The XC9306 Synchronous Buck-Boost converter from Torex Semiconductor has been designed to prolong battery life and efficiency in a single-cell Li-ion battery application where the output voltage is within the battery voltage range.
A fully charged Li-ion battery starts at a high operating voltage, but as the battery is discharged its operating voltage declines to the point it can no longer provide sufficient voltage to power its load, even if some charge remains. The XC9306 can extend the usable life of a battery by boosting (stepping up) the output voltage to provide sufficient power to continue operation. This extends battery life by more efficiently using the remaining charge of the battery.
The XC9306 uses a 6MHz switching frequency that allows for a smaller size inductor and capacitors, reducing the overall mounting area by as much as half. The buck-boost converter operates in fixed frequency PWM mode (MODE pin: “High”) using synchronous rectification to obtain maximum efficiency. At low load currents, the converter can be switched over to Power Save mode (MODE pin: “Low”) to maintain high efficiency over a wide load current range. The input voltage range is from 2.5V to 5.5V and the input current can be limited to a typical value of 3.1A, 1.3A or 0.49A. In addition, the XC9306 supports maximum output currents of 1.2A (Buck PWM Mode) and 0.8A (Boost PWM Mode).
The output voltage is programmable using an external resistor divider in the range 0.8V~5.0V. In addition the VSEL pin can be used to select a second output Voltage level for applications that require a lower chipset core Voltage during standby.
The XC9306 is readily available in the WLP-20-01 (wafer-level chip-scale) package measuring only 2.15 × 1.94 × 0.625mm.