Revolutionary Nomogram Designs for Discontinuous Fly-Back Converters

Power Supply Company Pulsiv Develops Innovative Graphical Technique

Power supply company Pulsiv has recently developed a groundbreaking graphical technique called a nomogram. This technique is designed to determine critical transformer parameters for fly-back converters operating in discontinuous conduction mode. According to the company, this intuitive tool can replace more complex equation-based methods, providing a fast and accurate visual process for identifying primary side inductance and minimum duty cycle.

In order to utilize this technique effectively, it is important to find the switching frequency and maximum duty cycle of the chosen fly-back controller. It should be noted that some controllers change switching frequency based on the fly-back operating voltage, so this must be taken into account. Additionally, the required peak current based on the output power and the minimum fly-back operating voltage should be selected.

Once these parameters have been determined, the nomogram can be used to draw straight lines across it, identifying suitable values for converter primary side inductance and minimum duty cycle based on the maximum operating voltage. It is crucial to check the fly-back controller datasheet to ensure that it can meet the minimum duty cycle requirement that has been found.

Pulsiv also offers a patented front-end power factor correction circuit that can be paired with a DCM fly-back converter in isolated low and medium power ac-dc power supplies. This eliminates the need for a boost-style PFC stage and is particularly useful for USB-C devices, LED drivers, and battery chargers. The novel front-end utilizes active valley-filling controlled by a microprocessor, resulting in reduced primary side inductance, lower leakage inductance, and higher total winding area, sometimes allowing for a smaller core.

Pulsiv's nomogram is a valuable tool for engineers, providing a precise and practical method for calculating complicated formulas using a parallel coordinate system. Results can be obtained quickly and reliably by simply drawing one or more lines, without the need to solve algebraic equations.

Pulsiv, originally a University of Plymouth spin-out, now has sites in Cambridge and on the Plymouth Science Park. Their innovative techniques and solutions continue to push the boundaries of power supply technology.