Linear Technology LTC1325CSW, LTC1325CN Datasheet
FEATURES
■
Fast Charge Nickel-Cadmium, Nickel-Metal-Hydride,
Lithium Ion or Lead-Acid Batteries under µP Control
■
Flexible Current Regulation:
– Programmable 111kHz PWM Current Regulator
with Built-In PFET Driver
– PFET Current Gating for Use with External Current
Regulator or Current Limited Transformer
■
Discharge Mode
■
Measures Battery Voltage, Battery Temperature and
Ambient Temperature with Internal 10-Bit ADC
■
Battery Voltage, Temperature and Charge Time
Fault Protection
■
Built-In Voltage Regulator and Programmable
Battery Attenuator
■
Easy-to-Use 3- or 4-Wire Serial µP Interface
■
Accurate Gas Gauge Function
■
Wide Supply Range: VDD = 4.5V to 16V
■
Can Charge Batteries with Voltages Greater Than V
■
Can Charge Batteries from Charging Supplies Greater
Than V
■
Digital Input Pins Are High Impedance in
DD
Shutdown Mode
U
APPLICATIONS
■
System Integrated Battery Charger
LTC1325
Microprocessor-Controlled
Battery Management System
U
DESCRIPTION
The LTC®1325 provides the core of a flexible, cost-effective solution for an integrated battery management system. The monolithic CMOS chip controls the fast charging
of nickel-cadmium, nickel-metal-hydride, lead-acid or
lithium batteries under microprocessor control. The device features a programmable 111kHz PWM constant
current source controller with built-in FET driver, 10-bit
ADC, internal voltage regulator, discharge-before-charge
controller, programmable battery voltage attenuator and
an easy-to-use serial interface.
The chip may operate in one of five modes: power shutdown, idle, discharge, charge or gas gauge. In power
shutdown the supply current drops to 30µ A and in the idle
mode, an ADC reading may be made without any switching
noise affecting the accuracy of the measurement. In the
discharge mode, the battery is discharged by an external
DD
transistor while the battery is being monitored by the
LTC1325 for fault conditions. The charge mode is terminated by the µP while monitoring any combination of
battery voltage and temperature, ambient temperature
and charge time. The LTC1325 also monitors the battery
for fault conditions before and during charging. In the gas
gauge mode the LTC1325 allows the total charge leaving
the battery to be calculated.
, LTC and LT are registered trademarks of Linear Technology Corporation.
TYPICAL APPLICATION
MPU
(e.g. 8051)
p1.4
p1.3
p1.2
+
R1
R2
R3
R4
U
Battery Charger for up to 8 NiCd or NiMH Cells
+
C2
10µF
LTC1325
C
REG
4.7µF
1
REG
2
D
OUT
3
D
IN
4
CS
5
CLK
6
LTF
7
MCV
8
HTF
9
GND
V
PGATE
DIS
V
BAT
T
BAT
T
AMB
V
SENSE
FILTER
18
DD
17
16
15
14
13
+
12
IN
11
10
C
F
1µF
100Ω
C
22µF
REG
R13
THERM 2
C1
0.1µF
IRF9730
R5
THERM 1
V
DD
R
R
4.5V TO 16V
TRK
DIS
LTC1325 • TA01
P1
1N6818
L1
62µH
BAT
R
SENSE
D1
IRFZ34
N1
1
LTC1325
WW
W
ABSOLUTE MAXIMUM RATINGS
(Notes 1, 2)
VDD to GND............................................................. 17V
All Other Pins................................ –0.3V to VDD + 0.3V
Operating Temperature Range ..................... 0°C to 70°C
Storage Temperature Range ................. –65°C to 150°C
Lead Temperature (Soldering, 10 sec)..................300°C
U
U
W
PACKAGE/ORDER INFORMATION
TOP VIEW
1
REG
2
D
OUT
3
D
IN
4
CS
5
CLK
6
LTF
7
MCV
8
HTF
9
GND
N PACKAGE
18-LEAD PDIP
T
= 125°C, θJA = 75°C/ W (N)
JMAX
T
= 125°C, θJA = 100°C/ W (SW)
JMAX
18
V
DD
17
PGATE
16
DIS
15
V
BAT
14
T
BAT
13
T
AMB
12
V
IN
11
SENSE
10
FILTER
SW PACKAGE
18-LEAD PLASTIC SO WIDE
ORDER PART
NUMBER
LTC1325CN
LTC1325CSW
Consult factory for Industrial and Military grade parts.
