TI BQ2007PN-N Fast-charge ic Datasheet

bq2007
Fast-Charge IC
-
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
Pin Connections
SEGC/MSEL
SEGB
SEGA
LED1
LED2
INH
COM
ALARM
TM
VSEL
FAST
DCMD
1
2
3
4
5
6
7
8
9
10
11
12
24
23
22
21
20
19
18
17
16
15
14
13
24-Pin Narrow DIP
or SOIC
PN200701.eps
SEGD/DSEL1
SEGE/DSEL2
SEGF/MULT
SEGG/QDSEL
MOD
VCC
VSS
DIS
TS
BAT
SNS
TCO
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 design
-
Ideal for small heat-sensitive
enclosures
General Description
The bq2007 is a highly integrated
monolithic CMOS IC designed to provide 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 monitor supports up to a seven-segment
bargraph or a single BCD digit display. 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.
➤ 24-pin, 300-mil SOIC or DIP
Pin Names
SEGC/
MSEL
Display output segment C/
driver mode select
SEGB
Display output segment B
SEGA
Display output segment A
LED1
Charge status output 1
LED2
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
9/96 B
1
SNS
Sense resistor input
BAT
Battery voltage
TS
Temperature sense
DIS
Discharge control
VSS
System ground
VCC
5.0V ± 10% power
MOD
Modulation control
SEGG/
QDSEL
Display output segment G/
charge status display select
SEGF/
MULT
Display output segment F/
multi-cell pack select
SEGE/
DSEL2
Display output segment E/
display select 2
SEGD/
DSEL1
Display output segment D/
display select 1
bq2007
The bq2007 indicates charge state status with an audio
alarm output option and two dedicated output pins with programmable display options. The DSEL1–2 inputs can select
one of the three display modes for the LED1–2 outputs.
The acceptable battery temperature range is set by an
internal low-temperature threshold and an external
high-temperature cutoff threshold. The absolute temperature is monitored as a voltage on the TS pin with
the external thermistor network shown in Figure 2.
Charger status is indicated for:
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 conditioning 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.
n
Charge pending
n
Charge in progress
n
Charge complete
n
Fault condition
Pin Descriptions
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.
SEGA–G
State-of-charge monitoring outputs. QDSEL
input selects the bargraph or BCD digit display mode. See Table 3.
MSEL
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
Display output segments A–G
Display driver mode select
Soft-programmed input selects LED or LCD
driver configuration at initialization. When
MSEL is pulled up to VCC, outputs SEGA–G are
LED interface levels; when MSEL is pulled
down to VSS, outputs SEGA–G are LCD levels.
DSEL1–
DSEL2
Display mode select 1–2
Soft-programmed inputs control the LED1—2
charger status display modes at initialization.
See Table 2.
MULT
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.
Fixed-cell pack select
Soft-programmed input is pulled up to VCC
when charging multi-cell packs and is pulled
down to VSS for charging packs with a fixed
number of cells.
QDSEL
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
(VCELL = VBAT - VSNS) exceeds the VMCV value and terminates 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.
State-of-charge display select
The QDSEL input controls the SEGA–G
state-of-charge display modes. See Table 3.
LED1–
LED2
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 actions, 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
TS
Input referenced to SNS for battery temperature monitoring negative temperature
coefficient (NTC) thermistor.
Common output for LCD/LED display
SEGA—G. Output is high-impedance during
initialization to allow reading of
soft-programmed inputs DSEL1, DSEL2,
MSEL, MULT, and QDSEL.
ALARM
DIS
VSEL
Timer mode select
VSS
Ground
TM is a three-level input that controls the settings for charge control functions. See Table 5.
VCC
VCC supply input
MOD
Current-switching control output
Voltage termination select
Push/pull output that controls the charging
current to the battery. MOD switches high to
enable current flow and low to inhibit current
flow.
This input switches the voltage detect
sensitivity. See Table 5.
FAST
Fast charge rate select
Functional Description
The FAST input switches between Fast and
Standard charge rates. See Table 4.
DCMD
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.
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
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.
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
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.
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
Discharge control
DIS is a push-pull output that controls an
external transistor to discharge the battery
before charging.
Audio output
Audio alarm output.
TM
Temperature sense input
Battery voltage input
Battery voltage sense input referenced to SNS
for the battery pack being charged. This resistor divider network is connected between the
positive and the negative terminals of the
battery. See Figure 1.
