In this article I have explained a very simple method of acquiring 220V DC from a 12V DC source. The idea utilizes inductor/oscillator based boost topology with the help of the IC 555.
Circuit Operation
Referring to the circuit diagram below, we see that the entire idea is based upon the versatile, evergreen IC 555.
Here it's configured in its standard astable multivibrator mode for generating the required pulses at a frequency determined by the resistors 4k7, 1k and the capacitor 680pF.
The duty cycle may be appropriately adjusted by experimenting the 1K resistor.
The output is received at pin#3 of the IC, which is fed to the gate of an N-channel mosfet.
When power is switched ON, the positive pulses emanating from pin#3 switch ON the mosfet into full conduction.
During the above periods the 12V high current potential is pulled to ground via the coil by the mosfet.
As we all know inductors always try to oppose instant changes in current polarity through it, therefore during the negative pulses when the mosfet remains switched OFF, forces the coil to dump the stored potential in it in the form of high voltage EMF pulse into the output.
This voltage may be equal to 220V DC and gives rise to the required potential at the shown outlet of the circuit.
The above straightforward operation is repeated continuously at the given frequency providing a sustained 220V DC at the output.
The BC547 and its base network is introduced for limiting the output voltage to the required degree.
For example if the required output is 220V, the 47K preset may be adjusted such that the220V mark never exceeds, irrespective of the coil back emf rate or the input voltage fluctuations.
The mosfet can be any 400V, 50 amp type, for example a NTD4302 may be used.
The coil wire should be thick enough to hold up to 30 or more amps.
Circuit Diagram
NOTE: THE MOSFET IS MISTAKENLY SHOWN AS IRF540, WHICH IS NOT APPROPRIATE FOR THIS APPLICATION, SO PLEASE REPLACE IT WITH AN IRF740 MOSFET.
WARNING: THIS CIRCUIT INVOLVES HIGH VOLTAGE, EXTREME CAUTION IS ADVISED WHILE HANDLING THIS CIRCUIT.
IC 555 Pinout Details
Mosfet IRF740 Pinout Details
How to Calculate the Inductor
Let's assume the maximum output current required is 5 Amps.
Then the total power output will be 220 * 5 = 1,100 Watts approximately.
So the maximum input current must be 1,100/12 = 92 Amps approximately.
The formula for calculating the Inductor is:
L = (Vin * D * (1 - D)) / (fs * ΔIL)
Where Vin = Input Voltage = 12 V
D = Duty cycle. This can be calculated as follows:
D ≈ 1 - (Vin(min) + Vds + Vf) / Vout
Where:
- D: Duty cycle
- Vin(min): Minimum input voltage
- Vds: Voltage drop across the MOSFET
- Vf: Voltage drop across the diode
- Vout: Output voltage
So, D ≈ 1 - (Vin(min) + Vds + Vf) / Vout
D ≈ 1 - [(12V + 0.5V + 0.7V)]/220V]
= 1 - 0.06 = 0.94
So, D = 0.94
fs = the 555 frequency at pin#3 or the MOSFET gate, let us assume the frequency to be around 300 kHz according to the R1, R2, C1 values for the IC 555 timing components.
ΔIL = Ripple current. Typically, the ripple current of 20-30% of the output current, so here it will be around 0.2 * 5 = 1 Amp
So, now let's plugin the above values in our Inductor formula:
L = (Vin * D * (1 - D)) / (fs * ΔIL)
= (12 * 0.94 * (1 - 0.94)) / (300000 * 1)
= 0.67 / 300000
= 0.0000022333 H or 2.2333 µH
So the value of the Inductor should be 2.2333 µH for getting 5 amp maximum output.
Comments
Thank you Manjumdar for sharing your ideas regarding this circuit built. It has been really helpful.
I am trying to tell you that if 150 watt voltage booster inverter is connected to 150 watt battery,without any load or minimum wattage of load on inverter.Then,battery backup depends on inverter rating or load rating????
it will obviously depend on the load, without a load the inverter will consume negligible amount of current.
Sir, if I connect 15 watt cfl bulb to 150 watt inverter with 200 watt battery.Then, how much hours it will keep bright.
