Rainbow Electronics DS2712 User Manual
Loose Cell NiMH Chargers
DS2711/DS2712
www.maxim-ic.com
DESCRIPTION
The DS2711 and DS2712 are ideal for in-system or
stand-alone charging of 1 or 2 AA or AAA NiMH
“loose” cells. Temperature, voltage, and charge time
are monitored to provide proper fast charging control
algorithms for nickel metal hydride (NiMH) batteries.
Battery tests are included to detect defective or
inappropriate cells such as alkaline primary batteries.
The DS2711/DS2712 support series and parallel
topologies, with independent monitoring and control of
each cell. Charging of NiCd chemistry cells is also
supported.
FEATURES
§ Charge 1 or 2 NiMH Cells
§ Detect and Avoid Charging Alkaline Cells
§ Precharge Deeply Depleted Cells
§ Fast Charge NiMH with -DV Termination
Sensitivity of 2mV (typ)
§ Monitor Voltage, Temperature, and Time for
Safety and Secondary Termination
§ Regulate Charge Current:
Linear Control (DS2711)
Switch-Mode Control (DS2712)
§ Drive PMOS or PNP-Type Pass Element or
Switch, or an Optocoupler
§ Compatible with Popular Optocouplers and
Integrated Primary Side PWM Controllers
§ Small 16-Pin SO Package
APPLICATIONS
Desktop/Stand-Alone Chargers (AAA/AA)
Digital Still Cameras
Music Players
Games
Toys
PIN CONFIGURATION
CC1
CC2
LED1
VSS
LED2
CSOUT
VN1
VN0
See Table 1 for Ordering Information.
1
2
3
4
5
6
7
8
16 SOIC
16
15
14
13
12
11
10
VP2
VP1
THM2
THM1
VDD
TMR
CTST
9
DMSEL
PIN DESCRIPTION
PIN NAME FUNCTION
1 CC1 Cell 1 Charge-Control Output
2 CC2 Cell 2 Charge-Control Output
3 LED1 Cell 1 Status
4 VSS
5 LED2 Cell 2 Status, Mode-Select Input
6 CSOUT Current-Sense Output
7 VN1 Current-Sense + Input
8 VN0 Current-Sense - Input
9 DMSEL Display-Mode Select
10 CTST Cell Test Threshold Set
11 TMR Charge Timer Set
12 VDD Chip-Supply Input (4.0V to 5.5V)
13 THM1 Cell 1 Thermistor Input
14 THM2 Cell 2 Thermistor Input
15 VP1 Cell 1 Positive-Terminal Sense Input
16 VP2 Cell 2 Positive-Terminal Sense Input
Ground Reference and Chip-Supply
Return
Table 1. ORDERING INFORMATION
PART MARKING PIN-PACKAGE
DS2711Z
DS2711Z/T&R DS2711
DS2712Z
DS2712Z/T&R DS2712
DS2711
DS2712
16 SOIC
16 SOIC,
Tape-and-Reel
16 SOIC
16 SOIC,
Tape-and-Reel
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DS2711/DS2712: Loose Cell NiMH Charger
ABSOLUTE MAXIMUM RATINGS*
Voltage on All Pins Relative to VSS -0.3V to +6V
Voltage on DMSEL V
+ 0.3V
DD
Continuous Sink Current CC1, CC2, LED1, LED2 and CSOUT 20mA
Operating Temperature Range -40°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
(4.0V £ VDD £ 5.5V; TA = -20°C to +70°C.)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Supply Voltage VDD (Note 1) 4.0 5.5 V
Input Voltage Range LED2, DMSEL -0.3 +5.5 V
DC ELECTRICAL CHARACTERISTICS
(4.0V £ VDD £ 5.5V, TA = -20°C to +70°C, unless otherwise noted.)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Supply Current, VDD I
UVLO Threshold V
UVLO Hysteresis V
Output-Voltage Low,
CC1, CC2, LED1, LED2
Output-Voltage Low,
CSOUT
Leakage Current,
CC1, CC2, LED1, LED2,
CSOUT
Threshold Voltage,
-DV Termination
Mode Test Current,
DMSEL, LED2
Input Logic-High,
DMSEL, LED2
Input Logic-Low, DMSEL,
LED2
Input Leakage Current,
DMSEL
Threshold Voltage, Cell
Test
Threshold Voltage, Cell
Voltage Low
Threshold Voltage, Cell
Voltage Max1
Threshold Voltage, Cell
Voltage Max2
Threshold Voltage Delta V
Operating mode 250 500
DD
VDD rising (Note 1) 3.5 3.9 V
UVLO
V
UHYS
V
OL1
V
OL2
I
LKG
V
-DV
I
(Notes 2, 3) 5 15
MTST
V
(Note 1)
IH
V
(Note 1) 0.2 V
IL
DD
V
UVLO
V
DD
I
