2003-2013 Microchip Technology Inc. DS21823D-page 1
MCP73841/2/3/4
Features
Linear Charge Management Controllers
High-Accuracy Preset Voltage Regulation:
-+
0.5% (max)
Four Preset Voltage Regulation Options:
- 4.1V - MCP73841-4.1, MCP73843-4.1
- 4.2V - MCP73841-4.2, MCP73843-4.2
- 8.2V - MCP73842-8.2, MCP73844-8.2
- 8.4V - MCP73842-8.4, MCP73844-8.4
Programmable Charge Current
Programmable Safety Charge Timers
Preconditioning of Deeply Depleted Cells
Automatic End-of-Charge Control
Optional Continuous Cell Temperature
Monitoring (MCP73841 and MCP73842)
Charge Status Output for Direct LED Drive
Automatic Power-Down when Input Power
Removed
Temperature Range: -40°C to 85°C
Packaging: MSOP-10 - MCP73841, MCP73842
MSOP-8 - MCP73843, MCP73844
Applications
Lithium-Ion/Lithium-Polymer Battery Chargers
Per sonal Data Assistants
Cellu lar Telephon es
Hand-Held Instruments
Cradle Chargers
•Digital Cameras
MP3 Players
Typical Application Circui t
Description
The MCP7384X family of devices are highly advanced
linear charge management controllers for use in
space-limited, cost-sensitive applications. The
MCP73841 and MCP73842 combine high accuracy,
constant-volt age, constant-current regulation, cell pre-
conditioning, cell temperature monitoring, advanced
safety timers, automatic charge termination and
charge status indication in space-saving, 10-pin
MSOP packages. The MCP73841 and MCP73842
provide complete, fully-functional, stand-alone charge
management solutions.
The MCP73843 and MCP73844 employ all the
features of the MCP73841 and MCP73842, with the
exception of the cell temperature monitor. The
MCP73843 and MCP73 844 are of fe red in 8-pin MSOP
packages.
The MCP73841 and MCP73843 are designed for
applications utilizing single-cell Lithium-Ion or Lithium-
Polymer battery packs. Two preset voltage regulation
options are available (4.1V and 4.2V) f or use with either
coke or graphite anodes. The MCP73841 and
MCP738 43 operate wi th an input volt age range of 4.5V
to 12V.
The MCP73842 and MCP73844 are designed for
applications utilizing dual series cell Lithium-Ion or
Lithium-Polymer battery packs. Two preset voltage
regulation options are available (8.2V and 8.4V). The
MCP73842 and MCP73844 operate with an input
voltage range of 8.7V to 12V.
The MCP7384X family of devices are fully specified
over the amb ient temperature rang e of -40°C to +8 5°C.
Package Types
+
-
VSS
DRV
SENSE
VDD VBAT
STAT1
36
7
1
2
MCP73843
8
10 µF
10 µF
100 k
100 m
5V Single
Lithium-Ion
Cell
NDS8434
MA2Q705
1A Lithium-Ion Battery Charger
EN 5
TIMER
40.1 µF
10-Pin MSOP
SENSE
VDD
STAT1
EN
DRV
VBAT
VSS
TIMER
1
2
3
4
8
7
6
5
MCP73843
MCP73844
8-Pin MSOP
VDD
STAT1
EN
THREF
VBAT
VSS
TIMER
THERM
2
3
4
5
9
8
7
6
MCP73841
MCP73842
SENSE DRV
110
Advanced Single or Dual Cell Lithium-Ion/
Lithium-Polymer Charge Management Controllers
MCP73841/2/3/4
DS21823D-page 2 2003-2013 Microchip Technology Inc.
Functional Block Diagram
Charge
Termination
Comparator
Voltage Control
Amplifier
VREF
IREG/10 Precondition
Control Charge_ok
Precon
VDD
Charge Current
Control Amplifier
+
VREF
VREF
Precondition
Comp.
VBAT
VSS
DRV
90 k
90 k
10 k
10 k
+
Charge
Current
Amplifier
VDD
SENSE
MCP 73841 and MCP73842 Only
300 k
(825 k)
12 k
1k
UVLO
Comparator
VUVLO
Temperature
Comparators
Bias and
Reference
Generator
VUVLO
VREF (1.2V)
Power-On
Delay VREF
Oscillator
Constant-Voltage/
Recharge Comp.
Charge Control,
Charge Timers,
And
Status Logic
Drv Stat 1
Charge_ok
IREG/10
THERM
EN
TIMER
STAT1
THREF
100 k
50 k
50 k
74.21 k
0.79 k
150.02 k
5.15 k
(4.29 k)
+
-
+
-
+
-
+
-
+
-
+
-
+
-
2003-2013 Microchip Technology Inc. DS21823D-page 3
MCP73841/2/3/4
1.0 ELECTRICAL
CHARACTERISTICS
Absolute Maximum Ratings
VDD.................................................................................13.5V
All inputs and outputs w.r.t. VSS ................ -0.3 to (VDD+0.3)V
Current at DRV Pin ......................................................±4 mA
Current at STAT1 Pin .................................................±30 mA
Maximum Junction Temperature, TJ.............................150°C
Storage temperature ............... .. .. .. ....... .. .. .... .-65°C to +150°C
ESD protection on all pins:
Human Body Model (1.5 k in Series with 100 pF)2kV
Machine Model (200 pF, No Series Resistance).............200V
*Notice: Stresses above those listed under “Maximum
Ratings” may cause permanent damage to the device. This is
a stress rating only and functional operation of the device at
those or any other conditions above those indicated in the
operational listings of this specification is not implied. Expo-
sure to max imum rati ng conditions for extended periods may
affect device reliability.
