversion is a constant in electronics design. Switch-Mode Power Supplies (SMPS) are the cornerstone of this endeavor, and their performance hinges on the capabilities of the controller IC. The Infineon TDA16831 stands out as a versatile and robust integrated circuit designed specifically for building free-running SMPS systems, particularly in off-line applications.

This controller excels in its simplicity and effectiveness. Operating on a fixed off-time, frequency-variable principle, it provides a distinct advantage. The switching frequency automatically decreases under light-load conditions. This inherent feature significantly reduces switching losses when they are least needed, leading to a marked improvement in overall system efficiency across a wide operational range without complex control schemes.

A key strength of the TDA16831 is its comprehensive suite of built-in protection features, which enhances the reliability of the final power supply. It integrates overvoltage protection (OVP), which safeguards against dangerously high output voltages. Furthermore, it includes an innovative overload and open-loop protection mechanism. In the event of an output short-circuit or a failure in the feedback loop, the controller safely limits the power delivery, preventing catastrophic failure of downstream components.

Designing with this IC is streamlined by its minimal external component count. The oscillator timing and off-time are set by a single resistor, simplifying the design process. The IC also features a high-voltage startup circuit, which allows it to draw power directly from the rectified mains voltage. This eliminates the need for a separate auxiliary startup supply, reducing both component cost and board space.

For control, the TDA16831 utilizes primary-side regulation (PSR). By sampling the voltage from an auxiliary winding on the main transformer, it can infer the output voltage without the need for an optocoupler-based feedback isolation circuit. This approach not only reduces component count and cost but also improves system reliability by removing a potential failure point.

In practice, the TDA16831 is an ideal choice for designers creating power supplies for consumer electronics, auxiliary power for appliances, and low-to-medium power adapters. Its ability to operate over a wide input voltage range and its rugged design make it suitable for harsh electrical environments.

ICGOOODFIND: The Infineon TDA16831 is a highly integrated and resilient SMPS controller that empowers designers to build efficient and reliable power supplies. Its combination of a variable frequency control method for high efficiency, a rich set of internal protections for safety, and primary-side regulation for cost reduction makes it an exceptional solution for a broad spectrum of off-line power conversion applications.

Keywords: SMPS Controller, Primary-Side Regulation, Overvoltage Protection, Variable Frequency, High-Voltage Startup