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Series Regulation

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premkumar9

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Hi,
My input is 11.5 to 15.5V DC. Output to be same as input from 11.5 to 12V and to remain at 12V after wards. Is this possible with a series regulator?
 
Hi,
My input is 11.5 to 15.5V DC. Output to be same as input from 11.5 to 12V and to remain at 12V after wards. Is this possible with a series regulator?
With a relay.
How? Can you give a sketch?
Yeah, I was afraid you'd ask me that. . .

From 11.5 to 12 you need series closed relay contacts.
From 12 + and above you need open relay contacts and a low drop regulator in parallel with the relay contacts, so the relay contacts would need to be driven by a voltage sensing comparator.

But, I don't know what to do with the region between 12.000 v and when the low drop out regulator kicks in. Not to sound like Bill Clinton, but it depends on what you mean by "same."
If the input voltage varies you could bridge the gap with a large capacitor. In that case, maybe you could intentionally dither the input voltage above and below the questionable region, but that would also make the relay oscillate.

I have to sleep on this one.
 
Last edited:
Hi,
My input is 11.5 to 15.5V DC. Output to be same as input from 11.5 to 12V and to remain at 12V after wards. Is this possible with a series regulator?

Is it possible to use a 'shunt' regulator in place of the series reg.?
 
Is this yet another thread for the traffic light project?
But it uses solar power because the electricity in India hardly ever works.

All the traffic lights in my city are LEDs. Some pedestrian crosswalks have a digital countdown timer display. There are car speed displays everywhere so that cars slow down. The parking meter pay places are solar powered. The electricity is very reliable.
 
If this is an auto elec. system you also need to worry about Load Dump Transients.
 
With a relay.

Yeah, I was afraid you'd ask me that. . .

From 11.5 to 12 you need series closed relay contacts.
From 12 + and above you need open relay contacts and a low drop regulator in parallel with the relay contacts, so the relay contacts would need to be driven by a voltage sensing comparator.

.

What should be the minimum drop between input and O/P for this low drop regulator?
 
The parking meter pay places are solar powered because their power requirement is low and it would cost a fortune to chop up parking lots to lay electrical wires then re-pave the parking lots, I guess.
Our electricity is extremely reliable and the voltage and frequency are constant.
 
The parking meter pay places are solar powered because their power requirement is low and it would cost a fortune to chop up parking lots to lay electrical wires then re-pave the parking lots, I guess.
Our electricity is extremely reliable and the voltage and frequency are constant.
Here power failures are there. A UPS would have taken care of that. Using solar power for some other reasons.
 
Is it possible to use a 'shunt' regulator in place of the series reg.?

I don't think so. My load is LED lights. Total current is 600mA. It increases approximately 300mA for every 1V increase. I want to avoid this by maintaining constant current at 600mA from power source. Here the power source is solar panel with battery and charge controller. The problem is the CC output is not regulated. So I wanted to try some solution which is more cost effective than using an additional DC-DC converter. If I can bring down the 11.5 to 15.5 V variation to 11.5 to 12.5, that is also OK (a compromise).
 
With a relay.

Yeah, I was afraid you'd ask me that. . .

From 11.5 to 12 you need series closed relay contacts.
From 12 + and above you need open relay contacts and a low drop regulator in parallel with the relay contacts, so the relay contacts would need to be driven by a voltage sensing comparator.

But, I don't know what to do with the region between 12.000 v and when the low drop out regulator kicks in. Not to sound like Bill Clinton, but it depends on what you mean by "same."
If the input voltage varies you could bridge the gap with a large capacitor. In that case, maybe you could intentionally dither the input voltage above and below the questionable region, but that would also make the relay oscillate.

I have to sleep on this one.

Seems more theoretical than practical.:)
 
Why go for solar power if electric supply is very reliable?
Because the cost of installing a mains drop is expensive. Plus, if very little power is needed, the flat monthly fee charged for having the meter is 10x-100x the actual usage cost.
Use a shunt regulator to keep the battery voltage with in it's limits.
Use a series current regulator or resistor to keep the LEDs happy.
You need both.
 
Because the cost of installing a mains drop is expensive. Plus, if very little power is needed, the flat monthly fee charged for having the meter is 10x-100x the actual usage cost.
Agree with the reasons to go for solar power.

Use a shunt regulator to keep the battery voltage with in it's limits.
Can I keep the battery voltage with in limits with out wasting power?
 
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