Is it possible to make an inverter without a transformer?

[rkenuox_]

INverter!!

hi,
im studying electrical eng'g. Wel it be possible to make a transformerless inverter??

any idea about this one, please help!!

here's my ym. reumsg_04@yahoo.com


ty

 

[banjo]

INverter!!

What are you trying to invert? Are you inverting a dc power supply voltage? If so, this is possible as long as the current requirements are not too severe. The circuit is very common and is called a charge pump. The following website will give a brief overview. From there your search engine will provide loads on info on the Internet.

https://en.wikipedia.org/wiki/Charge_pump

The common RS232 transceiver chips use charge pumps to generate the positive and negative voltages for the RS232 transmission lines. Look at the MAX232 or any of its clones.

 

[rkenuox_]

Re: INverter!!

thank you for that one.
it helps me a lot!!

can i ask if you have main ckt diagram of this transformerless inverter??

i have my email address: reumsg_04@yahoo.com


tnx a lot..

 

[banjo]

INverter!!

Here is a link to a datasheet with a block diagram about what is inside the charge pump IC. Most chips are very similar.

https://www.st.com/stonline/products/literature/ds/7403.pdf

 

[rkenuox_]

Re: INverter!!

thank you for that one,,

can u ask f u hane any crciut diagram of the transformerless unverter?

ty..

 

[Faizan Jawaid]

Re: INverter!!

Can u guys tell me how charge pump work? does it work on principle for voltage doublers using caps?

 

[banjo]

INverter!!

Charge pumps are quite a bit different than voltage doublers or multipliers using caps, however there are similarities. The standard voltage doubler uses an AC driving waveform and diodes to stack the peak AC voltage on top of each other.
Charge pumps use a DC input voltage. Internal to the charge pumps are switches that connect the capacitors in different configurations. The switches are electronically controlled by an internal state machine to close for particular lengths of time and in a particular sequence. Basically, they are transferring some of the charge in one cap to another. By arranging the switches and controlling their timing, it is possible to get a higher, lower or opposite polarity output voltage. The main drawback of charge pumps is the output current. It is not very high. A few tens of mA is easy. Above that level, charge pumps are difficult. They are a very good fit for small current applications like a couple of op-amps, or providing bias to an LCD, etc.
Look at the links in the previous posts, the block diagrams show the switches and you can trace the operation from there. You need not worry about the timing or closing order of the switches as the IC designer has already taken care of this for you.