Rainbow Electronics DS2715 User Manual

NiMH Battery Pack Charge Controlle

DS2715

www.maxim-ic.com

DESCRIPTION

The DS2715 is well suited for cost-sensitive charger applications where the battery is either internal or in a unique battery pack. It has been optimized for safe reliable charging of 1 to10 NiMH cells in series. The DS2715 has an internal gain block that can be selected as either a comparator or transconductance amplifier for charge current regulation. The DS2715 is configurable as a switched DC charger, a linear current regulator, or a switchmode current source. The DS2715 pre-conditions severely depleted cells are pre-conditioned before entering full charge mode. The DS2715 terminates full charge using the dT/dt technique. It requires an external thermistor for dT/dt detection. Over-temperature, under-temperature, and over-voltage detection prevents charging under unsafe environmental conditions. A user selectable charge timer allows charge rates from 0.15C to 2C. Fast-charge, top-off and charge done modes are included for highly reliable, safe charging of NiMH cells. Discharge mode allows the DS2715 to enter a

PIN CONFIGURATION

CC1

CC2

LED1

VSS

LED2

CSOUT

CTG

VN1

CTG

VN0

See Table 1 for Ordering Information.

Table 1.

BIAS

BATT

VP2

THM

VP1

THM2

THM1

SNS-

VDD

SNS+

TMR

DIV

CTST

MODE

DMSEL

16 SO

ORDERING INFORMATION

low power sleep state while the cell pack is being discharged.

FEATURES

§ Charges 1 to 10 NiMH Cells

§ Fast Charges up to a 2C Rate

§ Pre-Charge and Top-Off Charge Modes Help Cell

Conditioning

§ Load Detection Allows the DS2715 to Enter Low

Power Sleep Mode (Less than 10µA) while the Cell Pack is Discharged

PART MARKING PIN-PACKAGE

DS2715Z+

DS2715+

16 SO

DS2715Z+T&R DS2715+ 16 SO Tape-and-Reel

+ Denotes lead-free package.

OPERATIONAL DIAGRAM

CHARGE

SOURCE/LOAD

§ dT/dt Charge Termination Eliminates Cell Charge

Stress

§ Monitors Voltage, Temperature, and Time for

Safety and Secondary Termination

§ Regulates Current through Either Linear Control

or Switch-Mode Control

Vdd

Vch

DS2715

Vbatt

THM

Divide by n

n Cells

§ LED Outputs Display Charge State

§ Small 16-Pin SO Package

GROUND

Sense

APPLICATIONS

Portable DVD Players Portable Television Sets Handheld Gaming Test Equipment Handheld POS Terminals

Note: Some revisions of this device may incorporate deviations from published specifications known as errata. Multiple revisions of any device may be simultaneously available through various sales channels. For information about device errata, click here: www.maxim-ic.com/errata.

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DS2715: NiMH Cell Pack Charge Controller

ABSOLUTE MAXIMUM RATINGS*

Voltage on VDD and VCH Pins with Respect to VSS -0.3V to +18V Voltage on LED1 and LED2 Pins -0.3V to +18V Voltage on SNS- -0.3V to +0.3V Voltage on C Voltage on all Other Pins -0.3V to V

-0.3V to 6V

BIAS

Cbias

Continuous Sink Current VCH, LED1, and LED2 28mA Operating Temperature Range -20°C to +85°C Storage Temperature Range -55°C to +125°C Soldering Temperature See IPC/JEDECJ-STD-020

*This is a stress rating only and functional operation of the device at these or any other conditions above those indicated in the operation sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods of time may affect reliability.

RECOMMENDED DC OPERATING CONDITIONS

(4.5V £ VDD £ 16.5V; TA = 0°C to +70°C.)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Supply Voltage VDD (Note 1) 4.5 16.5 V

LED1, LED2 Voltage V

Mode Voltage V

VCH Voltage V

Capacitor Range C

BIAS

(Note 1) 0.0 16.5 V

LED

(Note 1) 0.0 V

MODE

(Note 1) 0.0 16.5 V

VCH

.02 .15 µF

Cbias

RT Resistor Range RRt 20 240 KΩ

DC ELECTRICAL CHARACTERISTICS

(4.5V £ VDD £ 16.5V, TA = 0°C to +70°C, unless otherwise noted.)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Operating Current (Note 2)