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, LED1 and LED2.
3
bq2007
Charge
Pending
Discharge
(Pulse-Trickle)
(Optional)
Top-Off
Fast Charging
Pulse-Trickle
(Optional)
DIS
MOD
or
MOD
260 s
Note
2080 s
260 s
Note
(Switching
Configuration)
(External
Regulation)
2080 s
Mode 1, LED2 Status Output
260 s
260 s
Mode 1, LED1 Status Output
Mode 2, LED2 Status Output
Mode 2, LED1 Status Output
Mode 3, LED2 Status Output
Mode 3, LED1 Status Output
Battery discharged to VEDV or battery within
temperature/voltage limits. (Discharge-before-charge not
qualified by temperature.)
Low-voltage fault: Battery voltage less than VEDV for under-voltage time-out.
Charge initiated. Battery outside temperature/voltage limits.
Note: See Table 4 for pulse-trickle period.
TD200701.eps
Figure 1. Example Charging Action Events
4
bq2007
Outputs LED 1–2 have three display modes that are
selected at initialization by the input pins DSEL1 and
DSEL2. The DSEL1 and DSEL2 input pins, when pulled
down to V SS , are intended for implementation of a
simple two-LED system. LED2 indicates the precharge
status (i.e., charge pending and discharge) and LED1 indicates the charge status (i.e., charging and completion).
DSEL1 pulled up to VCC and DSEL2 pulled down to VSS
mode is for implementation of a single tri-color LED such
that discharge, charging, and completion each have a unique
color. DSEL1 pulled down to VSS and DSEL2 pulled up to
VCC allows for fault status information to be displayed.
Charge Status Monitoring
The bq2007 charge status monitor may display the battery 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 VSS, 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 VBAT is greater than the internal
thresholds of V20, V40, V60, or V80, the respective 20%,
40%, 60%, or 80% display outputs are activated. The
b a t t er y v olt a g e d ir ec t ly in d ic a t es 2 0 % ch a r g e
increments, while the 10% charge increments use a
timer that is a function of the charge safety timer.
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 signal that is compatible with standard piezoelectric alarm
elements. A valid battery insertion is indicated by a single 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 typical duration at a 2-second typical repetition rate.
When MULT is pulled down to VSS and when VBAT
exceeds V20 during 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 VBAT exceed V40 prior to
the timer count completion, the charge status monitor
activates the 30% and 40% indications. This technique
Table 1. bq2007 Operational Summary
Charge Action
State
Battery absent
Charge initiation
Discharge-beforecharge
Charge pending
Conditions
VCC applied and VCELL ≥ VMCV
VCC applied or VCELL drops
from ≥ VMCV to < VMCV
DCMD high-to-low transition or to VSS on charge
initiation and VEDV < VCELL < VMCV
Charge initiation occurred and VTEMP ≥ VLTF or
VTEMP ≤ VTCO or VCELL < VEDV
Fast charging
Charge pending complete and FAST = VCC
Standard charging
Charge pending complete and FAST = VSS
Charge complete
Top-off pending
Top-off charging
Trickle charging
Fault
Definitions:
-∆V termination or VTEMP < VTCO or PVD ≥ 0 to
-3mV/cell or maximum time-out or VCELL > VMCV
VSEL = VCC, charge complete and VTEMP ≥ VLTF
or VTEMP ≤ VTCO or VCELL < VEDV
VSEL = VCC and charge complete and
time-out not exceeded and VTEMP > VTCO and
VCELL < VMCV
Charge complete and top-off disabled or
top-off complete or pending
Charge pending state and charge pending
time-out (tPEND) complete
MOD Output
Trickle charge per Table 4
DIS Output
Low
-
Low
Low
High
Trickle charge per Table 4
Low
Low if VSNS > 250mV;
high if VSNS < 200mV
Low if VSNS > 250mV;
high if VSNS < 200mV
Low
Low
-
-
Trickle charge per Table 4
Low
Activated per VSNS for
73ms of every 585ms
Low
Trickle charge per Table 4
Low
Trickle charge per Table 4
Low
VCELL = VBAT - VSNS; VMCV = 0.8 * VCC; VEDV = 0.262 * VCC or 0.4 * VCC; VTEMP = VTS - VSNS;
VLTF = 0.5 * VCC.
5
bq2007
The charge status display is blanked during the charge
pending state and when the battery pack is removed.
is used for all the odd percentage charge indications to
assure a monotonic charge status display.
