Datasheet

5
8024A–AVR–04/08
ATmega8HVA/16HVA
2. Overview
The ATmega8HVA/16HVA is a monitoring and protection circuit for 1-cell and 2-cell Li-ion appli-
cations with focus on high security/authentication, accurate monitoring, low cost and high
utilization of the cell energy. The device contains secure authentication features as well as
autonomous battery protection during charging and discharging. The chip allows very accurate
accumulated current measurements using an 18-bit ADC with a resolution of 0.84 µV. The fea-
ture set makes the ATmega8HVA/16HVA a key component in any system focusing on high
security, battery protection, accurate monitoring, high system utilization and low cost.
Figure 2-1. Block Diagram
A combined step-up and linear voltage regulator ensures that the chip can operate with supply
voltages as low as 1.8V for 1-cell applications. The regulator automatically switches to linear
mode when the input voltage is sufficiently high, thereby ensuring a minimum power consump-
tion at all times. For 2-cell applications, only linear regulation is enabled. The regulator
capabilities, combined with an extremely low power consumption in the power saving modes,
greatly enhances the cell energy utilization compared to existing solutions.
The chip utilizes Atmel's patented Deep Under-voltage Recovery (DUVR) mode that supports
pre-charging of deeply discharged battery cells without using a separate Pre-charge FET.
PORTA (2)
SRAMFlash
CPU
EEPROM
PV2
NV
OC
OD
FET
Control
Voltage
ADC
Voltage
Reference
Coulumb
Counter ADC
GND
VCC
R
ESET/dW
Power
Supervision
POR &
RESET
Watchdog
Oscillator
Watchdog
Timer
Oscillator
Circuits /
Clock
Generation
VREF
VREFGN
D
PI
NI
PA1..0
PA1..0
8/16-bit T/C1
8/16-bit T/C0
PORTB (4)
PB3..0
SPI
Voltage
Regulator
Charger
Detect
VFET
VREG
BATT
PV1
DATA BUS
CF1N CF2N
CF1P CF2P
V PTAT
Battery
Protection
Security
Module
PORTC (1)
PC0
Voltage Regulator
Monitor Interface
PB0
Oscillator
Sampling
Interface
Program
Logic
debugWIRE