Maxim MAX713MJE, MAX713CSE, MAX713EPE, MAX713CPE, MAX712EPE Datasheet

...
19-0100; Rev 3; 1/97
EVALUATION KIT MANUALS
FOLLOW DATA SHEET
NiCd/NiMH Battery
Fast-Charge Controllers
_______________General Description
The MAX712/MAX713 fast charge Nickel Metal Hydride (NiMH) and Nickel Cadmium (NiCd) batteries from a DC source at least 1.5V higher than the maximum battery voltage. 1 to 16 series cells can be charged at rates up to 4C. A voltage-slope detecting analog-to-digital convert­er, timer, and temperature window comparator determine charge completion. The MAX712/MAX713 are powered by the DC source via an on-board +5V shunt regulator. They draw a maximum of 5µA from the battery when not charging. A low-side current-sense resistor allows the battery charge current to be regulated while still supplying power to the battery’s load.
The MAX712 terminates fast charge by detecting zero voltage slope, while the MAX713 uses a negative voltage-slope detection scheme. Both parts come in 16­pin DIP and SO packages. An external power PNP tran­sistor, blocking diode, three resistors, and three capacitors are the only required external components.
For high-power charging requirements, the MAX712/ MAX713 can be configured as a switch-mode battery charger that minimizes power dissipation. Two evaluation kits are available: Order the MAX712EVKIT-DIP for quick evaluation of the linear charger, and the MAX713EVKIT­SO to evaluate the switch-mode charger.
________________________Applications
Battery-Powered Equipment
Laptop, Notebook, and Palmtop Computers Handy-Terminals Cellular Phones
Portable Consumer Products
Portable Stereos Cordless Phones
____________________________Features
Fast Charge NiMH or NiCd BatteriesVoltage Slope, Temperature, and Timer
Fast-Charge Cutoff
Charge 1 to 16 Series CellsSupply Battery’s Load while Charging (Linear Mode)Fast Charge from C/4 to 4C RateC/16 Trickle-Charge RateAutomatically Switch from Fast to Trickle ChargeLinear or Switch-Mode Power Control5µA Max Drain on Battery when Not Charging5V Shunt Regulator Powers External Logic
______________Ordering Information
PART
MAX712CPE
MAX712CSE MAX712C/D 0°C to +70°C MAX712EPE MAX712ESE MAX712MJE -55°C to +125°C
Ordering Information continued at end of data sheet.
*
Contact factory for dice specifications.
**
Contact factory for availability and processing to MIL-STD-883.
TEMP. RANGE PIN-PACKAGE
0°C to +70°C 0°C to +70°C
-40°C to +85°C 16 Plastic DIP
-40°C to +85°C
16 Plastic DIP 16 Narrow SO Dice*
16 Narrow SO 16 CERDIP**
__________Typical Operating Circuit
R2 150
Q1
2N6109
DC IN
R1
C4
0.01µF
MAX712/MAX713
__________________Pin Configuration
TOP VIEW
VLIMIT
1
BATT+
2
PGM0
3
PGM1
THI
TLO
TEMP
FASTCHG
________________________________________________________________
MAX712
4
MAX713
5 6 7 8
DIP/SO
REF
16
V+
15
DRV
14
GND
13
BATT-
12 11
CC
10
PGM3 PGM2
9
WALL 
CUBE
C1 1µF
R3
68k
10µF
SEE FIGURE 19 FOR SWITCH-MODE CHARGER CIRCUIT.
R4
22k
THI
V+
VLIMIT REF
TEMP
C2
0.01µF
DRV
BATT+
MAX712 MAX713
BATT- TLO GNDCC
Maxim Integrated Products
BATTERY
R
D1 1N4001
C3 10µF
SENSE
LOAD
1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800
NiCd/NiMH Battery Fast-Charge Controllers
ABSOLUTE MAXIMUM RATINGS
V+ to BATT-.................................................................-0.3V, +7V
BATT- to GND........................................................................±1V
BATT+ to BATT-
Power Not Applied............................................................±20V
With Power Applied................................The higher of ±20V or
DRV to GND ..............................................................-0.3V, +20V
FASTCHG to BATT-...................................................-0.3V, +12V
All Other Pins to GND......................................-0.3V, (V+ + 0.3V)
V+ Current.........................................................................100mA
DRV Current......................................................................100mA
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
MAX712/MAX713
ELECTRICAL CHARACTERISTICS
(IV+= 10mA, TA= T BATT-, not GND.)