ELECTRICAL CHARACTERISTICS
VDD = 12V ±5%, TA = 25°C, unless otherwise noted.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
DD
I
DD
I
PD
V
REG
LD
REG
LI
REG
TC
REG
V
DAC
V
HYST
V
OS
V
BATR
V
BATP
V
EDV
V
LTF
V
HTF
A
GG
V
OS(GG)
R
F
TOL
V
IL
V
IH
I
IL
I
IH
, V
BATD
VDD Supply Voltage ● 4.5 16 V
VDD Supply Current All TTL Inputs = 0V or 5V, No Load on REG ● 1200 2000 µA
VDD Supply Current Power-Down Mode, All TTL Inputs = 0V or 5V ● 30 50 µA
Regulator Output Voltage No Load ● 3.047 3.072 3.097 V
Regulator Load Regulation Sourcing Only, I
= 0mA to 2mA –1 – 5 mV/mA
REG
Regulator Line Regulation No Load, VDD = 4.5V to 16V –60 –100 µV/V
Regulator Output Tempco No Load, 0°C < TA < 70°C 50 ppm/°C
DAC Output Voltage VR1 = 1, VR0 = 1, 100% Duty Ratio, I
VR1 = 1, VR0 = 0, 100% Duty Ratio, I
VR1 = 0, VR0 = 1, 100% Duty Ratio, I
VR1 = 0, VR0 = 0, 100% Duty Ratio, I
Fault Comparator Hysteresis V
Fault Comparator Offset V
V
for BATR = 1 100 mV
BAT
V
for BATP = 1 ● V
BAT
V
V
HTF
MCV
HTF
MCV
= 1V, V
= V
= 1V, V
= V
= 0.9V, V
EDV
= 2V ±10 mV
LTF
= 0.9V, V
EDV
= 2V
LTF
= 100mV ±20 mV
BATR
= 100mV ±50 mV
BATR
= I (Note 7) 140 160 180 mV
CHRG
= I/3 48 55 62 mV
CHRG
= I/5 30 34 38 mV
CHRG
= I/10 16 18 21 mV
CHRG
– 1.8 V
DD
Internal EDV Voltage ● 860 900 945 mV
LTF, MCV Voltage Range 1.6 2.8 V
MCV
HTF Voltage Range 0.5 1.3 V
Gas Gauge Gain –0.4V < V
Gas Gauge Offset –0.4V < V
< 0V –4
SENSE
< 0V (Note 6) ±1 LSB
SENSE
Internal Filter Resistor 1000 Ω
Battery Divider Tolerance All Division Ratios ● –2 2 %
Input Low Voltage CLK, CS, D
Input High Voltage CLK, CS, D
Low Level Input Current V
High Level Input Current V
, VCS or V
CLK
, VCS or V
CLK
IN
IN
= 0V ● –2.5 2.5 µA
DIN
= 5V ● –2.5 2.5 µA
DIN
● 0.8 1.3 V
● 1.7 2.4 V
U
2
LTC1325
ELECTRICAL CHARACTERISTICS
VDD = 12V ±5%, TA = 25°C, unless otherwise noted.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
OL
V
OH
I
OZ
V
OHFET
V
OLFET
t
dDO
t
dis
t
en
t
hDO
t
rDOUT
t
fDOUT
f
CLK
t
rPGATE
t
fPGATE
f
OSC
Output Low Voltage D
Output High Voltage D
OUT
OUT
, I
= 1.6mA ● 0.4 V
OUT
, I
= –1.6mA ● 2.4 V
OUT
Hi-Z Output Leakage VCS = 5V ● ±10 µA
DIS or PGATE Output High VDD = 4.5V to 16V ● VDD – 0.05 V
DIS or PGATE Output Low VDD = 4.5V to 16V ● 0.05 V
Delay Time, CLK↓ to D
Delay Time, CS↑ to D
Delay Time, CLK↓ to D
Time D
D
OUT
D
OUT
Remains Valid After CLK↓ See Test Circuits ● 30 ns
OUT
Rise Time See Test Circuits ● 250 ns
Fall Time See Test Circuits ● 100 ns
Valid See Test Circuits ● 650 ns
OUT
Hi-Z See Test Circuits ● 510 ns
OUT
Enabled See Test Circuits ● 400 ns
OUT
Serial I/O Clock Frequency CLK Pin ● 25 500 kHz
PGATE Rise Time C
PGATE Fall Time C