OL
V
DD
I
OL
V
DD
Output inactive
After t
After power-up mode
I
IL1
select,
DMSEL = V
V
CTST
V
BAT-LOW
V
BAT-MAX1
V
BAT-MAX2
BAT-MAX∆
R
CTST
CC1 = CC2 = high-Z
(Note 4)
CC1 = CC2 = high-Z
(Note 4)
CC1, CC2 active
(Note 4)
V
BAT-MAX2
(Note 5)
falling from above
= 5.0V,
= 20mA (Note 1)
= 5.0V,
= 20mA (Note 1)
= 5.0V,
1.0 2.0 3.0 mV
THO
40 mV
1.0 V
0.75 1.25 V
-1 +1
-
V
DD
0.2V
V
-1 +1
or VSS
DD
= 80kW
85 100 115 mV
0.9 1.0 1.1 V
1.55 1.65 1.75 V
1.64 1.75 1.86 V
- V
BAT-MAX1
90 100 110 mV
mA
mA
mA
mA
2 of 13
DS2711/DS2712: Loose Cell NiMH Charger
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Threshold Voltage,
Thermistor - Min
Threshold Voltage,
Thermistor - Max
Threshold Voltage,
Thermistor - Stop
Threshold Current, TMR
Pin Suspend
Presence Test Current,
VP1, VP2
Reverse Leakage
Current, VP1, VP2
V
THM-MIN
V
THM-MAX
V
THM-STOP
I
TMR-SUS
I
PTST
I
LKGR
(Notes 1, 4, 6)
(Notes 1, 4, 6) 0.30
(Notes 1, 4, 6)
0.1 0.5
Parallel: V
Series: V
= 0V, VP1 = 1.5V,
V
DD
VP2 = 3.0V
≥ 4.0V,
DD
≥ 4.5V
DD
10 15
2
V
DD
0.73
V
DD
0.33
V
DD
0.29
x
x
x
V
0.36 V
V
mA
mA
mA
Current-Sense Reference
Voltage
Gain, Current-Sense
Error Amp
Gain, Current-Sense
Comparator
Propagation Time,
Current-Sense
Comparator
Hysteresis, CurrentSense Comparator
V
(Note 1, 4, 7)
IREF
G
DS2711 (Note 8) 0.9 1.5
M
G
DS2712 (Note 8) 10
M
t
PDLY
V
HYS-COMP
DS2712, 2mV
over/underdrive
DS2712 22 24 26 mV
125 mV
-6% +6% %
-1
W
-1
W
0.25
ms
ELECTRICAL CHARACTERISTICS: TIMING
(4.0V £ VDD £ 5.5V, TA = -20°C to +70°C, unless otherwise noted.)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Internal Timebase Period t
Internal Timebase
Accuracy
Duty Factor, Series Fast
Charge
Duty Factor, Series
Precharge/Top-Off
Duty Factor, Parallel Fast
Charge
Duty Factor, Parallel
Precharge/Top-Off
Duty Factor, Maintenance
Charge
0.96 s
BASE
-10 +10 %
CC1 0.969
CC1 0.250
CC1, CC2 0.484
CC1, CC2 0.125
CC1, CC2 0.0156
Cell Test Interval t
Precharge Time-Out t
Fast-Charge Termination
Hold-Off Period
Fast-Charge Flat Voltage
Time-Out
Charge Timer Period t
Charge Timer Accuracy
Charge Timer Range t
31 s
CTST
V
PCHG
t
4 minutes
THO
t
V
FLAT
CTMR
CTMR-RANGE
< V
CELL
not increasing 16 minutes
CELL
R
= 100kW
TMR
= 100kW
R
TMR
34 minutes
BAT-MIN
0.5 10 h
3 of 13
1.0 h
-5 +5 %
Note 1:
Note 2:
Note 3:
Note 4:
Note 5:
Note 6:
Note 7:
Note 8:
Voltages relative to V
I
current is applied as a source current and as a sink current within 5ms after power-up.
MTST
When operating in two-cell-series charge configuration, the DMSEL pin must have less than 50pF of external load capacitance
for proper operation. If the load capacitance is greater than 50pF, a resistor voltage divider should be used to maintain DMSEL
at V
/ 2.
DD
Specification applicable during charge cycle with T
V
V
Tested with I
Gain tested with 1mV step with I
and V
BAT-MAX1
THM-MIN, VTHM-MAX,
CSOUT
.
SS
are generated from the same reference. Their ranges never overlap.
BAT-MAX1
and V
= -1mA.
are fixed ratios of V
THM-STOP
CSOUT
Figure 1. BLOCK DIAGRAM
= -1mA.
DS2711/DS2712: Loose Cell NiMH Charger
= 0°C to +70°C.
A
Their ranges never overlap.
DD.
VDD
CC1
CC2
LED1
LED2
DMSEL
CTST
TMR
3.7V
Cell
Test
Charge
Timer
Charge
Mod e
Sele ct
0.1V
BIAS
UVLO
Oscillator
State Machine
Presence Test
Pre-Charge
Fast Charge
Cell Tests
Top-Off Charge
Maintenance Charge
Watchdog
ABORT
I
PTST
I
PTST
VP1
Voltage
and
Temperature
Measurement
VP2
VN1
THM1
THM2
+
&
-
VN0
VSS
-
CSOUT
+
0.125V
DS2711
SUSPEND
4 of 13
+
DS2712
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