DC CHARACTERISTICS
Electrical Specifications: Unless otherwise indicated, all limits apply for VDD= [VREG(Typ)+0.3V] to 12V, TA = -40°C to +85°C.
Typical values are at +25°C, VDD = [VREG(Typ) + 1V].
Parameters Sym Min Typ Max Units Conditions
Supply Input
Supply Voltage VDD
MCP73841, MCP73843 4.5 12 V
MCP73842, MCP73844 8.7 12 V
Supply Current ISS
0.25
0.75 4
4µA
mA Disabled
Operating
VDD =VREG(Typ)+1V
UVLO Start Threshold VSTART
MCP73841, MCP73843 4.25 4.45 4.60 V VDD Low-to-High
MCP73842, MCP73844 8.45 8.65 8.90 V VDD Low-to-High
UVLO Stop Threshold VSTOP
MCP73841, MCP73843 4.20 4.40 4.55 V VDD High-to-Low
MCP73842, MCP73844 8.40 8.60 8.85 V VDD High-to-Low
Voltage Regulation (Constant-Voltage Mode)
Regulated Output Voltage VREG
MCP73841-4.1,
MCP73843-4.1 4.079 4.1 4.121 V VDD = [VREG(T yp)+1V], IOUT = 10 mA,
TA = -5°C to +55°C
MCP73841-4.2,
MCP73843-4.2 4.179 4.2 4.221 V VDD = [VREG(T yp)+1V], IOUT = 10 mA,
TA = -5°C to +55°C
MCP73842-8.2,
MCP73844-8.2 8.159 8.2 8.241 V VDD = [VREG(T yp)+1V], IOUT = 10 mA,
TA = -5°C to +55°C
MCP73842-8.4,
MCP73844-8.4 8.358 8.4 8.442 V VDD = [VREG(T yp)+1V], IOUT = 10 mA,
TA = -5°C to +55°C
Line Regulation VBAT/
VBAT)|/VDD
0.025 0.25 %/V VDD = [VREG(Typ)+1V] to 12V,
IOUT = 10 mA
Load Regulation VBAT|/VBAT 0.01 0.25 % IOUT = 10 mA to 150 mA,
VDD = [VREG(Typ)+1V]
Supply Ripple Attenuation PSRR -58 dB IOUT = 10 mA, 100 Hz
–-42– dBI
OUT = 10 mA, 1 kHz
–-30– dBI
OUT = 10 mA, 10 kHz
Output Reverse Leakage
Current IDISCHARGE –0.41 µAV
DD Floating, VBAT = VREG(Typ)
Current Regulation (Fast Charge Constant-Current Mode)
Fast Charge Current
Regulation Threshold VFCS 100 110 120 mV VDDVSENSE,
TA = -5 °C to +55°C
MCP73841/2/3/4
DS21823D-page 4 2003-2013 Microchip Technology Inc.
Preconditioning Current Regulation (Trickle Charge Constant-Current Mode)
Precondition Current
Regulation Threshold VPCS 51015mVV
DD – VSENSE,
TA = -5 °C to +55°C
Precondition Threshold Vo ltage VPTH
MCP73841-4.1,
MCP73843-4.1 2.70 2.80 2.90 V VBAT Low-to-High
MCP73841-4.2,
MCP73843-4.2 2.75 2.85 2.95 V VBAT Low-to-High
MCP73842-8.2,
MCP73844-8.2 5.40 5.60 5.80 V VBAT Low-to-High
MCP73842-8.4,
MCP73844-8.4 5.50 5.70 5.90 V VBAT Low-to-High
Charge Termination
Charge Termination Threshold VTCS 4710mVV
DD – VSENSE,
TA = -5°C to +55°C
Automatic Recharge
Recharge Threshold Voltage VRTH
MCP73841,
MCP73843 VREG-
300 mV VREG-
200 mV VREG-
100 mV VV
BAT High-to-Low
MCP73842,
MCP73844 VREG-
600 mV VREG-
400 mV VREG-
200 mV VV
BAT High-to-Low
External MOSFET Gate Drive
Gate Drive Current IDRV 2 mA Sink, CV Mode
-0.5 m A Source, CV Mode
Gate Drive Minimum Voltage VDRVMIN ––1.0VV
DD = 4.5V
Gate - Source Clamp Voltage VGS -7.0 -4.5 V VDD = 12.0V
Thermistor Reference - MCP73841, MCP73842
Thermistor Reference Output
Voltage VTHREF 2.475 2.55 2.625 V TA = +25°C, VDD = VREG(Typ)+1V,
ITHREF = 0 m A
Temperature Coefficient TCTHREF –+50 ppm/°C
Thermistor Reference Sourc e
Current ITHREF 200 µA
Thermistor Reference Line
Regulation VTHREF/
VTHREF)|/
VDD
0.1 0.25 %/V VDD=[VREG(Typ)+1V] to 12V
Thermistor Reference Load
Regulation VTHREF/
VTHREF
0.01 0.10 % ITHREF = 0 mA to 0.20 mA
Thermistor Comparator - MCP73841, MCP73842
Upper Trip Threshold VT1 1.18 1.25 1.32 V
Upper Trip Point Hysteresis VT1HYS –-50 mV
Lower Trip Threshold VT2 0.59 0.62 0.66 V
Lower Trip Point Hysteresis VT2HYS –80–mV
Input Bias Current |IBIAS|–2µA
Status Indicator
Sink Current ISINK 4712mA
Low Output Voltage VOL 200 400 mV ISINK = 1 mA
Input Leakage Current ILK –0.011 µAI
SINK = 0 mA, VSTAT1 = 12V
DC CHARACTERISTICS (CONTINUE D)
Electrical Specifications: Unless otherwise indicated, all limits apply for VDD= [VREG(Typ)+0.3V] to 12V, TA = -40°C to +85°C.
