TEXAS INSTRUMENTS bq2003 Technical data

查询BQ2003供应商

bq2003

Fast-Charge IC

Features

Fast charge and conditioning of

➤

nickel cadmium or nickel-metal
hydride batteries

Hysteretic PWM switch-mode

➤

current regulation or gated con
trol of an external regulator

Easily integrated into systems

➤

or used as a stand-alone charger

Pre-charge qualification of tem

➤

perature and voltage

Direct LED outputs display

➤

battery and charge status

Fast-charge termination by

➤

temperature/∆time, -∆V, maxi-

∆

mum voltage, maximum tem­perature, and maximum time

➤ Optional top-off charge

Pin Connections

CCMD

DCMD

DVEN

TM

TM

BAT

V

1

2

TS

SS

16

1

2

15

3

14

4

13

5

12

6

11

7

10

8

9

V

CC

DIS

MOD

CHG

TEMP

MCV

TCO

SNS

General Description

The bq2003 Fast Charge IC provides
comprehensive fast charge control
functions together with high-speed
switching power control circuitry on a
monolithic CMOS device.

­Integration of closed-loop current
control circuitry allows the bq2003
to be the basis of a cost-effective so
lution for stand-alone and system­integrated chargers for batteries of

­one or more cells.

Switch-activated discharge-before­charge allows bq2003-based chargers
to support battery conditioning and
capacity determination.

High-efficiency power conversion is
accomplished using the bq2003 as a
hysteretic PWM controller for
switch-mode regulation of the charg­ing current. The bq2003 may alterna­tively be used to gate an externally
regulated charging current.

Pin Names

CCMD Charge command/select

DCMD Discharge command

DVEN -∆V enable/disable

TM

TM

TS Temperature sense

BAT Battery voltage

V

SS

Timer mode select 1

1

Timer mode select 2

2

System ground

Fast charge may begin on applica
tion of the charging supply, replace
ment of the battery, or switch de
pression. For safety, fast charge is
inhibited unless/until the battery
temperature and voltage are within
configured limits.

Temperature, voltage, and time are
monitored throughout fast charge.

-

Fast charge is terminated by any of
the following:

Rate of temperature rise

n

(∆T/∆t)

Negative delta voltage (-∆V)

n

Maximum voltage

n

Maximum temperature

n

Maximum time

n

After fast charge, an optional top-off
phase is available. Constant-cur­rent maintenence charge is provided
by an external trickle resistor.

SNS Sense resistor input

TCO Temperature cutoff

MCV Maximum voltage

TEMP Temperature status

output

CHG Charging status output

MOD Charge current control

DIS Discharge control

V

CC

5.0V±10% power

-

-

-

16-Pin DIP or SOIC

PN200301.eps

SLUS095A - OCTOBER 1999 I

1

bq2003

Pin Descriptions

CCMD,
DCMD

DVEN

TM
TM

TS

BAT

Vss

SNS

Charge initiation and discharge-before­charge control inputs

These two inputs control the conditions that
begin a new charge cycle and enable
discharge-before-charge. See Table 1.

-∆V enable input

This input enales/disables -∆V charge termina
tion. If DVEN is high, the -∆V test is enabled.
If DVEN is low, -∆V test is disabled. The state
of DVEN may be changed at any time.

Timer mode inputs

–

1

2

TM

and TM2are three-state inputs that con

1

figure the fast charge safety timer, -∆V hold­off time, and that enhance/disable top-off.
See Table 2.

Temperature sense input

Input, referenced to SNS, for an external
thermistor monitoring battery temperature.

Single-cell voltage input

The battery voltage sense input, referenced
to SNS. This is created by a high-impedance
resistor divider network connected between
the positive and the negative terminals of
the battery.

Ground

Charging current sense input

SNS controls the switching of MOD based on
the voltage across an external sense resistor
in the current path of the battery. SNS is the
reference potential for the TS and BAT pins.
If SNS is connected to V
high at the beginning of charge and low at
the end of charge.

, MOD switches

SS

-

-

TCO

MCV

TEMP

CHG

MOD

DIS

V

CC

Temperature cutoff threshold input

Input to set maximum allowable battery
temperature. If the potential between TS
and SNS is less than the voltage at the TCO
input, then fast charge or top-off charge is
terminated.

Maximum-Cell-Voltage threshold input

Input to set maximum single-cell equivalent
voltage. If the voltage between BAT and SNS
is greater than or equal to the voltage at the
MCV input, then fast charge or top-off charge
is inhibited.

Note: For valid device operation, the
voltage level on MCV must not exceed

0.6 ∗ V

CC

.

