How to Design Battery Charger Applications that Require External Microcontrollers and Related System-Level Issues
Notebook computers increasingly require complex battery charging algorithms and systems. This article provides information and background on lithium-ion (Li+), nickel-cadmium (NiCd), and nickel-metal-hydride (NiMH) batteries and related system-level switch-mode and linear battery chargers. These voltage regulators and current regulators are controlled by external microprocessors like the 8051 or Microchip PIC, and examples are provided with these controllers. An overview of requirements for charging common battery chemistries with Maxim battery charger ICs is provided, along with a discussion of system-level trade-offs and firmware design tips, and a list of World Wide Web engineering resources.
The previous issue of Maxim's Engineering Journal (Vol. 27) discussed new developments in stand-alone battery chargers. This second article of a two-part series explores the system-level issues in applying battery-charger ICs.
Over the past five years, market pressures on portable equipment have transformed the simple battery charger
into a sophisticated switch-mode device capable of charging an advanced battery in 30 minutes. This development also marks a departure from the self-contained, stand-alone charger ICs of only a few years ago. Some of those ICs included considerable intelligence: enough to handle the complex task of fast charging
advanced batteries.