Typical values are at +25°C, VDD = [VREG(Typ) + 1V].
Parameters Sym Min Typ Max Units Conditions
2003-2013 Microchip Technology Inc. DS21823D-page 5
MCP73841/2/3/4
AC CHARACTERISTICS
TEMPERATURE SPECIFICATIONS
Enab le In p ut
Input High-Voltage Level V IH 1.4 - V
Input Low-Voltage Level VIL –-0.8V
Input Leakage Current ILK –0.011 µAV
ENABLE = 12V
Electrical Specifications: Unless otherwise indicated, all limits apply f or VDD= [VREG(T yp)+0.3V] to 12V, T A = -40°C to +85° C. Typ-
ical values are at +25°C, VDD= [VREG(Typ)+1V].
Parameters Sym Min Typ Max Units Conditions
UVLO Start Delay tSTART ––5msecV
DD Low-to-High
Current Regulation
Transition T ime Out of
Preconditioning tDELAY ––1msecV
BAT< VPTH to VBAT > VPTH
Current Rise Time Out of
Preconditioning tRISE ––1msecI
OUT Rising to 90% of IREG
Fast Charge Safety Timer Period tFAST 1.1 1.5 1.9 Hours CTIMER = 0.1 µF
Preconditioning Current Regulation
Preconditioning Charge Safety
Timer Period tPRECON 45 60 75 Minutes CTIMER = 0.1 µF
Charge Termination
Elapsed T ime Termination Period tTERM 2.2 3.0 3.8 Hours CTIMER = 0.1 µF
Status Indicators
Stat us Output turn-off tOFF 200 µsec ISINK = 10 mA to 0 mA
Stat us Output turn-on tON 200 µsec ISINK = 0 mA to 10 m A
Electrical Specifications: Unless otherwise specified, all limits apply for VDD= [VREG(Typ)+0.3V] to 12V.
Typical values are at +25°C, VDD= [VREG(Typ)+1.0V].
Parameters Sym Min Typ Max Units Conditions
Temperature Ranges
Specified Temperature Range TA-40 +85 °C
Operating Temperature Range TA-40 +125 °C
Storage Temperature Range T A-65 +150 °C
Thermal Package Resistances
Thermal Resistance, MSOP-10 JA 113 °C/W 4-Layer JC51-7 Standard Board,
Natural Convection
Thermal Resistance, MSOP-8 JA 206 °C/W Single-Layer SEMI G42-88 Board,
Natural Convection
DC CHARACTERISTICS (CONTINUE D)
Electrical Specifications: Unless otherwise indicated, all limits apply for VDD= [VREG(Typ)+0.3V] to 12V, TA = -40°C to +85°C.
Typical values are at +25°C, VDD = [VREG(Typ) + 1V].
Parameters Sym Min Typ Max Units Conditions
MCP73841/2/3/4
DS21823D-page 6 2003-2013 Microchip Technology Inc.
2.0 TYPICAL PERFORMANCE CURVES
Note: Unless otherwise indicated, VDD = [VREG(Typ) + 1V], IOUT = 10 mA and TA= +25°C.
FIGURE 2-1: Battery Regulation Voltage
(VBAT) vs. Charge Current (IOUT).
FIGURE 2-2: Battery Regulation Voltage
(VBAT) vs. Supply Voltage (VDD).
FIGURE 2-3: Battery Regulation Voltage
(VBAT) vs. Supply Voltage (VDD).
FIGURE 2-4: Supply Current (ISS) vs.
Charge Current (IOUT).
FIGURE 2-5: Supply Current (ISS) vs.
Supply Voltage (VDD).
FIGURE 2-6: Supply Current (ISS) vs.
Supply Voltage (VDD).
Note: The g r ap hs and t ables prov id ed following this n ote are a sta t istic al summ ar y b as ed on a lim ite d n um ber of
samples and are provided for informational purposes only. The performance characteristics listed herein
are not tested or guaranteed. In some graphs or tables, the data presented may be outside the specified
operating range (e.g., outside specified power supply range) and therefore outside the warranted range.