= 1500pF ● 150 ns
LOAD
= 1500pF ● 150 ns
LOAD
Internal Oscillator Frequency Charge Mode, Fail-Safes Disabled 90 111 130 kHz
A/D Converter
Offset Error VIN Channel (Note 3) ● ±2 LSB
Linearity Error VIN Channel (Notes 3, 4) ● ±0.5 LSB
Full-Scale Error VIN Channel (Note 3) ● ±1 LSB
On-Channel Leakage VIN Channel ON Only (Notes 3, 5) ● ±10 µA
Off-Channel Leakage VIN Channel OFF (Notes 3, 5) ● ±10 µA
UWW
RECO E DED CHARACTERISTICS
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
t
hDI
t
dsuCS
t
dsuDI
t
WHCLK
t
WLCLK
t
WHCS
t
WLCS
The ● denotes specifications which apply over the full operating
temperature range.
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: All voltage values are with respect to the GND pin.
Note 3: V
unless otherwise stated. ADC clock is the serial CLK.
Hold Time, DIN After CLK↑ 150 ns
Setup Time, CS Before First CLK↑ 1 µs
Setup Time, DIN Stable Before First CLK↑ 400 ns
CLK High Time 0.8 µs
CLK Low Time 1 µs
CS High Time Between Data Transfers 1 µs
CS Low Time During Data Transfer MSBF = 1 43 CLK Cycles
MSBF = 0 52 CLK Cycles
Note 4: Linearity error is specified between the actual end points of the
A/D transfer curve.
Note 5: Channel leakage is measured after channel selection.
Note 6: Gas gauge offset excludes A/D offset error.
within specified min and max limits, CLK (Pin 5) = 500kHz,
REG
Note 7: I = V
(Duty Ratio)/R
DAC
voltage with control bits VR1 = VR0 = 1, duty ratio = 1 and R
SENSE
, where V
is the DAC output
DAC
SENSE
determined by the user.
is
3
LTC1325
TEMPERATURE (°C)
0
0
SHUTDOWN CURRENT (µA)
5
15
20
25
20
40
50 90
1325 G06
10
10 30
60
70
80
VDD = 12V
VDD = 16V
VDD = 4.5V
TEMPERATURE (°C)
0
V
DD
SUPPLY CURRENT (µA)
1000
900
800
700
600
500
400
300
200
100
0
20
40
50 90
1325 G03
10 30
60
70
80
VDD = 16V
VDD = 4.5V
VDD = 12V
UW
TYPICAL PERFORMANCE CHARACTERISTICS
Regulator Output Voltage vs
Load Current
3.077
3.076
3.075
3.074
3.073
3.072
3.071
REGULATOR OUTPUT VOLTAGE (V)
3.070
0.5 1.0 1.5 2.5 3.52.0 4.0
0
VDD = 16V
VDD = 12V
VDD = 4.5V
LOAD CURRENT (mA)
Charge Current vs Battery Voltage
160
140
VDD = 12V, R
120
L = 100µH, P1: IRF9531
100
80
60
CHARGE CURRENT (mA)
40
20
0
0
VR1 = 1, VR0 = 1
= 1Ω,
SENSE
VR1 = 1, VR0 = 0
VR1 = 0, VR0 = 1
VR1 = 0, VR0 = 0
468
2
BATTERY VOLTAGE (V)
TA = 27°C
3.0
10 12
1325 G01
1325 G04
Regulator Output Voltage vs
Temperature
3.082
I
3.081
3.080
3.079
3.078
3.077
3.076
3.075
3.074
REGULATOR OUTPUT VOLTAGE (V)
3.073
3.072
= 0
REG
VDD = 16V
VDD = 12V
VDD = 4.5V
10 30
20
0
DAC Output Voltage vs
40
TEMPERATURE (°C)
70
50 90
60
80
1325 G02
Temperature
180
160
140
120
VDD = 12V
100
80
60
40
DAC OUTPUT VOLTAGE (mV)
20
0
0
10 20
