Find Jobs
Hire Freelancers

Design me a 5V supervisory circuit to cut 3A power

$10-30 USD

Completed
Posted almost 9 years ago

$10-30 USD

Paid on delivery
Background: I'm building a product based around the raspberry pi. Together with all the periphals the product draws a little less than 3A from the same 5V source (switched 5V power supply). I've solved the problems with blackouts and sudden power losses but having some issues with brownouts. When power at some point is below specified minimum level 4.75V the raspberry starts acting incorrectly. Sometimes it results in a kernel panic and sometimes the SD-card gets permanently corrupted. Both cases are inacceptable since they render the device unusable (In the second case it's forever). Case: I would like to have a supervisory circuit between the power supply and my product. If the power is lower than 4.75V it should be cut and not restored until some time has passed. Ideas: I'm thinking that the supervisory components like a MCP1x0-485 from microchip together with appropriate transistors or motsfets can be useful? But I'm a software guy and open to suggestions. Task: I want a design of a supervisor circuit that can take 5V DC power on one side and deliver 4,75V or higher on the other end but never less than 4,75V (no upper limit required). In case of less than 4,75 on the supply side, a stabilization period is requested (open to suggestions based on component selection). I want a circuit schema layout and a parts list from Farnell, no pcb-layout needed. If you can find me a solution with few components and/or low cost (but still reliable) I'll hit the bonus button when we're done.
Project ID: 7400317

About the project

8 proposals
Remote project
Active 9 yrs ago

Looking to make some money?

Benefits of bidding on Freelancer

Set your budget and timeframe
Get paid for your work
Outline your proposal
It's free to sign up and bid on jobs
Awarded to:
User Avatar
hi sir i am an expert electrical engineer I can do it for you. I have almost 4 years of experience in this field. I assure you quality work and ontime delivery Please reply to discuss it further Regards
$50 USD in 1 day
4.9 (230 reviews)
7.8
7.8
8 freelancers are bidding on average $43 USD for this job
User Avatar
Hi there, Have a nice day. There are multiple solution to the problem. The main cause for this is due to sudden current drain that causes the board to get reset. Now coming to solution. 1. check if there are some fuses in Resb Pi (like watch do timer), if you disable them you can prevent the corrupting SD card. 2. Design a circuit that keeps the Voltage level between 5.0V and 6.0V so you may not face such situations. I am not fully sure about 1, but for 2 iam fully confident that it will work. Please feel free to contact. Best Regards, Shahbaz.
$50 USD in 1 day
4.5 (50 reviews)
6.9
6.9
User Avatar
Hello sir I am interested to your project. I am familiar with electronics, microcontroller as well as PCB design by eagle. Thanks.
$35 USD in 3 days
4.8 (73 reviews)
5.6
5.6
User Avatar
i have read and understand your requirement............ kindly open chat to proceed it further.......................................................................................................................................................................................................................................................................................................................................
$55 USD in 2 days
4.5 (32 reviews)
5.2
5.2
User Avatar
A proposal has not yet been provided
$50 USD in 3 days
3.3 (13 reviews)
5.7
5.7
User Avatar
A proposal has not yet been provided
$35 USD in 2 days
0.0 (0 reviews)
0.0
0.0
User Avatar
I'm thinking all you'll need is a voltage comparator, a mosfet, some resistors and a reference voltage (a zener diode may be fine for this). The idea is that once your supply voltage goes lower than ~4.8v, the comparator will turn off the mosfet, which will act as a switch on the power supply line. Using a feedback resistor, we can also introduce some historesis so the power will not come back on for the rpi until the supply voltage is upto around 4.9v. I'm assuming your planning to get this done with surface mount parts, would this be correct? Also, depending on a number of different factors, we may be able to get away with using a zener diode, otherwise we may have to look at a more accurate voltage reference.
$39 USD in 1 day
0.0 (0 reviews)
0.0
0.0
User Avatar
I have experience working on FET shutdown circuits and can provide you a solution using the MCP part listed along with 2 FETs and a couple of resistors. Thanks,
$30 USD in 1 day
0.0 (0 reviews)
1.4
1.4

About the client

Flag of SWEDEN
Täby, Sweden
5.0
10
Payment method verified
Member since Apr 5, 2014

Client Verification

Thanks! We’ve emailed you a link to claim your free credit.
Something went wrong while sending your email. Please try again.
Registered Users Total Jobs Posted
Freelancer ® is a registered Trademark of Freelancer Technology Pty Limited (ACN 142 189 759)
Copyright © 2024 Freelancer Technology Pty Limited (ACN 142 189 759)
Loading preview
Permission granted for Geolocation.
Your login session has expired and you have been logged out. Please log in again.