Charge Status Display Modes
When MULT is pulled up to VCC, the bq2007 charge
status monitor directly displays 1 32 of the charge safety
timer as a percentage of full charge. This method is recommended over the voltage-based method when charging 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.
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 VSS, pins SEGA–G drive the decoded seven
segments of a single BCD digit display, and when QDSEL
is pulled up to VCC, pins SEGA–G drive the seven segments of a bargraph display.
During discharge with MULT pulled down to VSS, the
charge status monitor indicates the percentage of the battery voltage by comparing VBAT to the internal discharge
voltage reference thresholds. In BCD format, the discharge thresholds V80, V60, V40, and V20 correspond 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.
In the bargraph display mode, outputs SEGA–G allow options for a three-segment to seven-segment bargraph display. The three-segment charge status display uses outputs SEGB, SEGD, and SEGF for 30%, 60%, and 90%
charge indications, respectively. The four-segment charge
status display uses outputs SEGA, 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 SEGA–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.
During discharge and when MULT is pulled up to VCC,
the state-of-charge monitor BCD format displays the
discharge condition, letter “d,” whereas the bargraph format has no indication.
Table 2. bq2007 Charge Status Display Summary
Mode
DSEL1 = L
DSEL2 = L
(Mode 1)
DSEL1 = H
DSEL2 = L
(Mode 2)
DSEL1 = L
DSEL2 = H
(Mode 3)
Note:
Charge Action State
Battery absent
Charge pending (temp. limit, low voltage)
Discharge in progress
Charging
Charge complete
Fault (low-voltage time-out)
Battery absent
Discharge in progress, pending
Charging
Charge complete
Fault (low-voltage time-out)
Battery absent
Charge pending (temp. limit, low voltage)
Discharge in progress
Charging
Charge complete
Fault (low-voltage time-out)
LED1
0
0
0
Flashing
1
0
0
1
1
0
0
0
0
0
Flashing
1
0
1 = on; 0 = off; L = pulled down to VSS; H = pulled up to VCC.
6
LED2
0
Flashing
1
0
0
0
0
1
0
1
0
0
Flashing
Flashing
0
0
1
DIS
0
0
1
0
0
0
0
1
0
0
0
0
0
1
0
0
0
ALARM
0
0
0
0
High tone
High tone
0
0
0
High tone
High tone
0
0
0
0
High tone
High tone
bq2007
Display Driver Modes
Battery Voltage and Temperature
Measurement
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 VCC at initialization. The output pin COM is the common anode
connection for LED SEGA–G.
The battery voltage and temperature are monitored
within set minimum and maximum limits. When MULT is
pulled up to VCC, battery voltage is sensed at the BAT pin
by a resistive voltage divider that divides the terminal
voltage between 0.262 ∗ VCC (VEDV) and 0.8 ∗ VCC (VMCV).
The bq2007 charges multi-cell battery packs from a minimum 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:
The LCD interface mode is enabled when the MSEL
soft-programmed input pin is pulled to VSS at initialization. An internal oscillator generates all the timing signals 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
SEGA–G pins is driven with the correct-phase AC signal
to activate the LCD segment. In bargraph or BCD mode,
output pins SEGA–G interface to LED or LCD segments.
R1
N
= (
)−1
R2
1.33
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 ∗ VCC (VEDV) and 0.8 ∗ VCC
Table 3. bq2007 Charge Status Display Summary
Mode
QDSEL = H
QDSEL = L
Note:
Display Indication
SEGA
SEGB
SEGC
SEGD
SEGE
SEGF
SEGG
20% charge
1
0
0
0
0
0
0
30% charge
1
1
0
0
0
0
0
40% charge
1
1
1
0
0
0
0
60% charge
1
1
1
1
0
0
0
80% charge
1
1
1
1
1
0
0
90% charge
1
1
1
1
1
1
0
Charge complete
1
1
1
1
1
1
1
0% charge—digit 0
1
1
1
1
1
1
0
10% charge—digit 1
0
1
1
0
0
0
0
20% charge—digit 2
1
1
0
1
1
0
1
30% charge—digit 3
1
1
1
1
0
0
1
40% charge—digit 4
0
1
1
0
0
1
1
50% charge—digit 5
1
0
1
1
0
1
1
60% charge—digit 6
1
0
1
1
1
1
1
70% charge—digit 7
1
1
1
0
0
1
0
80% charge—digit 8
1
1
1
1
1
1
1
90% charge—digit 9
1
1
1
1
0
1
1
Charge complete—letter F
1
0
0
0
1
1
1
Fault condition—letter E
1
0
0
1
1
1
1
Discharge—letter d
0
1
1
1
1
0
1
1 = on; 0 = off; L = pulled down to VSS; H = pulled up to VCC.