Temperature status output

Push-pull output indicating temperature
status. TEMP is low if the voltage at the TS
pin is not within the allowed range to start
fast charge.

Charging status output

Push-pull output indicating charging status.
See Figure 1.

Current-switching control output

MOD is a push/pull output that is used to
control the charging current to the battery.
MOD switches high to enable charging cur
rent flow and low to inhibit charging current
flow.

Discharge FET control output

Push-pull output used to control an external
transistor to discharge the battery before
charging.

VCCsupply input

5.0 V, ±10% power input.

-

2

bq2003

Functional Description

Figure 3 shows a state diagram and Figure 4 shows a
block diagram of the bq2003.

Battery Voltage and Temperature
Measurements

Battery voltage and temperature are monitored for
maximum allowable values. The voltage presented on
the battery sense input, BAT, should represent a
single-cell potential for the battery under charge. A
resistor-divider ratio of:

RB1

= N - 1

RB2

is recommended to maintain the battery voltage within
the valid range, where N is the number of cells, RB1 is

Table 1. New Charge Cycle and Discharge Stimulus

CCMD DCMD New Charge Cycle

Pulled Up/Down to:

V

SS

V

CC

V

SS

V

CC

(V

(V

A falling edge on CCMD or DCMD

V

CC

V

SS

V

SS

V

CC

Started by:

VCCrising to valid level

Battery replacement

falling through V

CELL

A rising edge on CCMD
VCCrising to valid level

Battery replacement

falling through V

CELL

A rising edge on CCMD A rising edge on DCMD
A falling edge on CCMD A rising edge on DCMD

the resistor connected to the positive battery terminal,
and RB2 is the resistor connected to the negative bat
tery terminal. See Figure 1.

Note: This resistor-divider network input impedance to
end-to-end should be at least 200kΩ and less than 1MΩ.

A ground-referenced negative temperature coefficient
thermistor placed in proximity to the battery may be used
as a low-cost temperature-to-voltage transducer. The tem
perature sense voltage input at TS is developed using a re
sistor-thermistor network between V

and battery’s nega

CC

tive terminal See Figure 1. Both the BAT and TS inputs
are referenced to SNS, so the signals used inside the IC are:

V

BAT-VSNS=VCELL

and

V

TS-VSNS=VTEMP

Discharge-Before-Charge

Started by:

MCV

MCV

)

)

A rising edge on DCMD

A rising edge on DCMD

-

-

-

-

V

DC

bq2003

External Trickle Resistor Negative Temperature

Pass Element

MOD

RB1

BAT

RB2

SNS

PACK+

PACK-

Coefficient Thermister

T

S

bq2003

SNS

V

CC

RT1

RT2

PACK +

N
T
C

PACK -

Fg2003a2.eps

Figure 1. Voltage and Temperature Monitoring and Trickle Resistor

3

bq2003

Discharge-Before-Charge

The DCMD input is used to command discharge-before­charge via the DIS output. Once activated, DIS becomes
active (high) until V

falls below V

CELL

at which time

EDV,

DIS goes low and a new fast charge cycle begins. See
Table 1 for the conditions that initiate discharge-before­charge. Discharge-before-charge is qualified by the
same voltage and temperature conditions that qualify a
new charge cycle start (see below). If a discharge is ini
tiated but the pack voltage or temperature is out of
range, the chip enters the charge pending mode and
trickle charges the battery until the voltage and tem
perature qualification conditions are met, and then
starts to discharge.

Starting A Charge Cycle

The stimulus required to start a new charge cycle is de
termined by the configuration of the CCMD and DCMD
inputs. If CCMD and DCMD are both pulled up or
pulled down, then a new charge cycle is started by (see
Figure 2):

1. V

2. V

rising above 4.5V

CC

falling through the maximum cell voltage,

CELL

V

MCV

.V

is the voltage presented at the MCV

MCV

input pin, and is configured by the user with a re­sistor divider between V
lowed range is 0.2 to 0.4 ∗ V

and ground. The al-

CC

.

CC

3. A rising edge on CCMD if it is pulled down, or a fal
ling edge on CCMD if it is pulled up.

Starting a new charge cycle may be limited to a push­button or logical pulse input only by pulling one member
of the DCMD and CCMD pair up while pulling the other
input down. In this configuration a new charge cycle
will be started only by a falling edge on CCMD if it is
pulled up, and by a falling edge on CCMD if it is pulled
down. See Table 1.

