Atmel ATmega32HVB, ATA6870 User Manual
APPLICATION NOTE
User Guide for Atmel ATA6870 and Atmel ATmega32HVB
Evaluation Kit Hardware
ATA6870-DK10
Features
● Evaluation of Atmel
● Monitoring of 12 battery cells
● Monitoring:
● Overvoltage (every cell)
● Undervoltage (every cell)
● Overheating
● Overcurrent
● Open clamp detection
● 12-bit battery cell measurement
● 12-bit temperature measurement
● Controlling of charge/discharge FETs
● Status LEDs for easy evaluation
● Charge balancing
● Coulomb counting for SOC determination
Figure 1. Atmel ATA6870-DK10
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ATA6870
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1. Introduction
ATA6 870
Cell 12
Cell 11
ATA6 870
Monitoring (V,T)
Coulomb counting
ATmega32HVB
Charge/
Discharge
Control Unit
Cell 02
Cell 01
The Atmel® ATA6870-DK10 is a demonstration board for the Atmel ATA6870, which offers an easy way to start evaluation of
battery applications using the Atmel ATmega32HVB in combination with the Atmel ATA6870. The included software
demonstrates implementation of a 12 Cell Battery Management System. The supplied code serves as an example of how to
use the Atmel ATMega32HVB and Atmel ATA6870 together. The example is not a complete application intended for use
with smart batteries, and it is best to use the devices in a slightly different way in a smart battery application.
2. Safety Precautions When Using Li-ion Batteries
Please observe the safety guidelines supplied with the batteries. If improperly used or defective, li-ion and polymer batteries
and packs may explode and cause a fire.
3. Demonstration Board
The Atmel ATA6870-DK10 was developed to allow easy evaluation of control software for a microcontroller which controls
multiple Atmel ATA6870s. The sample code supplied demonstrates a simple permanent running measurement of voltages
and temperatures.
Figure 3-1. Board Concept
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3.1 System Start
Follow these steps to launch the system.
3.1.1 Installing the Hardware
●
Connect the load/charger to be powered between pack+ and pack- on J1
● For demonstration purposes it is possible to use a resistor to simulate a load
● Connect the battery cell stack to the screw connectors on the demonstration board
● Led 1 indicates the enabled status of the demonstration board (controlled by microcontroller SW)
● In case of emulating cells such as a voltage divider, apply sufficient voltage (see Section 3.3 “Powering the Board” on
page 5)
3.1.2 Number of Cells
It is possible to run the board with a reduced number of cells. The minimum voltage for each IC is 6.9V. Cell 1 and cell 6
(MBAT) have to be connected. The missing cells should be connected to the upper cell potential of the module. For further
information refer to the Atmel ATA6870 datasheet Section 7.3: Reduced Number of Battery Cells Configuration. For the
voltage range see Section 3.3 “Powering the Board” on page 5. If fewer than 6 cells are used per IC, the config.h file should
be adjusted (CELLSIC# under General Setting). See Section 4.1 “Supplied Code” on page 7 for further information on how to
configure the supplied software correctly.
3.2 The Demonstration Board
Figure 3-2. Evaluation Board with 2 Stacked Atmel ATA6870 and Atmel ATMega32HVB
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3.2.1 On-board Features
The demonstration board includes the following items:
● 2 Atmel
®
ATA6870 QFN 7mm 7mm
● Atmel ATMega32HVB
● 12 external N-channel MOSFETs for balancing of battery cells
● Connectors
● ISP connector for programming/debugging the Atmel ATMega32HVB
● Screw connectors for connecting up to 12 battery cells
Table 3-1. Connector Overview
J7 Function J8 Function
1 CELL- 1 VDDHVM
2 PAC K- 2
3 3 VCC
4 VFET 4 GND
5 5 IRQ
6 GND 6 CLK
7 OD 7 MISO
8 OC 8 MOSI
9 RESET 9 SCK
10 GND 10 CS_N
J1 Connector for charger/device to be powered
J2 ISP connector
J3 Upper battery stack (cells 7-12)
J4 Bottom battery stack (cells 1-6)
J9 Jumper to enable/disable MISO line of Atmel ATA6870
J9 should never be set while the Atmel ATmega32HVB is being programmed or while it is entering debug mode. It can be
mounted as soon as AVR Studio prompts for additional SPI lines to be connected in debug mode or after the device has
been correctly programmed.
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Figure 3-3. Connectors
3.3 Powering the Board
3.3.1 Power Supply
The board supports supply voltages from 13.8V (6.9V per Atmel ATA6870) to 60V. However, to run the board on voltages
below 24V the ZDiode D3 needs to be replaced with a jumper to supply the Atmel
the jumper is mounted, the stack voltage should not exceed 48V! The Atmel ATmega32HVB supports operating voltage from
4V to 24V.
3.3.2 Emulating Cells
Battery cells can be emulated by connecting a voltage divider to the specified clamps. Section 3.1.1 “Installing the Hardware”
on page 3 describes how to connect cells. The voltage limits for this setup are the same as for real batteries. Section 3.3.1
“Power Supply” on page 5 specifies these limits.
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ATmega32HVB with sufficient voltage. If
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5
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