Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsPMICsPMIC - battery management Charge management NiCd, NiMH SOIC 16 Surface-mount

19-0100; Rev 7; 7/13

MAX712/MAX713

NiCd/NiMH Battery

Fast-Charge Controllers

EVALUATION KIT AVAILABLE

For pricing, delivery, and ordering information, please contact Maxim Direct

at 1-888-629-4642, or visit Maxim’s website at www.maximintegrated.com.

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 convert-

er, 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 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.

The evaluation kit is available: Order the MAX712EVKIT-

DIP for quick evaluation of the linear charger.

________________________Applications

Battery-Powered Equipment

Laptop, Notebook, and Palmtop Computers

Handy-Terminals

Cellular Phones

Portable Consumer Products

Portable Stereos

Cordless Phones

Features

o Fast-Charge NiMH or NiCd Batteries

o Voltage Slope, Temperature, and Timer

Fast-Charge Cutoff

o Charge 1 to 16 Series Cells

o Supply Battery’s Load While Charging

(Linear Mode)

o Fast Charge from C/4 to 4C Rate

o C/16 Trickle-Charge Rate

o Automatically Switch from Fast to Trickle Charge

o Linear Mode Power Control

o 5µA (max) Drain on Battery when Not Charging

o 5V Shunt Regulator Powers External Logic

MAX712

MAX713

THI

150Ω

68kΩ

22kΩ

10μF

0.01μF

1μF

10μF

0.01μF

DRV

2N6109

DC IN

WALL

CUBE

1N4001

BATTERY

SENSE

V+

VLIMIT

BATT+

REF

TEMP

BATT- TLO GNDCC

LOAD

Typical Operating Circuit

REF

V+

DRV

GND

BATT-

PGM3

PGM2

VLIMIT

BATT+

PGM0

PGM1

THI

TLO

TEMP

FASTCHG

TOP VIEW

MAX712

MAX713

DIP/SO

Pin Configuration

PART

MAX712CPE

MAX712CSE

MAX712C/D 0°C to +70°C

0°C to +70°C

TEMP RANGE PIN-PACKAGE

16 Plastic DIP

16 Narrow SO

Dice*

Ordering Information

Ordering Information continued at end of data sheet.

Contact factory for dice specifications.

Contact factory for availability and processing to MIL-STD-883.

MAX712EPE

MAX712ESE

MAX712MJE -55°C to +125°C

-40°C to +85°C

-40°C to +85°C 16 Plastic DIP

16 Narrow SO

16 CERDIP**

Summary of content (17 pages)

