MAX712ESE ,NiCd/NiMH Battery Fast-Charge ControllersApplications*Contact factory for dice specifications.**Contact factory for availability and process ..
MAX712ESE+ ,NiCd/NiMH Battery Fast-Charge ControllersFeaturesThe MAX712/MAX713 fast-charge Nickel Metal Hydride ♦ Fast-Charge NiMH or NiCd Batteries(NiM ..
MAX712ESE+T ,NiCd/NiMH Battery Fast-Charge ControllersELECTRICAL CHARACTERISTICS(I = 10mA, T = T to T , unless otherwise noted. Refer to the Typical Oper ..
MAX712ESE+T ,NiCd/NiMH Battery Fast-Charge ControllersELECTRICAL CHARACTERISTICS(I = 10mA, T = T to T , unless otherwise noted. Refer to the Typical Oper ..
MAX713CPE ,NiCd/NiMH Battery Fast-Charge ControllersELECTRICAL CHARACTERISTICS(I = 10mA, T = T to T , unless otherwise noted. Refer to Typical Operatin ..
MAX713CPE ,NiCd/NiMH Battery Fast-Charge ControllersFeaturesThe MAX712/MAX713 fast charge Nickel Metal Hydride ' Fast Charge NiMH or NiCd Batteries(NiM ..
MB47358 ,DUAL OPERATIONAL AMPLIFIERFUJITSU SEMICONDUCTORDS04-11104-3EDATA SHEETLINEAR ICDUAL OPERATIONAL AMPLIFIERMB47358DUAL OPERATIO ..
MB47393 ,DUAL COMPARATORFUJITSU SEMICONDUCTORDS04-12103-4EDATA SHEETASSPDUAL COMPARATORMB47393n DESCRIPTIONThe Fujitsu MB47 ..
MB47393P ,Dual comparatorFUJITSU SEMICONDUCTORDS04-12103-4EDATA SHEETASSPDUAL COMPARATORMB47393n DESCRIPTIONThe Fujitsu MB47 ..
MB47393P ,Dual comparatorFUJITSU SEMICONDUCTORDS04-12103-4EDATA SHEETASSPDUAL COMPARATORMB47393n DESCRIPTIONThe Fujitsu MB47 ..
MB47393PF ,Dual comparatorFUJITSU SEMICONDUCTORDS04-12103-4EDATA SHEETASSPDUAL COMPARATORMB47393n DESCRIPTIONThe Fujitsu MB47 ..
MB4752A ,SUBSCRIBER LINE INTERFACE IC" mm;
gr T$544-A874
'j?itl,'l,lllill,ililill MB4752A April 1987
'llllllllllllllllllllllllill ..
MAX712CPE-MAX712CSE-MAX712EPE-MAX712ESE
NiCd/NiMH Battery Fast-Charge Controllers
_______________General DescriptionThe 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 convert-
er, timer, and temperature window comparatordetermine
charge completion. The MAX712/MAX713 are powered
by the DC source via an on-board +5V shunt regulator.
They draw a maximum of 5mA 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 16-
pin DIP and SO packages. An external power PNP tran-
sistor, 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 MAX713EVKIT-
SO to evaluate the switch-mode charger.
________________________ApplicationsBattery-Powered Equipment
Laptop, Notebook, and Palmtop Computers
Handy-Terminals
Cellular Phones
Portable Consumer Products
Portable Stereos
Cordless Phones
____________________________FeaturesFast Charge NiMH or NiCd BatteriesVoltage Slope, Temperature, and Timer
Fast-Charge CutoffCharge 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
MAX712/MAX713
NiCd/NiMH Battery
Fast-Charge Controllers
__________Typical Operating Circuit
__________________Pin Configuration
MAX712/MAX713
NiCd/NiMH Battery
Fast-Charge Controllers
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS(IV+= 10mA, TA= TMINto TMAX, unless otherwise noted. Refer to Typical Operating Circuit. All measurements are with respect to
BATT-, not GND.)
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.
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
±2V x (programmed cells)
DRV to GND..............................................................-0.3V, +20V
FASTCHGto BATT-...................................................-0.3V, +12V
All Other Pins to GND......................................-0.3V, (V+ + 0.3V)
V+ Current.........................................................................100mA
DRV Current......................................................................100mA
REF Current.........................................................................10mA
Continuous Power Dissipation (TA= +70°C)
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
ELECTRICAL CHARACTERISTICS (continued)(IV+ = 10mA, TA= TMINto TMAX, unless otherwise noted. Refer to Typical Operating Circuit. All measurements are with respect to
BATT-, not GND.)
