ATMEGA16HVB_1 Datasheet, PDF (108/273 Pages) ATMEL Corporation – 8-bit Microcontroller with 16K/32K Bytes In-System Programmable Flash

ATmega16HVB/32HVB
19. Coulomb Counter - Dedicated Fuel Gauging Sigma-delta ADC
19.1 Features
• Sampled System Coulomb Counter
• Low Power Sigma-Delta ADC Optimized for Coulomb Counting
• Instantaneous Current Output with 3.9 ms Conversion Time
– 13 bit Resolution (including sign bit)
– Interrupt on Instantaneous Current Conversion Complete
• Accumulate Current Output
– Programmable Conversion Time: 128/256/512/1024 ms
– 18-bit Resolution (including sign bit)
– Interrupt on Accumulation Current Conversion Complete
• Regular Current Detection Mode
– Programmable Sampling Interval: 256/512/1024/2048 ms
• Programmable Input Voltage Range ± 100/200mV
– Allowing Measurement of ± 20/40A @ 5 mΩ
• Offset canceling by input polarity switching
19.2 Overview
ATmega16/32HVB features a dedicated Sigma-Delta ADC (CC-ADC) optimized for Coulomb
Counting. By sampling the charge or discharge current flowing through an external sense resis-
tor RSENSE, the CC-ADC is used to track the flow of current going into and out of the battery
cells.
Figure 19-1. Coulomb Counter Block Diagram
8-BIT DATABUS
Regular
Current Level
Instantaneous
Current
Register
IRQ
Current
Comparator
Control &
Status
Registers
Accumulate
Current
Register
RSENSE
PI
Polarity
Switcher
NI
Sigma Delta
modulator
IRQ
Decimation
Filter
IRQ
Decimation
Filter
8042A–AVR–07/09
The CC-ADC has a programmable voltage range allowing trade-off to be made between resolu-
tion, dynamic range and external sense resistor RSENSE.
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