VR1 = 1, VR0 = 1
VR1 = 1, VR0 = 0
VR1 = 0, VR0 = 1
VR1 = 0, VR0 = 0
40 60 70
30 50
TEMPERATURE (°C)
1325 G05
VDD Supply Current vs
Temperature
Shutdown Current vs Temperature
Fault Comparator Threshold vs
Temperature
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
FAULT COMPARATOR THRESHOLD (V)
0
4
V
CELL
V
FOR HTF = HIGH, V
TBAT
V
CELL
0
10 30
20
FOR EDV = HIGH
FOR BATR = HIGH
TEMPERATURE (°C)
Fault Comparator Threshold vs
Temperature
11
10
V
FOR BATP = HIGH, VDD = 12V
BAT
9
8
7
V
6
= 0.4V
HTF
70
60
50
80
1325 G07
40
5
4
3
FAULT COMPARATOR THRESHOLD (V)
2
1
0
V
V
FOR MCV = HIGH, V
CELL
V
TBAT
V
FOR HTF = HIGH, V
TBAT
10 30
20
FOR LTF = HIGH, V
TBAT
FOR LTF = HIGH, V
40
TEMPERATURE (°C)
FOR MCV = HIGH, V
CELL
HTF
50
= 2.8V AND
MCV
MCV
LTF
= 1.35V
60
= 2.8V
LTF
= 1.6V
= 1.6V
70
80
1325 G08
Gas Gauge Gain and Offset vs
Temperature
0
V
= –0.2V AND –0.4V
SENSE
–0.5
INCLUDES CHANGES IN V
WITH TEMPERATURE
–1.0
–1.5
–2.0
–2.5
–3.0
–3.5
–4.0
GAS GAUGE GAIN AND OFFSET (COUNTS)
–4.5
GAS GAUGE GAIN
10 20 30 40 50 80
0
TEMPERATURE (°C)
REG
GAS GAUGE OFFSET
7060
1325 G09
UW
TEMPERATURE (°C)
0
CLK TO D
OUT
VALID DELAY TIME (ns)
400
500
600
60
1325 G18
300
200
10 20 30 50 7040
80
100
0
700
D
OUT
GOING HIGH
D
OUT
GOING LOW
TYPICAL PERFORMANCE CHARACTERISTICS
LTC1325
PGATE Rise Time vs
Load Capacitance
1200
1000
800
600
400
PGATE RISE TIME (ns)
200
0
Discharge Rise and Fall Time
vs Load Capacitance
14
12
10
8
6
4
2
DISCHARGE RISE AND FALL TIME (µs)
0
0
Oscillator Frequency vs
Temperature
118
117
116
115
114
113
112
111
110
OSCILLATOR FREQUENCY (kHz)
109
108
–40
TA = 27°C
TA = 70°C
4 8 12 16
LOAD CAPACITANCE (nF)
TA = 70°C
= 27°C
T
A
= 0°C
T
A
6
10
8
4
2
LOAD CAPACITANCE (nF)
40
20
0
–20
TEMPERATURE (°C)
TA = 0°C
RISE TIME
FALL TIME
14
12 16
60
80
1325 G10
18
1325 G13
1325 G16
2020 6 10 14 18
20
100
PGATE Fall Time vs
Load Capacitance
1000
900
800
700
600
500
400
300
PGATE FALL TIME (ns)
200
100
0
42 6 10 14 18
0
LOAD CAPACITANCE (nF)
TA = 27°C
TA = 70°C
8
Minimum Charging Supply vs
Number of Cells
16
14
12
10
8
6
4
MINIMUM CHARGE VOLTAGE (V)
2
0
1
CLK to D
= 0.15, VR1 = 1,VR0 = 1
R
SENSE
L = 10µH TO 100µH
IRF9Z30PFET, 1N5819 DIODE
R
= 1, VR1 = 1, VR0 = 1
SENSE
L = 25µH TO 100µH
IRF9Z30PFET, 1N5819 DIODE
TA = 27°C, NiCd BATTERIES
= 1.4V NOMINAL
V
CELL
35
2468
NUMBER OF CELLS
Enable Delay Time
OUT
vs Temperature
500
450
400
350
300
250
200
ENABLE DELAY TIME (ns)
150
OUT
100
50
CLK TO D
0
0
10 30
20
40
TEMPERATURE (°C)
TA = 0°C
12
50
Differential Nonlinearity
1.0
VDD = 12V
= 500kHz
f
CLK
0.5
0
–0.5
DIFFERENTIAL NONLINEARITY (LSB)
16
20
LTC1325 G11
–1.0
128 384 640
0
256
512
CODE
768
896
1024
1325 G12