4.196
4.197
4.198
4.199
4.200
4.201
4.202
4.203
10 100 1000
IOUT (mA)
VBAT (V)
+55°C
+25°C
-5°C
MCP73841-4.2V
VDD = 5.2 V
4.196
4.197
4.198
4.199
4.200
4.201
4.202
4.203
4.5 6.0 7.5 9.0 10.5 12.0
VDD (V)
VBAT (V)
+55°C
+25°C
-5°C
MCP73841-4.2V
IOUT = 1000 mA
4.196
4.197
4.198
4.199
4.200
4.201
4.202
4.203
4.5 6.0 7.5 9.0 10.5 12.0
VDD (V)
VBAT (V)
MCP73841-4.2V
IOUT = 10 mA
+55°C
+25°C
-5°C
0.00
0.20
0.40
0.60
0.80
1.00
1.20
1.40
10 100 1000
IOUT (mA)
ISS (mA)
+25°C
+85°C
-45°C
MCP73841-4.2V
VDD = 5.2 V
0.00
0.20
0.40
0.60
0.80
1.00
1.20
1.40
4.5 6.0 7.5 9.0 10.5 12.0
VDD (V)
ISS (mA)
+25°C
+85°C
-45°C
MCP73841-4.2V
IOUT = 1000 mA
0.00
0.20
0.40
0.60
0.80
1.00
1.20
1.40
4.5 6.0 7.5 9.0 10.5 12.0
VDD (V)
ISS (mA)
MCP73841-4.2V
IOUT = 10 mA
-45°C
+25°C
+85°C
2003-2013 Microchip Technology Inc. DS21823D-page 7
MCP73841/2/3/4
Note: Unless otherwise indicated, VDD = [VREG(Typ) + 1V], IOUT = 10 mA and TA= +25°C.
FIGURE 2-7: Battery Regulation Voltage
(VBAT) vs. Charge Current (IOUT).
FIGURE 2-8: Battery Regulation Voltage
(VBAT) vs. Supply Voltage (VDD).
FIGURE 2-9: Battery Regulation Voltage
(VBAT) vs. Supply Voltage (VDD).
FIGURE 2-10: Supply Current (ISS) vs.
Charge Current (IOUT).
FIGURE 2-11: Supply Current (ISS) vs.
Supply Voltage (VDD).
FIGURE 2-12: Supply Current (ISS) vs.
Supply Voltage (VDD).
8.390
8.392
8.394
8.396
8.398
8.400
8.402
8.404
8.406
8.408
10 100 1000
IOUT (mA)
VBAT (V)
+55°C
+25°C
-5°C
MCP73842-8.4V
VDD = 9.4 V
8.390
8.392
8.394
8.396
8.398
8.400
8.402
8.404
8.406
8.408
8.8 9.2 9.6 10 10.4 10.8 11.2 11.6 12
VDD (V)
VBAT (V)
+55°C
+25°C
-5°C
MCP73842-8.4V
IOUT = 1000 mA
8.390
8.392
8.394
8.396
8.398
8.400
8.402
8.404
8.406
8.408
8.8 9.2 9.6 10.0 10.4 10.8 11.2 11.6 12.0
VDD (V)
VBAT (V)
MCP73842-8.4V
IOUT = 10 mA +55°C
+25°C
-5°C
0.00
0.20
0.40
0.60
0.80
1.00
1.20
1.40
10 100 1000
IOUT (mA)
ISS (mA)
+25°C+85°C
-45°C
MCP73842-8.4V
VDD = 9.4 V
0.00
0.20
0.40
0.60
0.80
1.00
1.20
1.40
8.8 9.2 9.6 10.0 10.4 10.8 11.2 11.6 12.0
VDD (V)
ISS (mA)
+25°C
+85°C
-45°C
MCP73842-8.4V
IOUT = 1000 mA
0.00
0.20
0.40
0.60
0.80
1.00
1.20
1.40
8.8 9.2 9.6 10.0 10.4 10.8 11.2 11.6 12.0
VDD (V)
ISS (mA)
MCP73842-8.4V
IOUT = 10 mA
-45°C
+25°C
+85°C
MCP73841/2/3/4
DS21823D-page 8 2003-2013 Microchip Technology Inc.
Note: Unless otherwise indicated, VDD = [VREG(Typ) + 1V], IOUT = 10 mA and TA= +25°C.
FIGURE 2-13: Output Reverse Leakage
Current (IDISCHARGE) vs. Battery Voltage (VBAT).
FIGURE 2-14: Thermistor Reference
Voltage (VTHREF) vs. Thermistor Bias Current
(ITHREF).
FIGURE 2-15: Thermistor Reference
Voltage (VTHREF) vs. Supply Voltage (VDD).
FIGURE 2-16: Output Reverse Leakage
Current (IDISCHARGE) vs. Battery Voltage (VBAT).
FIGURE 2-17: Thermistor Reference
Voltage (VTHREF) vs. Thermistor Bias Cur rent
(ITHREF).
FIGURE 2-18: Thermistor Reference
Voltage (VTHREF) vs. Supply Voltage (VDD).
