Texas Instruments DV2007S1, BQ2007STR, BQ2007S, BQ2007PN Datasheet

Features

➤

Fast charging and conditioning of
NiCd and NiMH batteries

-

Precise charging independent
of battery pack number of cells

-

Discharge-before-charge on
demand

-

Pulse trickle charge
conditioning

-

Battery undervoltage and
overvoltage protection

➤

Built-in 10-step voltage-based
charge status monitoring

-

Charge status display options
include seven-segment
monotonic bargraph and fully
decoded BCD digit

-

Display interface options for
direct drive of LCD or LED
segments

-

Charger state status
indicators for pending,
discharge, charge, completion,
and fault

-

Audible alarm for charge
completion and fault
conditions

➤

Charge control flexibility

-

Fast or Standard speed
charging

-

Top-off mode for NiMH

-

Charge rates from

C

8

to 2C

(30 minutes to 8 hours)

➤

Charge termination by:

-

Negative delta voltage (-∆V)

-

Peak voltage detect (PVD)

-

Maximum voltage

-

Maximum time

-

Maximum temperature

➤ High-efficiency switch-mode de-

sign

-

Ideal for small heat-sensitive
enclosures

➤ 24-pin,300-mil SOIC or DIP

General Description

The bq2007 is a highly integrated
monolithic CMOS IC designed to pro

­vide intelligent battery charging and
charge status monitoring for stand­alone charge systems.

The bq2007 provides a wide variety of
charge status display formats. The
bq2007 internal charge status moni

­tor supports up to a seven-segment
bargraph or a single BCD digit dis

­play. The bargraph display indicates
up to seven monotonic steps, whereas
the BCD digit counts in ten steps of
10% increments. The bq2007 output
drivers can direct-drive either an
LCD or LED display.

Charge action begins either by appli­cation of the charging supply or by
replacement of the battery pack. For
safety, charging is inhibited until
battery temperature and voltage are
within configured limits.

1

1

PN200701.eps

24-Pin Narrow DIP

or SOIC

2
3
4
5

6
7
8

24
23

22

21
20
19
18

17
9
10

16

15
11
12

14

13

SEGC/MSEL

SEG

B

SEG

A

LED

1

LED

2

INH

COM

ALARM

TM
VSEL
FAST

DCMD

SEGD/DSEL

1

SEGE/DSEL

2

SEGF/MULT
SEGG/QDSEL
MOD
V

CC

V

SS
DIS
TS
BAT
SNS
TCO

Fast-Charge IC

bq2007

Pin Connections Pin Names

SEGC/ Display output segment C/
MSEL driver mode select

SEG

B

Display output segment B

SEG

A

Display output segment A

LED

1

Charge status output 1

LED

2

Charge status output 2

INH

Charge inhibit input

COM Common LED/LCD output

ALARM Audio alarm output

TM Timer mode select

VSEL Voltage termination select

FAST Fast charge rate select

DCMD

Discharge command

TCO Temperature cutoff

SNS Sense resistor input

BAT Battery voltage

TS Temperature sense

DIS Discharge control

V

SS

System ground

V

CC

5.0V±10% power

MOD Modulation control

SEG

G

/ Display output segment G/

QDSEL charge status display select

SEG

F

/ Display output segment F/

MULT multi-cell pack select

SEG

E

/ Display output segment E/

DSEL

2

display select 2

SEG

D

/ Display output segment D/

DSEL

1

display select 1

9/96 B

The acceptable battery temperature range is set by an
internal low-temperature threshold and an external
high-temperature cutoff threshold. The absolute tem

­perature is monitored as a voltage on the TS pin with
the external thermistor network shown in Figure 2.

The bq2007 provides for undervoltage battery protection
from high-current charging if the battery voltage is less
than the normal end-of-discharge value. In the case of a
deeply discharged battery, the bq2007 enters the
charge-pending state and attempts trickle-current condi

­tioning of the battery until the voltage increases. Should
the battery voltage fail to increase above the discharge
value during the undervoltage time-out period, a fault
condition is indicated.

Discharge-before-charge may be selected to automatically
discharge the battery pack on battery insertion or with a
push-button switch. Discharge-before-charge on demand
provides conditioning services that are useful to correct or
prevent the NiCd voltage depression, or “memory” effect,
and also provide a zero capacity reference for accurate
capacity monitoring.

After prequalification and any required discharge­before-charge operations, charge action begins until one of
the full-charge termination conditions is detected. The
bq2007 terminates charging by any of the following methods:

n Negative delta voltage (-

∆

V)

n

Peak voltage detect (PVD)

n

Maximum absolute temperature

n

Maximum battery voltage

n

Maximum charge time-out

The bq2007 may be programmed for negative delta
voltage (-∆V) or peak voltage detect (PVD) charge
termination algorithms. The VSEL input pin selects -∆V
or PVD termination to match the charge rate and
battery characteristics.