7
bq2007
R1
VCC
VCC
BAT
TS
bq2007
N
T
C
bq2007
R2
SNS
SNS
RSNS
RSNS
VSS
VSS
BAT Voltage Connection
Thermistor Connection
NTC = negative temperature coefficient thermistor.
FG200701.eps
Figure 2. Voltage and Temperature Limit Measurement
(VCELL) is compared to the low-voltage threshold (VEDV)
and charge will be inhibited if VCELL < VEDV. The condition trickle current and fault time-out are a percentage
of the fast charge rate and maximum time-out (MTO).
(VMCV). The bq2007 charges fixed-cell battery packs of N
cells. The battery voltage divider is set by the divider ratio equation:
R1
N
= (
)−1
R2
2
Initiating Charge Action and
Discharge-Before-Charge
Note: The resistor-divider network impedance
should be above 200KΩ to protect the bq2007.
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 VMCV to below VMCV. Power applied is detected
by the rising edge of VCC when a battery is inserted.
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.
Discharge-before-charge (see Figure 3) is initiated automatically 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
Temperature and Voltage
Prequalifications
For charging to be initiated, the battery temperature
must fall within predetermined acceptable limits. The
voltage on the TS pin (VTS) is compared to an internal lowtemperature fault threshold (VLTF) of (0.5 ∗ VCC) and the high
temperature cutoff voltage (VTCO) on the TCO pin. For charging to be initiated, VTS must be less than VLTF and greater
than VTCO. Since VTS decreases as temperature increases, the
TCO threshold should be selected to be lower than 0.5 ∗ VCC
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
VTS is greater than 0.8 ∗ VCC. See Figure 2.
DCMD
bq2007
Always Discharge
The bq2007 provides undervoltage battery protection by
trickle-current conditioning of a battery that is below
the low-voltage threshold (VEDV). The battery voltage
DCMD
bq2007
Discharge on
Command
Figure 3. Discharge-Before-Charge
8
bq2007
Table 4. bq2007 Charge Action Control Summary
Trickle
Rep Rate
-∆V C 32
Trickle
Rep Rate
PVD C 64
2400
219Hz
109Hz
1200
109Hz
55Hz
600
55Hz
27Hz
100%
600
219Hz
109Hz
80 (C)
100%
300
109Hz
55Hz
40 (2C)
100%
150
55Hz
27Hz
TM
Input
State
Time-out
Period
(min)
VSS
Float
640 (C 8)
25%
VSS
VSS
320 (C 4 )
25%
VSS
VCC
160 (C 2)
25%
VCC
Float
160 (C 2)
VCC
VSS
VCC
VCC
regardless of charging activity. The DCMD pin is internally pulled up to VCC; therefore, not connecting this pin
results in disabling the discharge-before-charge function. 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
(VEDV).
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.
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 disabling 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 accordingly. See Table 4.
-∆V or PVD Termination
Table 5 summarizes the two modes for full-charge
voltage termination detection. When V SEL = V SS ,
negative delta voltage detection occurs when the voltage
seen on the BAT pin falls 12mV (typical) below the
maximum sampled value. V SEL = V CC 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 VBAT for -∆V or PVD termination is from 0.262
∗ VCC to 0.8 ∗ VCC.
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 Standard rate, it continues until terminated by any of the following conditions:
n
Negative delta voltage (-∆V)
n
Peak voltage detect (PVD)
n
Hold-off
period
(sec)
MOD
Duty
Cycle
FAST
Input
State
Table 5. VSEL Configuration
VSEL
Detection
Method
Top-Off
Maximum temperature cutoff (TCO)
VSS
-∆V
Disabled
C
n
Maximum time-out (MTO)
VCC
PVD
Enabled
C
n
Maximum cutoff voltage (MCV)
9
Pulse Trickle
Rate
32
64
bq2007
Maximum Temperature, Maximum
Voltage, and Maximum Time Safety
Terminations
DC
Source
Switch
bq2007
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 (VTS), which is
compared to an internal high-temperature cutoff
threshold of VTCO. The TCO reference level provides the
maximum limit for battery temperature during
charging. MCV termination occurs when VCELL > 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.