Integral Nonlinearity
1.0
VDD = 12V
= 500kHz
f
CLK
0.5
0
–0.5
INTEGRAL NONLINEARITY (LSB)
7
1325 G14
–1.0
128 384 640
0
CLK to D
256
512
CODE
Valid Delay Time
OUT
768
896
1024
1325 G15
vs Temperature
70
60
80
1325 G17
5
LTC1325
PIN FUNCTIONS
UUU
REG (Pin 1): Internal Regulator Output. The regulator
provides a steady 3.072V to the internal analog circuitry
and provides a temperature stable reference voltage for
generating MCV, HTF, LTF and thermistor bias voltages
with external resistors. Requires a 4.7µ F or greater bypass
capacitor to ground.
D
(Pin 2): TTL Data Output Signal for the Serial
OUT
Interface. D
3-wire interface, or remain separated to form a 4-wire
interface. Data is transmitted on the falling edge of CLK
(Pin 5).
DIN (Pin 3): TTL Data Input Signal for the Serial Interface.
The data is latched into the chip on the rising edge of the
CLK (Pin 5).
CS (Pin 4): TTL Chip Select Signal for the Serial Interface.
CLK (Pin 5): TTL Clock for the Serial Interface.
LTF (Pin 6): Minimum Allowable Battery Temperature
Analog Input. LTF may be generated by a resistive divider
between REG (Pin 1) and ground.
MCV (Pin 7): Maximum Allowable Cell Voltage Analog
Input. MCV may be generated by a resistive divider between REG (Pin 1) and ground.
HTF (Pin 8): Maximum Allowable Battery Temperature
Analog Input. HTF may be generated by a resistive divider
between REG (Pin 1) and ground.
GND (Pin 9): Ground.
FILTER (Pin 10): The external filter capacitor CF is con-
nected to this pin. The filter capacitor is connected to the
output of the internal resistive divider across the battery to
reduce the switching noise while charging. In the gas
gauge mode, CF along with an internal RF = 1k form a
lowpass filter to average the voltage across the sense
resistor.
and DIN may be tied together to form a
OUT
SENSE (Pin 11): The Sense pin controls the switching of
the 111kHz PWM constant current source in the charging
mode. The Sense pin is connected to an external sense
resistor R
charging loop forces the average voltage at the Sense pin
to equal a programmable internal reference voltage V
The battery charging current is equal to V
In the gas gauge mode the voltage across the Sense pin
is filtered by an RC network (RF and CF), amplified by
an inverting gain of four, then multiplexed to the ADC so
the average discharge current through the battery may
be measured and the total charge leaving the battery
calculated.
VIN (Pin 12): General Purpose ADC Input.
T
(Pin 13): Ambient Temperature Input. Connect to an
AMB
external thermistor network. Tie to REG if not used. May
be used as another general purpose ADC input.
