BQ2013H Datasheet, PDF(5/24 Page) Texas Instruments – Gas Gauge IC for Power- Assist Applications

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BQ2013H Datasheet, PDF (5/24 Pages) Texas Instruments – Gas Gauge IC for Power- Assist Applications

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bq2013H

perature. Discharge current is load compensated based 1. Last Measured Discharge (LMD) or learned

on the value stored in location LCOMP (address = 0eh).

battery capacity:

LCOMP allows the bq2013H to automatically adjust for

continuous small discharge currents. The bq2013H com-

pensates self discharge for the load value as well as tem-

perature.

LMD is the last measured discharge capacity of the

battery. On initialization (application of VCC or bat-

tery replacement), LMD = PFC. During subsequent

discharges, the LMD is updated with the latest

The main counter, Nominal Available Capacity (NAC),

measured capacity in the Discharge Count Register

represents the available battery capacity at any given

(DCR) representing a discharge from full to below

time. Battery charging increments the NAC register,

EDV. The maximum decrease in LMD because of a

while battery discharging, self-discharge decrement the

DCR update is 25% of LMD. A qualified discharge

NAC register and increment the DCR (Discharge Count

is necessary for a capacity transfer from the DCR

to the LMD register. The LMD also serves as the

error based on the value in the offset location OFFSET

100% reference threshold used by the relative dis-

(address = 0bh.)

play mode.

The Discharge Count Register (DCR) is used to update 2. Programmed Full Count (PFC) or initial bat-

the Last Measured Discharge (LMD) register only if a

tery capacity:

complete battery discharge from full to empty occurs

without any partial battery charges. Therefore, the

bq2013H adapts its capacity determination based on the

actual conditions of discharge.

The initial LMD and gas gauge rate values are pro-

grammed by using PFC. The PFC also provides the

100% reference for the absolute display mode. The

bq2013H is configured for a given application by se-

The batteryâs initial capacity is equal to the Pro-

lecting a PFC value from Table 2. The correct PFC

grammed Full Count (PFC) shown in Table 2. Until

may be determined by multiplying the rated bat-

LMD is updated, NAC counts up to but not beyond this

tery capacity in mAh by the sense resistor value:

threshold during subsequent charges. This approach al-

lows the gas gauge to be charger-independent and com-

Battery capacity (mAh) * sense resistor (â¦) =

patible with any type of charge regime.

PFC (mVh)

Selecting a PFC slightly less than the rated capac-

ity for absolute mode provides capacity above the

full reference for much of the batteryâs life.

Inputs

Charge

Current

Rate and

Temperature

Compensation

Discharge

Current

Load

Compensation

Self-Discharge

Timer

Load and

Temperature

Compensation

Main Counters

and Capacity

Reference (LMD)

< +

Nominal

Available

Last

Measured

Charge

Discharged

(NAC)

(LMD)

(offset corrected)

Discharge

Count

Qualified Register

Transfer (DCR)

Temperature

Translation

Temperature Step,

Other Data

Outputs

Chip-Controlled

Available Charge

LED Display

Serial

Port

FG2013H2.eps

Figure 2. Operational Overview

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