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6 3.8 4.0 4.2
VBAT (V)
IDISCHARGE (µA)
+25°C
+85°C
-45°C
MCP73841-4.2V
VDD = Float
2.540
2.542
2.544
2.546
2.548
2.550
2.552
2.554
2.556
2.558
2.560
0 25 50 75 100 125 150 175 200
ITHREF (µA)
VTHREF (V)
+85°C
+25°C
-45°C
MCP73841-4.2V
VDD = 5.2 V
2.540
2.544
2.548
2.552
2.556
2.560
2.564
2.568
4.5 6.0 7.5 9.0 10.5 12.0
VDD (V)
VTHREF (V)
+85°C
+25°C
-45°C
MCP73841-4.2V
ITHREF = 100 µA
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
4.0 4.4 4.8 5.2 5.6 6.0 6.4 6.8 7.2 7.6 8.0 8.4
VBAT (V)
IDISCHARGE (µA)
MCP73842-8.4V
VDD = Float
-45°C
+25°C
+85°C
2.540
2.542
2.544
2.546
2.548
2.550
2.552
2.554
2.556
2.558
2.560
0 25 50 75 100 125 150 175 200
ITHREF (µA)
VTHREF (V)
+25°C
+85°C
-45°C
MCP73842-8.4V
VDD = 9.4 V
2.540
2.544
2.548
2.552
2.556
2.560
2.564
2.568
8.8 9.2 9.6 10.0 10.4 10.8 11.2 11.6 12.0
VDD (V)
VTHREF (V)
MCP73842-8.4V
ITHREF = 100 µA
+85°C
+25°C
-45°C
2003-2013 Microchip Technology Inc. DS21823D-page 9
MCP73841/2/3/4
Note: Unless otherwise indicated, VDD = [VREG(Typ) + 1V], IOUT = 10 mA and TA= +25°C.
FIGURE 2-19: Line Transient Response.
FIGURE 2-20: Load Transient Response.
FIGURE 2-21: Power Supply Ripple
Rejection.
FIGURE 2-22: Line Transient Response.
FIGURE 2-23: Load Transient Response.
FIGURE 2-24: Power Supply Ripple
Rejection.
VDD
VBAT
MCP73841-4.2V
VDD Stepped From 5.2V to 6.2V
IOUT = 10 mA
COUT = 10 µF, X7R, Ceramic
MCP73841-4.2V
VDD = 5.2V
COUT = 10 µF, X7R, Ceramic VBAT
IOUT
100 mA
10 mA
-80
-70
-60
-50
-40
-30
-20
-10
0
0.01 0.1 1 10 100 1000
Frequency (kHz)
Attenuation (dB)
MCP73841-4.2V
VDD = 5.2 V
VAC = 100 mVp-p
IOUT = 10 mA
COUT = 10 µF, X7R, CERAMIC
VDD
VBAT
MCP73841-4.2V
VDD Stepped From 5.2V to 6.2V
IOUT = 500 mA
COUT = 10 µF, X7R, Ceramic
VBAT
MCP73841-4.2V
VDD = 5.2V
COUT = 10 µF, X7R, Ceramic
IOUT500 mA
10 mA
-80
-70
-60
-50
-40
-30
-20
-10
0
0.01 0.1 1 10 100 1000
Frequency (kHz)
Attenuation (dB)
MCP73841-4.2V
VDD = 5.2 V
VAC = 100 mVp-p
IOUT = 100 mA
COUT = 10 µF, X7R, CERAMIC
MCP73841/2/3/4
DS21823D-page 10 2003-2013 Microchip Technology Inc.
3.0 PIN DESCRIPT IONS
The descriptions of the pins are listed in Table 3-1.
TABLE 3-1: PIN DESCRIPTION TABLE
3.1 Charge Current Sense Input
(SENSE)
Charge current is sensed via the voltage developed
across an ex terna l p r ec is ion se ns e res is tor. The s ens e
resistor must be placed between the supply voltage
(VDD) and the external pass transistor (Q1). A 220 m
sense resistor produces a fast charge current of
500 mA, typically.
3.2 Battery Management I nput Supp ly
(VDD)
A supply voltage of [VREG(Typ) + 0.3V] to 12V is
recommended. Bypass to VSS with a minimum of
4.7 µF.
3.3 Charge Status Output (STAT1)
Current limited, open-drain drive for direct connection
to a LED for charge status indication. Alternatively, a
pull-up resistor can be applied for interfacing to a host
microcontroller.
3.4 Logic Enable (EN)
Input to force c ha rge termin ati on, in iti ate c harge, cl ear
faults or disable automatic recharge.
3.5 Cell Temperature Sensor Bias
(THREF)
Voltage reference to bias external thermistor for
continuous cell temperature monitoring and
prequalification.
3.6 Cell Temperature Se nsor Input
(THERM)
Input for an external thermistor for continuous cell-
temperature monitoring and pre-qualification. Apply a
volt age e qua l to 0.85V t o dis able tempe rature-sens ing.
3.7 Timer Set (TIMER)
All safety timers are scaled by CTIMER/0.1 µF.
3.8 Battery Management 0V Reference
(VSS)
Connect to negative terminal of battery.
3.9 Battery Voltage Sense (VBAT)
Voltage sense input. Connect to positive terminal of
battery. Bypass to VSS with a minimum of 4.7 µF to
ensure loop stability when the battery is disconnected.
A precision internal resistor divider regulates the final
voltage on this pin to VREG.
3.10 Drive Output (DRV)
Direct output drive of an external P-channel MOSFET
for current and voltage regulation.
MCP73841,
MCP73842
Pin No.
MCP73843,
MCP73844
Pin No. Name Function
1 1 SENSE Charge Current Sense Input
22V
DD Battery Management Input Supply
3 3 STAT1 Charge Status Output
4 4 EN Logic Enable
5 THREF Cell Temperature Sensor Bias
6 THERM Cell Temperature Sensor Input
75TIMERTimer Set
86V
SS Battery Management 0V Reference
97V
BAT Battery Voltage Sense
10 8 DRV Drive Outpu t
2003-2013 Microchip Technology Inc. DS21823D-page 11
MCP73841/2/3/4
4.0 DEVICE OVERVIEW
The MC P7384X fami ly of devic es are hig hly advan ced,
linear charge management controllers. Figure 4-1
depicts the operational flow algorithm from charge
initiation to completion and automatic recharge.