To provide maximum safety for battery and system,
charging terminates based on maximum temperature
cutoff (TCO), maximum cutoff voltage (MCV), and
maximum time-out (MTO). The TCO threshold is the
maximum battery temperature limit for charging. TCO
terminates charge action when the temperature sense
input voltage on the TS pin drops below the TCO pin
voltage threshold. MCV provides battery overvoltage
protection by detecting when the battery cell voltage
(V

CELL=VBAT-VSNS

) exceeds the VMCV value and ter

­minates fast charge, standard charge, or top-off charge.
The maximum time-out (MTO) termination occurs when
the charger safety timer has completed during the active
charge state.

The bq2007 indicates charge state status with an audio
alarm output option and two dedicated output pins with pro

­grammable display options. The DSEL1–2 inputs can select

one of the three display modes for the LED1–2 outputs.

Charger status is indicated for:

n

Charge pending

n

Charge in progress

n

Charge complete

n

Fault condition

Pin Descriptions

SEG

A–G

Display output segments A–G

State-of-charge monitoring outputs. QDSEL
input selects the bargraph or BCD digit dis

-

play mode. See Table 3.

MSEL

Display driver mode select

Soft-programmed input selects LED or LCD
driver configuration at initialization. When
MSEL is pulled up to V

CC

, outputs SEG

A–G

are
LED interface levels; when MSEL is pulled
down to V

SS

, outputs SEG

A–G

are LCD levels.

DSEL

1

–

DSEL

2

Display mode select 1–2

Soft-programmed inputs control the LED

1—2

charger status display modes at initialization.
See Table 2.

MULT

Fixed-cell pack select

Soft-programmed input is pulled up to V

CC

when charging multi-cell packs and is pulled
down to V

SS

for charging packs with a fixed

number of cells.

QDSEL

State-of-charge display select

The QDSEL input controls the SEG

A–G

state-of-charge display modes. See Table 3.

LED

1

–

LED

2

Charger status outputs 1–2

Charger status output drivers for direct
drive of LED displays. Display modes are
selected by the DSEL input. See Table 2.

INH

Charge inhibit input

When low, the bq2007 suspends all charge ac

­tions, drives all outputs to high impedance, and
assumes a low-power operational state. When
transitioning from low to high, a charge
cycle is initiated. See page 10 for details.

2

bq2007

COM

Common LCD/LED output

Common output for LCD/LED display
SEG

A—G

. Output is high-impedance during
initialization to allow reading of
soft-programmed inputs DSEL

1

, DSEL2,

MSEL, MULT, and QDSEL.

ALARM

Audio output

Audio alarm output.

TM

Timer mode select

TM is a three-level input that controls the set

-

tings for charge control functions. See Table 5.

VSEL

Voltage termination select

This input switches the voltage detect
sensitivity. See Table 5.

FAST

Fast charge rate select

The FAST input switches between Fast and
Standard charge rates. See Table 4.

DCMD

Discharge command

The DCMD

input controls the discharge­before-charge function. A negative-going
pulse initiates a discharge action. If DCMD
is connected to VSS, automatic discharge­before-charge is enabled. See Figure 3.

TCO

Temperature cut-off threshold input

Minimum allowable battery temperature­sensor voltage. If the potential between TS
and SNS is less than the voltage at the TCO
input, then any fast charging or top-off
charging is terminated.

SNS

Sense resistor input

SNS controls the switching of MOD output based
on an external sense resistor. This provides the
lower reference potential for the BAT pin and the
TS pin.

BAT

Battery voltage input

Battery voltage sense input referenced to SNS
for the battery pack being charged. This resis

­tor divider network is connected between the
positive and the negative terminals of the
battery. See Figure 1.

TS

Temperature sense input

Input referenced to SNS for battery tem

­perature monitoring negative temperature
coefficient (NTC) thermistor.

DIS

Discharge control

DIS is a push-pull output that controls an
external transistor to discharge the battery
before charging.

V

SS

Ground

V

CC

VCCsupply input

MOD

Current-switching control output

Push/pull output that controls the charging
current to the battery. MOD switches high to
enable current flow and low to inhibit current
flow.

Functional Description

Figure 1 illustrates charge control and display status
during a bq2007 charge cycle. Table 1 summarizes the
bq2007 operational features. The charge action states
and control outputs are given for possible input
conditions.

Charge Action Control

The bq2007 charge action is controlled by input pins

DCMD

, VSEL, FAST, and TM. When charge action is
initiated, the bq2007 enters the charge-pending state,
checks for acceptable battery voltage and temperature,
and performs any required discharge-before-charge
operations. DCMD

controls the discharge-before-charge
function, and VSEL, FAST, and TM select the charger
configuration. See Tables 4 and 5.

During charging, the bq2007 continuously tests for
charge termination conditions: negative delta voltage,
peak voltage detection, maximum time-out, battery
over-voltage, and high-temperature cutoff. When the
charge state is terminated, a trickle charge continues to
compensate for self-discharge and maintain the fully
charged condition.

Charge Status Indication

Table 2 summarizes the bq2007 charge status display
indications. The charge status indicators include the
DIS output, which can be used to indicate the discharge
state, the audio ALARM output, which indicates charge
completion and fault conditions, and the dedicated
status outputs,LED

1

and LED2.

