基于API9221設(shè)計(jì)的多種輸入鋰電池充電技術(shù)
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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 PPR 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. The termination current is 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.
API9221主要特性:
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應(yīng)用:
Handheld Consumer Devices
Cell Phones, PDAs, MP3 Players
Handheld Test Equipment
Digital Still Cameras
Multimedia players
圖1.API9221功能方框圖
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