Sudip, please calculate it here:
https://www.homemade-circuits.com/p/battery-calculator.html
sir how to get 24v in the circuit? and what is the frequency???
andrie, you will need to reduce the inductance of the inductor by some trial and error to get 24V at the output….for 24V you can remove the BJT and the zener diode stages which are shown at the output section of the circuit.
hello sir, please i want to make a transformerless inverter (no ferrite core transformer) with 12vdc input and 220vac as output, the wattage should be between 200watts and 500watts. is it possible?
Sir which ic I used for Dc 12v to 220v Ac up to 20amp current
I didn't understand what you are saying?
sorry that's impossible….
yes it should be also rated at above 300V…you can replace it with a IRF840
In the schematic, the output 220 volts is connected across the drain – source terminals of the 30 v mosfet ??
hello sir
can i use this circuit for charging of a dc input fan?
wat is the case when the input given 12v battery is discharged?
can i giv a input to this circuit by 12v rechargeble battery?
which mosfet i hav to use to this circuit (say the mosfet number)?
Sir you have mentioned that we can use TIP122 instead of NTD4302, then what should be the pin configuration of TIP122? I mean how should I connect the transistor into the circuit?
Thank you sir for your reply I will be using TIP122 instead of NTD4302 since I couldn't find them in the shop.
Dipto, yes it's possible, join its base to pin3 of the IC via a 10K resistor, emitter to ground and collector to coil
can i use IRFZ44N mosfet
Sir
I want to make a power inverter for 48v dc to 220v ac. Plz guide me…
Krishna, you can try the following:
https://www.homemade-circuits.com/2014/11/48-v-inverter-circuit.html
Hi Swagatam !
May I ask if this circuit can be used to power a laptop charger ?
Thanks
Hi Roney, yes you can used it for charging a laptop from your car battery, the inductor will need to be dimensioned and tweaked appropriately until the required 19v is achieved…
You can get high voltage at high frequency (not 50Hz) but the current would be around 100mA. How much is your load?
ok I tried building this circuit on electronic work bench but only got 8v out,
keep the BC547 disconnected initially and then check…
Which coil would i use to get 110v at 50hz
you'll have to find it by experimenting with different number of turns.
hi iam doing a project in which i need to convert 6v DC to 230v AC . after converting can i use any electrical appliances from the output of 230v AC
search for any IC 4047 inverter circuit and you can use it for your application
hi swagatam majumdar,
is possible with this circuit to fed an solenoid water valve (7w) as valve of washing machine or an little motor (4w) as flat of wave oven?
maybe is better to think an inverter circuit more complex as that you have posted in other pages?
thank you so much
regards
andrea
Hi Andrea, for a DC application, the above circuit could be used, but for AC devices an inverter would be more preferable.
220v ac 2amp load
you will need a 400 watt inveter for that, the above circuit will not work
plz reply i m waiting
hello nitin,
please tell me all the technical details of your project, only then i would be able to suggest regarding the above circuit integration.
hello sir nice work…i m planing electrick go kart powerd by sewing machine motor can i use this circuit??
i have 30ah battery ..sorry for bad english…reply fast..thank u sir….u r genius,
Hi Swagatam
I am working to use this circuit (excluding the transistor network) as a simple laptop charger from car battery.
1) One option needs a mosfet with following properties:
25V, 5A and RDS(on) 3.5 Ohms
I am not sure if such mosfet is available because such RDS(on) value is for small current mosfets.
2) The second option is to reduce the input voltage to 6V but, that needs high current regulator.
Which of these two options is more practical?
it's 44 milliohms which is a lot better than 3.5ohms, meaning the ON resistance of the drain to source will be just 44 milliohms.
But that is 44mOhms whereas I need 3.5Ohms!
Hi Abu-Hafss,
The first option looks fine, you can use a higher rated mosfet such as IRF540 etc. it would also work as good and fulfill the results.
Hi Swagatam
Can this circuit be used to power a 30-40W soldering iron?
If yes, would 12V-5A input be enough?
Hi Abu-Hafss,
yes it can be used, 12v/5amp would be just enough for that.
Hi Swagatam
I am considering to use this transformerless circuit to provide high voltage in CDI. Any comments/modifications?
Hi Abu-Hafss,
Just connect a couple of 10uF250V(in parallel) across the output, no diodes are needed.