3

bq2007

4

bq2007

Fast Charging

Top-Off

(Optional)

TD200701.eps

Dis-

charge

(Optional)

Charge

Pending

(Pulse-Trickle)

DIS

MOD

MOD

Mode 1, LED2 Status Output

Charge initiated. Battery outside temperature/voltage limits.

or

Battery discharged to V

EDV

or battery within
temperature/voltage limits. (Discharge-before-charge not
qualified by temperature.)

Pulse-Trickle

(Switching

Configuration)

(External

Regulation)

Mode 1, LED1 Status Output

Mode 2, LED2 Status Output

Mode 2, LED1 Status Output

Mode 3, LED2 Status Output

260 s

2080 s

260 s

2080 s

260 s

Note

260 s

Note

Note: See Table 4 for pulse-trickle period.

Mode 3, LED1 Status Output

Low-voltage fault: Battery voltage less than V

EDV

for under-voltage time-out.

Figure 1. Example Charging Action Events

Outputs LED

1–2

have three display modes that are

selected at initialization by the input pins DSEL

1

and

DSEL

2

. The DSEL1and DSEL2input pins, when pulled

down to V

SS

, are intended for implementation of a

simple two-LED system. LED

2

indicates the precharge

status (i.e., charge pending and discharge) and LED

1

indi

­cates the charge status (i.e., charging and completion).
DSEL

1

pulled up to VCCand DSEL2pulled down to V

SS

mode is for implementation of a single tri-color LED such
that discharge, charging, and completion each have a unique
color. DSEL

1

pulled down to VSSand DSEL2pulled up to

V

CC

allows for fault status information to be displayed.

Audio Output Alarm

The bq2007 audio alarm output generates an audio tone
to indicate a charge completion or fault condition. The
audio alarm output is a symmetrical duty-cycle AC sig

­nal that is compatible with standard piezoelectric alarm
elements. A valid battery insertion is indicated by a sin

­gle high-tone beep of

1

2

-second typical duration. The
charge completion and fault conditions are indicated by
a 9.5- to 15-second high-tone sequence of

1

2

-second typi-

cal duration at a 2-second typical repetition rate.

Charge Status Monitoring

The bq2007 charge status monitor may display the bat

­tery voltage or charge safety timer as a percentage of
the full-charged condition. These options are selected
with the MULT soft-programmed input pin.

When MULT is pulled down to V

SS

, the battery charge
status is displayed as a percentage of the battery
voltage, and the single-cell battery voltage at the BAT
pin is compared with internal charge voltage reference
thresholds. When V

BAT

is greater than the internal

thresholds of V

20,V40,V60

,orV80, the respective 20%,
40%, 60%, or 80% display outputs are activated. The
battery voltage directly indicates 20% charge
increments, while the 10% charge increments use a
timer that is a function of the charge safety timer.

When MULT is pulled down to V

SS

and when V

BAT

exceeds V20during charging, the 20% charge indication
is activated and the timer begins counting for a period
equal to

1

64

to

1

32

of the charge safety time-out period.
When the timer count is completed, the 30% charge
indication is activated. Should V

BAT

exceed V40prior to
the timer count completion, the charge status monitor
activates the 30% and 40% indications. This technique

5

bq2007

Charge Action

State Conditions MOD Output DIS Output

Battery absent V

CC

applied and V

CELL

≥

V

MCV

Trickle charge per Table 4 Low

Charge initiation

V

CC

applied or V

CELL

drops

from≥V

MCV

to < V

MCV

- Low

Discharge-before­charge

DCMD

high-to-low transition or to VSSon charge

initiation and V

EDV

< V

CELL

< V

MCV

Low High

Charge pending

Charge initiation occurred and V

TEMP

≥

V

LTF

or

V

TEMP

≤

V

TCO

or V

CELL

< V

EDV

Trickle charge per Table 4 Low

Fast charging

Charge pending complete and FAST = V

CC

Low if V

SNS

> 250mV;

high if V

SNS

< 200mV

Low

Standard charging

Charge pending complete and FAST = V

SS

Low if V

SNS

> 250mV;

high if V

SNS

< 200mV

Low

Charge complete

-∆V termination or V

TEMP

< V

TCO

or PVD≥0 to

-3mV/cell or maximum time-out or V

CELL

> V

MCV

--

Top-off pending

VSEL = V

CC

, charge complete and V

TEMP

≥

V

LTF

or V

TEMP

≤

V

TCO

or V

CELL

< V

EDV

Trickle charge per Table 4 Low

Top-off charging

VSEL = V

CC

and charge complete and

time-out not exceeded and V

TEMP

> V

TCO

and

V

CELL

< V

MCV

Activated per V

SNS

for

73ms of every 585ms Low

Trickle charging

Charge complete and top-off disabled or

top-off complete or pending

Trickle charge per Table 4 Low

Fault

Charge pending state and charge pending

time-out (t

PEND

) complete

Trickle charge per Table 4 Low

Definitions: V

CELL

= V

BAT

- V

SNS;VMCV

= 0.8*VCC;V

EDV

= 0.262*VCCor 0.4*VCC;V

TEMP

= VTS- V

SNS

;

V

LTF

= 0.5*VCC.

