This thesis focuses on development of electronic printed circuit boards for a battery-powered kitchen blender.
In the beginning we review the Li-ion technology, its specifications and electrical characteristics. We take a close look at charging voltage and charging current limitations. This limitations need to be closely observed and monitored to provide stable and safe operation of Li-ion cells.
The system of portable battery powered kitchen blender could be divided into five segments: external switch-mode power supply, printed circuit board of current and voltage limiter, printed circuit board of battery balancer and motor driver, blender’s main motor.
The major challenge of this thesis represent the development of printed circuit board of current and voltage limiter and printed circuit board of battery balancer and motor driver. For development of voltage and current limiter we used readily available solution MAX1737. MAX1737 is price adequate and represents high efficiency solution for charging Li-ion batteries. Battery balancer and motor driver is realized with usage of ATmega16 microcontroller, which is sensing the voltage of every single cell. In event of cell overvoltage in regarding to average cell voltage of battery, the part of the charging current is redirected through cell bypass. Use of bypass provides slower charging of individual cells end enables battery balancing.
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