Power Supply Circuit Design Calculations

[Baranidaran]

Dear All,

I can found and understand simple power supply circuit whose input is 230Vac and output is 5Vdc.
But, I cannot understand how to select the passive components of the circuit? Does anyone publish the design calculations for the power supply circuit?

Regards,
Baranidaran

 

[thunderdantheman]

Is this a SMPS or transformer/rectifier?

 

[Baranidaran]

transformer/ rectifier

 

[Genovator]

Using only a 5V transformer will not convert 230VAC to 5VAC. The resultant step-down voltage will be
5x√2 = 7.07VAC
√2 is multiplied because AC is a sinusoidal wave.
When you are passing it through diodes to rectify, voltage drop across diodes= 0.7+0.7 = 1.4V(at least two diodes needed)
Now the output voltage is about 7.07-1.4 = 5.67V(approx). Now it seems to be safe to use.
Now the maximum current you need should be of same rating as of transformer. i.e, 2A transformer can provide you upto 2A current.
So if you are using transformer/rectifier circuit, then you need very less passive components....

 

[mrarslanahmed]

design depends not only depend on the output voltage but also on the current which your load is going to take from the supply

if design is for small current like .5A and 5v then your transformer and diodes filters and regulators will be of smaller size but if the design is for say 3A current you will need larger transformer and diode rating and filtering requirement will increase .....

so your design requirement will reflect the component to be used.......