Table 1. bq2007 Operational Summary

is used for all the odd percentage charge indications to
assure a monotonic charge status display.

When MULT is pulled up to V

CC

, the bq2007 charge

status monitor directly displays

1

32

of the charge safety

timer as a percentage of full charge. This method is rec

-

ommended over the voltage-based method when charg

­ing fixed-cell packs where the battery terminal voltages
can vary greatly between packs. This method offers an
accurate charge status indication when the battery is
fully discharged. When using the timer-based method,
discharge-before-charge is recommended.

During discharge with MULT pulled down to V

SS

, the

charge status monitor indicates the percentage of the bat

­tery voltage by comparing V

BAT

to the internal discharge

voltage reference thresholds. In BCD format, the dis

­charge thresholds V

80,V60,V40

, and V20correspond to a
battery charge state indication of 90%, 70%, 50%, and 30%,
respectively. In bargraph format, the same discharge
thresholds correspond to a battery charge state indication
of 90%, 60%, 40%, and 30%, respectively. Differences in
the battery charge state indications are due to the finer
granularity of the BCD versus the bargraph format.

During discharge and when MULT is pulled up to V

CC

,
the state-of-charge monitor BCD format displays the
discharge condition, letter “d,” whereas the bargraph for­mat has no indication.

The charge status display is blanked during the charge
pending state and when the battery pack is removed.

Charge Status Display Modes

The bq2007 charge status monitor can be displayed in
two modes summarized in Table 3. The display modes
are a seven-segment monotonic bargraph or a seven­segment BCD single-digit format. When QDSEL is
pulled down to V

SS

, pins SEG

A–G

drive the decoded seven
segments of a single BCD digit display, and when QDSEL
is pulled up to V

CC

, pins SEG

A–G

drive the seven seg

-

ments of a bargraph display.

In the bargraph display mode, outputs SEG

A–G

allow op

-

tions for a three-segment to seven-segment bargraph dis

-

play. The three-segment charge status display uses out

-

puts SEG

B

,SEGD, and SEGFfor 30%, 60%, and 90%
charge indications, respectively. The four-segment charge
status display uses outputs SEG

A

, SEGC, SEGD,and

SEG

E

for 20%, 40%, 60%, and 80% indications,
respectively. The seven-segment charge status monitor
uses all segments.

The BCD display mode drives pins SEG

A–G

with the
decoded seven-segment single-digit information. The
display indicates in 10% increments from a BCD zero
count at charge initiation to a BCD nine count indicat­ing 90% charge capacity. Charge completion is indicated
by the letter “F,” a fault condition by the letter “E,” and
the discharge condition by the letter “d.” See Table 3.

6

bq2007

Mode Charge Action State LED

1

LED

2

DIS ALARM

DSEL

1

= L

DSEL

2

= L

(Mode 1)

Battery absent 0000

Charge pending (temp. limit, low voltage) 0 Flashing 0 0

Discharge in progress 0110

Charging Flashing 0 0 0

Charge complete 1 0 0 High tone

Fault (low-voltage time-out) 0 0 0 High tone

DSEL

1

= H

DSEL

2

= L

(Mode 2)

Battery absent 0000

Discharge in progress, pending 1110

Charging 1000

Charge complete 0 1 0 High tone

Fault (low-voltage time-out) 0 0 0 High tone

DSEL

1

= L

DSEL

2

= H

(Mode 3)

Battery absent 0000

Charge pending (temp. limit, low voltage) 0 Flashing 0 0

Discharge in progress 0 Flashing 1 0

Charging Flashing 0 0 0

Charge complete 1 0 0 High tone

Fault (low-voltage time-out) 0 1 0 High tone

Note: 1 = on; 0 = off; L = pulled down to VSS; H = pulled up to VCC.

Table 2. bq2007 Charge Status Display Summary

Display Driver Modes

The bq2007 is designed to interface with LCD or LED
type displays. The LED signal levels are driven when
the MSEL soft-programmed input is pulled to V

CC

at ini

­tialization. The output pin COM is the common anode
connection for LED SEG

A–G

.

The LCD interface mode is enabled when the MSEL
soft-programmed input pin is pulled to V

SS

at initializa

­tion. An internal oscillator generates all the timing sig

­nals required for the LCD interface. The output pin
COM is the common connection for static direct-driving
of the LCD display backplane and is driven with an AC
signal at the frame period. When enabled, each of the
SEG

A–G

pins is driven with the correct-phase AC signal
to activate the LCD segment. In bargraph or BCD mode,
output pins SEG

A–G

interface to LED or LCD segments.

Battery Voltage and Temperature
Measurement

The battery voltage and temperature are monitored
within set minimum and maximum limits. When MULT is
pulled up to V

CC

, battery voltage is sensed at the BAT pin
by a resistive voltage divider that divides the terminal
voltage between 0.262 ∗ V

CC(VEDV

) and 0.8 ∗ VCC(V

MCV

).

