Need SwitchMode Voltage Regulator

[polashd]

I need Circuit diagram of SwitchMode adjustable Voltage Regulator

The features of the circuit should be:

- Transformer less (transformers are heavy and wastes electrical energy more (as heat)

- Should be able to take input from 220V AC and also 9V DC (Battery) (if single diagram can’t do both, 2 different diagram will also be ok)

- Voltage adjustable (30V – 6V) , little more or less is OK.

- I prefer LM317T IC (as it is easily available and I’m familiar with it)

- If Inductor is used, description of the inductor (how to make it, readymade inductor is not available in my place (Bangladesh) )
Can anyone please help me?

Note 01: I got an inductor core (like the attached pic) which has around 50 turns of wire (may be 18 / 19 Awg). Can you guess the specification of the core and how to build inductor required for the circuit.

Note 02: Does AWG of wire matters, if yes, how

Polash

 

[Gary B]

I think you need to reconsider your request.

First, what is the output current range you need and what regulation level (how much can the output vary with a change on the input voltage or output current) do you need to maintain?

Second, do you need more than 9 volts output when on battery? If so, then a regulator won’t do; you need a full DC to DC converter and step up transformer to get the higher voltage. The alternative would be to go to a 36-48 volt battery.

Third, if you intend to connect to the mains, a transformer is desired just from a safety standpoint. Given item two, it could be combined as a three winding unit.

Fourth, does this thing have to charge the battery? If so what chemistry and capacity is the battery? In this case, it makes sense to add another winding just for the battery charging circuit.

Last, with a need to drop that much voltage when on AC, it probably makes sense to go two-stage. An SCR phase control preregulator followed by your switch-mode post regulator. While this can in theory be done with a direct connection, I have never seen it done that way. That fact alone should tell you that attempting this without a transformer is a bad idea.

All in all, you would probably be better off just buying a UPS.

 

[polashd]

I think you need to reconsider your request.

First, what is the output current range you need and what regulation level (how much can the output vary with a change on the input voltage or output current) do you need to maintain?

Second, do you need more than 9 volts output when on battery? If so, then a regulator won’t do; you need a full DC to DC converter and step up transformer to get the higher voltage. The alternative would be to go to a 36-48 volt battery.

Third, if you intend to connect to the mains, a transformer is desired just from a safety standpoint. Given item two, it could be combined as a three winding unit.

Fourth, does this thing have to charge the battery? If so what chemistry and capacity is the battery? In this case, it makes sense to add another winding just for the battery charging circuit.

Last, with a need to drop that much voltage when on AC, it probably makes sense to go two-stage. An SCR phase control preregulator followed by your switch-mode post regulator. While this can in theory be done with a direct connection, I have never seen it done that way. That fact alone should tell you that attempting this without a transformer is a bad idea.

All in all, you would probably be better off just buying a UPS.

First: Output current range may be 20ma - 200ma. As I intent to connect multiple arrays of LED voltage should be as stable as possible. I'll use current limiting resistor with each array. (I already made one using transformer and LM317T voltage regulator circuit which runs 6 different arrays (26V +/- <1V each). Now I want to get rid of the Size, Heat and energy Wastage of the Transformer.

Second: No step up. Its for different emergency lighting.

Third: Transformer less is the main requirement.

Fourth: No. Not for battery charging

 

[polashd]

please suggest me whether transformer less voltage regulator is not possible or not

I'm not an expert in electronics

 

[Gary B]

Yes, it is possible but no, it is not recommended because of the ease of electrocution; especially since European power mains do not have an included safety ground or polarized plugs to ensure a predictable orientation. At the minimum if there is no transformer, then the entire device must be double insulated and the power cord must be connected through a safety interlock so power is disconnected any time the enclosure is opened. Also, service of the completed device must be limited to technical personnel who have had power systems safety training. Anything less and you run a very good chance of killing somebody.

Last, transformer losses are probably the smallest waste of power in the entire circuit.

 

[polashd]

Yes, it is possible but no, it is not recommended because of the ease of electrocution; especially since European power mains do not have an included safety ground or polarized plugs to ensure a predictable orientation. At the minimum if there is no transformer, then the entire device must be double insulated and the power cord must be connected through a safety interlock so power is disconnected any time the enclosure is opened. Also, service of the completed device must be limited to technical personnel who have had power systems safety training. Anything less and you run a very good chance of killing somebody.

Last, transformer losses are probably the smallest waste of power in the entire circuit.

As you mentioned at Last -transformer wastes very small power'- are you sure?
I'm asking because In different web sites it is said that efficiency of topical transformers is around 50%. Very efficient transformer shows 85% efficiency (Max).

Following your suggestion, if I decide to use transformer, can you please provide me a good and efficient diagram of switch mode Voltage regulator (adjustable). Again I prefer LM317T (because of availability).

One more request. Can you tell me about the Inductor core in the pic (Identification, parameters). How can I make a 600uH inductor with it.

thanks again
Polash

 

[Gary B]

Guessing at the size and composition of the core and assuming that it is about 1” in diameter and permalloy dust, I come up with a fraction of a turn for 600 μH. Not a good choice for a choke that size. For something that small I would go with air core, especially if you are operating in the UHF band where a choke that size makes sense.

 

[polashd]

Guessing at the size and composition of the core and assuming that it is about 1” in diameter and permalloy dust, I come up with a fraction of a turn for 600 μH. Not a good choice for a choke that size. For something that small I would go with air core, especially if you are operating in the UHF band where a choke that size makes sense.

My intention is to make a 600 uH inductor in a voltage regulator circuit (IC LM317T)

 

[fernando_g]

The LM317 is a linear....

The LM317 is a linear (not switchmode) regulator.
Go to the national semi web site, and look for the simple-switcher or LED-driver family of regulators. Then you would have to determine which of the many suitable devices is available where you live.

And as Gary B mentions....... it would be a big, dangerous mistake attempting to do a transformer-less supply if you do not have experience with off-line switchers.