Showing posts with label Power-Electronics. Show all posts
Showing posts with label Power-Electronics. Show all posts

Saturday, February 11, 2017

Battery Management and Supply Design

As you have have pointed out, my circuit is not driving any motor or such loads...but it is driving a Wireless Module which draws about 165mA to 240mA from my circuit during transmission [for 4 sec] and normally it takes upto 114mA. After a time-out of 1min, I put my uC P89V51RD2 to powerdown mode [200uA in this state].

Read articles in the link you provided, thanks for that! - Continued from uC Board is Misbehaving on Brown Out.

My other problem is that my batteries get supercharged upto 5.8V, and as per spec's of most IC' they are bound to operate faithfully upto 5.25[max 5.5v], so how do I solve this issue? I want that my boards get only 5.25v even if my battery is having voltages 5.25+, without increasing my existing current consumption to noticeable value.

Moreover I'm in need of a cutt-off circuit which will take away the load from my batteries when my battery has reached 4.00V, & the charger charges my battery independently. Do you have any thing which will suite my purpose?

Mail from MO

Have two supplies, the one for uC can be a small Ni-Cad battery charged by a diode by the bigger battery which supplies the 200mA for RF drivers.

So when the big battery is loaded and the supply dips the shock is not felt by uC. or isolate it by SMPS and isolate the grounds. The ground return current of RF module 200mA must be lifting the ground of uC or some Logic.

Start by trying to locate the problem, first power RF and uC boards with isolated lines from two lab-test 10A power supplies. If both are in same board, cut tracks and power them separately. The grounds should meet at point the two sections interface.

If that works without problem, you know it is related to supply, now step-by-step go back to the battery and charger you have built keeping isolation intact. Look for spikes-glitches on power lines of uF when RF module active. Check if that is close to or leaking RF to uC circuits.

The battery charger circuit should limit voltage and current to battery specs. If you are not using a charger chip then while testing make sure the charger has a regulator or use LM317 to clamp voltage to 5.6 or 5.5 as per your design.

There are charger chips from maxim, national for battery charge management. If you have a need for extra voltage the you have to use SMPS boost switcher. which may take the low battery 4 to 8 which can be regulated to 5 using 7805.

This may be getting bit complex, first try to find what is the problem, it may be just the board design.

Battery Management and Supply Design

You can also use a Single Maxim Chip for all these functions. ...

Supervisor ICs Monitor Battery-Powered Equipment

A feature-laden µP supervisor (IC1), with the help of the µP itself, performs a variety of functions in this typical application circuit. You can get these functions all together or in various combinations, by selecting one of the many available microprocessor (µP) supervisor IC....

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Sunday, January 24, 2016

Drive or Fire Thyristors SCR with Pulses

message: Hi, i'm looking at building a power supply 0-35v ,0-100A adjustable cv and cc. I stumbled across your circuit drive-scr-thyristor-with-555 is there a link to describe what phase logic is required to complete the basic design ?

What would the cost be to supply me a working design based on thyristor control ? my use is for electroplating, i'm not trade, but an enthusiastic amateur Kind regards

SA - USA - 2010


I will not be able to supply prototypes or make one for you. I could help with the system design. Electroplating Systems can be made with Thyristors or MOSFETS.

Thyristors, SCR, Triacs are driven by Pulses. The pulses must have adequate current and voltage levels. This depends on the Power of the device and see in the specs.

Unlike Power Transistors that need continuous bias to keep it ON, these devices just need to be Fired and may need a Isolation Pulse Transformer too. MOSFETS may need a continuous bias and very less drive current, but the ON pulse must overcome the gate capacitance.

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Saturday, April 18, 2015

Battery Boost Circuits

(This is a thread of my Google Talk many years ago - you will be able to notice text communication is quite difficult. sometimes even verbal expression will not specify the need, We need clear drawings and specs)

Sam: Hi! Anantha  I was going thrugh some IC like MAX8880/MAX8881, can u help me with using that with input from my batteries?
dapj: let me see

Sam: It's datasheet says that Supply current [Iin] = 10uA max does it mean it will draw a max of 10uA from my battery?

dapj: it looks like it will work from 2.5 to 12V and it can give you a 5v out 200ma
Sam: Exactly!
dapj: is 5V enough 200mA too, but it cannot boost voltage

Sam: my concern is with my input. What about using rechargeable batteries [4x1, 2100mAh] to act as input to this IC. will it consume 10uA if I do so while my load to the output may vary from 100mA to 200uA

Battery Boost Circuits Max8880

dapj: if you want 5V you need to feed this atleast 5.5V this chip does not consume anything (the uA is Standby consumption )but it is not a voltage doublet or a charge pump

Step-Up/Step-Down Converter Features Ultra-Low Quiescent Current

Sam: OK, I need to feed it anything between 5.5 -12V, Do we get recharge battery near about 2V, 2100mA
dapj - a 12 v battery can be recharged when 11.8V is reached it may charge upto 12.8 V in Li ion

Fast, smart NiCD/NiMh battery charger - The MAX713 is designed for NiCd batteries, while the 712 is for NiMh batteries.

Friday, September 22, 2006

How to Calculate THD

I want to know about IEEE 519 Harmonics standards. And Formulas to calculate Total Harmonic Distortion (THD) for Voltage and Current according IEEE standards. Till now i am calculating by taking Square root of the ratio of the sum of the squares of the total harmonics to the fundamental harmonics.

And i am measuring the I THD and V THD by using fluke meter. I want to know how to calculate the THD as per IEEE standards.

Mail from RB


Have a look at these links ...

grouper.ieee.org/groups/519/index.html
techstreet.com/ Search Here ..
apqa.org/2002mtgs/oct2002.htm

powerstandards.com/tutorials/Harmonics.htm
purebits.com/appnote8.html
eng-tips.com/ Search Here ....
psihq.com/iread/harmonic.htm
powerelectronics.com/mag/power_power_transformer_attenuates/
ecmweb.com/news/electric_ensuring_generator_ups/index.html
powerelec.ece.utk.edu/research_multilevel_converters.html
orf.od.nih.gov/PoliciesAndGuidelines/DesignPolicy/HTMLVer/Revisions.htm
easypower.com/harmonics.html
keyitec.com/keyitec3D.html

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Thank you sir,

i ll try to go through the web sites.

Mail from RB


Monday, April 03, 2006

DC Motor Speed Control

The following was submitted on February 1st, 2006 at 08:49AM (PST). HiQFormMail version 1.5.1 - 196.205.30.60 - Subject: delabs Schematic Source Request. Circuit: speed motor control dc 200 v

mail from MD


Study Resources Below

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