API9221

Car/Wall or USB Supply Input Lithium Battery Charger

with OVP USB Bypass and 10mA LDO

API9221

Document number: DS32204 Rev. 1 - 2

8 of 17

www.diodes.com

May 2010

© Diodes Incorporated

Functional Description

Logic Description

A Logic State Table and diagrams of timing and charge profile are given at the end of this description.

external pull-up resistor connected to the system microcontroller I/O power supply. The API9221 has an internal

resistor connected from this pin to GND, typically 600k

Ω. In many applications a suitable pull-up resistor value is

100k

appropriate supply such as the microcontroller I/O supply, or can be left open circuit. A suitable value is 100k

Ω.

Alternatively these can each be used to drive an indicator LED up to a maximum of 10mA.

overvoltage protection threshold.

reached. Together with other conditions as described below, the voltage at the battery connection BAT is used to

and the battery voltage has reached 4.2V (± 1%). In this state, the charger remains active and is able to supply

Conditions.

Auxiliary Outputs

controller to power up initially.

USB Bypass, USB_BYP

The output USB_BYP provides power from the USB input when a valid power supply voltage is present at the

VUSB input. It is current limited to 400mA (nominally). It is therefore safely limited in current and voltage within

the USB standard.

VDC Low dropout regulator VDC_LDO

This output provides a regulated 4.94V supply, up to 10mA, when a valid power supply voltage is present at the

VDC input.

Charge Conditions

Before charging can begin, one of the two input voltages must also exceed the battery voltage enough to

LOW

, charging begins regardless of the state of the other supply. The valid input conditions are:

for VDC:

and

for VUSB:

and

All these threshold voltages have defined hysteresis.