3.2 Shunt network
A shunt resistor (70mOhm, 1%) is placed in the charge/discharge path of the battery.
The shunt resistor is used to measure the current that flows in and out of the battery.
The ATtiny devices are measuring the voltage over the shunt (differentially ADC
reading) and can use this information to calculate the current flow and adjust the
charge voltage/current accordingly, or terminate the charging.
Since the maximum voltage at the terminals of the shunt depend on the number and
type of the batteries connected, a resistor divider network is used to reduce the
voltage seen by the ATtiny. The resistor divider network can be configured to 1/2, 1/4,
1/8, 1/12 or 1/16 of the shunt terminal voltages by setting the corresponding jumpers:
One set of jumpers (J405) configure the resistor divider on the positive side of the
shunt and one set of jumpers (J406) the negative side. The side of the shunt that is
considered “positive” is positive while charging a battery. If other resistor divider
values are desired the resistors must be replaced.
The ATmega644 can also measure the shunt voltage, but only with 9 bit accuracy, as
opposed to the ATtiny, which measure with 10 bit accuracy.
Figure 3-2. The shunt resistor and configurable divider network (section of the BC100 schematics).
4
AVR451
8088A-AVR-09/07
相关PDF资料
ATAVRDB101 MODULE DISPLAY LCD/RGB BACKLIGHT
ATAVRMC100 KIT EVALUATION FOR AT90PWM3
ATAVRMC200 KIT EVAL FOR AT90PWM3 ASYNC
ATAVRMC300 BOARD EVAL LV MOTOR CONTROL PWR
ATAVRMC303 BOARD EVAL MOTOR CTRL W/XMEGA
ATAVRMC320 KIT EVAL MOTOR CTRL CAN/LIN
ATAVRSB100 SMART BATTERY DEVELOPMENT KIT
ATAVRSB200 KIT EVAL FOR AVR SMART BATTERY
相关代理商/技术参数
ATAVRBFLY 功能描述:开发板和工具包 - AVR Evaluation tool w/preloaded firmware RoHS:否 制造商:Arduino 产品:Evaluation Boards 工具用于评估:ATMega32U4 核心:AVR 接口类型:I2C, UART, USB 工作电源电压:6 V to 20 V
ATAVRBLE-IOT 功能描述:SECURE AVR BLE IOT 制造商:microchip technology 系列:* 零件状态:在售 标准包装:1
ATAVRCABLEKIT 功能描述:电缆组件 AVR tools cable kit (USB+ribbon cables) RoHS:否 制造商:Molex 产品:Power Assemblies 类型:Cable Assembly 连接器端口 A:No Connector 连接器端口 A 管脚计数:4 连接器端口 B:No Connector 连接器端口 B 管脚计数: 型式:Male 线规 - 美国线规(AWG):20, 28 长度:0.305 m 颜色:Black, Red
ATAVRDB101 功能描述:处理器配件 Display module RoHS:否 制造商:Olimex Ltd. 产品:Cable 用于:
ATAVRDISPLAYX 功能描述:开发板和工具包 - AVR XMEGA Display Evaluation Kit RoHS:否 制造商:Arduino 产品:Evaluation Boards 工具用于评估:ATMega32U4 核心:AVR 接口类型:I2C, UART, USB 工作电源电压:6 V to 20 V
ATAVRDRAGON 功能描述:仿真器/模拟器 AVR Emulator and Progammer RoHS:否 制造商:Blackhawk 产品:System Trace Emulators 工具用于评估:C6000, C5000, C2000, OMAP, DAVINCI, SITARA, TMS470, TMS570, ARM 7/9, ARM Cortex A8/R4/M3 用于:XDS560v2
ATAVRFBKIT 功能描述:开发板和工具包 - AVR Dimmable Fluorescent Ballast kit RoHS:否 制造商:Arduino 产品:Evaluation Boards 工具用于评估:ATMega32U4 核心:AVR 接口类型:I2C, UART, USB 工作电源电压:6 V to 20 V
ATAVRFEB-P4 功能描述:ATAVRFEB-P4 制造商:microchip technology 系列:* 零件状态:在售 标准包装:1