4.1 Charge Qualification and
Preconditioning
Upon ins ertion of a battery or applic ation of an externa l
supply, the MCP7384X family of devices automatically
perfo rm a seri es of sa fety ch ecks to quali fy th e charg e.
The input source voltage must be above the
undervo lta ge lockou t threshold , the enable pi n must be
above the logic-high level and the cell temperature
monitor must be within the upper and lower thresholds.
The cell temperature monitor applies to both the
MCP73841 and MCP73842, with the qualification
parameters being continuously monitored. Deviation
beyond the limits automatically suspends or terminates
the charge cycle.
Once the qualification parameters have been met, the
MCP7384X initiates a charge cycle. The charge status
output is pulled low throughout the charge cycle (see
Table 5-1 for charge status outputs). If the battery
voltage is below the preconditioning threshold (VPTH),
the MC P73 84X p rec ond iti ons th e ba ttery with a trickl e-
charge. The preconditioning current is set to
approximately 10% of the fast charge regulation
current. The preconditioning trickle-charge safely
replenishes deeply depleted cells and minimizes heat
dissipation in the external pass transistor during the
initial charge cycle. If the battery voltage has not
exceeded the preconditioning threshold before the
preconditioning timer has expired, a fault is indicated
and the charge cycle is terminated.
4.2 Constant- Current Regulation –
Fast Charge
Preconditioning ends and fast charging begins, when
the battery voltage exceeds the preconditioning
threshold. Fast charge regulates to a constant-current,
IREG, based on the su ppl y v oltage min us the v ol tage at
the SENSE input (VFCS) devel oped by the drop ac ros s
an external sense resistor (RSENSE). Fast charge
continues until the battery voltage reaches the
regulati on volt a ge (VREG); or until the fast charge timer
expires . In this case, a fault is indicated and the charge
cycle is terminated.
4.3 Constant-Voltage Regulation
When the battery voltage reaches the regulation
voltage (VREG), constant-voltage regulation begins.
The MCP7384X monitors the battery voltage at the
VBAT pin. This input is tied directly to the positive
terminal of the battery. The MCP7384X is offered in
four fixed-voltage versions for single or dual series cell
battery packs with either coke or graphite anodes:
- 4.1V (MCP73841-4.1, MCP73843-4.1)
- 4.2V (MCP73841-4.2, MCP73843-4.2)
- 8.2V (MCP73842-8.2, MCP73844-8.2)
- 8.4V (MCP73842-8.4, MCP73844-8.4)
4.4 Charge Cycle Completion and
Auto mati c R e -Charge
The MCP7384X monitors the charging current during
the constant-voltage regulation phase. The charge
cycle is considered complete when the charge current
has diminished below approximately 7% of the
regulation current (IREG) or the elapsed timer has
expired.
The MCP7384X automatically begins a new charge
cycle w hen t he bat tery v olt age fa lls b elow th e rec harge
threshold (VRTH), assuming all the qualification
param ete rs are met.
2003-2013 Microchip Technology Inc. DS21823D-page 12
MCP73841/2/3/4
FIGURE 4-1: Operational Flow Algorithm - MCP73841 and MCP73842.
Preconditioning Phase
Charge Current = IPREG
Reset Safety Timer Yes
Initialize
No
Yes
VBAT > VPTH STAT1 = On
VBAT > VPTH
Yes
VDD < VUVLO
No
No
Safety Timer
Yes Temperature OK
No
STAT1 = Flashing
Safety Timer Suspended
Charge Current = 0
Fault
Charge Current = 0
Res e t Safety Timer
or EN Low No
STAT 1 = Flashing
Constant-Current
Charge Current = IREG
Reset Safety Tim e r
VBAT = VREG
No
No
Safety Timer
Yes Temperature OK
Constant-Voltage Phase
Output Voltage = VREG
IOUT < ITERM
Yes
VBAT < VRTH
Elapsed Timer Charge Termination
Charge Current = 0
Res e t Sa f e ty Timer
No
STAT1 = Off
Yes
Yes
Temperature OK
No
STAT1 = Flashing
Safety Timer Suspended
Charge Current = 0
Yes
Yes
VDD < VUVLO
or EN Low
No
Yes
Yes
Temperature OK No
STAT1 = Flashing
Charge Current = 0
Yes
No
STAT1 = Off
VDD > VUVLO
Phase
Expired
Expired
No
STAT 1 = Flashing
Safety Timer Suspended
Charge Current = 0
EN High
Expired
Note: The qualification parameters are continuously
monitored throughout the charge cycle.
Note
Note
2003-2013 Microchip Technology Inc. DS21823D-page 13
MCP73841/2/3/4
5.0 DETAILED DESCRIPTION
5.1 Analog Circuitry
5.1.1 CHARGE CURRENT SENSE INPUT
(SENSE)
Fast charge current regulation is maintained by the
voltage drop developed across an external sense
resistor (RSENSE) applied to the SENSE input pin. The
following formula calculates the value for RSENSE:
The preconditioning trickle-charge current and the
charge te rmina tion current are scale d to appro xima tely
10% and 7% of IREG, respectively.
5.1.2 BATTERY MANAGEMENT INPUT
SUPPL Y (V DD)
The VDD input is the input supply to the MCP7384X.
