3V To 5V Boost DC-DC Converter using MAX711

The circuit shown here is a compact and high-efficiency boost converter that has been designed for hand-held equipment. This boost converter converts 2 cells (3V) DC power into 5V DC with output load current up to 500mA. Typical efficiency when boosting battery inputs is 85%. The circuit is based on MAX711 which integrates a step-up DC-DC converter with a linear regulator to provide step-up voltage conversion. The circuit is optimized for battery applications where the input varies above and below the regulated output voltage. The project has an input range from +1.8V to +11V. The circuit is set for 5V output but it has an adjustable output that can be set from +2.7V to +5.5V with the help of two R3, R4 resistors. The IC contains a comparator for low battery detection. If the voltage at LBI+ falls below that at LBI- (typically connected to REF), LBO goes low. Hysteresis is typically 50mV. You can set the low-battery monitor’s threshold with two resistors, R1 and R2.