MCIMX286CVM4B Freescale Semiconductor, MCIMX286CVM4B Datasheet - Page 908

• Manufacturer Part Number: MCIMX286CVM4B
• Description: IC MPU I.MX286 289MAPBGA
• Manufacturer: Freescale Semiconductor
• Series: i.MX28r

Specifications of MCIMX286CVM4B

• Core Processor: ARM9
• Core Size: 32-Bit
• Speed: 454MHz
• Connectivity: CAN, EBI/EMI, Ethernet, I²C, MMC, SmartCard, SPI, SSI, UART/USART, USB OTG
• Peripherals: DMA, I²S, LCD, POR, PWM, WDT
• Program Memory Size: 128KB (32K x 32)
• Program Memory Type: Mask ROM
• Ram Size: 32K x 32
• Voltage - Supply (vcc/vdd): 1.25 V ~ 5.25 V
• Data Converters: A/D 17x12b
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 289-LFBGA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Number Of I /o: -
• Eeprom Size: -
• Lead Free Status / Rohs Status: Compliant

Battery Charger
To enable optimum performance over the battery range, the DC-DC converter needs to be
provided with the battery voltage, which is measured by the battery pin LRADC. Normally,
LRADC channel 7 is dedicated to periodically measuring the battery voltage with a period
in the millisecond range for most applications. The voltage is automatically placed into the
BATT_VAL field of the HW_POWER_BATTMONITOR register through the
HW_LRADC_CONVERSION register. If necessary, software can turn off the automatic
battery voltage update and set the BATT_VAL field manually.
11.6 Battery Charger
The battery charger is essentially a linear regulator that has current and voltage limits.
Charge current is software-programmable within the HW_POWER_CHARGE register.
Li-Ion batteries can be charged at the lower of 1C, 785 mA, or the VDD5V current limit.
USB charging is typically limited to 500 mA or less to meet compliance requirements. Also,
battery charge current will be automatically reduced if the current demands from VDD4P2
and the battery charger exceed the CHARGE_4P2_ILIMIT. Full battery charge current will
be restored once the VDD4P2 + battery charge current falls below the
CHARGE_4P2_ILIMIT value.
Typical charge times for a Li-Ion battery are 1.5 to 3 hours with >70% of the charge delivered
in the first hour.
The battery charge voltage limit is 4.2 V for the Li-Ion batteries.
The Li-Ion charge is typically stopped after a certain time limit OR when the charging
current drops below 10% of the charge current setting. The HW_POWER_CHARGE register
includes controls for the maximum charge current and for the stop charge current. While
the charger is delivering current greater than the stop charge limit, the
HW_POWER_STS_CHRGSTS bit will be high. This bit should be polled (a low rate of 1
second or greater is fine) during charge. When the bit goes low, the charging is complete.
It would be good practice to check that this bit is low for two consecutive checks, as the
DC-DC switching might cause a spurious low result. Once this bit goes low, the charger
can either be stopped immediately or stopped after a top-off time limit. Although the charger
will avoid exceeding the charge voltage limit on the battery, it is NOT recommended to
leave the charger active indefinitely. It should be turned off when the charge is complete.
One can programatically monitor the battery voltage using the LRADC. The charger has
its own (very robust) voltage limiting that operates independently of the LRADC. But
monitoring the battery voltage during the charge might be helpful for reporting the charge
progress.
i.MX28 Applications Processor Reference Manual, Rev. 1, 2010
908
Freescale Semiconductor, Inc.