By Mao Ye, Applications Engineer, Battery Management Applications, Texas Instruments.

Battery-powered portable devices such as cellular phones have become an important part of people’s daily lives in the past few years. Many types of adapters are available to charge the lithium-ion (Li-ion) battery and power the system, and their electrical specifications usually differ from one manufacturer to another. This challenges system designers to build portable devices that will meet safety and reliability requirements when used with different adapters. This article describes a new battery-charger front-end (CFE) IC, the Texas Instruments (TI) bq243xx, which is optimized to improve the safety of charging Li-ionpowered systems. Together with the battery-charger IC and the protection module in a battery pack, a charging system using the bq243xx CFE provides more robust system-level protection.

TI SYS/BIOS is a real-time operating system kernel. It is also a component of TI RTOS. TI RTOS is an integration system; it includes TI SYS/BIOS kernel, XDCtools, middleware, MCU driver library, and other kinds of components.

TI-RTOS is a one-stop solution for developing applications for TI embedded processors and is tightly integrated with TI’s Code Composer Studio™ (CCS) development environment.

TI-RTOS also provides many example project packages with which you may start to develop a project with TI SYS/BIOS.

This white paper describes the design of a DSP-based control system for erbium-doped fiber amplifiers in order to stabilize the wavelength of multiple pump lasers. The platform shows a single TMS320F2812 DSP (abbreviated “F2812” throughout this document) controlling the temperature of four lasers. The analog portions of the design were chosen to minimize the temperature measurement error and maximize the efficiency of the drive to the thermoelectric cooler. The platform highlights the advantages of using a single DSP in this application over using discrete TEC controller modules:

• the ability to control the edges of the PWM signals to the TEC drivers, minimizing electrical noise;
• the ability to use the programmability of the DSP to easily handle exception processing;
• the extendibility of the design to additional TEC channels;
• the ability to add function easily to the DSP to control other aspects of the design, such as back facet diode monitoring and dynamic gain flattening filtering.

The paper concludes showing methods to add additional channels to the base design and reduce the board space of the design.