5V to 13.5V dc dc boost converter

    The Max761 is a 300kHz fixed frequency boost regulator that integrates a N-channel power MOSFET which allows peak currents up to 1A. In the standard application circuit the IC is powered from the output voltage ( bootstrapped mode ) and provide a fixed output of 12V (FB pin is connected to ground). For a 13.5V output voltage, the IC is powered from the supply voltage ( non- bootstrapped mode ), external resistor divider must be used as you can see in the follow circuit diagram:

     With an input voltage of 4.5V to 5V, this circuit it produces  a 13.5V output voltage at a load current of  150mA. The proprietary current-limited PFM control scheme provide a high efficiency, typically over 80%. The output voltage can be calculated using this formula:

Vout=1,5Vx(1+R2/R1)

BOM list:

• U1   Max761
• L1   20..47uH/min. 1.1A Isat  inductor
• D1   SS14 / SL22 / MBRS130LT3 SMD Schottky diode
• C1   33uF/10V tantalum capacitor
• C2   33uF/min. 16V tantalum capacitor
• C3,C4   100nF/25V ceramic capacitors
• R1   15kΩ smd 1206 resistor
• R2   120kΩ smd 1206 resistor

 
Printed circuit board for the max761 boost converter

    The C2 capacitor must be rated at least 16V, my last 33uF/16V capacitor it burnt with a nice yellow-red flame accidentaly. I must to use a 47uF/16V capacitor instead.

Download schematic in pdf format from here.

9V battery replacement an 2.4V .. 3.6V to 9V small converter
5V dc-dc converter this circuit can deliver over 1.6A at 5V and still work at 2.0V