Power supply design help

arecssor said:

what will happen i remove the 56 ohm resistor connected in series with the each four series led in led panel, it will help to reduce the loss but what about the safety of led panel ?

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you can NOT remove the the resistor. LEDs need to the current limited [in some way].

you can REPLACE the action of the resistor using a constant-current regulator. There are fairly simple one and two transistor constant current circuits around. The two transistor designs are fairly voltage tolerant - the current limit does not change with the supply voltage. In my experience with one design a 20% change in voltage resulted in a less than 5% change in current.

If you used a constant-current regulator the supply voltage is not so important - you would not need a voltage regulator.

However the constant-current regulator , depending on the design, needs a one to several volts to operate. Perhaps this could be the most efficient and reliable approach.

Which is why I asked the questions in post #17 - which did not get answered.