Pulsewidth modulated controller integrated circuit: Four decades of progress [A Look Back]

The simple pulsewidth modulated (PWM) controller IC has made substantial progress in the last 39 years. Along the way, it has left several milestones. In addition, there is much more to achieve, especially as digital PWM controller chips begin to gain ground in the analog world. From a simple monolithic bipolar chip in 1975, designed by Silicon General‚s cofounder and power designer, Bob Mammano, to control a switched-mode power supply (SMPS), the pulsewidth modulated (PWM) controller architecture and integration has made remarkable progress in the last 39 years. Four decades later, advances in topology, semiconductor processes, and packaging have enabled this simple control circuit with a few functional blocks on a bipolar chip to reach everincreasing levels of integration, resulting in a complete power supply as a single board-mountable component. In addition to stimulating the development of SMPS supplies and creating a gigantic market for switching power supplies, it has also enabled a powermanagement integrated circuits (PMICs) industry that is worth tens of billions of dollars today. By research firm Micro-Tech Consultants' estimate, the switching power supply market comprising ac-dc switchers and dc-dc converters was worth over US$29 billion last year and is expected to increase to over US$29.5 billion this year.