MOD
Battery
Under Charge
SNS
RSNS
Figure 4. Constant-Current Switching
Regulation
Top-Off and Pulse Trickle Charging
Charge Inhibit
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 VSEL = 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.
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 ∗
VCC and 0.05 ∗ VCC. The nominal regulated current is
IREG = 0.225V/RSNS. See Figure 4.
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.
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 VSNSLO (0.04 ∗ VCC nominal), the MOD
output is switched high to gate charge current through
the inductor to the battery. When the SNS voltage is
greater than VSNSHI (0.05 ∗ VCC nominal), the MOD output 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 VSS.
10
bq2007
Absolute Maximum Ratings
Minimum
Maximum
Unit
VCC
Symbol
VCC relative to VSS
-0.3
+7.0
V
VT
DC voltage applied on any pin excluding VCC relative to VSS
-0.3
+7.0
V
TOPR
Operating ambient temperature
-20
+70
°C
TSTG
Storage temperature
-40
+85
°C
TSOLDER
Soldering temperature
-
+260
°C
Note:
Parameter
VSNSHI
VSNSLO
VLTF
VHTF
VEDV
VMCV
V20
V40
V60
V80
V20
V40
V60
V80
Commercial
Permanent device damage may occur if Absolute Maximum Ratings are exceeded. Functional operation should be limited to the Recommended DC Operating Conditions detailed in this data sheet. Exposure to conditions beyond the operational limits for extended periods of time may affect device reliability.
DC Thresholds
Symbol
Notes
(TA = TOPR; VCC = 5V ± 10%)
Parameter
High threshold at SNS resulting in MOD = Low
Low threshold at SNS resulting in MOD = High
TS pin low-temperature
threshold
TS pin high-temperature
threshold
End-of-discharge voltage
MULT is pulled up to VCC
End-of-discharge voltage
MULT is pulled down to VSS
BAT pin maximum cell
voltage threshold
20% state-of-charge voltage
threshold at the BAT pin
40% state-of-charge voltage
threshold at the BAT pin
60% state-of-charge voltage
threshold at the BAT pin
80% state-of-charge voltage
threshold at the BAT pin
20% state-of-charge voltage
threshold at the BAT pin
40% state-of-charge voltage
threshold at the BAT pin
60% state-of-charge voltage
threshold at the BAT pin
80% state-of-charge voltage
threshold at the BAT pin
Rating
Tolerance
Unit
0.05 * VCC
± 25
mV
0.04 * VCC
± 10
mV
0.5 * VCC
± 30
mV
SNS = 0V
VTCO
± 30
mV
SNS = 0V
0.262 * VCC
± 30
mV
SNS = 0V
0.4 * VCC
± 30
mV
SNS = 0V
0.8 * VCC
± 30
mV
SNS = 0V
320
* VCC
± 30
mV
320
* VCC
± 30
mV
320
* VCC
± 30
mV
320
* VCC
± 30
mV
320
* VCC
± 30
mV
320
* VCC
± 30
mV
320
* VCC
± 30
mV
320
* VCC
± 30
mV
187
191
195
203
158
163
167
171
11
Notes
Fast or standard charge state;
MULT pulled to VSS
Fast or standard charge state;
MULT pulled to VSS
Fast or standard charge state;
MULT pulled to VSS
Fast or standard charge state;
MULT pulled to VSS
Discharge-before-charge state;
MULT pulled to VSS; DIS = 1
Discharge-before-charge state;
MULT pulled to VSS; DIS = 1
Discharge-before-charge state;
MULT pulled to VSS; DIS = 1
Discharge-before-charge state;
MULT pulled to VSS; DIS = 1
bq2007
Recommended DC Operating Conditions (TA = 0 to +70°C)
Symbol
Parameter
inimum
