PSC2945

PSC2945 combines a highly integrated switch-mode charger, to minimize single-cell Lithium-ion (Li-ion) charging time from a USB power source, and a boost regulator to power a USB peripheral from the battery. Its low impedance power path optimizes switch-mode operation efficiency, reduces battery charge time and extends battery life during discharging phase. The I2C serial interface with charging and system settings makes the device a truly flexible solution. The device supports 3.5-12V input voltage sources, including standard USB host port and USB charging port with programmable over-voltage protection. The device also supports USB On-the-Go operation by providing on the VBUS with an accurate current limit. The power path management regulates the system slightly above battery voltage but does not drop below 3.55V minimum system voltage (programmable). With this feature, the system keeps operating even when the battery is completely depleted or removed. When the input source current or voltage limit is reached, the power path management automatically reduces the charge current to zero and then starts discharges the battery until the system power requirement is met. This supplement mode operation keeps the input source from getting overloaded. The device initiates and completes a charging cycle when host control is not available. It automatically charges the battery in three phases: pre-conditioning, constant current, and constant voltage. In the end, the charger automatically terminates when the charge current is below a preset limit in the constant voltage phase. Later on, when the battery voltage falls below the recharge threshold, the charger automatically starts another charging cycle. The charge device provides various safety features for battery charging and system operation, including charging safety timer, and over-voltage/over-current protections. The STAT output reports the charging status. The INT output can be used to notify the host when VBUS insertion and withdrawal or a fault occurs. The PSC2945 is available in a 24-pin, 4mm x 4mm x 0.55mm QFN package.

Applications

• Cellular Phones
• Smart Phones
• PDAs
• Tablet
• Portable Media Players

Key features

• Fully Integrated, High-Efficiency Switching Mode 3A Charger.
• Charge Voltage Accuracy: ±0.5% 25°C
• ±7.5% Charge Current Regulation Accuracy
• 20V Absolute Maximum Input Voltage
• 13.9V Maximum Input Operating Voltage
• Weak Input Sources Accommodated by Reducing Charging Current to Maintain Minimum VBUS Voltage
• Power Path Management
• Instant system on with NO battery or deeply discharged battery
• Battery can be completely turned off after Charging Done
• Supports Ultra low leakage ship mode
• Programmable through I2C Interface:
• Input Current limit
• Fast-Charge/Termination Current
• Charger Voltage
• Termination Enable
• Small Footprint 1.2.2μH External Inductor
• Low Reverse Leakage to Prevent Battery Drain to VBUS
• High Battery Discharge Efficiency With 25mΩ Battery Discharge MOSFET
• High Integration Includes All MOSFETs, Current Sensing and Loop Compensation
• 10μA Low Battery Leakage Current to Support Ship Mode
• 12uA Low Battery Leakage Current in standby Mode
• 5V, 2A Boost Mode for USB OTG: 90% efficiency at 5V/1A
• QFN24L4x4mm2 package