The bq2007 charges multi-cell battery packs from a mini

­mum of N cells, to a maximum of 1.5 ∗ N cells. The battery
voltage divider is set to the minimum cell battery pack (N)
by the BAT pin voltage divider ratio equation:

R1 N

R2133

1=−(

.

)

When MULT is pulled down to V

SS

, tighter charge
voltage limits and voltage-based charge status display
are selected. This is recommended for charging packs
with a fixed number of cells where the battery voltage
divider range is between 0.4 ∗ V

CC(VEDV

) and 0.8 ∗ V

CC

7

bq2007

Mode Display Indication SEG

A

SEG

B

SEG

C

SEG

D

SEG

E

SEG

F

SEG

G

QDSEL = H

20% charge 1000000

30% charge 1100000

40% charge 1110000

60% charge 1111000

80% charge 1111100

90% charge 1111110

Charge complete 1111111

QDSEL = L

0% charge—digit 0 1111110

10% charge—digit 1 0110000

20% charge—digit 2 1101101

30% charge—digit 3 1111001

40% charge—digit 4 0110011

50% charge—digit 5 1011011

60% charge—digit 6 1011111

70% charge—digit 7 1110010

80% charge—digit 8 1111111

90% charge—digit 9 1111011

Charge complete—letter F 1000111

Fault condition—letter E 1001111

Discharge—letter d 0111101

Note: 1 = on; 0 = off; L = pulled down to VSS; H = pulled up to VCC.

Table 3. bq2007 Charge Status Display Summary

(V

MCV

). The bq2007 charges fixed-cell battery packs of N
cells. The battery voltage divider is set by the divider ra­tio equation:

R1 N
R22

1=−()

Note: The resistor-divider network impedance
should be above 200KΩto protect the bq2007.

When battery temperature is monitored for maximum
and minimum allowable limits, the bq2007 requires that
the thermistor used for temperature measurement have
a negative temperature coefficient. See Figure 2.

Temperature and Voltage
Prequalifications

For charging to be initiated, the battery temperature
must fall within predetermined acceptable limits. The
voltage on the TS pin (V

TS

) is compared to an internal low-

temperature fault threshold (V

LTF

) of (0.5 ∗ VCC) and the high

temperature cutoff voltage (V

TCO

) on the TCO pin. For charg

-

ing to be initiated, V

TS

must be less than V

LTF

and greater

than V

TCO

. Since VTSdecreases as temperature increases, the

TCO threshold should be selected to be lower than 0.5 ∗ V

CC

for proper operation. If the battery temperature is outside
these limits, the bq2007 holds the charge-pending state with a
pulse trickle current until the temperature is within limits.
Temperature prequalification and termination is disabled if
V

TS

is greater than 0.8 ∗ VCC. See Figure 2.

The bq2007 provides undervoltage battery protection by
trickle-current conditioning of a battery that is below
the low-voltage threshold (V

EDV

). The battery voltage

(V

CELL

) is compared to the low-voltage threshold (V

EDV

)

and charge will be inhibited if V

CELL<VEDV

. The condi­tion trickle current and fault time-out are a percentage
of the fast charge rate and maximum time-out (MTO).

Initiating Charge Action and
Discharge-Before-Charge

A charge action is initiated under control of: (1) battery
insertion or (2) power applied. Battery insertion is
detected when the voltage at the BAT pin falls from
above V

MCV

to below V

MCV

. Power applied is detected

by the rising edge of V

CC

when a battery is inserted.

Discharge-before-charge (see Figure 3) is initiated auto

­matically on application of power or battery insertion
when DCMD

is connected to VSS. Discharge-on-demand

is initiated by a negative-going pulse on the DCMD

pin

8

bq2007

FG200701.eps

bq2007

V

CC

BAT

R1

N
T
C

bq2007

V

CC

TS

SNS

SNS

BAT Voltage Connection Thermistor Connection

R2

NTC = negative temperature coefficient thermistor.

V

SS

R

SNS

V

SS

R

SNS

Figure 2. Voltage and Temperature Limit Measurement

bq2007

bq2007

DCMD

Always Discharge Discharge on

Command

DCMD

Figure 3. Discharge-Before-Charge

regardless of charging activity. The DCMD pin is inter

-

nally pulled up to V

CC

; therefore, not connecting this pin

results in disabling the discharge-before-charge func

­tion. When the discharge begins, the DIS output goes
high to activate an external transistor that connects a
load to the battery. The bq2007 terminates discharge­before-charge by detecting when the battery cell voltage
is less than or equal to the end-of-discharge voltage
(V

EDV

).

Charge State Actions

Once the required discharge is completed and temperature
and voltage prequalifications are met, the charge state is
initiated. The charge state is configured by the VSEL,
FAST, and TM input pins. The FAST input selects between
Fast and Standard charge rates. The Standard charge rate
is

1

4

of the Fast charge rate, which is accomplished by dis

­abling the regulator for a period of 286µs of every 1144µs
(25% duty cycle). In addition to throttling back the charge
current, time-out and hold-off safety time are increased ac

­cordingly. See Table 4.

