AFE

AFE for BMS Design 2 - Schematic Capture In part one of this series I looked at the inital concept of what an AFE is and a basic outline. In the previous post I presented the follow ideas for the design of the system : 9-15S LiPo battery (BQ76940) 100mA balance current 40A continuous duty current shunt, 50A peak PCB area less than 10x10cm panel LED SOC indication Ability to communicate to an external display to show detailed information Temperature sensing inside the battery pack Track the health of the pack Looking at this design, I selected to use a companion controller to work with the AFE for the inital design of this BMS. This is not technically required, and if you wish to impliment your own the schematic is almost identical except swapping the companion controller out for your selected device. ...

Getting Started with AFE’s for BMS design. Analog Front End IC’s are becoming more popular from major IC manufacturers. These chips are designed to wrap all the analogue circuitry required for the design and operation of a BMS system up into a small package. Reducing design and programming time for the designer(s). This forfill a useful segment of the market where the application may want different design parameters to a normal BMS design, or even just for learning the operation modes of a BMS. Texas Instruments makes a series of chips in the BQ769x0 line. These 3 forms of the chip cover usage cases for 3 to 15 series cells in the battery pack. However other manufacturers have created similar devices. Some, like TI, integrate the ADC and voltage reference on the same IC. For other brands a separate external ADC is required, this allows for higher accuracy at the cost of increased circuit complexity. ...