BQ2004ESLASHH datasheet(5/23 Pages) TI2

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VSEL Input

Voltage Termination

Low

Disabled

Float

∆V

High

PVD

Voltage Sampling

Each sample is an average of voltage measurements.

The IC takes 32 measurements in PVD mode and 16

measurements in -

∆V mode. The resulting sample peri-

ods (9.17ms and 18.18ms, respectively) filter out har-

monics centered around 55Hz and 109Hz. This tech-

nique minimizes the effect of any AC line ripple that

may feed through the power supply from either 50Hz or

60Hz AC sources. Tolerance on all timing is

±16%.

Temperature and Voltag e Termination

Hold-off

A hold-off period occurs at the start of fast charging.

During the hold-off period, -

∆V and ∆T/∆t termination

are disabled. The MOD pin is enabled at a duty cycle of

260

µs active for every 1820µs inactive. This modulation

results in an average rate 1/8th that of the fast charge

rate. This avoids premature termination on the voltage

spikes sometimes produced by older batteries when

fast-charge current is first applied. Maximum voltage

and maximum temperature terminations are not af-

fected by the hold-off period.

∆T/∆t Termination

The bq2004E/H samples at the voltage at the TS pin

every 34s, and compares it to the value measured two

samples earlier. If VTEMP has fallen 16mV

±4mV or

more, fast charge is terminated. The

∆T/∆t termination

test is valid only when VTCO <VTEMP <VLTF.

Temperature Sampling

Each sample is an average of 16 voltage measurements.

The resulting sample period (18.18ms) filters out har-

monics around 55Hz. This technique minimizes the ef-

fect of any AC line ripple that may feed through the

power supply from either 50Hz or 60Hz AC sources. Tol-

erance on all timing is

±16%.

Maximum Voltage, Temperature, and Time

Anytime VCELL rises above VMCV, the LEDs go off and cur-

rent flow into the battery ceases immediately. If VCELL

then falls back below VMCV before tMCV = 1.5s

±0.5s, the

chip transitions to the Charge Complete state (maximum

voltage termination). If VCELL remains above VMCV at the

expiration of tMCV, the bq2004E/H transitions to the Bat-

tery Absent state (battery removal). See Figure 3.

Maximum temperature termination occurs anytime

VTEMP falls below the temperature cutoff threshold

VTCO. Charge will also be terminated if VTEMP rises

above the low temperature fault threshold, VLTF, after

fast charge begins.

Corresponding

Fast-Charge

Rate

TM1

TM2

Typical

Fast-Charge

Safety

Time (min)

Typical

PVD, -

∆V

Hold-Off

Time (s)

Top-Off

Rate

Pulse-

Trickle

Rate

Pulse-

Trickle

Period (Hz)

2004E

2004H

2004E

2004H

2004E

2004H

2004E

2004H

2004E

2004H

C/4

C/8

Low

325

650

137

273

Disabled

C/2

C/4

Float

Low

154

325

546

Disabled

C/512

C/2

High

Low

154

273

546

Disabled

C/512

7.5

Low

Float

137

273

Disabled

C/512

3.75

7.5

Float

137

Disabled

C/512

1.88

3.75

C/2

C/4

High

Float

154

325

546

C/16

C/32

C/512

C/2

Low

High

154

273

546

C/8

C/16

C/512

7.5

Float

High

137

273

C/4

C/18

C/512

3.75

7.5

High

137

C/2

C/4

C/512

1.88

3.75

Note: Typical conditions = 25°C, VCC = 5.0V.

Table 1. Fast Charge Safety Time/Hold-Off/Top-Off Table

bq2004E/H

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