The VSEL input selects the voltage termination method.
The termination mode sets the top-off state and trickle
charge current rates. The TM input selects the Fast
charge rate, the Standard rate, and the corresponding
charge times. Once charging begins at the Fast or Stan

­dard rate, it continues until terminated by any of the fol

­lowing conditions:

n

Negative delta voltage (-∆V)

n

Peak voltage detect (PVD)

n

Maximum temperature cutoff (TCO)

n

Maximum time-out (MTO)

n

Maximum cutoff voltage (MCV)

Voltage Termination Hold-off

To prevent early termination due to an initial false peak
battery voltage, the -∆V and PVD terminations are
disabled during a short “hold-off” period at the start of
charge. During the hold-off period when fast charge is
selected (FAST = 1), the bq2007 will top off charge to
prevent excessive overcharging of a fully charged
battery. Once past the initial charge hold-off time, the
termination is enabled. TCO and MCV terminations are
not affected by the hold-off time.

-∆V or PVD Termination

Table 5 summarizes the two modes for full-charge
voltage termination detection. When V

SEL=VSS

,
negative delta voltage detection occurs when the voltage
seen on the BAT pin falls 12mV (typical) below the
maximum sampled value. V

SEL=VCC

selects peak
voltage detect termination and the top-off charge state.
PVD termination occurs when the BAT pin voltage falls
6mV per cell below the maximum sampled value. When
charging a battery pack with a fixed number of cells, the

-∆V and PVD termination thresholds are -6mV and 0 to

-3mV per cell, respectively. The valid battery voltage
range on V

BAT

for -∆V or PVD termination is from 0.262

∗ V

CC

to 0.8 ∗ VCC.

9

bq2007

VSEL

Detection

Method Top-Off

Pulse Trickle

Rate

V

SS

-∆V Disabled

C

32

V

CC

PVD Enabled

C

64

Table 5. VSEL Configuration

FAST
Input
State

TM
Input
State

Time-out

Period

(min)

MOD
Duty

Cycle

Hold-off

period

(sec)

Trickle

Rep Rate

-∆V

C

32

Trickle

Rep Rate

PVD

C

64

V

SS

Float 640 (

C

8

) 25% 2400 219Hz 109Hz

V

SS

V

SS

320 (

C

4

) 25% 1200 109Hz 55Hz

V

SS

V

CC

160 (

C

2

) 25% 600 55Hz 27Hz

V

CC

Float 160 (

C

2

) 100% 600 219Hz 109Hz

V

CC

V

SS

80 (C) 100% 300 109Hz 55Hz

V

CC

V

CC

40 (2C) 100% 150 55Hz 27Hz

Table 4. bq2007 Charge Action Control Summary

Maximum Temperature, Maximum
Voltage, and Maximum Time Safety
Terminations

The bq2007 also terminates charge action for maximum
temperature cutoff (TCO), maximum cutoff voltage
(MCV), and maximum time-out (MTO). Temperature is
monitored as a voltage on the TS pin (V

TS

), which is
compared to an internal high-temperature cutoff
threshold of V

TCO

. The TCO reference level provides the
maximum limit for battery temperature during
charging. MCV termination occurs when V

CELL>VMCV

.
The maximum time-out (MTO) termination is when the
charger safety timer countdown has completed during
the active charge state. If the MTO, MCV, or TCO limit
is exceeded during Fast charge, Standard charge, or
top-off states,charge action is terminated.

Top-Off and Pulse Trickle Charging

The bq2007 provides a post-detection timed charge
capability called top-off to accommodate battery chemis­tries that may have a tendency to terminate charge
prior to achieving full capacity. When V

SEL=VCC

, the
top-off state is selected; charging continues after Fast
charge termination for a period equal to the time-out
value. In top-off mode, the Fast charge control cycle is
modified so that MOD is activated for a pulse output of
73ms of every 585ms. This results in a rate

1

8

that of the
Fast charge rate. Top-off charge is terminated by maxi­mum temperature cutoff (TCO), maximum cutoff voltage
(MCV), or maximum time-out termination.

Pulse trickle is used to compensate for self-discharge
while the battery is idle and to condition a depleted
low-voltage battery to a valid voltage prior to high­current charging. The battery is pulse trickle charged
when Fast, Standard, or top-off charge is not active. The
MOD output is active for a period of 286µs of a period
specified in Table 4. This results in a trickle rate of

C

64

for PVD and

C

32

when -∆V is enabled.

Charge Inhibit

Fast charge, top-off, and pulse trickle may be inhibited
by using the INH

input pin. When low, the bq2007 sus­pends all charge activity, drives all outputs to high
impedance, and assumes a low-power operational state.
When INH

returns high, a fast-charge cycle is qualified

and begins as soon as conditions allow.