T
(Pin 14): Battery Temperature Input. Connect to an
BAT
external NTC thermistor network. Tie to REG if not used.
V
(Pin 15): Battery Input. An internal voltage divider is
BAT
connected between the V
all battery measurements to one cell voltage. The divider
is programmable to the following ratios: 1/1, 1/2, 1/3 . . .
1/15, 1/16. In shutdown and gas gauge modes the divider
is disconnected.
DIS (Pin 16): Active High Discharge Control Pin. Used
to turn on an external transistor which discharges the
battery.
PGATE (Pin 17): FET Driver Output. Swings from GND
to VDD.
VDD (Pin 18): Positive Supply Voltage. 4.5V < VDD < 16V.
and the negative side of the battery. The
SENSE
DAC/RSENSE
and Sense pins to normalize
BAT
DAC
.
.
6
BLOCK DIAGRAM
18
V
DD
5V
DIGITAL
REGULATOR
9
GND
5
CLK
4
CS
D
IN
D
OUT
SERIAL
3
2
A/D CONVERTER
I/O
10
10-BIT
2
W
DIGITAL INPUT CIRCUITS
CONTROL
LOGIC
PS, MSBF
DS0 TO DS1
3
SGL/DIFF
ADC
MUX
BATP, BATR, FMCV,
FEDV, FHTF, FLTF, t
7
MOD0 TO MOD1, PS
3
LTC1325
PS
OUT
3.072V
ANALOG
REGULATOR
FAULT
DETECT
CIRCUITRY
ANALOG AND DIGITAL V
DIV0 TO DIV3
4
ADC REFERENCE
t
OUT
DD
1
REG
16
DIS
6
LTF
8
HTF
7
MCV
12
V
IN
13
T
AMB
14
T
BAT
15
V
BAT
DIVIDER
TIMEOUT LOGIC
TEST CIRCUITS
Load Circuit for t
D
OUT
T
OUT
TO0 TO TO2
dDO
3
, tr and t
1.4V
3k
100pF
LTC1325 • TC01
GAS GAUGE
111kHz
OSCILLATOR
DR0 TO DR3
DUTY RATIO
GENERATOR
f
5 MOD0 TO MOD1, VR0 TO VR1, PS
PS
CHARGE LOOP
AND
GAS GAUGE
3
LTC1325 • BD
Load Circuit for t
TEST POINT
D
OUT
3k
100pF
CHARGE
dis
and t
11
SENSE
10
FILTER
17
PGATE
en
5V t
WAVEFORM 2, t
dis
t
WAVEFORM 1
dis
LTC1325 • TC02
en
7
LTC1325
0.4V
2.4V
t
r
t
f
LTC1325 • TC04
TEST CIRCUITS
Voltage Waveforms for D
D
CLK
OUT
0.8V
t
dDO
On and Off Channel Leakage Voltage Waveforms for t
3.072V
NOTE: EXTERNAL CHANNELS ONLY––
, T
BAT
AMB
AND V
IN
T
Delay Time, t
OUT
dDO
2.4V
0.4V
LTC1325 • TC03
Voltage Waveforms for D
Rise and Fall Times, tr, t
OUT
f
dis
I
ON
A
I
OFF
A
ON CHANNEL
OFF
}
CHANNELS
LTC1325 • TC05
WAVEFORM 1
(SEE NOTE 1)
WAVEFORM 2
(SEE NOTE 2)
NOTE 1: WAVEFORM 1 IS FOR AN OUTPUT WITH INTERNAL CONDITIONS
SUCH THAT THE OUTPUT IS HIGH UNLESS DISABLED BY CS.
NOTE 2: WAVEFORM 2 IS FOR AN OUTPUT WITH INTERNAL CONDITIONS
SUCH THAT THE OUTPUT IS LOW UNLESS DISABLED BY CS.
CS
D
OUT
t
dis
D
OUT
2V
90%
10%
LTC1325 • TC06
Voltage Waveforms for t
CS
D
IN
CLK
D
OUT
START
121222324
en
VR1
0.4V
t
en
THREE-STATE NULL
0.4V
D9
LTC1325 • TC07
8
Loading...