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:tAis the A/D sampling interval (Table 3).
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.
MAX712/MAX713
NiCd/NiMH Battery
Fast-Charge Controllers
__________________________________________Typical Operating Characteristics(TA = +25°C, unless otherwise noted.)100k1M10k10M
CURRENT-SENSE AMPLIFIER
FREQUENCY RESPONSE (with 15pF)FREQUENCY (Hz)
GAIN (dB)
PHASE (DEGREES)
MAX712/13 LOG1
-20101k
CURRENT-SENSE AMPLIFIER
FREQUENCY RESPONSE (with 10nF)FREQUENCY (Hz)
GAIN (dB)
PHASE (DEGREES)
10010k
MAX712/13 LOG2
CURRENT ERROR-AMPLIFIER
TRANSCONDUCTANCE
VOLTAGE ON CC PIN (V)
DRV PIN SINK CURRENT(mA)
MAX712/13 LOG3
SHUNT-REGULATOR VOLTAGE
vs. CURRENT
CURRENT INTO V+ PIN (mA)
V+ VOLTAGE (V)
MAX712/13 LOG4
ALPHA THERMISTOR PART No. 13A1002
STEINHART-HART INTERPOLATION
BATTERY TEMPERATURE(°C)
TEMP PIN VOLTAGE (V)
BATTERY THERMISTOR RESISTANCE (k
0.8
MAX712/MAX713
NiCd/NiMH Battery
Fast-Charge Controllers
____________________________Typical Operating Characteristics (continued)(TA = +25°C, unless otherwise noted.)
MAX713
NiMH BATTERY-CHARGING
CHARACTERISTICS AT C RATE
CHARGE TIME (MINUTES)
CELL VOLTAGE (V)
CELL TEMPERATURE (
MAX712/713
MAX713
NiCd BATTERY-CHARGING
CHARACTERISTICS AT C/2 RATE
CHARGE TIME (MINUTES)
CELL VOLTAGE (V)
CELL TEMPERATURE (
MAX712/713
MAX713
NiMH BATTERY-CHARGING
CHARACTERISTICS AT C/2 RATE
CHARGE TIME (MINUTES)
CELL VOLTAGE (V)
CELL TEMPERATURE (
MAX712/713
MAX713
CHARGING CHARACTERISTICS OF A
FULLY CHARGED NiMH BATTERY
CHARGE TIME (MINUTES)
CELL VOLTAGE (V)
CELL TEMPERATURE (
°C)
MAX712/713
MAX713
CHARGING CHARACTERISTICS OF A
FULLY CHARGED NiMH BATTERY
CHARGE TIME (MINUTES)
CELL VOLTAGE (V)
CELL TEMPERATURE (
°C)
MAX712/713
MAX713
NiCd BATTERY-CHARGING
CHARACTERISTICS AT C RATE
CHARGE TIME (MINUTES)
CELL VOLTAGE (V)
CELL TEMPERATURE (
MAX712/713
1.509060
MAX712/MAX713
NiCd/NiMH Battery
Fast-Charge Controllers
______________________________________________________________Pin Description
MAX712/MAX713
NiCd/NiMH Battery
Fast-Charge Controllers
____________________Getting StartedThe 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 neces-
sary if lower heat dissipation is desired. 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. Decide on a charge rate (Tables 3 and 5). The slow-
est 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:
IFAST= (capacity of battery in mAh)–––––––––––––––––––––––––(charge time in hours)
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 power-
conversion efficiency of the MAX712/MAX713. Decide on the number of cells to be charged (Table 2).
If your battery stack exceeds 11 cells, see the Linear-
Mode High Series Cell Countsection. Whenever
changing the number of cells to be charged, PGM0
and PGM1 must be adjusted accordingly. Attempting
to charge more or fewer cells than the number pro-
grammed can disable the voltage-slope fast-charge
termination circuitry. The internal ADC’s input volt-
age range is limited to between 1.4V and 1.9V (see
the Electrical Characteristics), and is equal to 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 cir-
cuitry can be disabled. 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 Powering the
MAX712/MAX713 section for more details). For linear-mode designs, calculate the worst-case
power dissipation of the power PNP and diode (Q1
and D1 in the Typical Operating Circuit) in watts,
using the following formula:
PDPNP= (maximum wall-cube voltage under
load - minimum battery voltage) x (charge current
in amps)
If the maximum power dissipation is not tolerable for
your application, refer to the Detailed Descriptionor
use a switch-mode design (see Switch-Mode
Operationin the Applications Informationsection,
and see the MAX713 EV kit manual). For both linear and switch-mode designs, limit cur-
rent into V+ to between 5mA and 20mA. For a fixed
or narrow-range input voltage, choose R1 in the
Typical Operation Circuitusing the following formula:
R1 = (minimum wall-cube voltage - 5V) / 5mA
For designs requiring a large input voltage variation,
choose the current-limiting diode D4 in Figure 19. Choose RSENSEusing the following formula:
RSENSE = 0.25V / (IFAST)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.
