5

8024AS–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)

SRAM

Flash

CPU

EEPROM

PV2

NV

OC

OD

FET

Control

Voltage

ADC

Voltage

Reference

Coulumb

Counter ADC

GND

VCC

RESET/dW

Power

Supervision

POR &

RESET

Watchdog

Oscillator

Watchdog

Timer

Oscillator

Circuits /

Clock

Generation

VREF

VREFGND

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

VPTAT

Battery

Protection

Security

Module

PORTC (1)

PC0

Voltage Regulator

Monitor Interface

PB0

Oscillator

Sampling

Interface

Program

Logic

debugWIRE