-

If the battery is within the configured temperature and
voltage limits, the IC begins fast charge. The valid bat

­tery voltage range is V

EDV<VBAT<VMCV

= 0.2 ∗ VCC± 30mV

V

EDV

The valid temperature range is V

where:

HTF<VTEMP<VLTF

where:

-

= [(1/8 ∗ V

V

HTF

V

is the voltage presented at the TCO input pin, and is

TCO

= 0.4 ∗ VCC± 30mV

V

LTF

) + (7/8 ∗ V

LTF

)] ± 30mV

TCO

configured by the user with a resistor divider between V
and ground. The allowed range is 0.2 to 0.4 ∗ VCC.

If the temperature of the battery is out of range, or the
voltage is too low, the chip enters the charge pending
state and waits for both conditions to fall within their
allowed limits. There is no time limit on the charge
pending state; the charger remains in this state as long
as the voltage or temperature conditons are outside of

-

-

,

CC

Charge

Pending

DIS

MOD Switch-Mode Configuration

or

MOD External Regulation
(SNS Grounded)

CHG Status Output

TEMP Status Output

Charge cycle start.
Battery outside temperature limits.

Discharge

(Optional)

Battery discharged to 0.2 VCC.

Battery within temperature limits.

Fast Charging Top-Off

Figure 2. Charge Cycle Phases

4

sec

4

(Optional)

.

34 sec.

TD200301a.eps

Table 2. Fast-Charge Safety Time/Hold-Off/Top-Off Table

Corresponding

Fast-Charge Rate TM1 TM2

C/4 Low Low 360 137 Disabled
C/2 Float Low 180 820 Disabled

1C High Low 90 410 Disabled
2C Low Float 45 200 Disabled
4C Float Float 23 100 Disabled

C/2 High Float 180 820 C/16

1C Low High 90 410 C/8
2C Float High 45 200 C/4
4C High High 23 100 C/2

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

the allowed limits. If the voltage is too high, the chip
goes to the battery absent state and waits until a new
charge cycle is started.

Fast charge continues until termination by one or more
of the five possible termination conditions:

Delta temperature/delta time (∆T/∆t)

n

n Negative delta voltage (-

n

Maximum voltage

n

Maximum temperature

n

Maximum time

V)

∆

-∆V Termination

If the DVEN input is high, the bq2003 samples the volt
age at the BAT pin once every 34s. If V

CELL

is lower
than any previously measured value by 12mV ±4mV,
fast charge is terminated. The -∆V test is valid in the
range V

- (0.2 ∗ VCC)<V

MCV

CELL<VMCV

.

Voltage Sampling

Each sample is an average of 16 voltage measurements
taken 57µs apart. The resulting sample period (18.18ms)
filters out harmonics around 55Hz. This technique mini
mizes 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%.

Voltage Termination Hold-off

A hold-off period occurs at the start of fast charging.
During the hold-off period, -∆V termination is disabled.
This avoids premature termination on the voltage spikes
sometimes produced by older batteries when fast-charge
current is first applied. ∆T/∆t, maximum voltage and

bq2003

Typical Fast Charge

and Top-Off
Time Limits

maximum temperature terminations are not affected by
the hold-off period.

∆T/∆t Termination

The bq2003 samples at the voltage at the TS pin every
34s, and compares it to the value measured two samples
earlier. If V

TEMP

charge is terminated. The ∆T/∆t termination test is
valid only when V

TCO<VTEMP<VLTF

Temperature Sampling

Each sample is an average of 16 voltage measurements
taken 57µs apart. The resulting sample period
(18.18ms) filters out harmonics around 55Hz. 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%.

-

Maximum Voltage, Temperature, and Time

Anytime V
goes off) immediately. If the bq2003 is not in the voltage
hold-off period, fast charging ceases if V
MCV for a minimum of t
low V

MCV

Charge Complete state (maximum voltage termination). If
V

remains above V

CELL

­transitions to the Battery Absent state (battery removal).

See Figure 3.

If the bq2003 is in the voltage hold-off period when
V

CELL

charging continues until the expiration of the hold-off
period. Temperature sampling continues during the
hold-off period as well. If a new battery is inserted be
fore the hold-off period expires, it continues in the fast
charge cycle started by its predecessor. No precharge
qualification is performed, and a temperature sample

rises above V

CELL

before 1.5t

rises above V

Typical -∆V/MCV

Hold-Off

Time (seconds)

has fallen 16mV ±4mV or more, fast

.

CHG goes high (the LED

MCV,

remains above

.IfV

MCV

±50ms, the chip transitions to the

MCV

beyond 1.5t

MCV

the LED goes out but fast

MCV,

CELL

then falls back be

CELL

MCV

, the bq2003

Top-Off

Rate

-

-

-

5