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MCP73827
Single Cell Lithium-Ion Charge Management Controller with Mode Indicator and Charge Current Monitor
Features
* Linear Charge Management Controller for Single Lithium-Ion Cells * High Accuracy Preset Voltage Regulation: + 1% (max) * Two Preset Voltage Regulation Options: - 4.1V - MCP73827-4.1 - 4.2V - MCP73827-4.2 * Programmable Charge Current * Automatic Cell Preconditioning of Deeply Depleted Cells, Minimizing Heat Dissipation During Initial Charge Cycle * Charge Status Output for LED Drive or Microcontroller Interface * Charge Current Monitor Output * Automatic Power-Down when Input Power Removed * Temperature Range: -20C to +85C * Packaging: 8-Pin MSOP
Description
The MCP73827 is a linear charge management controller for use in space-limited, cost sensitive applications. The MCP73827 combines high accuracy constant voltage, controlled current regulation, cell preconditioning, and charge status indication in a space saving 8-pin MSOP package. The MCP73827 provides a stand-alone charge management solution. The MCP73827 charges the battery in three phases: preconditioning, controlled current, and constant voltage. If the battery voltage is below the internal low-voltage threshold, the battery is preconditioned with a foldback current. The preconditioning phase protects the lithium-ion cell and minimizes heat dissipation. Following the preconditioning phase, the MCP73827 enters the controlled current phase. The MCP73827 allows for design flexibility with a programmable charge current set by an external sense resistor. The charge current is ramped up, based on the cell voltage, from the foldback current to the peak charge current established by the sense resistor. This phase is maintained until the battery reaches the charge-regulation voltage. Then, the MCP73827 enters the final phase, constant voltage. The accuracy of the voltage regulation is better than +1% over the entire operating temperature range and supply voltage range. The MCP73827-4.1 is preset to a regulation voltage of 4.1V, while the MCP73827-4.2 is preset to 4.2V. The charge status output, MODE, indicates when the charge cycle has transitioned to constant voltage mode. The charge cycle can be terminated by a timer that is started when the MODE pin goes to a logic High or by monitoring the charge current monitor output, IMON, for a minimum current.
+ Single Lithium-Ion - Cell 5 2 4 10 F
Applications
* * * * * * Single Cell Lithium-Ion Battery Chargers Personal Data Assistants Cellular Telephones Hand Held Instruments Cradle Chargers Digital Cameras
Typical Application Circuit
500 mA Lithium-Ion Battery Charger MA2Q705 VIN 5V 10 F 100 m 332 8 100 k 1 3 NDS8434
6 7 VSNS VDRV VIN VBAT
The MCP73827 operates with an input voltage range from 4.5V to 5.5V. The MCP73827 is fully specified over the ambient temperature range of -20C to +85C.
SHDN GND MODE IMON MCP73827
Package Type
MSOP
SHDN 1 GND 2 MODE 3 IMON 4 MCP73827 8 VIN 7 VSNS 6 VDRV 5 VBAT
(c) 2007 Microchip Technology Inc.
DS21704B-page 1
+ IMON - 100 k 138 k CHARGE CURRENT MONITOR AMPLIFIER MODE
- 12 k -
500 k CHARGE CURRENT CONTROL AMPLIFIER VREF (1.2V) SHUTDOWN, REFERENCE GENERATOR VIN VOLTAGE CONTROL AMPLIFIER
SHDN
VREF 112.5 k + - 0.3V CLAMP 75 k GND CHARGE CURRENT FOLDBACK AMPLIFIER
37.5 k
NOTE 1: Value = 340.5K for MCP73827-4.1 Value = 352.5K for MCP73827-4.2
+
DS21704B-page 2
+ VIN 1.1 k - + CHARGE CURRENT AMPLIFIER + VBAT VREF 352.5 k (NOTE 1) 75 k MODE COMPARATOR VDRV
MCP73827
Functional Block Diagram
VIN
VSNS
(c) 2007 Microchip Technology Inc.
MCP73827
1.0
1.1
ELECTRICAL CHARACTERISTICS
Maximum Ratings*
PIN FUNCTION TABLE
Pin Name Description
1 2 3 4 5 6 7 8
SHDN GND MODE IMON VBAT VDRV VSNS VIN
Logic Shutdown Battery Management 0V Reference Charge Status Output Charge Current Monitor Cell Voltage Monitor Input Drive Output Charge Current Sense Input Battery Management Input Supply
VIN ...................................................................... -0.3V to 6.0V All inputs and outputs w.r.t. GND ................-0.3 to (VIN+0.3)V Current at MODE Pin .............................................. +/-30 mA Current at VDRV .......................................................... +/-1 mA Maximum Junction Temperature, TJ.............................. 150C Storage temperature .....................................-65C to +150C ESD protection on all pins .................................................. 4 kV
*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. Exposure to maximum rating conditions for extended periods may affect device reliability.