The MCP7384X automatically enters a power-down
mode if the voltage on the VDD input falls below the
undervoltage lockout voltage (VSTOP). This feature
prevents draining the battery pack when the VDD
supply is not present.
5.1.3 CELL TEMPERATURE SENSOR
BIAS (THREF)
A 2.55V voltage reference is provided to bias an
external thermistor for continuous cell temperature
monitoring and pre-qualification. A ratio metric window
comparison is performed at threshold levels of
VTHREF/2 and VTHREF/4. Cell temperature monitoring
is provided by both the MCP73841 and MCP73842.
5.1.4 CELL TEMPERATURE SENSOR
INPUT (THERM)
The MCP73841 and MCP73842 continuously monitor
temperature by comparing the voltage between the
THERM input and VSS with the upper and lower
temperature thresholds. A negative or positive
temperature coefficient (NTC or PTC) thermistor and
an external voltage divider typically develop this
voltage. The temperature-sensing circuit has its own
reference, to which it performs a ratio metric
comparison. Therefore, it is immune to fluctuations in
the suppl y input (VDD). The temperature-sensing circuit
is removed from the system when VDD is not applied,
eliminating additional discharge of the battery pack.
Figure 6-1 depicts a typical application circuit with
connection of the THERM input. The resistor values of
RT1 and RT2 are calculated with the following
equations.
For NTC thermistors:
For PTC thermistors:
Applying a voltage equal to 0.85V to the THERM input
disabl es tem perature moni tori ng.
5.1.5 TIMER SET INPUT (TIMER)
The TIMER input programs the period of the safety
timers by placing a timing capacitor (CTIMER) between
the TIMER input pin and VSS. Three safety timers are
programmed via the timing capacitor.
The preconditioning safety timer period:
The fast charge safety timer period:
The elapsed time termination period:
The preconditioning timer starts after qualification and
resets when the charge cycle transitions to the con-
stant-current, fast charge phase. The fast charge and
elapsed timers start once the MCP7384X transitions
from preconditioning. The fast charge timer resets
when the charge cycle transitions to the constant-volt-
age phase . The elaps ed timer will exp ire and termina te
the charge if the sensed current does not diminish
below the termination threshold.
RSENSE VFCS
IREG
------------
=
where:
IREG is the desired fast charge current in amps
RT12RCOLD RHOT
RCOLD RHOT
----------------------------------------------
=
RT22RCOLD RHOT
RCOLD 3RHOT
----------------------------------------------
=
RT12RCOLD RHOT
RHOT RCOLD
----------------------------------------------
=
RT22RCOLD RHOT
RHOT 3RCOLD
----------------------------------------------
=
where:
values at the temperature window of interest.
RCOLD and RHOT are the thermistor resistance
tPRECON CTIMER
0.1F
-------------------1.0Hours=
tFAST CTIMER
0.1F
-------------------1.5Hours=
tTERM CTIMER
0.1F
-------------------3.0Hours=
MCP73841/2/3/4
DS21823D-page 14 2003-2013 Microchip Technology Inc.
5.1.6 BATTERY VOLTAGE SENSE (VBAT)
The MCP7384X monitors the battery voltage at the
VBAT pin. This input is tied directly to the positive
terminal of the battery. The MCP7384X is offered in
four fixed-voltage versions for single or dual series cell
battery packs, with either coke or graphite anodes:
- 4.1V (MCP73841-4.1, MCP73843-4.1)
- 4.2V (MCP73841-4.2, MCP73843-4.2)
- 8.2V (MCP73842-8.2, MCP73844-8.2)
- 8.4V (MCP73842-8.4, MCP73844-8.4)
5.1.7 DRIVE OUTPUT (DRV)
The MCP7384X controls the gate drive to an external
P-channel MOSFET. The P-channel MOSFET is
controlled in the linear region regulating current and
voltage supplied to the cell. The drive output is
automatically turned off when the voltage on the VDD
input falls below the undervoltage lockout voltage
(VSTOP).
5.2 Digital Circuitry
5.2.1 CHARGE STATUS OUTPUT (STAT1)
A status output provides information on the state-of-
charge. The current-limited, open-drain output can be
used to illuminate an external LED. Optio nally , a pull-u p
resistor can be used on the output for communication
with a host microcontroller. Table 5-1 summarizes the
state of the status output during a charge cycle.
TABLE 5-1: STATUS OUTPUTS
The f lashin g rate ( 1 Hz ) is b ased off a time r capaci tor
(CTIMER) of 0.1 µF. The rate will vary based on the
value of the timer capacito r.
5.2.2 LOGIC ENABLE (EN)
The logic-enable input pin (EN) can be used to
terminate a charge anytime during the charge cycle,
initiate a charge cycle or initiate a recharge cycle.
Applyin g a logic -high in put signa l to t he EN pin, o r tying
it to the input source, enables the device. Applying a
logic-low input signal disables the device and
terminat es a charge cycle. When d isabled, the d evice’ s
supply current is reduced to 0.25 µA, typically.