Idle Current I

Discharge Current I

UVLO Threshold V

UVLO Hysteresis V

VCH Sink Current I

LED1, LED2 Sink Current I

Leakage Current, VCH, LED1, LED2 THM Pin Leakage Current V

Pin Leakage

BATT

Current

Linear Mode, V

DDA

DDS

DDD

UVLO

UVLO-HYS

OL-Vch

OL-LED

LKG

LKG-THM

LKG-Vbatt

Comparator Mode, V

= 16.5V

VDD < V

UVLO

Discharge latch set (Note 2) 200 µA

VDD Rising (Note 3) 3.8 3.9 4.0 V

VDD Falling 35 mV

VOL = 1.5V 20 mA

VOL = 1.0V 20 mA

Pin inactive or Device Idle -1 +1 µA

-1 +1 µA

-50 +50 nA

= 16.5V 1.3 1.6 mA

150 250 µA

10 µA

Voltage V

BIAS

DIV Pin Load Current I

Current Sense Amplifier Gain Current Sense Comparator Gain

0 < I

Cbias

500 uA

Div

100µA < I

ERR

(Note 7) 10 Ω

COMP

< 0.4ma 3.9 4.0 4.3 V

Cbias

< 20mA 5 6.25 7.5 Ω

Vch

-1

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DS2715: NiMH Cell Pack Charge Controller

AC ELECTRICAL CHARACTERISTICS

(4.5V £ VDD £ 16.5V, TA = 0°C to +70°C, unless otherwise noted.)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

UVLO Debounce Time t

10 µs

UVLO

Current Sense Comparator Propagation

(Note 7) 250 ns

COMP

Delay

Discharge Detect Propagation Delay

Return To Normal Function (Op-Amp or Comparator Mode)

RNF

From detection of current reversal

Time from reset of discharge latch

1 µs

RT Timing Accuracy tRt (Note 4) -10 +10 %

Internal Clock Accuracy t

-10 +10 %

BASE

ELECTRICAL CHARACTERISTICS: CHARGING

(4.5V £ VDD £ 16.5V, TA = 0°C to +70°C, unless otherwise noted.)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Fast Charge Comparator Threshold Fast Charge Comparator Hysteresis Top-off and Pre-Charge Comparator Threshold Top-off and Pre-Charge Comparator Hysteresis Discharge Latch Reset Threshold Discharge Latch Set Threshold Low Battery Detect Threshold

Fast charge -127 -121 -115 mV

Fast charge -31 -28 -25 mV

HYS-FC

Top-off and pre-charge -38 -33 -28 mV

Top-off and pre-charge -10 -8 -6 mV

HYS-TO

DCHG-RST

DCHG-SET

-15 -10 -5 mV

Reverse current through sense resistor

From presence detect into pre-charge

5 10 15 mV

0.95 1.0 1.05 V

Cell Detect Threshold V

No Cell Detect Threshold V

Presence Detect Threshold Hysteresis

Minimum Charge Temp V

Maximum Charge Temp V

Over Temp V

dT/dt Detect T

dT/dt Blanking Time t

Fast Charge Timer Range Top-Off to Fast Charge Duration Ratio

1.50 1.55 1.60 V

DET

1.60 1.65 1.70 V

OPEN

90 100 110 mV

HYS-PD

(Note 5, 6)

THM-MIN

THM-MAX

THM-STOP

(Note 5, 6)

0.425 0.5 0.575 ºC/min

TERM

3.85 4.3 4.75 Min

BLANK

0.5 6 Hours

1:2

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2.88 2.92 2.96 V 0 ºC

1.28 1.32 1.36 V 45 ºC

1.12 1.16 1.20 V 50 ºC

DS2715: NiMH Cell Pack Charge Controller

Note 1: Note 2: Note 3: Note 4: Note 5: Note 6: Note 7:

Voltages relative to V Does not include current through V Below this voltage no I/O pins are active. Does not include tolerance of R V

and resistor tolerances must be added to determine actual threshold.

BIAS

Specified temperature thresholds are only valid if recommended thermistor types are used. Specification is guaranteed by design.

, RT, and DIV pins.

resistor.

DETAILED PIN DESCRIPTION

PIN NAME DESCRIPTION

1 C 2 VCH Cell Stack Charge Control Output 3 VSS Ground Reference and Chip Supply Return 4 LED1 Charging Indicator Output 5 LED2 Done Indicator Output 6 VSS Ground Reference and Chip Supply Return 7 CTG Connect to Ground 8 CTG Connect to Ground

9 MODE

10 DIV

11 SNS+ Positive Current Sense. Connect to the pack side of the sense resistor. 12 SNS- Negative Current Sense. Connect to the cell stack side of the sense resistor. 13 VDD Chip Supply Input: +4.0V to +5.5V range. 14 RT Failsafe Timeout. Timeout is selected by an external resistor from RT to VSS.

15 THM

16 V

Bypass for Internal Voltage Regulator

BIAS

Mode Select. Connect to V

for linear mode of operation or C

mode of operation. Thermistor Divider. Stable output to form a resistor divider for measuring temperature on THM.

Thermistor Input. Connect to a thermistor located in the cell pack and a divider resistor from the Div pin. Battery Voltage Sense Input. Connect to a divider from the positive terminal of the

BATT

cell stack to measure the voltage of a single cell.

for comparator

BIAS

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