MAX8903BETI+T

The MAX8903BETI+T is a wide input voltage range, PMIC (Power Management ICs) AC Adapter/Portable System Power Solution for 3.4V Battery Charging. It has a flexible DC (direct current) High Voltage Buck-Boost regulator, with a shutdown mode, that works from the input power source, to generate a regulated output current to charge the battery. This Integrated Circuit, which is available in a variety of packages, offers several advantages for shrink wrapped applications, such as enhanced fabrication yield, minimized components and board space, and higher power efficiency. In addition, the device is designed to be protected against extreme overvoltage and overtemperature conditions.

Application Field

The MAX8903BETI+T is capable of charging a variety of secondary high voltage Li-Ion (Lithium-Ion) and Li-Polymer battery chemistries by inserting a thin film of Safety-Latch-based shutdown FET (Field-Effect Transistor). As a result, it is best suited for low to medium power applications such as notebook computers, digital cameras, and smartphone chargers. Its other applications include portable and personal electronics, automotive and telecom applications, as well as medical device charging. Designs with this PMIC also benefit from a high quality form factor, as well as reduced system cost, size and complexity.

Working Principle

This IC operates with a standard dual-power supply, one for controlling the DC/DC converter (LDC) block, and the other for anticipating delay in order to control both the input and output current limit. The external MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors) are used to create a wide input voltage at the beginning of the DC/DC converter. This voltage is then regulated with the control voltage (intended to achieve a desired boost/buck ratio) provided by the voltage reference, and then used as an input to the LDC block to obtain a desired output power level.The LDC block then further modulates the output current according to the output current limit setting.

In this design, the charging process is designed to take place in the linear region of the voltage-current curve. This is done in order to keep the battery safe against hazardous conditions like overcharging or over-discharging. The charge is terminated by indicating a voltage saturation condition or a current level below minimum threshold.

Conclusion

The MAX8903BETI+T has proven to be an effective, reliable and robust solution for 3.4V battery charging. Its wide input range, small form factor, and improved power efficiency, makes it an attractive option for a variety of applications. The device is protected against extreme overvoltage and overtemperature conditions, making it a safe and reliable choice for secondary high voltage Li-Ion and Li-Polymer battery charging.