Hi Swagatam
The out put is sort triangular waves of AC 230V (fluctuating between 0-230V not between 230 and -230 at 510Hz. How do we convert it to DC??? Single rectifier or bridge rectifier is not working, the output remains the same.
Maybe, the simulator is experiencing some difficulties in performing the rectification. Based on your experience, if you simulate in your mind, do you think the rectifier/capacitor should work to give a smooth DC output?
Hi Abu-Hafss,
You can experiment with the number of turns of the inductor for getting different voltage levels at the output, because that's the only component that is directly related with voltage boosting.
Hi Swagatam
As per my usual practice, I have simulated this circuit and got following findings;
The frequency is 510Hz. If it is decreased to 50-100Hz, the output becomes more than 1kV.
The inductor is 250µH. The capacitor is 10µF.
Following is the wave pattern:
https://dl.dropboxusercontent.com/u/20969135/230V%20output.gif
There is one issue i.e. how do we convert it to 230VDC? The CDI capacitor needs HV DC for charging which is provided thru a diode (half wave rectification) but, this output cannot be rectified, neither thru half wave rectification nor full wave.
If the capacitor value is increased, the output decreases.
Hi Abu-Hafss,
Yes, it's worth trying.
sir can i use the polyester fluorescent ballast for inductor…
It will depend on the output voltage requirement, if the inductor is able to produce it then it would be fine.
Thank you sir for your reply, I'll try it.
Rashid
Hello Sir,
How can i modify this circuit to run a 150 or 100W fan.
Thank you in advance.
Rashid
Hello Rashid,
you will have to modify the coil by experimenting a little with the no of turns and wire gauge until it satisfies the conditions.
Obaid just take out 220V AC, add a step down transformer that makes it 24V and then add a bridge rectifier and two filter capacitors electrolytic 10uF 25V and a 7812 IC, u'll get 12V
okay sure i will try that and see what is the result, Thanks again sir.
Thank you sir, I had tried joule before but the problem is the current supply is not high enough.I need at least 100mA. Can I know how to increase the current or is there any way to do it?
Use parallel wire winding, meaning use two or three wires together and then wind them as per the data, this will increase the current of the transformer,also you will have to use more number of cells in parallel for supplying the required amount of current.
Hi Sir, sorry to ask this question here as I could not find a dc to dc step up circuit in your forum. I am thinking is it possible to modify this circuit to step up 2vdc to 12vdc? Thank you.
Dear Jayanta,
You can try the second circuit shown in this link, but I am not sure about the transformer details you may have experiment with its size and wire gauge:
https://www.homemade-circuits.com/high-current-10-to-20-amp-automatic/
Dear sir ,
I have a battery 12v 32ah sf sonic jet , how can i charge by home made circuit ,I would like to use it as 200 Watt CFL inverter, kindly help me to making a 3 amp constant current battery charger,
thanking you,
Jayanta Roy
Hi Unknown,
the above circuit will require a minimum of 4V to operate correctly, I think you should try the following circuit, might just work:
https://www.homemade-circuits.com/2012/10/1-watt-led-driver-using-joule-thief.html
you can use the square wave symbol range for checking the frequency operation of the circuit…..
if it's not working with a mosfet you can try a transistor instead, try a TIP122.
Your DMM should have a frequency measuring option, normally indicated with "kHz" symbol, otherwise it won't help.
In response to the 555 frequency triggering, when the mosfet is in the ON state, the inductor stores the specified amount of electrical energy in it and during the mosfet OFF state reverts it to the output. This back emf from the coil constitutes the 220V at the ouput…
It would be dangerous to use the above type of configuration for your requirement, you may try the following design:
https://www.homemade-circuits.com/2013/06/0-300v-variable-voltage-current.html
Please refer to this post, it has all the details:
https://www.homemade-circuits.com/2013/05/55v-110a-n-channel-mosfet-irf3205.html
Yes you can use a DMM which has a frequency feature in it.
hello again,
i need to make a just opposite project converting 220v AC to 12v/24v DC help me please or please give me link of the same 🙂
It will be difficult for me to identify exactly how you fixed the mosfet, I hope you've put it correctly.
What kind of inductor did you use and is your IC generating the required high frequency?? these two factors determine the correct operating conditions for the circuit.