LM2678 – 3.3V, 12V, 5V 5A switching fixed voltage regulator circuits

Here is circuit switching regulator 5V 5A for digital circuit.
Use IC LM2678-5.0 is High Efficiency 5V 5A Step-Down Voltage Regulator This is good power supply, small size and do not hot.

Friends want to build the digital power supply which this circuit “Top Linear power supply regulator 5V 5A with 7812 and LM723” is good quality, but as the too old circuit. Not suitable for this era. So I to find a new and very powerful also an Energy savings.

5V 5A switching regulator for digital by LM2678

Considering these reasons. We will Using an ICs Switching supply. Because of has very high performance. High energy, while the low energy input.

LM2678 can respond to fully our needs. We can supply approximately 5A. The circuit and very easy to use. See information on the manufacturer’s manual, very easy to understand explanations. It uses a little equipment is only 9 pieces. And Cin = 3x15uF 50V, C2-0.47uF 63V , C3-0.01uF 63V , D1 – 6TQ045S, L1-22uH, Cout=2x180uF 16V as figure 1

Advantage of this range is very wide input voltage. From 8 vots to 40 volts DC power and does not need to be very smooth. But must be have the current 5 A or more. And this circuit high performance. Generate heat loss at low IC can use a small cooler (heat sink).

LM2678 Features

LM2678 (5A)DC to DC step down voltage regulator. (Switching power supply regulator)

Wide input voltage 8Vdc to 40Vdc.

Part number:

– LM2678-3.3 (3.3Vdc output)

– LM2678-5 (5Vdc output)

– LM2678-12 (12Vdc output)

– LM2678-ADJ (1.2Vdc to 37Vdc output)
Component list


– 45uF 50V electrolytic capacitor

– 0.47uF

– 6TQ045S high speed schottky diode

– Output 100V electrolytic capacitor (higher voltage, lower ESR)

360uF (for 3.3V and 5V version)

220uF (for 12V version)

– 0.01uF

Wire coil inductors

15uH (for 3.3V and 5V version)

22uH (for 12V version)

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3 thoughts on “LM2678 – 3.3V, 12V, 5V 5A switching fixed voltage regulator circuits”

  1. can i use 10 Ni-mh battery rated 2400 for the input supply??
    by using 10 Ni-mh il get a voltage output of 12v.
    please reply. thank you.


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