Telecom Power Supply Designing
Summary: Doing so usage note describes a compact 5W flyback, high-frequency, switching converter for Telecom applications. Most elements of the design course of action are discussed: power-stage selection and style, transformer design, core size calculations, RCD snubber style, MOSFET selection, input and results filter designs, frequency payout, power-loss and effectiveness calculation, and layout and safety guidelines.
Telecom power supplies are specified for operation over a wide input-voltage range (36V to 75V) but with circuit performance optimized at 48V. Such circuit designs should be compact, efficient, and have a low profile to comply with the tight spacing between cards. This app note discusses a 5W flyback converter for telecom applications, based on the MAX5021 IC—a universal offline power-supply controller.
A telecom power supply contains many family cards. Hooked up in fashion=”text-decoration: underline;”>parallel to the high-power backplane, every has its own input-filter capacitor and low-voltage power converter. The big number of input-filter capacitors in parallel extent the consider of each to a couple of microfarads, crafting the power-supply design pretty difficult.
The MAX5021 IC is a high-frequency, current-mode PWM controller suitable for wide-input-range, separated telecom power products. It enables the layout of small, effective, power-converter circuits. A fixed-switching frequency of 262kHz controls shifting losses while allowing moderately small power components. The IC includes undervoltage lockout function using big hysteresis and a low startup up to date. Doing so final results in low-loss designs for supremacy products that function a wide input-voltage range and low output supremacy. Cycle-by-cycle up to date limiting (attained using a fastinternal comparator) minimizes overdesign in the MOSFET and transformer. Other showcases involve maximum-duty-cycle limiting and high-peak system for the obtain and sink-drive currents.