Trickle-Charge VSENSE
Voltage-Slope Sensitivity (Note 3)
Battery-Voltage to Cell-Voltage Divider Accuracy
MIN
to T
±2V x (programmed cells)
, unless otherwise noted. Refer to
MAX
5mA < IV+< 20mA
V+ = 0V, BATT+ = 17V PGM0 = PGM1 = BATT-, BATT+ = 30V
0mA < I
REF
Per cell
0V < TEMP < 2V, TEMP voltage rising
1.2V < V PGM0 = PGM1 = V+
V
PGM3 = V+ PGM3 = open PGM3 = REF PGM3 = BATT­MAX713 MAX712
V
LIMIT
DRV
LIMIT
= V+
= 10V
< 1mA
REF Current.........................................................................10mA
Continuous Power Dissipation (T
Plastic DIP (derate 10.53mW/°C above +70°C............842mW
Narrow SO (derate 8.70mW/°C above +70°C .............696mW
CERDIP (derate 10.00mW/°C above +70°C................800mW
Operating Temperature Ranges
MAX71_C_E .......................................................0°C to +70°C
MAX71_E_E .................................................... -40°C to +85°C
MAX71_MJE ................................................. -55°C to +125°C
Storage Temperature Range.............................-65°C to +150°C
Lead Temperature (soldering, 10sec).............................+300°C
Typical Operating Circuit
CONDITIONS
< 2.5V, 5mA < I
DRV
< 20mA,
. All measurements are with respect to
= +70°C)
A
1.5 3.9 7.0
4.5 7.8 12.0
12.0 15.6 20.0
26.0 31.3 38.0
-2.5 0
UNITSMIN TYP MAXPARAMETER
mV/t
per cell
V4.5 5.5V+ Voltage
mA5IV+(Note 1)
µA5BATT+ Leakage k30BATT+ Resistance with Power On µF0.5C1 Capacitance nF5C2 Capacitance
V1.96 2.04REF Voltage V0.35 0.50Undervoltage Lockout V1.25 2.50External VLIMIT Input Range V02THI, TLO, TEMP Input Range
mV-10 10THI, TLO Offset Voltage (Note 2)
µA-1 1THI, TLO, TEMP, VLIMIT Input Bias Current
mV-30 30VLIMIT Accuracy
V1.6 1.65 1.7Internal Cell Voltage Limit
mV225 250 275Fast-Charge VSENSE
mV
A
%-15 15Timer Accuracy %-1.5 1.5
mA30DRV Sink Current
2 _______________________________________________________________________________________
NiCd/NiMH Battery
Fast-Charge Controllers
ELECTRICAL CHARACTERISTICS (continued)
(IV+ = 10mA, TA= T BATT-, not GND.)
FASTCHG Low Current FASTCHG High Current
Note 1: The MAX712/MAX713 are powered from the V+ pin. Since V+ shunt regulates to +5V, R1 must be small enough to allow at
least 5mA of current into the V+ pin.
Note 2: Offset voltage of THI and TLO comparators referred to TEMP. Note 3: t
is the A/D sampling interval (Table 3).
A
Note 4: This specification can be violated when attempting to charge more or fewer cells than the number programmed. To ensure
proper voltage-slope fast-charge termination, the (maximum battery voltage) ÷ (number of cells programmed) must fall within the A/D input range.
MIN
to T
, unless otherwise noted. Refer to
MAX
V
FASTCHG
V
FASTCHG
Battery voltage ÷ number of cells programmed
CONDITIONS
= 0.4V = 10V
Typical Operating Circuit
. All measurements are with respect to
UNITSMIN TYP MAXPARAMETER
mA2
µA10
V1.4 1.9A/D Input Range (Note 4)
__________________________________________Typical Operating Characteristics
(TA = +25°C, unless otherwise noted.)
20
10
0
GAIN (dB)
-10
-20
CURRENT-SENSE AMPLIFIER
FREQUENCY RESPONSE (with 15pF)
C2 = 15pF
FASTCHG = 0V
A
Φ
BATT-
+
V
IN
-
GND
1k
CURRENT-
SENSE 
AMP
FREQUENCY (Hz)
CC
BATT-
100k
V
OUT
+
-
1M10k 10M
40
MAX712/13 LOG1
0
V
-40
PHASE (DEGREES)
-80
-120
20
10
GAIN (dB)
-10
-20
CURRENT-SENSE AMPLIFIER
FREQUENCY RESPONSE (with 10nF)
0
Φ
10 1k
100 10k
FREQUENCY (Hz)
C2 = 10nF
FASTCHG = 0V
A
V
40
MAX712/13 LOG2
0
-40
PHASE (DEGREES)
-80
-120
MAX712/MAX713
CURRENT ERROR-AMPLIFIER
TRANSCONDUCTANCE
100
FASTCHG = 0V, V+ = 5V
10
1
DRV PIN SINK CURRENT(mA)
0.1
1.95 1.97 2.01 2.05
1.99 2.03
VOLTAGE ON CC PIN (V)
_______________________________________________________________________________________ 3
MAX712/13 LOG3
V+ VOLTAGE (V)
SHUNT-REGULATOR VOLTAGE
vs. CURRENT
5.8 DRV NOT SINKING CURRENT
5.6
5.4
5.2
5.0
4.8
4.6
4.4
4.2
4.0
10 20 50
060
DRV SINKING CURRENT
30
40
CURRENT INTO V+ PIN (mA)
MAX712/13 LOG4
ALPHA THERMISTOR PART No. 13A1002
STEINHART-HART INTERPOLATION
1.6
1.4
1.2
1.0
0.8
0.6
TEMP PIN VOLTAGE (V)
0.4
0.2 10 20 50
060
BATTERY TEMPERATURE(°C)
35 30
25
20
15
10
5
BATTERY THERMISTOR RESISTANCE (k)
30
40
0
NiCd/NiMH Battery Fast-Charge Controllers
____________________________Typical Operating Characteristics (continued)
(TA = +25°C, unless otherwise noted.)
