A very simple and high efficient DC-DC 5 volts power supply circuit can be constructed using ADP2302 or ADP2303 nonsynchronous step down regulator , designed by Analog Devices .
Both of this circuits support a wide input voltage range from 3 volts up to 20 volts .
The difference between this two fixed frequency , current mode control, step down regulators is that ADP2302 support a maximum load current of 2A and the ADP2303 regulator support a maximum load current of 3A .
This schematic circuit is a step down dc converter that will provide a 5 volts output voltage at a maximum 2A load , from a 12 volts input voltage .
The output voltage of the ADP2302 , ADP2303 can be set down to 0.8 V for the adjustable version, while the fixed output version is available in preset output voltage options of 5.0 V, 3.3 V, and 2.5 V.
This circuit use a 700 kHz operating frequency that allows small inductor and ceramic capacitors to be used, providing a compact solution.
For this DC DC converter circuit we will use the ADP2303ARDZ-5.0 which is the ADP2303 fixed voltage 5 volts version .
If you want to use the variable output voltage version you can use the circuit bellow and change the components value like in the table bellow .
The recommended vales for the Shotky diodes that can be used for this project are : Vishay SSB43L or SSA33L , ON Semiconductor MBRS330T3 , Diodes Inc. B330B .
If you need to choose another part for the coil , please read the datasheet to see the recommended parts .
Using MAX668 integrated circuit you can build a very simple and high efficiency 12 volts power supply circuit from 3 though 5 volts using few electronic components. With Max668 you can design various power supply circuits using few external components . This power supply circuit based on the MAX668 integrated circuit is a high efficiency step up converter that will provide an fixed output regulated voltage around 12 volts at a maximum output current of 2.3 amperes . This 12 volts power supply circuit will provide a 12 volts output voltage from a 3.3 to 5.5 input voltage .
The LTC4362 IC is an monolithic overvoltage protection overcurrent protection 2.5V to 5.5V systems. LTC4362 overvoltage protection and overcurrent protection is designed for portable devices with multiple power supply options including wall adaptors, car battery adaptors and USB ports.
The LTC4362 controls an internal 40mΩ N-channel MOSFET in series with the input power supply. During overvoltage transients, the LTC4362 turns off the MOSFET within 1μs, isolating downstream components from the input supply.
In most applications, the LTC4362 rides through inductive cable transients without requiring transient voltage suppressors or other external components. An internal current sense resistor is used to implement overcurrent protection.
As you can see in the circuit diagram , the LTC4362 IC requires few external components and can be very easy designed for desired application .
Main features of the LTC4362 overvoltage overcurrent protector are :
2.5V to 5.5V Operation ,Overvoltage Protection Up to 28V , Internal 40mΩ N-Channel MOSFET and 31mΩ RSENSE ,Avalanche Rated MOSFET Requires, <1μs Overvoltage Turn-Off, Gentle Shutdown , 2% Accurate 5.8V Overvoltage Threshold , 20% Accurate 1.5A Overcurrent Threshold, Reverse Voltage Protection Driver ,Low Current Shutdown.
The circuit diagram showed bellow , is a 5V System Protected from 24V Power Supplies and Overcurrent .