Multiple input lithium battery charging technology based on API9221 design - News - Global IC Trade Starts Here Free Join

The API9221 is a multi-input lithium battery charger that can be powered by a car/wall adapter or USB power supply. The device includes OVP USB bypass and 4.9V/10mA LDO.USB overvoltage protection 5.4V, wall adapter overvoltage protection 6.9V, safe power supply Input up to 28V, maximum fast charging current 1.2A, separate resistor programmable charge current and charge termination, reverse current protection and thermal protection. Mainly used in handheld consumer electronics, mobile phones, PDAs, MP3 players, handheld test equipment, Digital camera and multimedia player. This article introduces the main features of API9221, functional block diagram and application circuit diagram.

API9221: Car/Wall or USB Supply Input Lithium Battery Charger with OVP USB Bypass and 10mA LDO

The API9221 has two supply inputs for highly integrated portable applications, enabling charging from a USB host, wall adapter, or car adapter.

The PPT pin indicates to a host controller that a safe and valid supply is connected to either VUSB or VDC. The higher charge current option from VDC will take priority if both supplies are connected. The host controller can control the state of charging via the enable Pin EN. The API9221 implements the constant current/constant voltage (CC/CV) charge algorithm for Lithium based battery cells. The connected cell will be charged to 4.2V with an accuracy of 1% over the entire temperature range. Programmable via an external resistor, RIMIN.

The CHG pin indicates when the termination current is reached, and is reset by EN, power off, or battery below 3.9V. The maximum charge current can be programmed independently via the resistors RIUSB and RIVDC.

The API9221 comes with several protection features. To prevent system damage, the VUSB pin uses over voltage protection (OVP) at 5.4V, and the VDC OVP is at 6.9V. Above these levels, the non-operating device is protected against damage up To 28V. For control and system start-up the API9221 has a current limited linear regulator.

To protect the chip against excessive power dissipation, temperature monitoring is integrated, which folds back the current to a safe level. As the temperature rises, this fold-back begins at 125°C without completely interrupting charging.

Main features of API9221:

• Linear Lithium Ion / Lithium Polymer charging IC

• Supplied from USB host or car/wall adapter

• Overvoltage protection USB: 5.4V, wall: 6.9V

• Supply inputs safe up to 28V

• Fast charging with maximum current of 1.2A

• Integrated linear regulator of 4.9V at 10mA with current limit

• Separate resistor-programmable charging current for wall and USB

• Resistor programmable end-of-charge

• Current limit on USB bypass path

• indicator pins for charging and power present

• Enable pin to enable host control charging

• Reverse current protection

• Thermal protection

• DFN4030-12: Available in “Green” Molding Compound (No Br, Sb)

• Lead Free Finish/ RoHS Compliant

API9221 application:

• Handheld Consumer Devices

• Cell Phones, PDAs, MP3 Players

• Handheld Test Equipment

• Digital Still Cameras

• Multimedia players

Figure 1. Functional block diagram of API9221