DC CHARACTERISTICS: MCP73827-4.1, MCP73827-4.2
Unless otherwise specified, all limits apply for VIN = [VREG(typ)+1V], RSENSE = 500 m, TA = -20C to +85C. Typical values are at +25C. Refer to Figure 1-1 for test circuit. Parameter Supply Voltage Supply Current Voltage Regulation (Constant Voltage Mode) Regulated Output Voltage Line Regulation Load Regulation Output Reverse Leakage Current External MOSFET Gate Drive Gate Drive Current Gate Drive Minimum Voltage Current Regulation (Controlled Current Mode) Current Sense Gain Current Limit Threshold Foldback Current Scale Factor Charge Status Indicator - MODE Threshold Voltage Low Output Voltage Leakage Current Shutdown Input - SHDN Input High Voltage Level Input Low Voltage Level Input Leakage Current Charge Current Monitor - IMON Charge Current Monitor Gain AIMON -- 26 -- V/V VIMON / (VIN-VSNS) VIH VIL ILK 40 -- -- -- -- -- -- 25 1 %VIN %VIN A VSHDN=0V to 5.5V VTH VOL ILK -- -- -- VREG -- -- -- 400 1 V mV A ISINK = 10 mA ISINK=0 mA, VMODE=5.5V ACS VCS K -- 40 -- 100 53 0.43 -- 75 -- dB mV A/A (VSNS-VDRV) / VBAT (VIN-VSNS) at IOUT IDRV VDRV -- 0.08 -- -- -- 1.6 1 -- -- mA mA V Sink, CV Mode Source, CV Mode VREG VBAT VBAT ILK 4.059 4.158 -10 -1 -- 4.1 4.2 -- +0.1 8 4.141 4.242 10 1 -- V V mV mV A MCP73827-4.1 only MCP73827-4.2 only VIN = 4.5V to 5.5V, IOUT = 75 mA IOUT=10 mA to 75 mA VIN=Floating, VBAT=VREG Sym VIN IIN Min 4.5 -- -- Typ -- 0.5 250 Max 5.5 15 560 Units V A Shutdown, VSHDN = 0V Constant Voltage Mode Conditions
(c) 2007 Microchip Technology Inc.
DS21704B-page 3
MCP73827
TEMPERATURE SPECIFICATIONS
Unless otherwise specified, all limits apply for VIN = 4.5V-5.5V Parameters Symbol Min Typ Max Units Conditions
Temperature Ranges
Specified Temperature Range Operating Temperature Range Storage Temperature Range TA TA TA -20 -40 -65 -- -- -- +85 +125 +150 C C C Single Layer SEMI G42-88 Standard Board, Natural Convection
Package Thermal Resistance
Thermal Resistance, 8L-MSOP JA -- 206 -- C/W
VIN = 5.1V (MCP73827-4.1) VIN = 5.2V (MCP73827-4.2)
RSENSE
NDS8434
IOUT
22 F 7 VSNS 8 100 k 100 k 1 3 VIN SHDN MODE 6 VDRV VBAT GND IMON 5 2 4 22 F
VOUT
MCP73827 FIGURE 1-1: MCP73827 Test Circuit.
DS21704B-page 4
(c) 2007 Microchip Technology Inc.
MCP73827
2.0
Note:
TYPICAL PERFORMANCE CHARACTERISTICS
The graphs and tables provided following this note are a statistical summary based on a limited number 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.
Note: Unless otherwise indicated, IOUT = 10 mA, Constant Voltage Mode, TA = 25C. Refer to Figure 1-1 for test circuit.
4.205 4.204
300
4.202 4.201 4.200 4.199 4.198 4.197 4.196 4.195 0 200 400 600 800 1000
Supply Current (A)
4.203
280
Output Voltage (V)
260
240
220
200 0 200 400 600 800 1000
Output Current (mA)
Output Current (mA)
FIGURE 2-1: Output Voltage vs. Output Current (MCP73827-4.2).
FIGURE 2-4:
Supply Current vs. Output Current.
4.205 4.204 4.203 IOUT = 1000 mA
300
IOUT = 1000 mA
4.202 4.201 4.200 4.199 4.198 4.197 4.196 4.195 4.5 4.6 4.7 4.8 4.9 5.0 5.1 5.2 5.3 5.4 5.5
Supply Current (A)
280
Output Voltage (V)
260
240
220
200 4.5 4.6 4.7 4.8 4.9 5.0 5.1 5.2 5.3 5.4 5.5
Input Voltage (V)
Input Voltage (V)
FIGURE 2-2: Output Voltage vs. Input Voltage (MCP73827-4.2)
FIGURE 2-5:
Supply Current vs. Input Voltage.
