API9221

Document number: DS32204 Rev. 3 - 3

2 of 16

www.diodes.com

June 2016

© Diodes Incorporated

API9221

Typical Application Circuit

API9221

ON

OFF

VDC_LDO

EN

PPR

CHG

BAT

GND

USB_BYP

IMIN

IUSB

IVDC

To Battery

To MCU

USB_BYP

LDO Output

VDC

VUSB

USB Input

DC Input

I/O_VDD

I/O_VDD

Pin Descriptions

Name

Pin #

Descriptions

VDC

1

Input Pin from a

Wall AC/DC or Car

Adapter

The recommended input to this pin is 4.5V to 6.7V with a maximum safe value of

28V. If a sufficient voltage is detected on VDC, no charge current is taken from the

VUSB pin. Internal OVP trips at 6.9V. The input current can be programmed with a

resistor at IVDC (pin 9). Decoupling with a 1

μF ceramic capacitor is

recommended.

VUSB

2

USB Host Device

Input

The recommended input to this pin is 4.5V to 5.3V with a maximum safe value of

28V. Internal OVP trips at 5.4V. The supply current drawn at this pin is the sum

of the charge current and the USB_BYP current. Decoupling with a 1

μF ceramic

capacitor is recommended. Special attention has to be given to the maximum

capacitance on the USB connection. Refer to the USB standard.

PPR

3

Power Present

Signal Output,

Active-Low

The power present pin can indicate to a host processor that an external source is

present and that current can be derived from the input. This is an open drain

output pin, which goes LOW when a valid source voltage is connected to either

VUSB or VDC. If connected to a processor I/O a pull up resistor should be

utilized.

Alternatively this pin can be used to drive an indicator LED up to 10mA.

CHG

4

Charge Indicator

Output, Active-Low

Open drain pin is pulled LOW when charging is performed.

Goes high when

charge current reaches IMIN. Remains high (including top-up), until the battery

voltage falls below 3.9V or the device is power cycled or

connected to a processor I/O a pull up resistor should be utilized.

Alternatively this pin can be used to drive an indicator LED up to 10mA.

EN

5

Charge Enable

Input, Active-Low

Logic level input pin to control charging from an external processor. An internal

600kΩ (nominally) pull-down resistor is provided, This pin normally requires a pull

up resistor when connected to a processor I/O.

IMIN

6

Current Setting for

End-Of-Charge

State

The end-of-charge current is set by a resistor connected from this pin to GND.

This applies to charging from either VDC or VUSB.

IUSB

7

Current Setting,

USB Power

The USB input maximum charging current is set by a resistor connected from this

pin to GND. This current is also limited by a thermally controlled current fold-back

circuit.

GND

8

Ground

Ground return path.

IVDC

9

Current Setting,

Wall or Car Adapter

VDC input maximum charging current is set by a resistor connected from this pin

to GND. This current is also limited by a thermally controlled current fold-back

circuit.

USB_BYP

10

USB Bypass Output

Provides an external load path from the USB input, with current limiting. Protected

against reverse current.

BAT

11

Battery Connector

Connect this pin to the positive terminal of the battery. This pin is also used to

monitor the charge state of the battery. It is not recommended to operate the part

without a battery connected to this pin. Protected against reverse current.

VDC_LDO

12

LDO Output

Low current linear regulator for system supply, available when a valid VDC input

supply is used.

Stabilize with a 0.1μF to 1μF ceramic capacitor to ground.

Protected against reverse current.