The term "Power Management" includes all power-rail control functions implemented in a circuit board. Every circuit board is powered from one or more sources called the input, or primary, power supplies. Typically, input power rails are controlled by power-management functions, such as hot-swap control and redundant power-rail control. On the payload side, power management functions include sequencing, monitoring, supervisory signal generation, trimming and margining.
Also, every circuit board performs one or more functions using a number of ICs, such as ASICs, CPUs, FPGAs, and so on. These ICs are called the payload ICs. The circuit board generates multiple power rails from the input supplies to power these payload ICs, using board-mounted supplies called primary and secondary supplies.
A new book entitled A Guide to Power Supply Management and Control, from Lattice Semiconductor Corp., provides technical details and design considerations for implementing some common circuit board power management functions. It also provides generalized, cost-effective solutions for each of these functions that can be customized to meet a circuit board’s specific voltage, current and control environment. While it is specific to Lattice Semiconductor products, it also provides useful discussion of approaches, sequencing, and operational algorithms applicable to other products and designs.
We are pleased to present Chapter 6, entitled "Power Supply OR'ing Controllers" in three parts, in pdf format (no registration required), as follows:
- Part 1: What is power rail OR'ing?, Challenges of designing a MOSFET OR'ing circuit, +5V power supply OR'ing (using MOSFETs) circuit, click here.
- Part 2: Power supply OR'ing of three or more 5V supply rails using MOSFETs, N-rail (12V/24V) OR'ing, click here.
- Part 3: -48V supply OR'ing through MOSFETs, click here.
About the Author
Srirama (“Shyam”) Chandra is a widely-published author and recognized authority on power management. He is the Product Marketing Manager for programmable mixed signal products at Lattice Semiconductor Corporation. Prior to joining Lattice, Shyam worked for Vantis and AMD in sales and applications and previously was a telecom design engineer with Indian Telephone Industries. Shyam received his Masters degree in Electrical Engineering from the Indian Institute of Technology, Madras.