This switching power supply circuit diagram is based on the MC33374 high power voltage switching regulator IC manufactured by Motorola Semiconductor . This MC33374 switching power supply circuit will provide a maximum output power around 90 W and require few external components .
The MC33374 switchingregulator IC is a monolithic high voltage power switching regulators that combine the required converter functions with a unique programmable state controller .
The MC33374 switching regulator IC is designed to operate directly from a rectified AC line source, and in flyback converter applications are capable of providing an output power in excess of 150 W with a fixed AC input of 100 V, 115 V, or 230 V, and in excess of 90 W with a variable AC input that ranges from 85 V to 265 V.
The MC33374 switching regulator offers features like : Programmable State Controller , On–Chip 700 V SENSEFET Power Switch Circuit , Rectified AC Line Source Operation from 85 V to 265 V , On–Chip 700 V Active Off–Line Start–Up Circuit , Latching PWM for Double Pulse Suppression , Cycle–By–Cycle Current Limiting , Input Undervoltage Lockout with Hysteresis , Non–Latching Internal Thermal Shutdown .
This MC33374 switching power supply circuit has a efficiency of 83.2 % at 115 V AC input voltage and a 85.4 % efficiency at 230 V with IO= 6 A .
The output voltage of this switching power supply is 15 volts and the maximum output current is 6 A .
The hard part of these switching power supply circuit is to design the T1 transformer , but you have the design data for that bellow , or you can buy a transformer from Coilcraft .
Z1 is a zenner diode and is used to limit the voltage on Pin 5 and a damper circuit consisting of resistor R2 and capacitor C2.
A simple 12 volts voltage regulator that can be used to supply your electronic devices from your car can be constructed using few common components . This 12 volts car adapter circuit use a 12.7 volts zenner diode but maybe you can’t find a 12,7 volts zenner , so in that case you can use a 12 v or 13 volts zenner diode . If you will use a 12 volts zenner you will need to stick in another diode like 1N4001 (in this case the output voltage will be a little under 12 ) and if you will use a 13 volts zenner the output voltage will be around 12.3 volts .
The 2N3055 transistor must be mounted on a heatsink .
Sometimes in your car you need a constant 12 volts power supply for some devices . In this case you can use this type of circuit , that is based on a LM1084 voltage positive regulator with a maximum dropout of 1.5V at 5A of load current ; or you can use thistype of regulator that use common electrical components .
The LM1084 is available in an adjustable version and three fixed voltages versions : 3.3V, 5.0V and 12.0V (for more informationlook here) .
To prevent the overheating , the regulator must be mounted on a heatsink .