ATmega406 Atmel Corporation, ATmega406 Datasheet - Page 106

• Manufacturer Part Number: ATmega406
• Manufacturer: Atmel Corporation

Specifications of ATmega406

• Flash (kbytes): 40 Kbytes
• Pin Count: 48
• Max. Operating Frequency: 1 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 8
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 18
• Ext Interrupts: 4
• Usb Speed: No
• Usb Interface: No
• Twi (i2c): 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 11
• Adc Resolution (bits): 12
• Adc Speed (ksps): 1.9
• Resistive Touch Screen: No
• Temp. Sensor: Yes
• Crypto Engine: No
• Sram (kbytes): 2
• Eeprom (bytes): 512
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -30 to 85
• I/o Supply Class: 4.0 to 25
• Operating Voltage (vcc): 4.0 to 25
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 2
• Output Compare Channels: 3
• Pwm Channels: 2
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

18. Coulomb Counter - Dedicated Fuel Gauging Sigma-delta ADC
18.1
106
Features
ATmega406
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ATmega406 features a dedicated Sigma-Delta ADC (CC-ADC) optimized for Coulomb Counting
to sample the charge or discharge current flowing through the external sense resistor R
Two different output values are provided, Instantaneous Current and Accumulate Current. The
Instantaneous Current Output has a short conversion time at the cost of lower resolution. The
Accumulate Current Output provides a highly accurate current measurement for Coulomb
Counting.
The sampling Coulomb Counter provides a highly accurate and flexible solution. Accuracy can
easily be traded against conversion time. It also provides Regular Current detection. This allows
ultra-low power operation in Power-save mode when small charge or discharge currents are
flowing.
Figure 18-1. Coulomb Counter Block Diagram
Sampled System Coulomb Counter
Low Power Sigma-Delta ADC Optimized for Coulomb Counting
Instantaneous Current Output with 3.9 ms Conversion Time
Accumulate Current Output with Programmable Conversion Time: 125/250/500/1000 ms
Input voltage Range Larger than ± 0.15V, Allowing Measurement of more than ± 30A @ 5 mΩ
13-bit Resolution (including sign) corresponding to 53.7 µV (10.7 mA @ 5 mΩ) for Instantaneous
Current Output
18-bit Resolution (including sign) corresponding to 1.68 µV (0.335 µA @ 5 mΩ) for Accumulate
Current Output
Input Offset Less than 10 µV for the ADC
Interrupt on Instantaneous Current Conversion Complete
Interrupt on Accumulate Current Conversion Complete
Interrupt on Regular Current with Programmable Compare Level and Programmable Sampling
Interval: 250/500/1000/2000 ms
R
SENSE
PI
NI
Sigma Delta
Comparator
Current IRQ
modulator
Current
Regular
Level
IRQ
Decimation
8-BIT DATABUS
IRQ
Control &
Register
Status
Decimation
2548E–AVR–07/06
IRQ
SENSE
.