4.205 4.204
IOUT = 10 mA
300
IOUT = 10 mA
280
4.202 4.201 4.200 4.199 4.198 4.197 4.196 4.195 4.5 4.6 4.7 4.8 4.9 5.0 5.1 5.2 5.3 5.4 5.5
Supply Current (A)
4.203
Output Voltage (V)
260
240
220
200 4.5 4.6 4.7 4.8 4.9 5.0 5.1 5.2 5.3 5.4 5.5
Input Voltage (V)
Input Voltage (V)
FIGURE 2-3: Output Voltage vs. Input Voltage (MCP73827-4.2)
FIGURE 2-6:
Supply Current vs. Input Voltage.
(c) 2007 Microchip Technology Inc.
DS21704B-page 5
MCP73827
Note: Unless otherwise indicated, IOUT = 10 mA, Constant Voltage Mode, TA = 25C. Refer to Figure 1-1 for test circuit.
12
VIN = Floating VSHDN = VOUT
Output Reverse Leakage Current (A)
300
o
10 8 6 4 2 0 2.0 2.5 3.0 3.5 4.0
Supply Current (A)
85 C 25 C -20 C
o o
275 250 225 200 175 150
4.5
-20
-10
0
10
20
30
40
o
50
60
70
80
Output Voltage (V)
Temperature ( C)
FIGURE 2-7: Output Reverse Leakage Current vs. Output Voltage.
FIGURE 2-10: Supply Current vs. Temperature.
Output Reverse Leakage Current (A)
1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0.0 2.0 2.5 3.0 3.5 4.0 4.5
VIN = Floating VSHDN = GND 85 C 25 C -20 C
o o o
4.206 4.204
Output Voltage (V)
4.202 4.200 4.198 4.196 4.194 4.192 4.190 -20 -10 0 10 20 30 40
o
50
60
70
80
Output Voltage (V)
Temperature ( C)
FIGURE 2-8: Output Reverse Leakage Current vs. Output Voltage.
FIGURE 2-11: Output (MCP73827-4.2).
Voltage
vs.
Temperature
4.500 4.000
4.5 4.0 3.5
Output Voltage (V)
3.500 3.000 2.500 2.000 1.500 1.000 0.500
Output Voltage (V)
3.0 2.5 2.0 1.5 1.0 0.5
Power Up
Power Down
0.000 0 20 40 60 80 100 120 0.0 0 1 2 3 4 5 6 4 7 3 8 2 9 1 10 0
Output Current (mA)
Input Voltage (V)
FIGURE 2-9:
Current Limit Foldback.
FIGURE 2-12: Power-Up / Power-Down.
DS21704B-page 6
(c) 2007 Microchip Technology Inc.
MCP73827
Note: Unless otherwise indicated, IOUT = 10 mA, Constant Voltage Mode, TA = 25C. Refer to Figure 1-1 for test circuit.
FIGURE 2-13: Line Transient Response.
FIGURE 2-15: Load Transient Response.
FIGURE 2-14: Line Transient Response.
FIGURE 2-16: Load Transient Response.
(c) 2007 Microchip Technology Inc.
DS21704B-page 7
MCP73827
3.0 PIN DESCRIPTION
3.5 Cell Voltage Monitor Input (VBAT)
The descriptions of the pins are listed in Table 3-1.
Pin Name Description
1 2 3 4 5 6 7 8
SHDN GND MODE IMON VBAT VDRV VSNS VIN
Logic Shutdown Battery Management 0V Reference Charge Status Output Charge Current Monitor Cell Voltage Monitor Input Drive Output Charge Current Sense Input Battery Management Input Supply
Voltage sense input. Connect to positive terminal of battery. Bypass to GND with a minimum of 10 F to ensure loop stability when the battery is disconnected. A precision internal resistor divider regulates the final voltage on this pin to VREG.
3.6
Drive Output (VDRV)
Direct output drive of an external P-channel MOSFET pass transistor for current and voltage regulation.
3.7
Charge Current Sense Input (VSNS)
TABLE 3-1:
Pin Function Table.
Charge current is sensed via the voltage developed across an external precision sense resistor. The sense resistor must be placed between the supply voltage (VIN) and the source of the external pass transistor. A 50 m sense resistor produces a fast charge current of 1 A, typically.
3.1
Logic Shutdown (SHDN)
3.8
Input to force charge termination, initiate charge, or initiate recharge.
Battery Management Input Supply (VIN)
3.2
Battery Management 0V Reference (GND)
A supply voltage of 4.5V to 5.5V is recommended. Bypass to GND with a minimum of 10 F.
Connect to negative terminal of battery.
3.3
Charge Status Output (MODE)
Open-drain drive for connection to an LED for charge status indication. Alternatively, a pull-up resistor can be applied for interfacing to a microcontroller. A low impedance state indicates foldback current limit or controlled current phase. A high impedance indicates constant voltage phase or battery cell disconnected.
3.4
Charge Current Monitor (IMON)
Amplified output of the voltage difference between VIN and VSNS. A host microcontroller can monitor this output with an A/D converter.
