• Skip to main content
  • Skip to primary sidebar

Homemade Circuit Projects

Need circuit help? Post them in the comments! I've answered over 50,000!

Blog | Categories | About | Contact | Calculators-online
You are here: Home / Power Supply Circuits / Connecting Voltage Regulators 78XX in Parallel for High Current
warning message: electricity is dangerous, proceed with caution
78XXinparallelforhighercurrent

Connecting Voltage Regulators 78XX in Parallel for High Current

Last Updated on November 24, 2022 by Swagatam 61 Comments

In this post we investigate how to connect popular voltage regulator ICs such as 7812, 7805 in parallel for acquiring high current output from the ICs.

Table of Contents
  • Technical Specifications
  • Solving the Circuit Request
  • High Current from IC 7805 using 2N3055 External Transistor

Voltage regulator chips mostly have their maximum current output specs fixed to some predetermined levels. Increasing them to a higher level would normally call for external out board transistors and complicated associated circuitry which might be difficult to configure for the new hobbyists. Connecting a few of them in parallel, possibly solves the problem.

The idea was requested by Mr.Raja.

Technical Specifications

Sir,
could i use three L 7815 voltage regulator ic in parallel, to get 15 volt 4 amps dc current from about 20 volt 5 amp dc source?

Sir, as LM 338 and their equivalent ic s ( which gives 5 amps ) are not available in my town. I planned to use three 7815 in parallel. Is my idea works? If so please help me.
How can i connect them in parallel ? Could i connect input of all three 7815 ic by a common wire or i should separate mutually by a diode of 2 amp? And what about out put, should i separate them or use
a common wire? And i think, i can connect the negative terminal of ic with a common wire. Is it? Please guide me.

Solving the Circuit Request

Although not recommended by many, the issue can be handled simply by connecting the regulators in parallel, as shown in the following diagram.

Here we can see the terminals of the all the three ICs connected in parallel except the output pins which are terminated with individual diodes.

However the above connection might face a crucial drawback. Since all the ICs wouldn't have precisely identical characteristics and specs could vary with their current limits, and ultimately lead to one of them supplying greater amount of current than the other, and overheating in the course.

Although this won't pose a threat to the ICs as these are always thermally protected from inside, it's never a good idea to have a semiconductor device sizzle unnecessarily.

The issue can be very easily tackled by connecting the counterparts over a common heatsink, as shown in the diagram below.

Since the tab for the ICs connect with their identical common leads (ground lead), doesn't need any sort of isolation in the form of mica isolation kit etc.

Just make sure to put them over a common aluminium plate, and then you can relax as the heat dissipation across the plate would result in correct transition of heat enabling each one with an equal share of current at their respective outputs which in return would result in an optimally combined higher current outputs, as required.

Circuit Diagram

78XX regulators in parallel for increasing current capacity

High Current from IC 7805 using 2N3055 External Transistor

Although using 7805 or 7812 ICs in parallel is a good way of getting an enhanced current output from these chips, a better alternative is perhaps by using an external power transistor, as indicated in the following diagram:

a simple to get high current from a 7805 IC
simple way to get high current regulated 12 volts from a 7812 IC

You can get as high as 5 amps from the above setup using a single 7805 IC and a 2N3055 transistor. The output will as regulated as a 78XX IC can provide. The output will be around 5 V 5 amps or 12 V 5 amps depending on which 78XX IC is used.

You can tweak the output voltage slightly by manipulating the number of 1N4007 diodes at the GND terminal of the IC.

The current output can be further adjusted by adjusting the value of the 100 ohm base resistor.

You'll also like:

  • 1.  1A Step-Down Voltage Regulator Circuit – Switched Mode 78XX Alternative
  • 2.  How to Design a Bench Power Supply Circuit
  • 3.  Simplest One Transistor Regulated Power Supply Circuit
  • 4.  Over Current Cut-off Power Supply Using Arduino
  • 5.  Making a Regulated 9V Battery Eliminator Circuit
  • 6.  5 V to 10 V Converter for TTL Circuits

Filed Under: Power Supply Circuits Tagged With: 78XX, Connecting, High, Parallel, Regulators, Voltage

About Swagatam

I am an electronics engineer and doing practical hands-on work from more than 15 years now. Building real circuits, testing them and also making PCB layouts by myself. I really love doing all these things like inventing something new, designing electronics and also helping other people like hobby guys who want to make their own cool circuits at home.

And that is the main reason why I started this website homemade-circuits.com, to share different types of circuit ideas..

If you are having any kind of doubt or question related to circuits then just write down your question in the comment box below, I am like always checking, so I guarantee I will reply you for sure!

Previous Post: « 5630 SMD LED Driver/Tube light Circuit
Next Post: How to Protect MOSFETs – Basics Explained »
Subscribe
Notify of
guest
guest
61 Comments
Inline Feedbacks
View all comments

Primary Sidebar

circuit simulator image

Subscribe to get New Circuits in your Email

Categories

  • Arduino Projects (90)
  • Audio and Amplifier Projects (132)
  • Automation Projects (17)
  • Automobile Electronics (101)
  • Battery Charger Circuits (84)
  • Datasheets and Components (105)
  • Electronics Theory (140)
  • Free Energy (38)
  • Games and Sports Projects (11)
  • Grid and 3-Phase (19)
  • Health related Projects (25)
  • Home Electrical Circuits (12)
  • Indicator Circuits (15)
  • Inverter Circuits (89)
  • Lamps and Lights (142)
  • Meters and Testers (71)
  • Mini Projects (46)
  • Motor Controller (64)
  • Oscillator Circuits (28)
  • Pets and Pests (15)
  • Power Supply Circuits (89)
  • Remote Control Circuits (50)
  • Security and Alarm (64)
  • Sensors and Detectors (103)
  • SMPS and Converters (31)
  • Solar Controller Circuits (60)
  • Temperature Controllers (42)
  • Timer and Delay Relay (49)
  • Transmitter Circuits (29)
  • Voltage Control and Protection (38)
  • Water Controller (36)

Other Links

  • Privacy Policy
  • Cookie Policy
  • Disclaimer
  • Copyright
  • Videos
  • Sitemap

People also Search

555 Circuits | 741 Circuits | LM324 Circuits | LM338 Circuits | 4017 Circuits | Ultrasonic Projects | SMPS Projects | Christmas Projects | MOSFETs | Radio Circuits | Laser Circuits | PIR Projects |

Social Profiles

  • Twitter
  • YouTube
  • Instagram
  • Pinterest
  • My Facebook-Page
  • Quora
  • Stack Exchange
  • Linkedin
  • Recent Comments

    • Swagatam on Simplest AM Radio Circuit
    • Swagatam on Simple Online UPS Circuit
    • Saroj Sahu on Simple Online UPS Circuit
    • michel van simaeys on Simplest AM Radio Circuit
    • Swagatam on Simplest AM Radio Circuit

    © 2025 · Swagatam Innovations