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

MP2611 Rev. 1.12

www.MonolithicPower.com

20

12/7/2012

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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

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 4.7μF ceramic capacitor

connected between ACIN-pin to PGND is

necessary to avoid noise interference.

C2

RS1

STAT1

STAT2

NTC

TMR

BATT

CSP

SW

MP2611

USBM

Input Port

ACIN

R3

USBIN

VREF33

R1

R2

C3

AGND

L

1-cell

battery

EN

OFF

ON

PGND

C4

1

2

3

4

5

6

7

8

9

10

11

12

13

14

R7

M1

MODE

AC

USB

200k

2N7002

22uF

1.5k

1.5k

1uF

0.1uF

22uF

50m

2.2uH

R4

C1

4.7uF

R8

C5

20

1uF

Figure 10: Single Input Port Application Circuit –2