LTC4088

Demonstration Circuit 1007 is a high efficiency USB power manager with PowerPath^™ control and Li-Ion/Polymer battery charger featuring the LTC4088. It includes a synchronous switching input regulator, a full featured battery charger and an ideal diode. Designed specifically for USB applications, the LTC4088’s switching regulator automatically limits its input current to either 100mA, 500mA or 1A for wall-powered applications via logic control. There are also 2.5mA and 500μA suspend modes to prevent the battery from running down when the product is connected to a suspended USB bus.

The switching input stage provides power to VOUT where power sharing between the application circuit and the battery charger is managed. Unlike linear PowerPath controllers, the LTC4088’s switching input stage can use nearly all of the 0.5W or 2.5W available from the USB port with minimal power dissipation. This feature allows the LTC4088 to provide more power to the application and battery and eases thermal issues in space constrained applications.

An ideal diode ensures that the system power is available from the battery when the input current limit is reached or if the USB or wall supply is removed. The optional external P-channel MOSFET supplements the internal ideal diode by reducing R_ON and increasing efficiency.

A CHRG LED indicates four possible states of the battery charger. Charging is indicated when the LED is steady-ON. Not charging is indicated by a steady-OFF. A NTC fault is indicated by a slow blinking rate (1.5Hz) and a bad battery is indicated by a fast blinking rate (6.1Hz).

The LTC4088 is available in the low profile 14-Lead 4mm × 3mm × 0.75mm DFN surface mount package.