ATEVK527 Atmel, ATEVK527 Datasheet - Page 6

• Manufacturer Part Number: ATEVK527
• Description: KIT EVAL PWM AVR USB 4 SERIES
• Manufacturer: Atmel
• Series: AVR®r

Specifications of ATEVK527

• Main Purpose: Power Management, Battery Charger
• Embedded: Yes, MCU, 8-Bit
• Utilized Ic / Part: ATmega16U4, ATmega32U4
• Primary Attributes: 1 Cell- Li-Ion
• Secondary Attributes: Graphical User Interface, USB Interface
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

3.2.3 Charge Stages
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AVR146
Lithium-Ion battery charge follows three stages:
1. Prequalification current: Charging of a Li-Ion battery starts with a test of battery
2. Constant current. The charge continues with applying constant current to the
3. Constant voltage. After battery threshold voltage has been reached the charger will
The below figure illustrates voltage and current of a lithium-ion battery during
charging.
Figure 3-1. Charge stages and limits of a VARTA™ EasyPack 550mAh
In the figure above, “Overcharge” is the level at which cell protection circuitry cuts in
and opens a solid-state switch and discontinues the charge current path. After this,
battery voltage typically needs to drop several hundred millivolts before the current
path is restored. “Overdischarge” is the level at which the current path is cut in order
to prevent the battery from over-discharging.
Voltage/Current
voltage. If the voltage is under a defined threshold (PREQUAL_VOLTAGE), the
charge starts with a fixed low current.
battery. The size of the charge current is battery-dependent and given by the
manufacturer. This stage is complete when battery voltage has reached the
threshold given by the manufacturer.
switch from supplying constant current to supplying constant voltage. This stage is
complete when charge current has dropped below the threshold given by the
manufacturer.
4.2V
3V
100mA
10mA
CONSTANT CURRENT CHARGE
260mA
Vbatt
ICUTOFF
Ibatt
CONSTANT VOLTAGE CHARGE
OVERDISCHARGE VOLTAGE LIMIT
OVERCHARGE VOLTAGE LIMIT
7801A-AVR-06/08
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