DS21704B-page 8
(c) 2007 Microchip Technology Inc.
MCP73827
4.0 DEVICE OVERVIEW
4.3 Constant Voltage Regulation
The MCP73827 is a linear charge management controller. Refer to the functional block diagram on page 2 and the typical application circuit, Figure 6-1. When the cell voltage reaches the regulation voltage, VREG, constant voltage regulation begins. The MCP73827 monitors the cell voltage at the VBAT pin. This input is tied directly to the positive terminal of the battery. The MCP73827 is offered in two fixed-voltage versions for battery packs with either coke or graphite anodes: 4.1V (MCP73827-4.1) and 4.2V (MCP73827-4.2).
4.1
Charge Qualification and Preconditioning
Upon insertion of a battery or application of an external supply, the MCP73827 verifies the state of the SHDN pin. The SHDN pin must be above the logic High level. If the SHDN pin is above the logic High level, the MCP73827 initiates a charge cycle. The charge status output, MODE, is pulled low throughout throughout the preconditioning and controlled current phases (see Table 5-1 for charge status outputs). If the cell is below the preconditioning threshold, 2.4V typically, the MCP73827 preconditions the cell with a scaled back current. The preconditioning current is set to approximately 43% of the fast charge peak current. The preconditioning safely replenishes deeply depleted cells and minimizes heat dissipation in the external pass transistor during the initial charge cycle.
4.4
Charge Cycle Completion
The charge cycle can be terminated by a host microcontroller when the output of the charge current monitor, IMON, has diminished below approximately 10% of the peak output voltage level. Alternatively, the transition of the charge status output, MODE, can be used to initialize a timer to terminate the charge. The charge is terminated by pulling the shutdown pin, SHDN, to a logic Low Level.
4.2
Controlled Current Regulation - Fast Charge
Preconditioning ends and fast charging begins when the cell voltage exceeds the preconditioning threshold. Fast charge utilizes a foldback current scheme based on the voltage at the VSNS input developed by the drop across an external sense resistor, RSENSE, and the output voltage, VBAT. Fast charge continues until the cell voltage reaches the regulation voltage, VREG.
(c) 2007 Microchip Technology Inc.
DS21704B-page 9
MCP73827
5.0
5.1
5.1.1
DETAILED DESCRIPTION
Analog Circuitry
CHARGE CURRENT MONITOR (IMON)
5.2
5.2.1
Digital Circuitry
SHUTDOWN INPUT (SHDN)
Refer to the typical application circuit, Figure 6-1.
The shutdown input pin, SHDN, can be used to terminate a charge anytime during the charge cycle, initiate a charge cycle, or initiate a recharge cycle. Applying a logic High input signal to the SHDN pin, or tying it to the input source, enables the device. Applying a logic Low input signal disables the device and terminates a charge cycle. In shutdown mode, the device's supply current is reduced to 0.5 A, typically. 5.2.2 CHARGE STATUS OUTPUT (MODE)
The IMON pin provides an output voltage that is proportional to the battery charging current. It is an amplified version of the sense resistor voltage drop that the current loop uses to control the external P-channel pass transistor. This voltage signal can be applied to the input of an A/D Converter and used by a host microcontroller to display information about the state of the battery or charge current profile. 5.1.2 CELL VOLTAGE MONITORED INPUT (VBAT)
The MCP73827 monitors the cell voltage at the VBAT pin. This input is tied directly to the positive terminal of the battery. The MCP73827 is offered in two fixed-voltage versions for single cells with either coke or graphite anodes: 4.1V (MCP73827-4.1) and 4.2V (MCP73827-4.2). 5.1.3 GATE DRIVE OUTPUT (VDRV)
A charge status output, MODE, provides information on the state of charge. The open drain output can be used to illuminate an external LED. Optionally, a pull-up resistor can be used on the output for communication with a microcontroller. Table 5-1 summarizes the state of the charge status output during a charge cycle.
Charge Cycle State Mode
Qualification Preconditioning Controlled Current Fast Charge Constant Voltage Disabled - Sleep mode Battery Disconnected TABLE 5-1: Charge Status Output.
OFF ON ON OFF OFF OFF
The MCP73827 controls the gate drive to an external P-channel MOSFET, Q1. 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 input supply falls below the voltage sensed on the VBAT input. 5.1.4 CURRENT SENSE INPUT (VSNS)
Fast charge current regulation is maintained by the voltage drop developed across an external sense resistor, RSENSE, applied to the VSNS input pin. The following formula calculates the value for RSENSE: V CS RSENSE = ----------I OUT Where: VCS is the current limit threshold IOUT is the desired peak fast charge current in amps. The preconditioning current is scaled to approximately 43% of IPEAK. 5.1.5 SUPPLY VOLTAGE (VIN)
The VIN input is the input supply to the MCP73827. The MCP73827 automatically enters a power-down mode if the voltage on the VIN input falls below the voltage on the VBAT pin. This feature prevents draining the battery pack when the VIN supply is not present.