Charge Cycle State Stat1
Qualification OFF
Preconditioning ON
Constant-Current Fast
Charge ON
Constant-Voltage ON
Charge Complete OFF
Safety Timer Fault Flashing
(1 Hz, 50% duty cycle)
Cell Temperature Invalid Flashing
(1 Hz, 50% duty cycle)
Disabled - Sleep mode OFF
Battery Disconnected OFF
2003-2013 Microchip Technology Inc. DS21823D-page 15
MCP73841/2/3/4
6.0 APPLICATIONS
The MCP7384X is designed to operate in conjunction
with either a host microcontroller or in stand-alone
applications. The MCP7384X provides the preferred
charge algorithm for Lithium-Ion and Lithium-Polymer
cells: constant-current followed by constant-voltage.
Figure 6-1 depicts a typical stand-alone application
circuit, while Figure 6-2 depicts the accompanying
charge profile.
FIGURE 6-1: Typical App li cat io n Circui t.
FIGURE 6-2: Typical Char ge Prof il e.
VDD VSS
VBAT
DRV
THERM
EN
SENSE 1
2
3
4
10
9
8
7
MCP73841 TIMER
56
STAT1
Voltage
+
-
Battery
Pack
RSENSE
CTIMER
Optional
THREF
RT1
RT2
Q1
Reverse
Blocking
Diode
Regulated
Wall Cu be
Regulation Voltage
(VREG)
Regulation Current
(IREG)
Transition Threshold
(VPTH)
Precondition Current
(IPREG)
Precondition
Safety Timer Fast Charge
Safety Timer Elapsed Time
Termination Timer
Charge
Current
Charge
Voltage
Preconditioning
Phase Constant-Current
Phase Constant-Voltage
Phase
Termination Current
(ITERM)
MCP73841/2/3/4
DS21823D-page 16 2003-2013 Microchip Technology Inc.
6.1 Application Circuit Design
Due to the low efficiency of linear charging, the most
important fa ctors are thermal design and cos t, which are
a direct function of the input voltage, output current and
thermal impedance between the external P-channel
pass transistor and the ambient cooling air. The worst-
case situation occurs when the device has transitioned
from the preconditioning phase to the constant-current
phase. In this situation, the P-channel pass transistor
has to dissipate the maximum power. A trade-off must
be made between the charge current, cost and thermal
requirements of the ch arger.
6.1.1 COMPONEN T SELECTION
Selection of the external components in Figure 6-1 are
crucial to the integrity and reliability of the charging
system. The following discussion is intended to be a
guide for the component selection process.
6.1.1.1 Sense Resistor
The preferred fast charge current for Lithium-Ion cells
is at the 1C rate, with an absolute maximum current at
the 2C rate. For example, a 500 mAh battery pack has
a preferred fast charge current of 500 mA. Chargi ng at
this rate provides the shortest charge cycle times
withou t degradatio n to the battery p ack perfo rmance or
life.
The curren t sense resistor ( RSENSE) is calculate d by:
For the 500 mAh battery pack example, a standard
value 220 m, 1% resistor provides a typical fast
charge current of 500 mA and a maximum fast charge
current of 551 mA. W orst-case powe r dissip ation in the
sense res ist or is:
A Panasonic® ERJ-6RQFR22V, 220 mW, 1%, 1/8W
resistor in a standard 0805 package is more than
sufficient for this application.
A larger value sense resistor will decrease the fast
charge cu rrent and powe r dissip ation in both the sense
resistor and external pass transistor, but will increase
charge cycle times. Design trade-offs must be
considered to minimize space while maintaining the
des ired performanc e.
6.1.1.2 External Pass Transistor
The externa l P-ch ann el MOSF ET is determ in ed by the
gate-to-source threshold voltage, input voltage, output
voltage and fast charge current. Therefore, the
selec ted P-ch annel MOS FET must satisf y the th ermal
and electrical design requirements.
Thermal Considerations
The worst-case power dissipation in the external pass
transistor occurs when the input voltage is at the
maximum and the device has transitioned from the
preconditioni ng phase to the constant-current ph ase. In
this case, the power dissipation is:
Power dissipation with a 5V, ±10% input voltage
source, 220 m, 1% sense resistor is:
Utilizing a Fairchild™ NDS8434 or an International
Rectifier IRF7404 mounted on a 1in2 pad of 2 oz.
copper, the junction temperature rise is 75°C,
approximately. This would allow for a maximum
operating ambient temperature of 75°C.
By increasing the size of the copper pad, a higher ambi-
ent temperature can be realized, or a lower value
sense resistor could be utilized.
Alternatively, different package options can be utilized
for more or less power dissi pation. Agai n, design trade-
offs should be considered to minimize size while
maintaining the desired performance.
Electrical Considerations
The gate-to -source thresho ld voltag e and RDSON of the
external P-channel MOSFET must be considered in the
design phase.
The wors t-case VGS pro vided by the contr oller occu rs
when the input voltage is at the minimum and the fast
charge cu rrent regu lation thresho ld is at the maximum .
The worst-ca se VGS is:
RSENSE VFCS
IREG
------------
=
Where:
IREG is the desired fast charge current.
PowerDissipation 220m551mA2
66.8mW==
PowerDissipation VDDMAX VPTHMIN
IREGMAX
=
Where:
VDDMAX is the maximum input voltage.
IREGMAX is the maximum fast charge current.
VPTHMIN is the minimum transition threshold voltage.
PowerDissipation 5.5V2.75V551mA1.52W==
VGS VDRVMAX VDDMIN VFCSMAX=
Where:
VDRVMAX is the maximum sink voltage at the
VDRV output
VDDMIN is the minimum input voltage source
VFCSMAX is the maximum fast charge current
regulation threshold