2A, Single-Inductor Buck-Boost DC-DC Converter and WLED Driver
The STBB3JCC from STMicroelectronics is a fixed frequency, high efficiency, buck-boost dc-dc converter which provides output voltages from 1.2V to 5.5V starting from input voltage from 1.8V to 5.5V. Due to very low sensing voltage, only 100mV and very low RDS(on) of integrated power MOSFET, it achieves very high efficiency driving high brightness white LED in constant current mode.
Targeted applications include high-brightness WLED drivers, single cell Li-Ion, two-cell and three-cell alkaline, and Ni-MH powered devices, memory card power supplies, tablet computers, smartphones and digital cameras.
The device can operate with input voltages higher than, equal to, or lower than the output voltage making the product suitable for cell lithium-Ion applications where the output voltage is within the battery voltage range. The MODE pin allows the selection between auto mode and forced pwm mode, taking advantage from either lower power consumption or best dynamic performance.
The device also includes soft-start control, thermal shutdown, and current limit. The STBB3JCC is packaged in Flip Chip 20 bumps with 2.5 x 1.75 mm.
Summary of Features
- 100mV feedback signal
- Input voltage range from 1.8V to 5.5V
- 2A output current at 3.3 VOUT in buck mode (VIN= 3.6V to 5.5V)
- 800mA output current at 3.3 VOUT in boost mode (VIN ≥2.0V)
- Typical efficiency higher than 94%
- Automatic transition between step-down and boost mode
- Adjustable output voltage from 1.2V to 5.5V
- Power save mode (PS) at light load
- 0MHz fixed switching frequency
- Adjustable switching frequency up to 2.4MHz (by external synchronous square signal)
- Device quiescent current less than 50µA
- Load disconnect during shutdown
- Shutdown function and soft-start
- Shutdown current <1µA
- Available in Flip Chip 20, pitch = 0.4 mm