5V Boost Converter circuit .
A simple 5V boost converter using LTC3440 is shown here. LTC3440 is a highly efficient DC to DC converter that can be operated from input voltages below, above or equal to the output voltage. In terms of synchronous rectification, LTC3440 provides up to 96% efficiency and up to 600mA of output current is guaranteed. The IC has a built in synchronizable oscillator whose frequency whose frequency can be adjusted from 300 KHz to 2 MHz.
In the circuit LTC3440 is wired as a 5V boost converter capable of delivering a steady 5V output @ 300mA from an input voltage from 2.7 to 4.2 V. Resistor R4 is used to set the oscillator frequency while resistors R1 and R2 is used to set the output to 5 volts. Resistor R3 and capacitor C1 forms a frequency compensation network while C3 serves as the input bypass capacitor. S1 is the shutdown switch and C2 is the output filter capacitor.
Circuit diagram of boost converter using LTC3440
Closing switch S1 will shutdown the IC.
Circuit can be powered from anything between 2.7 to 4.2V DC.
Diode D1 must be placed as close to the IC as possible on the PCB.
C1, C2, C3 are ceramic capacitors.