MAX712/MAX713
NiCd/NiMH Battery
Fast-Charge Controllers
Table 2. Programming the Number
of Cells
Table 3. Programming the Maximum
Charge TimeFigure 1. Block Diagram
MAX712/MAX713
NiCd/NiMH Battery
Fast-Charge Controllers
_______________Detailed DescriptionThe MAX712/MAX713 fast charge NiMH or NiCd batter-
ies by forcing a constant current into the battery. The
MAX712/MAX713 are always in one of two states: fast
charge or trickle charge. During fast charge, the
current level is high; once full charge is detected, the
current reduces to trickle charge. The device monitors
three variables to determine when the battery reaches
full charge: voltage slope, battery temperature, and
charge time.
Figure 1 shows the block diagram for the MAX712/
MAX713. The timer, voltage-slope detection, and temper-
ature comparators are used to determine full charge
state. The voltage and current regulator controls output
voltage and current, and senses battery presence.
Figure 2 shows a typical charging scenario with batteries
already inserted before power is applied. At time 1, the
MAX712/MAX713 draw negligible power from the bat-
tery. When power is applied to DC IN (time 2), the
power-on reset circuit (see the POWER_ON_RESETsig-
nal in Figure 1) holds the MAX712/MAX713 in trickle
charge. Once POWER-_ON-_RESETgoes high, the device
enters the fast-charge state (time 3) as long as the cell
voltage is above the undervoltage lockout (UVLO) volt-
age (0.4V per cell). Fast charging cannot start until (bat-
tery voltage) / (number of cells) exceeds 0.4V.
When the cell voltage slope becomes negative, fast
charge is terminated and the MAX712/MAX713 revert
to trickle-charge state (time 4). When power is removed
(time 5), the device draws negligible current from the
battery.
Figure 3 shows a typical charging event using tempera-
ture full-charge detection. In the case shown, the bat-
tery pack is too cold for fast charging (for instance,
brought in from a cold outside environment). During
time 2, the MAX712/MAX713 remain in trickle-charge
state. Once a safe temperature is reached (time 3), fast
charge starts. When the battery temperature exceeds
the limit set by THI, the MAX712/MAX713 revert to trick-
le charge (time 4).
MAX712/MAX713
NiCd/NiMH Battery
Fast-Charge ControllersThe MAX712/MAX713 can be configured so that voltage
slope and/or battery temperature detects full charge.
Figure 4 shows a charging event in which a battery is
inserted into an already powered-up MAX712/MAX713.
During time 1, the charger’s output voltage is regulated
at the number of cells times VLIMIT. Upon insertion of
the battery (time 2), the MAX712/MAX713 detect cur-
rent flow into the battery and switch to fast-charge
state. Once full charge is detected, the device reverts
to trickle charge (time 3). If the battery is removed (time
4), the MAX712/MAX713 remain in trickle charge and
the output voltage is once again regulated as in time 1.
Powering the MAX712/MAX713AC-to-DC wall-cube adapters typically consist of a trans-
former, a full-wave bridge rectifier, and a capacitor.
Figures 10–12 show the characteristics of three con-
sumer product wall cubes. All three exhibit substantial
120Hz output voltage ripple. When choosing an adapter
for use with the MAX712/MAX713, make sure the lowest
wall-cube voltage level during fast charge and full load is
at least 1.5V higher (2V for switch mode) than the maxi-
mum battery voltage while being fast charged. Typically,
the voltage on the battery pack is higher during a fast-
charge cycle than while in trickle charge or while supply-
ing a load. The voltage across some battery packs may
approach 1.9V/cell.
Table 4. MAX712/MAX713 Charge-State Transition Table††Only two states exist: fast charge and trickle charge.
*Regardless of the status of the other logic lines, a timeout or a voltage-slope detection will set trickle charge.
**If the battery is cold at power-up, the first rising edge on COLD will trigger fast charge; however, a second rising edge will
have no effect.
***Batteries that are too hot when inserted (or when circuit is powered up) will not enter fast charge until they cool and power is recycled.