Charge Current Control

The bq2007 controls charge current through the MOD
output pin. In a frequency-modulated buck regulator
configuration, the control loop senses the voltage at the
SNS pin and regulates to maintain it between 0.04 ∗
V

CC

and 0.05 ∗ VCC. The nominal regulated current is

I

REG

= 0.225V/R

SNS

. See Figure 4.

MOD pin is switched high or low depending on the
voltage input to the SNS pin. If the voltage at the SNS
pin is less than V

SNSLO

(0.04 ∗ VCCnominal), the MOD
output is switched high to gate charge current through
the inductor to the battery. When the SNS voltage is
greater than V

SNSHI

(0.05 ∗ VCCnominal), the MOD out

­put is switched low-shutting off charge current from the
supply. The MOD pin can be used to gate an external
charging current source. When an external current
source is used, no sense resistor is required, and the
SNS pin is connected to V

SS

.

10

bq2007

MOD

SNS

R

SNS

Switch

Battery

Under Charge

bq2007

DC

Source

Figure 4. Constant-Current Switching

Regulation

11

bq2007

Absolute Maximum Ratings

Symbol Parameter Minimum Maximum Unit Notes

V

CC

VCCrelative to V

SS

-0.3 +7.0 V

V

T

DC voltage applied on any pin ex

-

cluding V

CC

relative to V

SS

-0.3 +7.0 V

T

OPR

Operating ambient temperature -20 +70 °C Commercial

T

STG

Storage temperature -40 +85 °C

T

SOLDER

Soldering temperature - +260 °C

Note: Permanent device damage may occur if Absolute Maximum Ratings are exceeded. Functional opera

-

tion should be limited to the Recommended DC Operating Conditions detailed in this data sheet. Expo

-

sure to conditions beyond the operational limits for extended periods of time may affect device reliability.

DC Thresholds (T

A

= T

OPR

; VCC= 5V±10%)

Symbol Parameter Rating Tolerance Unit Notes

V

SNSHI

High threshold at SNS re­sulting in MOD = Low

0.05*V

CC

±

25

mV

V

SNSLO

Low threshold at SNS result­ing in MOD = High

0.04*V

CC

±

10

mV

V

LTF

TS pin low-temperature
threshold

0.5*V

CC

±

30

mV SNS = 0V

V

HTF

TS pin high-temperature
threshold

V

TCO

±

30

mV SNS = 0V

V

EDV

End-of-discharge voltage
MULT is pulled up to V

CC

0.262*V

CC

±

30

mV SNS = 0V

End-of-discharge voltage
MULT is pulled down to V

SS

0.4*V

CC

±

30

mV SNS = 0V

V

MCV

BAT pin maximum cell
voltage threshold

0.8*V

CC

±

30

mV SNS = 0V

V

20

20% state-of-charge voltage
threshold at the BAT pin

187

320

*

V

CC

±

30

mV

Fast or standard charge state;
MULT pulled to V

SS

V

40

40% state-of-charge voltage
threshold at the BAT pin

191

320

*

V

CC

±

30

mV

Fast or standard charge state;
MULT pulled to V

SS

V

60

60% state-of-charge voltage
threshold at the BAT pin

195

320

*

V

CC

±

30

mV

Fast or standard charge state;
MULT pulled to V

SS

V

80

80% state-of-charge voltage
threshold at the BAT pin

203

320

*

V

CC

±

30

mV

Fast or standard charge state;
MULT pulled to V

SS

V

20

20% state-of-charge voltage
threshold at the BAT pin

158

320

*

V

CC

±

30

mV

Discharge-before-charge state;
MULT pulled to V

SS

; DIS = 1

V

40

40% state-of-charge voltage
threshold at the BAT pin

163

320

*

V

CC

±

30

mV

Discharge-before-charge state;
MULT pulled to V

SS

; DIS = 1

V

60

60% state-of-charge voltage
threshold at the BAT pin

167

320

*

V

CC

±

30

mV

Discharge-before-charge state;
MULT pulled to V

SS

; DIS = 1

V

80

80% state-of-charge voltage
threshold at the BAT pin

171

320

*

V

CC

±

30

mV

Discharge-before-charge state;
MULT pulled to V

SS

; DIS = 1

12

bq2007

Recommended DC Operating Conditions (T

A

= 0 to +70°C)