DS21704B-page 10
(c) 2007 Microchip Technology Inc.
MCP73827
6.0 APPLICATIONS
lowed by constant voltage. Figure 6-1 depicts a typical stand-alone application circuit and Figure 6-2 depicts the accompanying charge profile. The MCP73827 is designed to operate in conjunction with a host microcontroller or in stand-alone applications. The MCP73827 provides the preferred charge algorithm for Lithium-Ion cells, controlled current folVOLTAGE REGULATED WALL CUBE
MA2Q705 332
RSENSE
Q1 NDS8434
IOUT
PACK+
10 F 22 k
100 m
10 F
SHDN 1 GND 2 MODE MCP73827 3 IMON 4 8 7 6 5
VIN VSNS VDRV VBAT + -
100 k
PACKSINGLE CELL LITHIUM-ION BATTERY PACK
FIGURE 6-1:
Typical Application Circuit.
PRECONDITIONING PHASE REGULATION VOLTAGE (VREG)
CONTROLLED CURRENT PHASE
CONSTANT VOLTAGE PHASE
CHARGE VOLTAGE
REGULATION CURRENT (IOUT(PEAK)) TRANSITION THRESHOLD
PRECONDITION CURRENT CHARGE CURRENT
5V MODE - CHARGE STATUS OUTPUT
0V 1.5V
IMON - CHARGE CURRENT MONITOR
0V
FIGURE 6-2:
Typical Charge Profile.
(c) 2007 Microchip Technology Inc.
DS21704B-page 11
MCP73827
6.1 Application Circuit Design
6.1.1.2 EXTERNAL PASS TRANSISTOR Due to the low efficiency of linear charging, the most important factors are thermal design and cost, which are a direct function of the input voltage, output current and thermal impedance between the external P-channel pass transistor, Q1, and the ambient cooling air. The worst-case situation is when the output is shorted. 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 charger. 6.1.1 COMPONENT SELECTION PowerDissipation = V INMAX x I OUT x K Where: VINMAX is the maximum input voltage IOUT is the maximum peak fast charge current K is the foldback current scale factor. Power dissipation with a 5V, +/-10% input voltage source, 100 m, 1% sense resistor, and a scale factor of 0.43 is: PowerDissipation = 5.5V x 758mA x 0.43 = 1.8W Utilizing a Fairchild NDS8434 or an International Rectifier IRF7404 mounted on a 1in2 pad of 2 oz. copper, the junction temperature rise is 90C, approximately. This would allow for a maximum operating ambient temperature of 60C. By increasing the size of the copper pad, a higher ambient 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 dissipation. Again, design tradeoffs should be considered to minimize size while maintaining the desired performance. Electrical Considerations The gate to source threshold voltage and RDSON of the external P-channel MOSFET must be considered in the design phase. The worst case, VGS provided by the controller occurs when the input voltage is at the minimum and the charge current is at the maximum. The worst case, VGS is: VGS = V DRVMAX - ( V INMIN - IOUT x R SENSE ) Where: VDRVMAX is the maximum sink voltage at the VDRV output The external P-channel MOSFET is determined by the gate to source threshold voltage, input voltage, output voltage, and peak fast charge current. The selected Pchannel MOSFET must satisfy the thermal 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 output is shorted. In this case, the power dissipation is:
Selection of the external components in Figure 6-1 is crucial to the integrity and reliability of the charging system. The following discussion is intended as 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. Charging at this rate provides the shortest charge cycle times without degradation to the battery pack performance or life. The current sense resistor, RSENSE, is calculated by: V CS RSENSE = ----------I OUT Where: VCS is the current limit threshold voltage IOUT is the desired fast charge current For the 500 mAH battery pack example, a standard value 100 m, 1% resistor provides a typical peak fast charge current of 530 mA and a maximum peak fast charge current of 758 mA. Worst case power dissipation in the sense resistor is:
2
PowerDissipation = 100m x 758mA = 57.5mW A Panasonic ERJ-L1WKF100U 100 m, 1%, 1 W resistor is more than sufficient for this application. A larger value sense resistor will decrease the peak fast charge current and power dissipation 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 desired performance.
DS21704B-page 12
(c) 2007 Microchip Technology Inc.
MCP73827
VINMIN is the minimum input voltage source IOUT is the maximum peak fast charge current RSENSE is the sense resistor Worst case, VGS with a 5V, +/-10% input voltage source, 100 m, 1% sense resistor, and a maximum sink voltage of 1.6V is: V GS = 1.6V - ( 4.5V - 758mA x 99m ) = - 2.8 V At this worst case VGS, the RDSON of the MOSFET must be low enough as to not impede the performance of the charging system. The maximum allowable RDSON at the worst case VGS is: VINMIN - I PEAK x R SENSE - V BATMAX RDSON = --------------------------------------------------------------------------------------------I OUT R DSON 4.5V - 758mA x 99m - 4.242V = -------------------------------------------------------------------------------- = 242m 758mA If a reverse protection diode is incorporated in the design, it should be chosen to handle the peak fast charge current continuously at the maximum ambient temperature. In addition, the reverse leakage current of the diode should be kept as small as possible. 6.1.1.5 SHUTDOWN INTERFACE
In the stand-alone configuration, the shutdown pin is generally tied to the input voltage. The MCP73827 will automatically enter a low power mode when the input voltage is less than the output voltage reducing the battery drain current to 8 A, typically. By connecting the shutdown pin as depicted in Figure 6-1, the battery drain current may be further reduced. In this application, the battery drain current becomes a function of the reverse leakage current of the reverse protection diode. 6.1.1.6 CHARGE STATUS INTERFACE
The Fairchild NDS8434 and International Rectifier IRF7404 both satisfy these requirements. 6.1.1.3 EXTERNAL CAPACITORS
The MCP73827 is stable with or without a battery load. In order to maintain good AC stability in the constant voltage mode, a minimum capacitance of 10 F is recommended to bypass the VBAT pin to GND. This capacitance provides compensation when there is no battery load. In addition, the battery and interconnections appear inductive at high frequencies. These elements are in the control feedback loop during constant voltage mode. Therefore, the bypass capacitance may be necessary to compensate for the inductive nature of the battery pack. Virtually any good quality output filter capacitor can be used, independent of the capacitor's minimum ESR (Effective Series Resistance) value. The actual value of the capacitor and its associated ESR depends on the forward trans conductance, gm, and capacitance of the external pass transistor. A 10 F tantalum or aluminum electrolytic capacitor at the output is usually sufficient to ensure stability for up to a 1 A output current. 6.1.1.4 REVERSE BLOCKING PROTECTION
The charge status indicator, MODE, can be utilized to illuminate an LED when the MCP73827 is in the controlled current phase. When the MCP73827 transitions to constant voltage mode, the MODE pin will transition to a high impedance state. A current limit resistor should be used in series with the LED to establish a nominal LED bias current of 10 mA. The maximum allowable sink current of the MODE pin is 30 mA.
6.2
PCB Layout Issues
For optimum voltage regulation, place the battery pack as close as possible to the device's VBAT and GND pins. It is recommended to minimize voltage drops along the high current carrying PCB traces. If the PCB layout is used as a heatsink, adding many vias around the external pass transistor can help conduct more heat to the back-plane of the PCB, thus reducing the maximum junction temperature.
The optional reverse blocking protection diode depicted in Figure 6-1 provides protection from a faulted or shorted input or from a reversed polarity input source. Without the protection diode, a faulted or shorted input would discharge the battery pack through the body diode of the external pass transistor.
(c) 2007 Microchip Technology Inc.
DS21704B-page 13
MCP73827
7.0
7.1
PACKAGING INFORMATION
Package Marking Information 8-Lead MSOP
XXXXXX YWWNNN
Example:
738271 e3 712NNN
Part Number MCP73827-4.1VUA MCP73827-4.2VUA
Code 738271 738272
Legend: XX...X Y YY WW NNN
e3
*
Customer-specific information Year code (last digit of calendar year) Year code (last 2 digits of calendar year) Week code (week of January 1 is week `01') Alphanumeric traceability code Pb-free JEDEC designator for Matte Tin (Sn) This package is Pb-free. The Pb-free JEDEC designator ( e3 ) can be found on the outer packaging for this package.
Note:
In the event the full Microchip part number cannot be marked on one line, it will be carried over to the next line, thus limiting the number of available characters for customer-specific information.
DS21704B-page 14
(c) 2007 Microchip Technology Inc.
MCP73827
8-Lead Plastic Micro Small Outline Package (MS or UA) [MSOP]
Note: For the most current package drawings, please see the Microchip Packaging Specification located at http://www.microchip.com/packaging
D N
E E1
NOTE 1 1 2 b A A2 c
e
A1
Units Dimension Limits Number of Pins Pitch Overall Height Molded Package Thickness Standoff Overall Width Molded Package Width Overall Length Foot Length Footprint Foot Angle Lead Thickness N e A A2 A1 E E1 D L L1 c
L1
MILLIMETERS MIN NOM 8 0.65 BSC - 0.75 0.00 - 0.85 - 4.90 BSC 3.00 BSC 3.00 BSC 0.40 0 0.08 0.60 0.95 REF - - 8 0.23 0.80 1.10 0.95 0.15 MAX
L
Lead Width b 0.22 - 0.40 Notes: 1. Pin 1 visual index feature may vary, but must be located within the hatched area. 2. Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not exceed 0.15 mm per side. 3. Dimensioning and tolerancing per ASME Y14.5M. BSC: Basic Dimension. Theoretically exact value shown without tolerances. REF: Reference Dimension, usually without tolerance, for information purposes only. Microchip Technology Drawing C04-111B
(c) 2007 Microchip Technology Inc.
DS21704B-page 15
MCP73827
NOTES:
DS21704B-page 16
(c) 2007 Microchip Technology Inc.
MCP73827
APPENDIX A: REVISION HISTORY
Revision B (February 2007) This revision includes updates to the packaging diagrams.
(c) 2007 Microchip Technology Inc.
DS21704B-page 17
MCP73827
PRODUCT IDENTIFICATION SYSTEM
To order or obtain information, e.g., on pricing or delivery, refer to the factory or the listed sales office. PART NO. Device -X.X Output Voltage X Temperature Range XX Package Examples:
a) b)
Device: MCP73827: Linear Charge Management Controller
MCP73827-4.1VUA: Linear Charge Management Controller, 4.1V
MCP73827-4.2VUA: Linear Charge Management Controller, 4.2V
c)
MCP73827-4.2VUATR: Linear Charge Management Controller, 4.2V, in tape and reel
Output Voltage:
4.1 = 4.1V 4.2 = 4.2V
Temperature Range:
V
= -20C to +85C
Package:
UA = Plastic Micro Small Outline (MSOP), 8-lead
DS21704B-page 18
(c) 2007 Microchip Technology Inc.
Note the following details of the code protection feature on Microchip devices: * * Microchip products meet the specification contained in their particular Microchip Data Sheet. Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the intended manner and under normal conditions. There are dishonest and possibly illegal methods used to breach the code protection feature. All of these methods, to our knowledge, require using the Microchip products in a manner outside the operating specifications contained in Microchip's Data Sheets. Most likely, the person doing so is engaged in theft of intellectual property. Microchip is willing to work with the customer who is concerned about the integrity of their code. Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code. Code protection does not mean that we are guaranteeing the product as "unbreakable."
*
* *
Code protection is constantly evolving. We at Microchip are committed to continuously improving the code protection features of our products. Attempts to break Microchip's code protection feature may be a violation of the Digital Millennium Copyright Act. If such acts allow unauthorized access to your software or other copyrighted work, you may have a right to sue for relief under that Act.
Information contained in this publication regarding device applications and the like is provided only for your convenience and may be superseded by updates. It is your responsibility to ensure that your application meets with your specifications. MICROCHIP MAKES NO REPRESENTATIONS OR WARRANTIES OF ANY KIND WHETHER EXPRESS OR IMPLIED, WRITTEN OR ORAL, STATUTORY OR OTHERWISE, RELATED TO THE INFORMATION, INCLUDING BUT NOT LIMITED TO ITS CONDITION, QUALITY, PERFORMANCE, MERCHANTABILITY OR FITNESS FOR PURPOSE. Microchip disclaims all liability arising from this information and its use. Use of Microchip devices in life support and/or safety applications is entirely at the buyer's risk, and the buyer agrees to defend, indemnify and hold harmless Microchip from any and all damages, claims, suits, or expenses resulting from such use. No licenses are conveyed, implicitly or otherwise, under any Microchip intellectual property rights.
Trademarks The Microchip name and logo, the Microchip logo, Accuron, dsPIC, KEELOQ, microID, MPLAB, PIC, PICmicro, PICSTART, PRO MATE, PowerSmart, rfPIC, and SmartShunt are registered trademarks of Microchip Technology Incorporated in the U.S.A. and other countries. AmpLab, FilterLab, Migratable Memory, MXDEV, MXLAB, SEEVAL, SmartSensor and The Embedded Control Solutions Company are registered trademarks of Microchip Technology Incorporated in the U.S.A. Analog-for-the-Digital Age, Application Maestro, CodeGuard, dsPICDEM, dsPICDEM.net, dsPICworks, ECAN, ECONOMONITOR, FanSense, FlexROM, fuzzyLAB, In-Circuit Serial Programming, ICSP, ICEPIC, Linear Active Thermistor, Mindi, MiWi, MPASM, MPLIB, MPLINK, PICkit, PICDEM, PICDEM.net, PICLAB, PICtail, PowerCal, PowerInfo, PowerMate, PowerTool, REAL ICE, rfLAB, rfPICDEM, Select Mode, Smart Serial, SmartTel, Total Endurance, UNI/O, WiperLock and ZENA are trademarks of Microchip Technology Incorporated in the U.S.A. and other countries. SQTP is a service mark of Microchip Technology Incorporated in the U.S.A. All other trademarks mentioned herein are property of their respective companies. (c) 2007, Microchip Technology Incorporated, Printed in the U.S.A., All Rights Reserved. Printed on recycled paper.
Microchip received ISO/TS-16949:2002 certification for its worldwide headquarters, design and wafer fabrication facilities in Chandler and Tempe, Arizona, Gresham, Oregon and Mountain View, California. The Company's quality system processes and procedures are for its PIC(R) MCUs and dsPIC DSCs, KEELOQ(R) code hopping devices, Serial EEPROMs, microperipherals, nonvolatile memory and analog products. In addition, Microchip's quality system for the design and manufacture of development systems is ISO 9001:2000 certified.
(c) 2007 Microchip Technology Inc.
DS21704B-page 19
WORLDWIDE SALES AND SERVICE
AMERICAS
Corporate Office 2355 West Chandler Blvd. Chandler, AZ 85224-6199 Tel: 480-792-7200 Fax: 480-792-7277 Technical Support: http://support.microchip.com Web Address: www.microchip.com Atlanta Duluth, GA Tel: 678-957-9614 Fax: 678-957-1455 Boston Westborough, MA Tel: 774-760-0087 Fax: 774-760-0088 Chicago Itasca, IL Tel: 630-285-0071 Fax: 630-285-0075 Dallas Addison, TX Tel: 972-818-7423 Fax: 972-818-2924 Detroit Farmington Hills, MI Tel: 248-538-2250 Fax: 248-538-2260 Kokomo Kokomo, IN Tel: 765-864-8360 Fax: 765-864-8387 Los Angeles Mission Viejo, CA Tel: 949-462-9523 Fax: 949-462-9608 Santa Clara Santa Clara, CA Tel: 408-961-6444 Fax: 408-961-6445 Toronto Mississauga, Ontario, Canada Tel: 905-673-0699 Fax: 905-673-6509
ASIA/PACIFIC
Asia Pacific Office Suites 3707-14, 37th Floor Tower 6, The Gateway Habour City, Kowloon Hong Kong Tel: 852-2401-1200 Fax: 852-2401-3431 Australia - Sydney Tel: 61-2-9868-6733 Fax: 61-2-9868-6755 China - Beijing Tel: 86-10-8528-2100 Fax: 86-10-8528-2104 China - Chengdu Tel: 86-28-8665-5511 Fax: 86-28-8665-7889 China - Fuzhou Tel: 86-591-8750-3506 Fax: 86-591-8750-3521 China - Hong Kong SAR Tel: 852-2401-1200 Fax: 852-2401-3431 China - Qingdao Tel: 86-532-8502-7355 Fax: 86-532-8502-7205 China - Shanghai Tel: 86-21-5407-5533 Fax: 86-21-5407-5066 China - Shenyang Tel: 86-24-2334-2829 Fax: 86-24-2334-2393 China - Shenzhen Tel: 86-755-8203-2660 Fax: 86-755-8203-1760 China - Shunde Tel: 86-757-2839-5507 Fax: 86-757-2839-5571 China - Wuhan Tel: 86-27-5980-5300 Fax: 86-27-5980-5118 China - Xian Tel: 86-29-8833-7250 Fax: 86-29-8833-7256
ASIA/PACIFIC
India - Bangalore Tel: 91-80-4182-8400 Fax: 91-80-4182-8422 India - New Delhi Tel: 91-11-4160-8631 Fax: 91-11-4160-8632 India - Pune Tel: 91-20-2566-1512 Fax: 91-20-2566-1513 Japan - Yokohama Tel: 81-45-471- 6166 Fax: 81-45-471-6122 Korea - Gumi Tel: 82-54-473-4301 Fax: 82-54-473-4302 Korea - Seoul Tel: 82-2-554-7200 Fax: 82-2-558-5932 or 82-2-558-5934 Malaysia - Penang Tel: 60-4-646-8870 Fax: 60-4-646-5086 Philippines - Manila Tel: 63-2-634-9065 Fax: 63-2-634-9069 Singapore Tel: 65-6334-8870 Fax: 65-6334-8850 Taiwan - Hsin Chu Tel: 886-3-572-9526 Fax: 886-3-572-6459 Taiwan - Kaohsiung Tel: 886-7-536-4818 Fax: 886-7-536-4803 Taiwan - Taipei Tel: 886-2-2500-6610 Fax: 886-2-2508-0102 Thailand - Bangkok Tel: 66-2-694-1351 Fax: 66-2-694-1350
EUROPE
Austria - Wels Tel: 43-7242-2244-39 Fax: 43-7242-2244-393 Denmark - Copenhagen Tel: 45-4450-2828 Fax: 45-4485-2829 France - Paris Tel: 33-1-69-53-63-20 Fax: 33-1-69-30-90-79 Germany - Munich Tel: 49-89-627-144-0 Fax: 49-89-627-144-44 Italy - Milan Tel: 39-0331-742611 Fax: 39-0331-466781 Netherlands - Drunen Tel: 31-416-690399 Fax: 31-416-690340 Spain - Madrid Tel: 34-91-708-08-90 Fax: 34-91-708-08-91 UK - Wokingham Tel: 44-118-921-5869 Fax: 44-118-921-5820
12/08/06
DS21704B-page 20
(c) 2007 Microchip Technology Inc.

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