MAX713
NiCd BATTERY-CHARGING
CHARACTERISTICS AT C RATE
CHARACTERISTICS AT C RATE
MAX713
NiMH BATTERY-CHARGING
1.55
1.50
1.45
CELL VOLTAGE (V)
1.40
V
V
CUTOFF
t
T
MAX712/MAX713
0
CHARACTERISTICS AT C/2 RATE
1.50
1.45
CELL VOLTAGE (V)
1.40
30 9060
CHARGE TIME (MINUTES)
MAX713
NiCd BATTERY-CHARGING
V
CUTOFF
t
V
T
MAX712/713
40
35
30
25
MAX712/713
35
30
25
MAX712/713
1.60
1.55
1.50
CELL VOLTAGE (V)
CELL TEMPERATURE (°C)
1.45
0
30 9060
CHARGE TIME (MINUTES)
V
V
T
t
CUTOFF
40
35
30
CELL TEMPERATURE (°C)
25
MAX713
NiMH BATTERY-CHARGING
CHARACTERISTICS AT C/2 RATE
MAX712/713
1.55
1.50
1.45
CELL VOLTAGE (V)
CELL TEMPERATURE (°C)
1.40
V
CUTOFF
t
V
T
40
35
30
CELL TEMPERATURE (°C)
25
0
50 150100
CHARGE TIME (MINUTES)
MAX713
CHARGING CHARACTERISTICS OF A 
FULLY CHARGED NiMH BATTERY
1.65
1.60
1.55
1.50
CELL VOLTAGE (V)
1.45
V
T
0
CHARGE TIME (MINUTES)
BETWEEN CHARGES
V
5152010
5-MINUTE REST 
t
CUTOFF
MAX712/713
40
35
30
25
0
CHARGING CHARACTERISTICS OF A 
1.65
1.60
1.55
1.50
CELL TEMPERATURE (°C)
CELL VOLTAGE (V)
1.45
0
50 150100
CHARGE TIME (MINUTES)
MAX713
FULLY CHARGED NiMH BATTERY
V
V
CUTOFF
t
5-HOUR REST 
BETWEEN CHARGES
T
51510
CHARGE TIME (MINUTES)
4 _______________________________________________________________________________________
MAX712/713
40
35
30
CELL TEMPERATURE (°C)
25
20
NiCd/NiMH Battery
Fast-Charge Controllers
______________________________________________________________Pin Description
PIN
3, 4
8
9, 10
VLIMIT1
PGM0,
PGM1
TLO6
FASTCHG
PGM2,
PGM3
Sets the maximum cell voltage. The battery terminal voltage (BATT+ - BATT-) will not exceed VLIMIT x (number of cells). Do not allow VLIMIT to exceed 2.5V. Tie VLIMIT to VREF for normal operation.
Positive terminal of batteryBATT+2 PGM0 and PGM1 set the number of series cells to be charged. The number of cells can be set from
1 to 16 by connecting PGM0 and PGM1 to any of V+, REF, or BATT-, or by leaving the pin open (Table
2). For cell counts greater than 11, see the or fewer cells than the number programmed may inhibit V fast-charge termination.
Trip point for the over-temperature comparator. If the voltage-on TEMP rises above THI, fast charge ends.THI5 Trip point for the under-temperature comparator. If the MAX712/MAX713 power on with the voltage-on
TEMP less than TLO, fast charge is inhibited and will not start until TEMP rises above TLO. Sense input for temperature-dependent voltage from thermistors.TEMP7 Open-drain, fast-charge status output. While the MAX712/MAX713 fast charge the battery, FASTCHG
sinks current. When charge ends and trickle charge begins, FASTCHG stops sinking current. PGM2 and PGM3 set the maximum time allowed for fast charging. Timeouts from 33 minutes to 264
minutes can be set by connecting to any of V+, REF, or BATT-, or by leaving the pin open (Table 3). PGM3 also sets the fast-charge to trickle-charge current ratio (Table 5).