Typical
Maximum
Unit
4.5
5.0
5.5
V
Notes
VCC
Supply voltage
VBAT
Voltage on BAT pin
0
-
VCC
V
VTS
Voltage on TS pin
0
-
VCC
V
Thermistor input
VTCO
Temperature cutoff on TCO
0
-
0.5 * VCC
V
Note 2
VCELL
Battery voltage potential
0
-
VCC
V
VBAT - VSNS
VTEMP
Voltage potential on TS
10%
0
-
VCC
V
VTS - VSNS
2.0
-
-
V
DCMD, FAST, VSEL, INH
VCC - 0.3
-
-
V
TM
Logic input low
-
-
0.8
V
DCMD, FAST, VSEL, INH
Tri-level input low
-
-
0.3
V
TM
VOH
Logic output high
VCC - 0.8
-
-
V
DIS, LED1–2, SEGA–G @ IOH =
-10mA; MOD @ IOH = -5mA
VOL
Logic output low
-
-
0.8
V
DIS, LED1–2, SEGA–G @ IOL =
10mA; MOD @ IOL = 5mA
VIH
Logic input high
Tri-level input high
VIL
VOHCOM
COM output
VCC - 0.8
-
-
V
IOHCOM
COM source
-40
-
-
mA
@ VOHCOM = VCC - 0.8V
ICC
Supply current
-
1
2.5
mA
No output load
IOH
DIS, LED1–2, SEGA–G source
-10
-
-
mA
@VOH = VCC - 0.8V
IOH
MOD
-5
-
-
mA
@VOH = VCC - 0.8V
IOL
DIS, LED1–2, SEGA–G sink
10
-
-
mA
@VOL = VSS + 0.8V
IOL
MOD
5
-
-
mA
@VOL = VSS + 0.8V
IIZ
Tri-state inputs floating
for Z state
-2.0
-
2.0
µA
TM
Input leakage
-
-
±1
µA
INH, VSEL, V = VSS to VCC
Input leakage
50
-
400
µA
DCMD, FAST, V = VSS to VCC
IL
@ IOHCOM = -40mA
IIL
Logic input low current
-
-
70
µA
TM, V = VSS to VSS + 0.3V
IIH
Logic input high current
-70
-
-
µA
TM, V = VCC - 0.3V to VCC
12
bq2007
Impedance
Symbol
Minimum
Typical
Maximum
Unit
RI
DC input impedance: pins
TS, BAT, SNS, TCO
50
-
-
MΩ
RPROG
Soft-programmed pull-up
resistor
150
-
200
KΩ
MSEL, DSEL1, DSEL2, MULT,
QDSEL; resistor value ± 10% tolerance
RFLT
Float state external
resistor
-
5
-
MΩ
TM
Minimum
Typical
Maximum
Unit
Timing
Symbol
Parameter
Notes
(TA = 0 to +70°C; VCC ± 10%)
Parameter
Notes
At VCC = ± 10%, TA = 0 to 60°C;
see Table 3
dFCV
Deviation of fast charge
safety time-out
0.84
1.0
1.16
-
tREG
MOD output regulation
frequency
-
-
300
kHz
tPEND
Charge pending time-out
-
25
-
%
Ratio of fast charge time-out;
see Table 4.
FCOM
Common LCD backplane frequency
-
73
-
Hz
LCD segment frame rate
FALARM
Alarm frequency output
-
3500
-
kHz High tone
tPW
Pulse width for DCMD and
INH pulse command
1
-
-
µs
Signal valid time
tMCV
Valid period for VCELL >
VMCV
0.5
-
1
sec
If VCELL ≥ VMCV for tMCV during
charge or top-off, then a transition
is recognized as
a battery replacement.
Note:
Typical is at TA = 25°C, VCC = 5.0V.
13
Typical regulation range;
VCC = 5.0V
bq2007
24-Pin DIP Narrow (PN)
24-Pin PN (0.300" DIP)
Inches
Millimeters
Dimension
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
S: 24-Pin S (0.300" SOIC)
24-Pin S (0.300" SOIC)
Inches
B
e
D
E
Millimeters
Dimension
A
Min.
Max.
Min.
Max.
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
H
A
C
.004
A1
L
14
bq2007
Data Sheet Revision History
Change No.
Page No.
1
11
Note:
Description
Nature of Change
Was VSNSHI - (0.01 * VCC);
is 0.04 * VCC
VSNSLO Rating
Change 1 = Sept. 1996 B changes from Dec. 1995.
Ordering Information
bq2007
Temperature:
blank = Commercial (-20 to +70°C)
N = Industrial (-40 to +85°C)*
Package Option:
PN = 24-pin narrow plastic DIP
S = 24-pin SOIC
Device:
bq2007 Fast-Charge IC
* Contact factory for availability.
15
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