PAGE 1
EVALUATION KIT AVAILABLE MAX712/MAX713 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.
PAGE 2
MAX712/MAX713 NiCd/NiMH Battery Fast-Charge Controllers ABSOLUTE MAXIMUM RATINGS V+ to BATT- .................................................................-0.3V, +7V BATT- to GND ........................................................................±1V BATT+ to BATTPower Not Applied............................................................±20V With Power Applied ................................The higher of ±20V or ±2V x (programmed cells) DRV to GND ..................................................
PAGE 3
MAX712/MAX713 NiCd/NiMH Battery Fast-Charge Controllers ELECTRICAL CHARACTERISTICS (continued) (IV+ = 10mA, TA = TMIN to TMAX, unless otherwise noted. Refer to the Typical Operating Circuit. All measurements are with respect to BATT-, not GND.) PARAMETER CONDITIONS MIN FASTCHG Low Current V FASTCHG = 0.4V FASTCHG High Current V FASTCHG = 10V A/D Input Range (Note 4) Battery voltage ÷ number of cells programmed TYP MAX UNITS 2 mA 1.4 10 µA 1.
PAGE 4
MAX712/MAX713 NiCd/NiMH Battery Fast-Charge Controllers Typical Operating Characteristics (continued) (TA = +25°C, unless otherwise noted.) MAX713 NiCd BATTERY CHARGING CHARACTERISTICS AT C RATE MAX713 NiMH BATTERY CHARGING CHARACTERISTICS AT C RATE MAX712/13 toc06 30 25 1.40 30 60 30 1.50 T 25 1.45 90 0 30 60 CHARGE TIME (MINUTES) MAX713 NiCd BATTERY-CHARGING CHARACTERISTICS AT C/2 RATE MAX713 NiMH BATTERY CHARGING CHARACTERISTICS AT C/2 RATE MAX712/13 toc09 V 30 T 25 1.
PAGE 5
MAX712/MAX713 NiCd/NiMH Battery Fast-Charge Controllers Pin Description PIN NAME FUNCTION 1 VLIMIT 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. Connect VLIMIT to VREF for normal operation. Alternatively, connect VLIMIT to V+ to set the maximum cell voltage to an internally preset 1.65V/cell.
PAGE 6
MAX712/MAX713 NiCd/NiMH Battery Fast-Charge Controllers Getting Started The MAX712/MAX713 are simple to use. A complete linear-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. 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.
PAGE 7
MAX712/MAX713 NiCd/NiMH Battery Fast-Charge Controllers Table 2. Programming the Number of Cells NUMBER OF CELLS Table 3.
PAGE 8
MAX712/MAX713 NiCd/NiMH Battery Fast-Charge Controllers Detailed Description CURRENT INTO CELL 1.5 1.4 CELL TEMPERATURE CELL VOLTAGE (V) The MAX712/MAX713 fast charge NiMH or NiCd batteries 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.
PAGE 9
MAX712/MAX713 NiCd/NiMH Battery Fast-Charge Controllers The 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 current flow into the battery and switch to fast-charge state.
PAGE 10
MAX712/MAX713 NiCd/NiMH Battery Fast-Charge Controllers charge until one of the three fast-charge terminating conditions is triggered. If DC IN exceeds 20V, add a cascode connection in series with the DRV pin as shown in Figure 5 to prevent exceeding DRV’s absolute maximum ratings. Select the current-limiting component (R1 or D4) to pass at least 5mA at the minimum DC IN voltage (see step 6 in the Getting Started section). The maximum current into V+ determines power dissipation in the MAX712/MAX713.
PAGE 11
MAX712/MAX713 NiCd/NiMH Battery Fast-Charge Controllers Table 5.
PAGE 12
MAX712/MAX713 NiCd/NiMH Battery Fast-Charge Controllers COUT (in farads) = (50 x ILOAD)/(VOUT x BWVRL) where BWVRL = loop bandwidth in Hz (10,000 recommended) COUT > 10µF ILOAD = external load current in amps VOUT = programmed output voltage (VLIMIT x number of cells) Current Loop Figure 6 shows the current-regulation loop for a linearmode circuit. To ensure loop stability, make sure that the bandwidth of the current regulation loop (BWCRL) is lower than the pole frequency of transistor Q1 (fB).
PAGE 13
MAX712/MAX713 NiCd/NiMH Battery Fast-Charge Controllers IN THERMAL CONTACT WITH BATTERY REF R3 THI T1 HOT R4 0.022μF TEMP +2.0V __________Applications Information AMBIENT TEMPERATURE Battery-Charging Examples R5 COLD T2 TLO MAX712 MAX713 Some battery packs come with a temperature-detecting thermistor connected to the battery pack’s negative terminal. In this case, use the configuration shown in Figure 9b.
PAGE 14
MAX712/MAX713 NiCd/NiMH Battery Fast-Charge Controllers Linear-Mode, High Series Cell Count The absolute maximum voltage rating for the BATT+ pin is higher when the MAX712/MAX713 are powered on. If more than 11 cells are used in the battery, the BATT+ input voltage must be limited by external circuitry when DC IN is not applied (Figure 15). Efficiency During Discharge The current-sense resistor, RSENSE, causes a small efficiency loss during battery use.
PAGE 15
MAX712/MAX713 NiCd/NiMH Battery Fast-Charge Controllers Q1 D1 DC IN TO BATTERY POSITIVE TERMINAL R2 150Ω OV = NO POWER 5V = POWER V+ 33kΩ MAX712 MAX713 Q2 VCC 10kΩ 500Ω OV = FAST VCC = TRICKLE OR NO POWER FASTCHG DRV BATT+ MAX712 MAX713 Figure 15. Cascoding to Accommodate High Cell Counts for Linear-Mode Circuits Figure 17. Logic-Level Status Outputs DC IN D1 R1 >4 CELLS MAX712 MAX713 CHARGE POWER 100kΩ V+ * 100kΩ RSENSE V+ * LOW RON LOGIC LEVEL N-CHANNEL POWER MOSFET GND Figure 16.
PAGE 16
MAX712/MAX713 NiCd/NiMH Battery Fast-Charge Controllers Ordering Information (continued) PART TEMP RANGE ___________________Chip Topography PIN-PACKAGE BATT+ MAX713CPE 0°C to +70°C 16 Plastic DIP MAX713CSE MAX713C/D MAX713EPE 0°C to +70°C 0°C to +70°C -40°C to +85°C 16 Narrow SO Dice* 16 Plastic DIP PGM0 MAX713ESE MAX713MJE -40°C to +85°C -55°C to +125°C 16 Narrow SO 16 CERDIP** PGM1 VLIMIT REF DRV *Contact factory for dice specifications.
PAGE 17
MAX712/MAX713 NiCd/NiMH Battery Fast-Charge Controllers Revision History REVISION NUMBER REVISION DATE 6 12/08 7 7/13 DESCRIPTION Removed switch mode power control and added missing package information Updated information on the VLIMIT pin PAGES CHANGED 1, 5, 6, 9, 10, 12, 13, 14, 16, 17 5, 11 Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses are implied.