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  1. #1
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    lm3524

    Hi all,

    I want to build a 12VDC to 127VAC-100W 60Hz inverter using LM3524 PWM controller.

    Is it possible?

    Is there a ready and tested project available to download?

    Regards,

    Fernando

    •   Alt1st June 2008, 14:17

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    lm 3524

    Hi,
    Not really, these are used for DC to DC converters.
    These circuits may be useful. The difference between 120 and 127V is probably not significant if you just want to generate mains line voltage from a 12V battery, if it is you will have to use a custom wound transformer, most of these actually are custom wound for inverters.

    http://www.aaroncake.net/circuits/inverter.asp
    http://www.interq.or.jp/japan/se-inoue/e_ckt30_1.htm

    Bob.



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    lm3524 application

    Aaon Cake's inverter doesn't work:
    1) Its capacitors are backwards and they blow up.
    2) Its transistors experience avalanche breakdown of their emitter-base junctions that wastes the small amount of power from them by creating high current spikes in capacitors that have the correct polarity which also causes them to blow up.
    3) The bias current of the transistors is way too low for an inverter.
    4) Its output is about 30W at a low voltage.

    The transformer and more powerful transistors has nothing to do with fixing it.

    The Japanese inverter is complicated because it doesn't use a center-tapped transformer.



    •   Alt5th June 2008, 18:11

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    lm3524 application note

    dear sirs,

    Neither of them uses LM3524. I need a circuit that uses LM3524.

    Fernando



    •   Alt5th June 2008, 23:00

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    inverter bridge circuit

    The Japanese inverter is complicated because it doesn't use a center-tapped transformer.
    This is a surprizing analysis to my opinion. What do you mean with complicated in this regard? The transformer is actually more simple. The H-bridge circuit has the interesting property not to suffer from transformer leakage inductance. With a proper layout, all overvoltages are directly cut by the reverse diodes and deflected to the bus voltage. I would accept the argument, that it isn't suitable for 12 V inverter due to higher voltage drop at the switches, although this must not necessarily count for FET switches.

    The circuit has other flaws anyway, the simple "one-for-two" gate driver is most likely causing bridge cross-currents. One would expect an adjustable dead-time for H-bridge drivers, normally.

    Unfortunately I have no schematic for a 3524 controlled inverter. But I've seen heaps of inverter circuits at EDboard during the past months. I'm pretty sure, that there should be something that fits.



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    pwm lm3524

    The Japanese site with the low power inverter that uses four Mosfets instead of having a center-tapped transformer and only two Mosfets, also has another low power inverter that uses a center-tapped transformer and only two sets of transistors instead of four Mosfets.



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    lm3524 inverter design

    This thread is ridiculous.

    you are asking for a schematic using a specific single channel pwm controller, yet you make no other demands, other than a 127 vac 60hz inverter.

    furthermore the LM3524 doesn't have dead time control, so this isn't going to work for a high frequency pwm sin wave inverter.

    that said, there is no reason to use it at all for a 60 hz center tap square wave inverter, the internal oscillator will not operate reliably below 1KHz as indicated by the theory of op in the datasheet.

    if you wanted to synchronize the internal osc. to a 60hz trigger, you still have to deal with a 44% maximum duty cycle, and a nonlinear sawtooth waveform, not to mention the fact that you would be using the chip solely for the flip-flop and output driver, when you may need an external mosfet driver anyway



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    100w inverter circuits using op -amp

    This thread is ridiculous.
    Not particularly, I think. It hasn't been said at all, if a square wave or sine PWM inverter is intended. As sine wasn't said, I heard square wave from the question.

    You are right, that a SG3524 isn't first choice for either of them. I think, however, that operational circuits for both versions could be designed. ST SG3524 datasheet is telling a 120 Hz to 500 kHz PWM oscillator range, 120 Hz is 60 Hz inverter output.

    @Audioguru: I see, that you meant, the H-bridge circuit is too complicated for the application. This may be true in case of a square wave inverter.



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    lm3524 mosfet

    you can make the inverter working with 3525 pwm controller but tehe output cannot drive the mosfet directly you have to add a gate drive using transistors. it better go for 3525 which can driectly connected to mosfet gate. in my old ups design i was using 3524



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    what is lm3524

    Hi Fernando !

    Try these links...

    h++p://www.edaboard.com/ftopic91039.html

    h++p://www.ehow.com/how_2281345_dc-ac-inverter-old-ups.html

    h++p://sound.westhost.com/project89.htm

    Best Regards.

    jackrs :D



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