Making car amplifier SMPS with tl494 + DC Protection

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Perry Babin said:
You're going to have to minimize the resistance between components to get significant power out of the supply. The thin wires between the various components are going to induce significant loss in the circuit.

What load are you using to test the circuit?

Are you connecting the load from the center tap to the positive output or are you connecting it from the positive output to the negative output?

How low is the voltage dropping across B+ and ground?


i am using a controller based circuit in which, i can control the output volts/amps as required....now, my load at testing was 15v at 9amps.

i have tested it with 20amps output at 6 volts...whatever configuration i use, this supply does not go beyond 130-140 watts...

center tap?....(did'nt understand your meaning)....i am using a single winding on the output with a bridge rectifier...

voltage drop was arround 10v at the output.

Thanks again for helping me out...i am sure, with the help of you all, i will be able to achieve what i want to achieve.
 
ok...let me say that again...

i am using this smps with my device....
now, my device can use any specified load (volts/amps) from the input power from smps which is 44v...

if i want, i can set my device configuration to use 15v at 9amps....
which i did....


so, the input voltages (which were 44v) at that usage on my device came down to 32 volts.
 
let me ask you guyz something...

its a bit off-topic but, if worked the way I want, then its 100% on topic.


i've been thinking about using a dc/ac inverter, since high-frequency powersupply is not the requirement.....i can use 44volts out of it if i can able to modify it....and convert AC to DC...

a 1000 watt inverter cost less then $70...

i have bought one...and opened to see...

there are two tl494's and three high-frequency transformers....two sides of mosfets... used in two different stages....

one stage is high-frequency stage...which is working on 40khz...and producing 130vdc using 4 mosfets...

and another stage is working on 50hz....using 19n20.....19amp 200v fairchild mosfet...

if i can only decrease the voltages from 110v to 44v....then its an awesome piece of hardware.... !!!


can any1 help in this?....
 
single supply is what i need....

in this inverter....there is a feedback...and i have tried to play with it...

but, the circuit is a bit complicated...and no matter what i do...it brings it back to 120v.....

now, for the winding....this inverter is using ferrite core....and from my past experience, i am never able to unlock the ferrite core....

coz they usually use adhesive....

i dont know about this one...but, i will check and see if its possible...

is there any way to remove adhesive easily and open the core without breaking it?
 
i have found this schematic from this forum...

this is almost the inverter which i am using right now....

now, if you notice, i have marked two variables on the schematic....which are on my inverter board...

by re-adjusting the variables....to maximum value (30k)...this inverter comes down to 65 volts....

i have even tried to put higher value resistors (more then 30k)...but, it seems like that its stuck on that voltages...

can any1 help on this after looking at the schematic...and guide me on how to go even lower then 65volts ?

Thanks again...
 

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aliazhar said:
single supply is what i need....

in this inverter....there is a feedback...and i have tried to play with it...

but, the circuit is a bit complicated...and no matter what i do...it brings it back to 120v.....



That's because it's from an AIMS 2.5kW DC-AC Inverter with a 120VAC Output. I posted it from a schemo a neighbor gave me.

Steve
 
ok...i did some tests...

as i mentioned before....there are three transformers in this inverter...

the first thing i did, was to remove all the transformers...

i have found that these transformers output is running parallel...with a bridge rectifier on each of them output...

i have also found that on the output winding of the transformer...there is a center tap which is not used in the cirucit...
so, what i did was to use this tap....

after using the tap (which is suppose to be on half of the output volts... i thought i will be able to get something less then 60volts....

but, no.....the circuit output is still 65v.....its like there is a voltage feedback, which needs to be modified for less then 65v....

is there any help i can get on this circuit?....what to modify on TL494 to get lower then 65volts ?


please help...

Thanks again.
 
I did it !!!!!

Thanks !!!!!!


if you notice on the second variable resistor....of 30k...

above that, there are two 39k resistors...which are coming from the output of the inverter....
i have reduce those values from 39k to 22k and it removed the variable of 30k and put a 56k resistor....

and i am getting 42.5 volts !!!!

you guyz are AWESOME !!!!! THANKS AGAIN !!!

now, one question....
is there gona be any problem if i put a bridge rectifier on the AC output which is coming from a full bridge mosfets and use it as DC ?

considering my total load on DC is about 630 Watts maximum.

Regards
 
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