DS2437 View Datasheet(PDF) - Dallas Semiconductor -> Maxim Integrated

Part Name

Description

Manufacturer

DS2437

Smart Battery Monitor

Dallas Semiconductor -> Maxim Integrated 

DS2437

The ICA is a scaled 8-bit (0.01C resolution) volatile binary counter which represents the amount of

capacity remaining in the battery in terms of the full capacity (1C), normalized to a count of 10010. Thus,

an ICA count of 10010 represents 1C of charge or 100% of capacity or fully charged, while a count of 0

represents 0% of capacity or fully discharged. The ICA will count up to 25510, but will not roll over if

incremented above 2.55C, which should not occur during charging. However, since charging typically

provides the battery with more than its rated capacity, the ICA should be reset to a count of 10010 when

charging is complete to indicate that the battery is at 100% of capacity and to ensure that later gas gauge

measurements are accurate.

The ICA is only incremented/decremented if the IAD bit is set to 1 in the CONFIGURATION

REGISTER. Refer to the “Memory Map” section for details of device configuration. Table 4 below

illustrates the contents of the ICA. See Memory Map section for the address location of the ICA.

ICA/Data Relationships Table 4

BATTERY

CAPACITY

2.55C

1.0C

0.5C

0.1C

0C

DIGITAL OUTPUT (Binary)

1111 1111

0110 0100

0011 0010

0000 1010

0000 0000

DIGITAL OUTPUT (Hex)

FFh

64h

32h

0Ah

00h

The Charging Current Accumulator (CCA) is a 2-byte (0.32C resolution) nonvolatile read/write counter

which represents the total charging current the battery has encountered in its lifetime. It is only updated

when current through RSENS is positive; i.e., the battery is being charged. Because this is a nonvolatile

register, the information will accumulate over the lifetime of the battery pack and will not be lost when

the battery becomes discharged.

Similarly, the Discharge Current Accumulator (DCA) is a 2-byte nonvolatile counter which represents the

total discharging current the battery has encountered over its lifetime. It features the same resolution as

the CCA and it also is shadowed to EEPROM in the background at the rate of once per 0.32C of

discharge current if the DS2437 is properly configured, thus allowing three EEPROM updates for each

complete discharge cycle of the battery pack. Table 5 illustrates the contents of the CCA/DCA registers.

In reference to the CCA/DCA, the DS2437 can be configured to function in any of three modes. Refer to

the Memory Map section for details of device configuration and for the address location of the

CCA/DCA.

1. The CCA/DCA is disabled. Charging/discharging current will not be accumulated, thus allowing free

use of EEPROM page 07h otherwise reserved for the CCA/DCA.

2. The CCA/DCA will accumulate charging/discharging current, but the information will NOT be

shadowed to EEPROM. The information could be lost or corrupted upon discharge of the battery

(depending upon the voltage to which discharged battery decays). The memory location is reserved

for the CCA/DCA, and the entire page SHOULD NOT be written to.

7 of 31

Share Link: