Datasheet MP2611GL Datasheet (MPS) [ru]

Page 1

MP2611

2A, 1-Cell Li-Ion Battery Switching Charger

The Future of Analog IC Technology

DESCRIPTION

The MP2611 is a monolithic switching charger with built-in power MOSFETs for a single-cell Li-Ion battery pack. It achieves up to a 2Acharge current that can be programmed through an accurate sense resistor over the whole input range. It can operate from separate inputs for USB or AC adapter: For USB input, the input current limit can be programmed to 500mA and 900mA through the USBM pin to cover both USB2.0 and USB3.0 standards.

The MP2611 regulates the charge current and battery voltage using two control loops to realize highly accurate constant-current charge and constant-voltage charge. A 100% duty cycle can be achieved when battery voltage is close to the input voltage due to the high-side P-Channel MOSFET.

Battery charge temperature and charging status are always monitored for each condition. Two status-monitor output pins indicate the battery charging status and input status. The MP2611 also features internal reverse-blocking protection.

The MP2611 is available in a 3mm x 4mm QFN14 package.

For USB and Adapter Power

FEATURES

• 4.5V-to-6V Operating Input Voltage

• Up to 100% Duty Operation.

• Up to 2A Programmable Charge Current

• ±0.5% Battery Voltage Accuracy

• Separate Inputs for USB and AC Adapter

• Fully-Integrated Power Switches

• Programmable Input Current Limit for the

USB Port

• No External Reverse Blocking Diode Required

• Charging Operation Indicators

• Programmable Safety Timer

• Thermal Shutdown

• Cycle-by-Cycle Over Current Protection

• Battery Temperature Monitor and Protection

APPLICATIONS

• Smartphones

• Portable Hand-Held Solutions

• Portable Media Players

All MPS parts are lead-free and adhere to the RoHS directive. For MPS green status, please visit MPS website under Products, Quality Assurance page.

“MPS” and “The Future of Analog IC Technology” are registered trademarks of Monolithic Power Systems, Inc.

TYPICAL APPLICATION

AC Adapter

Input

USB Port

NTC

1.5k

22uF

1uF

USBIN

STAT1

STAT2

VREF33

NTC

ACIN

MP2611

AGND

CSP

BATT

PGND

USBM

TMR

2.2uH

TMR

0.1uF

OFF

ILIM

RS1

50m

22uF

1-cell

battery

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MP2611 – 2A, 1-CELL SWITCHING CHARGER FOR USB AND ADAPTER POWER

ORDERING INFORMATION

Part Number* Package Top Marking

MP2611GL QFN14 (3x4mm) 2611

* For Tape & Reel, add suffix –Z (eg. MP2611GL–Z);

PACKAGE REFERENCE

TOP VIEW

EXPOSED PAD

ON BACKSIDE

ABSOLUTE MAXIMUM RATINGS

(1)

ACIN ........................................................... 7.5V

USBIN......................................................... 7.5V

SW ..................................... -0.3V to (V

+ 0.3V)

CSP, BATT .......................................-0.3V to 6V

All the Other Pins..............................-0.3V to 6V

Continuous Power Dissipation (T

=25°C)

(2)

............................................................. 2.6W

Junction Temperature...............................150°C

Lead Temperature ....................................260°C

Storage Temperature................. -65°C to 150°C

Recommended Operating Conditions

(3)

ACIN ..................................................4.5V to 6V

USBIN................................................4.5V to 6V

Operating Junction Temp. (T

)..-40°C to +125°C

Thermal Resistance

(4)

θJC

QFN14 (3mm x 4mm) ............. 48 ...... 10... °C/W

Notes:

1) Exceeding these ratings may damage the device.

2) The maximum allowable power dissipation is a function of the

maximum junction temperature T ambient thermal resistance 

. The maximum allowable continuous power dissipation at

any ambient temperature is calculated by P (MAX)-TA)/JA. Exceeding the maximum allowable power dissipation will cause excessive die temperature, and the regulator will go into thermal shutdown. Internal thermal shutdown circuitry protects the device from permanent damage.

3) The device is not guaranteed to function outside of its

operating conditions.

4) Measured on JESD51-7, 4-layer PCB.

(MAX), the junction-to-

, and the ambient temperature

(MAX) = (T

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MP2611 – 2A, 1-CELL SWITCHING CHARGER FOR USB AND ADAPTER POWER

ELECTRICAL CHARACTERISTICS

(5)

= 5V, TA= 25°C, Unless Otherwise Noted.

Parameters Symbol Condition Min Typ Max Units

AC Input

ACIN Operating Range V

ACIN Under Voltage Lockout (UVLO) Rising Threshold

ACIN Under Voltage Lockout (UVLO) Threshold Hysteresis

Switching Frequency fS 1.5 MHz

Constant Charger Current ICC RS1=50m 1.8 2 2.2 A

High-side PFET On Resistance R

Low-side NMOS On Resistance R

High-side PFET Peak Current Limit 3 3.5 A

Dead Time 10 ns

4.5 5 6 V

ACIN

3.55 3.75 3.95 V

UVLO

200 mV

H_DS(ON)

L_DS(ON)

130 m

200 m

Supply Current IIN

EN =0V, No load

EN =4V

2.0 mA

20 A

USB Input

USBIN Operating Range V

USBIN Under Voltage Lockout (UVLO) Rising Threshold

USBIN Under Voltage Lockout (UVLO) Threshold Hysteresis

USB Input Current limit I

4.5 5 6 V

USBIN

3.55 3.75 3.95 V

UVLO

200 mV

=82.5k,

USB_LIM

ILIM

= 5V, V

USBIN

=45.3k,

ILIM

= 5V, V

USBIN

BATT

=4V

450 500 mA

810 900 mA

High-side PFET On Resistance 110 m

USB Supply Current

EN =0V, No load

EN =4V, No load

2.0 mA

30 A

Battery Charger

Terminal Battery Voltage V

BATT_FULLVIN

Battery Over-Voltage Threshold V

Recharge Threshold at V

BATT

BOVP

RECHG

=5V 4.179 4.2 4.221 V

VIN=5V 4.26 4.34 4.42 V

4.0 V

Recharge Hysteresis 100 mV

Trickle-Charge Threshold VTC 3 V

Trickle-Charger Hysteresis 300 mV

Trickle-Charge Current ITC 10 15 %I

Termination Charge Current IBF 5 10 15 %I

Maximum Current-Sense Voltage (CSP to BATT)

STAT1/STAT2 Open-Drain Sink Current V

100 mV

=0.3V 9 mA

DRAIN

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MP2611 – 2A, 1-CELL SWITCHING CHARGER FOR USB AND ADAPTER POWER

ELECTRICAL CHARACTERISTICS (continued)

(5)

= 5V, TA= 25°C, Unless Otherwise Noted.

Parameters Symbol Condition Min Typ Max Units

VIN Min Head-room (Reverse Blocking) VIN-V

CSP, BATT Current I

CSP,IBATT

Charging Disabled 1 µA

Protection

Trickle-Charge Time C

Total Charge Time C

NTC High Temp. Rising Threshold V

NTC Low Temp. Falling Threshold V

Thermal Shutdown

(6)

TH_HighRNTC

TH_Low

SHTDWN

TMR

=NCP18XH103,50°C 30 32 34 %V

=NCP18XH103, 0°C 72 74 76 %V

NTC

EN Logic

EN Input Low Voltage

EN Input High Voltage

0.8 V

1.2 V

EN =4V

EN Input Current

VREF33 Output Voltage V

VREF33 Load Regulation V

Notes:

represents V

5) V

6) Guaranteed by design..

ACIN

or V

which depends on the input mode. The following is the same.

USBIN

VREF33

EN =0V

=0 to 20mA 0.2 V

LOAD

200 mV

BATT

=0.1µF 30 min

=0.1µF 180 min

REF33

150 °C

A

0.2

3.23 3.3 3.37 V

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MP2611 – 2A, 1-CELL SWITCHING CHARGER FOR USB AND ADAPTER POWER

TYPICAL CHARACTERISTICS

VIN=5V, C1=C2=22µF, C4=22µF, C Simulator, Unless Otherwise Noted.

BATT Voltage Accuracy vs. Temperature

AC/USB Mode

0.8

0.6

0.4

0.2

0.0

-0.2

-0.4

-0.6

-0.8

-1.0

-1.2

-1.4

-1.6

-40-25 -10 5 20 35 50 65 80 95110125

1.0

0.8

0.6

0.4

0.2

0.0

-0.2

-0.4

-0.6

-0.8

-1.0

-40-25-10 5 20 35 50 65 80 95110125

=0.1µF, L=1.5µH, RS1=50m, R

TMR

Charge Current Accuracy vs. Temperature

AC/USB Mode

1.50

1.25

1.00

0.75

0.50

0.25

0.00

-0.25

-0.50

-0.75

-1.00

-1.25

-1.50

-40-25-10 5 20 35 50 65 80 95 110125

=40.2k, Battery

ILIM

USB Current Limit Accuracy vs. Temperature

USB Mode, I

USB_LIM

=500mA

VREF Accuracy vs. Temperature

AC/USB Mode

1.20

1.00

0.80

0.60

0.40

0.20

0.00

-0.20

-0.40

-0.60

-0.80

-1.00

-1.20

-40-25-10 5 20 35 50 65 80 95110125

Quiescent Current vs. Temperature

VEN=0V, AC/USB Mode

2.0

1.8

1.6

1.4

1.2

1.0

0.8

0.6

QUIESCENT CURRENT (mA)

0.4

-40-25-10 5 20 35 50 65 80 95110125

Shutdown Current vs. Temperature

VEN=4V (Disabled), AC/USB Mode

-40-25-10 5 20 35 50 65 80 95 110125

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MP2611 – 2A, 1-CELL SWITCHING CHARGER FOR USB AND ADAPTER POWER

TYPICAL PERFORMANCE CHARACTERISTICS

VIN=5V, C1=C2=22µF, C4=22µF, C Simulator, Unless Otherwise Noted.

Breakdown Voltage

AC/USB Mode

4000

3500

3000

2500

2000

1500

1000

500

0123456789

INPUT VOLTAGE(V)

=0.1µF, L=1.5µH, RS1=50m, R

TMR

Battery Reverse Current

AC/USB Mode, VIN=PGND/Float

2.0

1.8

1.6

1.4

1.2

1.0

0.8

0.6

0.4

0.2

1.5 2 2.5 3 3.5 4 4.5 BATTERY VOTLAGE (V)

=40.2k, Battery

ILIM

Shutdown Current

VEN=4V (Disabled), AC/USB Mode

1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5

INPUT VOLTAGE (V)

Charge Full Voltage Accuracy vs. V

AC/USB Mode

0.100

0.075

0.050

0.025

0.000

-0.025

-0.050

-0.075

-0.100

4.5 4.9 5.3 5.7 6.1 6.5

VREF33 Regulation Accuracy

RS1=50m, AC Mode

0.20

0.15

0.10

0.05

0.00

-0.05

-0.10

-0.15

-0.20

-0.25

-0.30

-0.35

-0.40

-0.45

-0.50

4.5 5.0 5.5 6.0 6.5 INPUT VOLTAGE(V) BATTERY VOLTAGE (V)

BATT

Battery Float

=3.7V

Charge Current Accuracy vs. V

AC Mode

0.30

0.20

0.10

0.00

-0.10

-0.20

-0.30

4.5 4.9 5.3 5.7 6.1 6.5 INPUT VOLTAGE(V)INPUT VOLTAGE(V)

USBM Input Current Limit vs. 1000/R

USB Mode

1000

900

800

700

600

500

400

300

200

100

USB INPUT CURRENT LIMIT (mA)

0 5 10 15 20 25

ILIM

USBM Input Current Limit Accuracy

USB Mode

-5 0 200 400 600 800 1000

USB_LIM

SET POINT (mA)

Case Temperature vs. Battery Voltage

RS1=50m, AC Mode

100

3.0 3.2 3.4 3.6 3.8 4.0 4.2

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MP2611 – 2A, 1-CELL SWITCHING CHARGER FOR USB AND ADAPTER POWER

TYPICAL PERFORMANCE CHARACTERISTICS

VIN=5V, C1=C2=22µF, C4=22µF, C Simulator, Unless Otherwise Noted.

AC Mode Charge Curve

2.2

2.0

1.8

1.6

1.4

1.2

1.0

0.8

0.6

0.4

CHARGE CURRENT(A)

0.2 0

1.6 1.9 2.2 2.5 2.8 3.1 3.4 3.7 4.0 4.3

BATTERY VOLTAGE(V)

ACIN

=4.5V

=5V

Frequency vs. Battery Voltage

AC Mode

1800

1600

1400

1200

1000

800

FREQUENCY (kHz)

600

400

200

ACIN

1 1.4 1.8 2.2 2.6 3.0 3.4 3.8 4.2

BATTERY VOLTAGE(V)

=5V

ACIN

=4.5V

=6V

=0.1µF, L=1.5µH, RS1=50m, R

TMR

USB Mode Charge Curve USB Mode Charge Curve

1.6

1.4

1.2

0.8

0.6

0.4

CHARGE CURRENT (A)

0.2

1.6 1.9 2.2 2.5 2.8 3.1 3.4 3.7 4.0 4.3

BATTERY VOLTAGE (V)

USBIN

=5.5V

=5V

=4.5V

Frequency vs. Battery Voltage

USB Mode

1800

1600

1400

1200

1000

800

600

400

FREQUENCY (kHz)

200

1 1.4 1.8 2.2 2.6 3.0 3.4 3.8 4.2

BATTERY VOLTAGE (V)

USBIN

>5V

=4.5V

(continued)

2.5

1.5

0.5

CHARGE CURRENT (A)

USB_LIM

1.6 1.9 2.2 2.5 2.8 3.1 3.4 3.7 4.0 4.3

AC Mode Efficiency in TC/CC Charge

100

1.0 1.4 1.8 2.2 2.6 3.0 3.4 3.8 4.2

=40.2k, Battery

ILIM

USB_LIM

=2A

USB_LIM

=1.5A

=1A

=0.5A

BATTERY VOLTAGE(V)

=4.5V

ACIN

BATTERY VOLTAGE (V)

=6V

ACIN

=5V

CV Charge

100

400 800 1200 1600 2000

ACIN

=5V

ACIN

=4.5V

=6V

USB Mode EfficiencyAC Mode Efficiency in

100

=4.5V

USBIN

1.0 1.4 1.8 2.2 2.6 3.0 3.4 3.8 4.2 BATTERY VOLTAGE (V)CHARGE CURRENT (mA)

USBIN

=5V

USBIN

=5.5V

200mV/div.

VREF Startup Waveform

=3.7V, En On

BATT

REF33

2V/div.

STAT2 2V/div.

STAT 1 2V/div.

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MP2611 – 2A, 1-CELL SWITCHING CHARGER FOR USB AND ADAPTER POWER

TYPICAL PERFORMANCE CHARACTERISTICS

VIN=5V, C1=C2=22µF, C4=22µF, C Simulator, Unless Otherwise Noted.

BATT Float Waveform

USB/AC Mode

2V/div.

BATT

1V/div.

2V/div.

500mA/div.

Low Input Voltage Charge State

ACIN

1V/div.

BATT

1V/div.

2V/div.

1A/div.

AC Mode, V

ACIN

=4.5V, V

BATT

=4.02V

=0.1µF, L=1.5µH, RS1=50m, R

TMR

Low Input Voltage Charge State

ACIN

1V/div.

BATT

1V/div.

2V/div.

1A/div.

AC Mode, V

ACIN

=4.5V, V

BATT

Low Input Voltage Charge State

ACIN

1V/div.

BATT

1V/div.

2V/div.

1A/div.

AC Mode, V

ACIN

=4.5V, V

BATT

(continued)

=3.8V

ACIN

1V/div.

BATT

1V/div.

2V/div.

1A/div.

=4.18V

2V/div.

BATT

500mV/div.

2V/div.

500mA/div.

=40.2k, Battery

ILIM

Low Input Voltage Charge State

AC Mode, V

ACIN

=4.5V, V

BATT

=4V

TC Charge Steady State

AC/USB Mode, V

BATT

=1.5V

ACIN

2V/div.

BATT

1V/div.

2V/div.

500mA/div.

CC Charge Steady State

AC Mode, V

ACIN

=5V, V

BATT

=3.8V

500mA/div.

CC Charge Steady State

ACIN

1V/div.

BATT

1V/div.

2V/div.

USB Mode, V

USBIN

=5V, V

BATT

=3.8V

2V/div.

BATT

1V/div.

2V/div.

200mA/div.

CV Charge Steady State

AC / USB Mode, V

BATT

=4.2V

Page 9

MP2611 – 2A, 1-CELL SWITCHING CHARGER FOR USB AND ADAPTER POWER

TYPICAL PERFORMANCE CHARACTERISTICS

VIN=5V, C1=C2=22µF, C4=22µF, C Simulator, Unless Otherwise Noted.

Power On

BATT

2V/div.

ACIN

2V/div.

CHG

1A/div.

AC Mode, V

BATT

=3.8V

2V/div.

BATT

1V/div.

5V/div.

1A/div.

En Off

2V/div.

BATT

1V/div.

5V/div.

CHG

1A/div.

AC Mode, V

BATT

=3.8V

USBIN

1V/div.

1A/div.

=0.1µF, L=1.5µH, RS1=50m, R

TMR

Power Off

ACIN

CHG

AC Mode, V

BATT

=3.8V

AC Adapter Insertion

BATT

ACIN

CHG

ACIN

=6V, V

USBIN

=4.5V, V

BATT

(continued)

2V/div.

BATT

1V/div.

5V/div.

CHG

1A/div.

=4.1V

ACIN

1V/div.

USBIN

1V/div.

BATT

1V/div.

CHG

1A/div.

=40.2k, Battery

ILIM

En On

AC Mode, V

BATT=

3.8V

AC Adapter Removal

ACIN

=6V, V

USBIN

=4.5V, V

BATT

=4.1V

NTC

2V/div.

BATT

1V/div.

5V/div.

CHG

1A/div.

NTC Control

=3.7V

BATT

TMR

1V/div.

STAT 2 2V/div.

STAT 1 2V/div.

CHG

1A/div.

Timer Out

CTMR=150pF, V

BATT

=3.7V

Short-Circuit Protection

2V/div.

BATT

2V/div.

5V/div.

1A/div.

Page 10

MP2611 – 2A, 1-CELL SWITCHING CHARGER FOR USB AND ADAPTER POWER

PIN FUNCTIONS

Package

Pin #

1 ACIN

2 PGND

3 SW Switch Output. Connect to the switched side of the external inductor.

4 USBIN

5 AGND Analog Ground.

6 VREF33 Internal Linear Regulator Reference Output. Powered from ACIN or USBIN.

7 USBM

8 BATT Positive Battery Terminal.

9 CSP

13 NTC

14 TMR

Name Description

AC Adapter Power Input. Bypass ACIN to PGND with at least a 4.7F ceramic capacitor when the pin is not applied for powering.

Power Ground. Voltage reference for the regulated output voltage: Take extra care with its layout. Place this node should be placed outside of the switching diode (SW-pin) to the input ground path to prevent switching current spikes from inducing voltage noise into the part.

USB Power Input. Bypass USBIN to PGND with at least a 4.7F ceramic capacitor when the pin is not applied for powering.

USB Input Current-Limit Set. Connect a resistor from this pin to AGND to program the USB mode input current limit.

Battery Current Sense Positive Input. Connect resistor RS1 between CSP and BATT to sense the charge current.

STAT1

STAT2

On/Off Control Input.

Charging Status Indicator: 1. Charging; 2. End of charge; 3. Charging Suspended;

4. Fault; 5. Invalid Input Supply.

Thermistor Input. Connect a resistor from this pin to the VREF33 and the thermistor from this pin to AGND.

Internal Safety Timer Control. Connect a capacitor from this node to AGND to set the timer. And the timer can be disabled by connecting this pin to AGND.

Page 11

MP2611 – 2A, 1-CELL SWITCHING CHARGER FOR USB AND ADAPTER POWER

BLOCK DIAGRAM

Figure 1: Functional Block Diagram

Page 12

MP2611 – 2A, 1-CELL SWITCHING CHARGER FOR USB AND ADAPTER POWER

OPERATION

The MP2611 is a monolithic switching charger with built-in power MOSFETs for a single-cell LiIon battery pack. It achieves up to a 2A charge current that can be programmed through an accurate sense resistor over the whole input range. It can operate with separate inputs for USB and AC adapter: For USB mode, the input current limit can be programmed to 500mA and 900mA via the USBM-pin for both USB2.0 and USB3.0.

Charge Cycle (Trickle ChargeÆ CC ChargeÆ CV Charge)

The MP2611 regulates the charge current (I and battery voltage (V

) using two control

BATT

loops to realize highly-accurate constant current (CC) charge and constant voltage (CV) charge.

The device uses the resistor RS1 to sense the battery charge current and amplifies the signal using the internal amplifier A3 (Figure 1). The charge starts in trickle-charge mode (TC, 10% of the constant current I

) until the battery voltage

reaches 3V. If the charger stays in the tricklecharge mode until it triggers a time-out condition, the charging terminates. Otherwise, the charger operates in constant-current charging mode. The COMPI voltage, regulated by the amplifier GMI, determines the duty cycle.

CHG

)

ACIN and USBIN Detection

There are two separate battery charger inputs; ACIN for the AC adapter, and USBIN for the USB port.

ACIN is used as the battery-charger primary power supply. As soon as the ACIN voltage exceeds ACIN UVLO (3.75V), Q1 turns on and Q2 turns off. The adapter charges the battery with up to 2A constant charge current through the step-down DC/DC converter implemented by Q1 and Q3. The charge current can be set by RS1.

If the ACIN input is absent or less than 3.75V, the USBIN can act as the power supply for the battery charger: Q1 turns off and Q2 turns on. USB supply mode uses the input current limit loop so that the threshold can be programmed by connecting a resistor R

from the USBM-pin to

ILIM

AGND.

When ACIN and USBIN are both absent, Q1 and Q2 are completely off and the reverse blocking function blocks the battery reverse-leakage current to the input port.

Note that if ACIN and USBIN are both present, the device selects the AC adapter as the power supply of the charger. However, avoid this practice.

DC/DC Converter

When the battery voltage rises to the constantvoltage mode threshold, the amplifier GMV regulates the COMP-pin and the duty cycle. Consequently, the charger operates in constantvoltage mode.

The MP2611 integrates both the high-side switch and the synchronous low-side switch, which provides high efficiency and eliminates the external Schottky diode.

During normal operation, the high-side switch turns on for a period of time to ramp-up the inductor current at each rising edge of the internal oscillator, and switches off when the peak inductor current rises above the COMP voltage. Once the high-side switch turns off, the synchronous switch turns on immediately and stays on until the next cycle starts (see Figure 1).

The device allows the high-side switch to remain on for more than one switching cycle and increases the duty cycle while the input voltage drops close to the output voltage. When the duty

Figure 2: Li-Ion Battery Charge Profile

cycle reaches 100%, the high-side switch is held on continuously to deliver current to the output.

Page 13

MP2611 – 2A, 1-CELL SWITCHING CHARGER FOR USB AND ADAPTER POWER

Charge-Full Termination and Auto-Recharge

When the charge current drops below the termination threshold (I

) during the CV charge

phase, the charger ceases charging and the

STAT1

-pin becomes an open drain. The timer will also be reset and turned off. If the battery voltage falls below 4.0V, auto-recharge begins and the timer

restarts a new charge cycle.

Charger Status Indication

STAT1

and

STAT2

are two open-drain NMOS outputs that must connect to the VREF33 output or some other bias power supply through pull-up resistors. Their output logic level combinations indicate three status of the charger:

Table 1: Charging Status Indicator

STAT2

STAT1

Charger Status

Low Low Charging

End of Charge; Faults

Low High

(Thermal Shutdown;

Time-Out; NTC Fault)

Input Power Absent;

High High

IN-VBATT

<0.2V;

Disabled

Safety Timer Operation

The MP2611 adopts an internal timer to terminate charging if the timer times out. An external capacitor on the TMR-pin programs the timer duration.

The trickle mode charge time is:

t30(minutes)

Trickle_tmr

=×

TMR

0.1F

The total charge time is:

0.1F

TMR

Where C

t =3 (hours)

Total_tmr

is the capacitor connected from

TMR

TMR-pin to GND. The timer can be disabled by pulling TMR to GND.

The charger can exit the timer-out fault state and initiates a new charge cycle when one of the following conditions occurs:

(a) The battery voltage falls below the auto-

recharge threshold V

RECHG

;

(b) A power-on-reset (POR) event occurs;

(c)

is toggled.

Negative Thermal Coefficient (NTC) Thermistor

The MP2611 has a built-in NTC window comparator that allows it to sense the battery temperature via the thermistor packed internally in the battery. It ensures a safe battery operating environment. Connect an appropriately-valued resistor from VREF33 to the NTC-pin and connect the thermistor from the NTC-pin to AGND. The resistor divider with a dividing ratio depends on the battery temperature determins the voltage on the NTC-pin. Once the voltage at the NTC-pin is out of the NTC window, the MP2611 stops charging. The charger restarts if the voltage re-enters the NTC window range.

Short Circuit Protection

The MP2611 has an internal comparator to check for battery short circuit. Once V

falls below 2V,

BATT

the device detects a battery-short status and the cycle-by-cycle peak current limit falls to about 2A to limit the current spike during the battery-short transition. Furthermore, the switching frequency also folds back to minimize the power loss.

Thermal Shutdown Protection

To prevent the chip from overheating during charging, the MP2611 monitors the junction temperature, T thermal shutdown threshold (T

, of the die. Once TJ reaches the

SHTDWN

) of 150°C, the charger converter turns off. Charging restarts when T

falls below 130°C.

If a timer-out event occurs, the charging will be terminated and the

STAT1

will become an open

drain to indicate the fault.

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MP2611 – 2A, 1-CELL SWITCHING CHARGER FOR USB AND ADAPTER POWER

BATTERY CHARGE TIMING DIAGRAM

Figure 3: Battery Charge Timing Diagram

Note:

7) The

STAT1

and

are pulled up to VREF33 with an 1k resistor respectively.

STAT2

Page 15

MP2611 – 2A, 1-CELL SWITCHING CHARGER FOR USB AND ADAPTER POWER

OPERATION FLOW CHART

Figure 4: Normal Charging Operation and Fault Protection Flow Chart

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MP2611 – 2A, 1-CELL SWITCHING CHARGER FOR USB AND ADAPTER POWER

⋅

APPLICATION INFORMATION

Setting the Charge Current in AC Mode

In AC mode, RS1 sets the charge current (I of the MP2611 (see Typical Application). The equation to determine the programmable CCcharge is as follows:

CHG

)

Where V

is trickle charge threshold (3V) and η

is the current charge efficiency. Assume V

USBIN

CC_MAX

=5.5V, I

= 2.28A.

USB_LIM

=1.5A , =83%, thus

Assume I

100mV

=2A, thus: RS1=50m.

(1)

(A)

)RS1(m

For either AC mode or USB mode, the trickle charge current is given by the following equation:

10%II

CCTC

10mV

(A)

)RS1(m

(2)

Setting the USB Input Current Limit

In USB supply mode, connect a resistor from the USBM pin to AGND to program the input current limit for different USB ports. The relationship between the input current limit and setting resistor is as following:

Where R

USB_LIM

is greater than 18.5k so that I

ILIM

37000

ILIM

(mA)

)(kR

(3)

USB_LIM

is in the range of 0A to 2A. If using a resistor smaller than 18.5k, the MP2611 suppresses I applications, use a 45.3k R for USB3.0 mode, and use a 82.5k R (I

to a value less than 2A. For most

USB_LIM

ILIM

USB_LIM

=500mA) for USB2.0 mode.

USB_LIM

=900mA)

ILIM

Note that in USB mode, the MP2611 doesn’t monitor the charge current through RS1 during CC charge phase, but regulates the input current constant at the limitation value I

USB_LIM

. Thus the CC charge current varies with different input and battery voltages. Figure 5 shows the charge current vs. battery voltage curve when V

=5.5V.

USBIN

The maximum CC charge value can be calculated as:

IV

CC_MAX

USB_LIMUSBIN

⋅

(4)

(A)

Figure 5: I

Variation with V

CHG

USBIN

=5.5V

For certain battery packs, the CC charge current should never go too high so set the I on the I

CC_MAX

USB_LIM

based

Selecting the Inductor

Inductor selection trades off between cost, size, and efficiency. A lower inductance value corresponds with smaller size, but results in higher ripple currents, higher magnetic hysteretic losses, and higher output capacitances. However, a higher inductance value benefits from lower ripple current and smaller output filter capacitors, but results in higher inductor DC resistance (DCR) loss. From a practical standpoint, the inductor ripple current does not exceed 15% of the maximum charge current under worst cases. For a MP2611 with a typical 5V input voltage, the maximum inductor current ripple occurs at the corner point between trickle charge and CC charge (V

=3V). Estimate the required

BATT

inductance as:

Where V

, V

L⋅=

BATT

V-V

I

L_MAX

, and fS are the typical input

BATTIN

BATT

(5)

SIN

voltage, the CC charge threshold, and the switching frequency, respectively.

I

L_MAX

is the

maximum inductor ripple current ,which is usually 15% of the CC charge current.

Page 17

MP2611 – 2A, 1-CELL SWITCHING CHARGER FOR USB AND ADAPTER POWER

For I

=2A, VIN=5V, V

15%I=I

=3V and fs=1.5MHz, the

BATT

(6)

CCL_MAX

calculated inductance is 2.66µH. The maximum inductor peak current must exceed 2.3A. To optimize efficiency, chose an inductor with a DC resistance less than 50m. Choose the inductor 7447745022 from Wurth Corporation with ratings at L=2.2µH/3.5A /36m.

NTC Function

Figure 6 shows that an internal resistor divider sets the low temperature threshold and high temperature threshold at 74%·VREF33 and 32%·VREF33, respectively. For a given NTC thermistor, select appropriate R

and RT2 to set

the NTC window.

The thermistor (NCP18XH103) noted above has the following electrical characteristic:

At 0°C, R

At 50°C, R

NTC_Cold

= 27.445k;

= 4.1601k.

NTC_Hot

The following equations are derived assuming that the NTC window is between 0°C and 50°C:

//RR

NTC_ColdT2

//RRR

NTC_ColdT2T1

//RR

NTC_HotT2

//RRR

NTC_HotT2T1

According to equation (7) and equation (8), \R

8.7k and R applications, R

= 252.3k. Simplified for

=8.7k and RT2 = No Connect

TH_Low

VREF33

TH_High

VREF33

74%

32%

(7)

(8)

approximates the values.

Selecting the Input Capacitor

The input capacitors C1/C2 from the typical application circuit absorbs the maximum ripple current from the buck converter, which is given by:

)V(VV

−

For I

CC_MAX

CC_MAXRMS_MAX

=2A, VTC=3V, V

IN_MAX

TCIN_MAXTC

(9)

=6V, the maximum ripple current is 1A. Select the input capacitors so that the temperature rise due to the ripple current does not exceed 10°C. Use ceramic capacitors with X5R or X7R dielectrics because of their low ESR and small temperature coefficients. For most applications, use a 22µF capacitor.

Selecting the Output Capacitor

The output capacitor—C4 from the typical application circuit—is in parallel with the battery. C4 absorbs the high-frequency switching ripple current and smoothes the output voltage. Its impedance must be much less than that of the battery to ensure it absorbs the ripple current. Use a ceramic capacitor because it has lower ESR and smaller size that allows us to ignore the ESR of the output capacitor. Thus, the output voltage ripple is given by:

r

In order to guarantee the

(10)

Lf8C

±0.5% battery voltage

accuracy, the maximum output voltage ripple must not exceed 0.5% (e.g. 0.1%). The maximum output voltage ripple occurs at the minimum battery voltage of the CC charge and the maximum input voltage.

For V f

=1.5MHz,

IN_MAX

=6V, V

O_MAX

CC_MIN=VTC

%1.0

=3V, L=1.5µH,

, the output capacitor

can be calculated as:

IN_MAX

8f Lr

SO_MAX

(11)

Figure 6: NTC Function Block

C= =18.5F

We can then choose a 22µF ceramic capacitor.

Page 18

MP2611 – 2A, 1-CELL SWITCHING CHARGER FOR USB AND ADAPTER POWER

PCB Layout Guide

PCB layout is important to meet specified noise, efficiency and stability requirements. The following design considerations can improve circuit performance:

1) Route the power stage adjacent to their grounds. Aim to minimize the high-side switching node (SW, inductor), trace lengths in the high-current paths and the currentsense resistor trace. Keep the switching node short and away from the feedback network.

2) The exposed thermal pad on the backside of the MP2611 package must be soldered to the PGND plane. There must be sufficient thermal vias underneath the IC connected to the ground plane on the other layers.

3) Connect the charge current sense resistor to CSP (pin 9), BATT (pin 8) with a Kelvin contact. Minimize the length and area of this circuit loop.

4) Place the input capacitor as close as possible to the ACIN/USBIN and PGND pins. Place the output inductor close to the IC as and connect the output capacitor between the inductor and PGND of the IC. This minimizes the current path loop area from the SW pin through the LC filter and back to the PGND pin.

5) Connect AGND and PGND at a single point.

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MP2611 – 2A, 1-CELL SWITCHING CHARGER FOR USB AND ADAPTER POWER

TYPICAL APPLICATION CIRCUITS

Power-Path Management

Power-path applications require powering the system while simultaneously charging the battery. Traditional designs adopt the simplest battery-fed topology that connects the system to the battery directly. An obvious drawback is that it cannot operate the system with a drained battery.

Figure 7 shows an improved battery-fed topology. The additional circuit between the current sense resistor and the battery works like a variable

Figure 7: Improved Battery-Fed Power-Path Management Structure

resistor. While the battery voltage is less than the preset threshold (less than V MOSFET Q1 turns off. The 5 resistor, R

of 3V), the

, is

then in series with the battery to raise the system voltage to 1V (I

=0.2A assumed). As a result,

the system can also operate at low battery voltage. While the battery voltage is high enough, Q1 turns on to short though the R

resistor to

reduce power loss.

The power-path auto-selection topology shown in Figure 8 adopts external switches to decouple the system supply and battery charging process. Thus the adapter directly powers the system independent of the battery’s state as long as the adapter is plugged in. If the adapter is absent,

Figure 8: Power-Path Auto-Selection Structure

the battery supplements the system.

Replace M1 and M2 with a power diode each, to reduce the costs. However, the efficiency may decline due to the forward voltage drop of the diode. Even USBIN is not used, a least 4.7F capacitor is necessary connecting the pin to GND.

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MP2611 – 2A, 1-CELL SWITCHING CHARGER FOR USB AND ADAPTER POWER

Single Input Port Application

For some portable devices, only one input port that covers both AC adapter and USB port is adopted. The charger is then required to identify the input source (AC adapter or USB port) via an external logic signal from MODE-pin. MODE-pin pulled high indicates an AC adapter is connected, low indicates an USB port source.

Figure 9 shows a single input port application circuit. The MOSFET M1 is used to alter the input source. High-level voltage at MODE-pin turns on the M1 and the charger is then switched from USB input mode to AC input mode. The capacitor C5 and R5 are necessary to realize the soft-start of voltage at ACIN, increase the value if the recommended value in Figure 9 does not work.

Figure 9: Single Input Port Application Circuit –1

Figure 10 shows another single input port application circuit. For the AC adapter input, the high-level signal at MODE-pin turns on the M1 to connect the parallel resistor R4 at USBM-pin. Due to the increased input current limitation, charge current is enlarged. Please refer to the

Input Port

NTC

1.5k

1uF

22uF

4.7uF

ACIN

STAT1

STAT2

VREF33

NTC

USBIN

MP2611

AGND

CSP

BATT

PGND

USBM

TMR

Figure 10: Single Input Port Application Circuit –2

USB input current setting and choose the appropriate resistor based on the actual battery specification. R8 and C5 are necessary for soft tuning on and off of M1 to avoid unexpected USBM reference caused by noise. In addition, a least 4.7F ceramic capacitor connected between ACIN-pin to PGND is necessary to avoid noise interference.

2.2uH

TMR

0.1uF

OFF

RS1

50m

1-cell

22uF

battery

1uF

MODE

USB

ILIM

2N7002

200k

Page 21

MP2611 – 2A, 1-CELL SWITCHING CHARGER FOR USB AND ADAPTER POWER

Input OVP Application

For MP2611, the maximum rating of input voltage is only 7.5V. In order to prevent an unmatched adapter from being connected to damage this part, the input over-voltage protection (OVP) is required. Figure 11 shows the application circuit

for the input OVP, where the OVP threshold can be programmed via the resistor divider consist of R4 and R5. For the given parameters below, the OVP threshold is 6.2V and maximum input rating is extended to 18V (Limited by the TLVH431).

Figure 11: AC Input Mode with Input OVP

Page 22

MP2611 – 2A, 1-CELL SWITCHING CHARGER FOR USB AND ADAPTER POWER

PACKAGE INFORMATION

QFN 14 (3mm x 4mm)

PIN 1 ID MARKING

PIN 1 ID INDEX AREA

0.20 REF

2.90

3.10

TOP VIEW

0.30

0.50

0.18

0.30

3.90

4.10

0.50 BSC

PIN 1 ID OPTION A

0.80

1.00

0.00

0.05

0.30x45º TYP.

1.60

1.80

BOTTOM VIEW

PIN 1 ID OPTION B R0.20 TYP.

PIN 1 ID SEE DETAIL A

3.20

3.40

SIDE VIEW

2.90

0.70

0.25

0.50

1.70

RECOMMENDED LAND PATTERN

NOTE:

1) ALL DIMENSIONS ARE IN MILLIMETERS.

2) EXPOSED PADDLE SIZE DOES NOT INCLUDE MOLD FLASH.

3) LEAD COPLANARITY SHALL BE 0.10 MILLIMETER MAX.

4) DRAWING CONFORMS TO JEDEC MO-229, VARIATION VEED-5.

5) DRAWING IS NOT TO SCALE.

3.30

DETAIL A

NOTICE: The information in this document is subject to change without notice. Please contact MPS for current specifications.

Users should warrant and guarantee that third party Intellectual Property rights are not infringed upon when integrating MPS products into any application. MPS will not assume any legal responsibility for any said applications.

Page 23