Symbol Parameter inimum Typical Maximum Unit Notes

V

CC

Supply voltage 4.5 5.0 5.5 V 10%

V

BAT

Voltage on BAT pin 0 - V

CC

V

V

TS

Voltage on TS pin 0 - V

CC

V Thermistor input

V

TCO

Temperature cutoff on TCO 0 - 0.5*V

CC

V Note 2

V

CELL

Battery voltage potential 0 - V

CC

VV

BAT

- V

SNS

V

TEMP

Voltage potential on TS 0 - V

CC

VVTS- V

SNS

V

IH

Logic input high 2.0 - - V DCMD, FAST, VSEL, INH

Tri-level input high VCC- 0.3 - - V TM

V

IL

Logic input low - - 0.8 V DCMD, FAST, VSEL, INH

Tri-level input low - - 0.3 V TM

V

OH

Logic output high

V

CC

- 0.8

--V

DIS, LED

1–2

, SEG

A–G

@ IOH=

-10mA; MOD @ I

OH

= -5mA

V

OL

Logic output low - - 0.8 V

DIS, LED

1–2

, SEG

A–G

@ IOL=

10mA; MOD @ I

OL

= 5mA

V

OHCOM

COM output VCC- 0.8 - - V @ I

OHCOM

= -40mA

I

OHCOM

COM source -40 - - mA @ V

OHCOM

= VCC- 0.8V

I

CC

Supply current - 1 2.5 mA No output load

I

OH

DIS, LED

1–2

, SEG

A–G

source -10 - - mA @VOH= VCC- 0.8V

I

OH

MOD -5 - - mA @VOH= VCC- 0.8V

I

OL

DIS, LED

1–2

, SEG

A–G

sink 10 - - mA @VOL= VSS+ 0.8V

I

OL

MOD 5 - - mA @VOL= VSS+ 0.8V

I

IZ

Tri-state inputs floating
for Z state

-2.0 - 2.0

µ

A

TM

I

L

Input leakage - -

±

1

µ

A INH, VSEL, V = VSSto V

CC

Input leakage 50 - 400

µ

A DCMD, FAST, V = VSSto V

CC

I

IL

Logic input low current - - 70

µ

A TM, V = VSSto VSS+ 0.3V

I

IH

Logic input high current -70 - -

µ

A TM, V = VCC- 0.3V to V

CC

13

bq2007

Impedance

Symbol Parameter Minimum Typical Maximum Unit Notes

R

I

DC input impedance: pins
TS, BAT, SNS, TCO

50 - -

M

Ω

R

PROG

Soft-programmed pull-up
resistor

150 - 200

K

Ω

MSEL, DSEL

1

, DSEL2, MULT,

QDSEL; resistor value±10% tol

-

erance

R

FLT

Float state external
resistor

-5-

M

Ω

TM

Timing (T

A

= 0 to +70°C; V

CC

±

10%)

Symbol Parameter Minimum Typical Maximum Unit Notes

d

FCV

Deviation of fast charge
safety time-out

0.84 1.0 1.16 -

At VCC=±10%, TA= 0 to 60°C;
see Table 3

t

REG

MOD output regulation
frequency

- - 300 kHz

Typical regulation range;
V

CC

= 5.0V

t

PEND

Charge pending time-out - 25 - %

Ratio of fast charge time-out;
see Table 4.

F

COM

Common LCD backplane fre­quency

- 73 - Hz LCD segment frame rate

F

ALARM

Alarm frequency output - 3500 - kHz High tone

t

PW

Pulse width for DCMD and
INH

pulse command

1- -

µ

s

Signal valid time

t

MCV

Valid period for V

CELL

>

V

MCV

0.5 - 1 sec

If V

CELL

≥

V

MCV

for t

MCV

during
charge or top-off, then a transition
is recognized as
a battery replacement.

Note: Typical is at TA= 25°C, VCC= 5.0V.

14

bq2007

24-Pin DIP Narrow (PN)

24-Pin PN(0.300" DIP

)

Dimension

Inches Millimeters

Min. Max. Min. Max.

A 0.160 0.180 4.06 4.57

A1 0.015 0.040 0.38 1.02

B 0.015 0.022 0.38 0.56

B1 0.045 0.055 1.14 1.40

C 0.008 0.013 0.20 0.33

D 1.240 1.280 31.50 32.51

E 0.300 0.325 7.62 8.26

E1 0.250 0.300 6.35 7.62

e 0.300 0.370 7.62 9.40

G 0.090 0.110 2.29 2.79

L 0.115 0.150 2.92 3.81

S 0.070 0.090 1.78 2.29

e

B

.004

L

D

E

H

C

A1

A

S: 24-Pin S(0.300" SOIC

)

24-Pin S(0.300" SOIC

)

Dimension

Inches Millimeters

Min. Max. Min. Max.

A 0.095 0.105 2.41 2.67

A1 0.004 0.012 0.10 0.30

B 0.013 0.020 0.33 0.51

C 0.008 0.013 0.20 0.33

D 0.600 0.615 15.24 15.62

E 0.290 0.305 7.37 7.75

e 0.045 0.055 1.14 1.40

H 0.395 0.415 10.03 10.54

L 0.020 0.040 0.51 1.02

15

bq2007

Ordering Information

Data Sheet Revision History

Change No. Page No. Description Nature of Change

111V

SNSLO

Rating

Was V

SNSHI

- (0.01 * VCC);

is 0.04 * V

CC

Note: Change 1 = Sept. 1996 B changes from Dec. 1995.

bq2007 -

Package Option:

PN = 24-pin narrow plastic DIP
S = 24-pin SOIC

Device:

bq2007 Fast-Charge IC

* Contact factory for availability.

Temperature:

blank = Commercial (-20 to +70°C)
N = Industrial (-40 to +85°C)*

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