Compensation input for constant current regulation loopCC11
FUNCTIONNAME
Linear-Mode, High Series Cell Count
section. Charging more
MAX712/MAX713
Negative terminal of batteryBATT-12 System ground. The resistor placed between BATT- and GND monitors the current into the battery.GND13 Current sink for driving the external PNP current sourceDRV14
V+15
Shunt regulator. The voltage on V+ is regulated to +5V with respect to BATT-, and the shunt current powers the MAX712/MAX713.
2V reference outputREF16
_______________________________________________________________________________________ 5
NiCd/NiMH Battery Fast-Charge Controllers
____________________Getting Started
The MAX712/MAX713 are simple to use. A complete linear-mode or switch-mode fast-charge circuit can be designed in a few easy steps. A linear-mode design uses the fewest components and supplies a load while charging, while a switch-mode design may be neces­sary if lower heat dissipation is desired.
1) Follow the battery manufacturer’s recommendations on maximum charge currents and charge-termination methods for the specific batteries in your application. Table 1 provides general guidelines.
Table 1. Fast-Charge Termination Methods
Charge
MAX712/MAX713
Rate
> 2C
2C to C/2
< C/2
2) Decide on a charge rate (Tables 3 and 5). The slow­est fast-charge rate for the MAX712/MAX713 is C/4, because the maximum fast-charge timeout period is 264 minutes. A C/3 rate charges the battery in about three hours. The current in mA required to charge at this rate is calculated as follows:
Depending on the battery, charging efficiency can be as low as 80%, so a C/3 fast charge could take 3 hours and 45 minutes. This reflects the efficiency with which electrical energy is converted to chemical energy within the battery, and is not the same as the power­conversion efficiency of the MAX712/MAX713.
3) Decide on the number of cells to be charged (Table 2).
If your battery stack exceeds 11 cells, see the
Mode High Series Cell Count
changing the number of cells to be charged, PGM0
NiMH Batteries NiCd Batteries
V/t and temperature, MAX712 or MAX713
V/t and/or temperature, MAX712 or MAX713
V/t and/or temperature, MAX712
I
= (capacity of battery in mAh)
FAST
–––––––––––––––––––––––
(charge time in hours)
V/t and/or temperature, MAX713
V/t and/or temperature, MAX713
V/t and/or temperature, MAX713
section. Whenever
––
Linear-
and PGM1 must be adjusted accordingly. Attempting to charge more or fewer cells than the number pro­grammed can disable the voltage-slope fast-charge termination circuitry. The internal ADC’s input volt­age range is limited to between 1.4V and 1.9V (see
Electrical Characteristics
the voltage across the battery divided by the number of cells programmed (using PGM0 and PGM1, as in Table 2). When the ADC’s input voltage falls out of its specified range, the voltage-slope termination cir­cuitry can be disabled.
4) Choose an external DC power source (e.g., wall cube). Its minimum output voltage (including ripple) must be greater than 6V and at least 1.5V higher (2V for switch mode) than the maximum battery voltage while charging. This specification is critical because normal fast-charge termination is ensured only if this requirement is maintained (see
MAX712/MAX713
5) For linear-mode designs, calculate the worst-case power dissipation of the power PNP and diode (Q1 and D1 in the using the following formula:
PD load - minimum battery voltage) x (charge current in amps)
If the maximum power dissipation is not tolerable for your application, refer to the use a switch-mode design (see
= (maximum wall-cube voltage under
PNP
Operation
and see the MAX713 EV kit manual).
6) For both linear and switch-mode designs, limit cur­rent into V+ to between 5mA and 20mA. For a fixed or narrow-range input voltage, choose R1 in the
section for more details).
Typical Operating Circuit
in the
Applications Information
Typical Operation Circuit
R1 = (minimum wall-cube voltage - 5V) / 5mA
For designs requiring a large input voltage variation, choose the current-limiting diode D4 in Figure 19.
7) Choose R
8) Consult Tables 2 and 3 to set pin-straps before applying power. For example, to fast charge at a rate of C/2, set the timeout to between 1.5x or 2x the charge period, three or four hours, respectively.
using the following formula:
SENSE
RSENSE = 0.25V / (I
), and is equal to the
Powering the
) in watts,
Detailed Description
or
Switch-Mode
section,
using the following formula:
)
FAST
6 _______________________________________________________________________________________
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