TL494 Buck & Boost Converter
ฝัง
- เผยแพร่เมื่อ 1 ต.ค. 2024
- TL494 buck-boost converter with constant current and constant voltage control.
The circuit uses IRFZ44N Mosfet to switch high frequency of 36KHz with variable duty cycle to control the output voltage from 1.5v to 80v, where as the current can be adjustable from 40mA to 5A in which for current sensing I used 0.1ohm 10W shunt resistor at the output to measure the voltage drop on shunt and compare with reference voltage set by potentiometer and feed to the comparator of tl494 hence we can adjust the output current as well.
Components Required -
TL494/KA7500 IC
ATX PSU DC filter
PC817
IRFZ44N Mosfet
MBR20100CT schottky diode
UF4007 schottky diode
0.05 Shunt resistor
10K pot
LED
100ohm, 150ohm, 1Kohm, 2.2Kohm, 4.7Kohm, 10Kohm
10nF capacitor
16-pin IC base
PCB
Circuit & PCB -
drive.google.c...
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The capacitor at the output do not look like 100uf It is 47uf/150v does it work well؟؟
you can use higher capacity capacitor like 470uF or 1000uF this makes output stable
hey man! Quick question, how can we make 80V or even 130v with this circuit if the max drain-source voltage of the IRFZ44n is only 55v? Also, how can I go to 130v if the MBR20100CT is only rated for 100v? Thanks!
its dc to dc flyback converter the primary side of transformer is switched by Z44N hence no effect of high voltage of 100v or 130v comming at secondary side, and MBR20100CT can take high voltage for just moment
@@innovationic Thanks man! So the only thing that I have to change for this thing to go up to 130v is to put bigger filter electrolytic capacitors on the output? Do I have to mess with the R/C timing components? Thanks!
just upgrad the output diode and increase the number of turns in the secondary side of transformer
Just amazing... Excellent.
Many thanks!
If the principle diagram you shared with the printed circuit components you shared is wrong, it looks very different from electronic components.
in the PCB I used jumper wire as resistor symbol which is not shown in circuit all the components and their values are written on top silk layer
hi, friend. Could you make a new video clarifying the differences between the circuit and the pcb?
well the circuit and pcb is same but the difference is just having some extra resistors on pcb which I have used as jumper on pcb tracks to make pcb simple and I will update the given pcb and circuit as soon as possible thankyou
How to increase load capacity
Why optokuplor? And what turn transformer, primer, seconder?
The PC817 optocoupler is for voltage feedback, with the transformer’s primary and secondary coils each having 16 turns.
I notice that the current drop itself when you set it at 5A also voltage jump by itself?!
Thanks sir for effort ❤
because current is constant, thus the voltage will automatically regulate as the load
I won't 24 volt 20ampa is it possible? I don't won't boost mode only buck mode
this converter do both boost and buck so for step down just adjust preset
is negative and ground separate in circuit pls respond
both input & output are common ground
Sir , thank you so much for sharing your technical knowledge .
I am from Sri Lanka .
É possível aumentar a corrente inserindo outro mosfet?
yes adding mosfets will increase current capacity
Thanks for sharing
Keep up the good work
Thank you too
in your provided circuit pin13 out-ctrl is connected to Vref 5v pin 14 which used for push pull operation and both emitter of transistor is connected to gate of mosfet, so at same time one will try to turn on mosfet and one will try to turn of... i think mosfet is turning off for only dead time or remaining half duty cycle?..... pin 13 should be grounded for parallel mode operation of transistors.... am i missing something ? can you help me with this
You're absolutely correct. Pin 13 output control can be configured for either push-pull or parallel operation. In this scenario, pin 13 will be connected to GND for optimal performance.
@@innovationic is there any updated circuit provided by you ? .. i saw your lots of videos and really fascinated with your hard work.... also your crisp and detailed explanation and quick reply helped me to update my circuits. great job 👌👌👌
thankyou
the update in this circuit is just connect the pin 13 of TL494 with GND that's it 👍
Please the ground is common or separate?
gnd is common in whole circuit
Furthermore, in the pcb that you show already assembled in the video, you can see less resistance.
i want to use input voltage upto 35v .. should i use lm7812 to power the ic... so will the ref voltage functioning of the ic will work as normal ?
To ensure safe operation of the LM7812 with 35v input voltage, diodes can be added in series to drop excess voltage before the regulator
@@innovationic sry for miscomunication actually i want to use this buck boost with max input voltage of 35 volts... is it ok to give this high voltage to TL494 .. i found lm7812 has max input of 24 volts so it cannot be use... i also has one buck boost with uc3843 whose input is also limited .... for the safe operation of PWM controller what regulator should i use
you can try LM2596 buck converter or make auxiliary winding for driving TL494 just like smps
@@innovationic ok thanks
hello. Sorry to bother you again. On the PCB there are 2 resistors in series (10 - 100) between input negative and output negative. does not match the diagram.
In the PCB I have used multiple resistors, these works as jumper to avoid shorting or making PCB more complex also output and input negative are common its just mistake of having 10 ohm or 100 ohm resistor in series of 10 ohm and 100 ohm. I will fix it in a moment. Thankyou
24v to 340 volt
it looks like you are building inverter
Can i use 24 volt in put
yes input ranges from 9v to 30v and output can from 1.2v to 80v
brother i have made this PCB and tell me one more thing do I have to solder two jumpers wires at the bottom of the PCB or not please respond. many thanks!
jumper is needed for this circuit make all as shown in pcb
Thanks for your reply on last comment one thing more, so now there is no need for jumpers that you connected at bottom of pcb(1resistor and 1jumper)
still needed the jumper as shown in form of resistor
bro are you using TL494 in push pull mode ie max duty cycle 0.5 model or single ended mode please explain im bit confused
this converter is in flyback mode where two coils are coupled through common core, first coil is used as primary and second coil is as secondary.
Bro have you done 2 separate windings on core to make it transformer?
yes
hi, friend. a query. I have seen some similar circuits that use the uc3843 and the LM358. In this case, the lm358 is not used because the tl494 fulfills that function?
yes exactly tl494 have dual op amp for controlling current and voltage both
okay. Thank you very much for answering. congratulations for the video.
thankyou
Which pin of the tl494 you use to adjust the output current please and thank you
pin 16 of TL494 as shown with box in circuit diagram
@@innovationic I alway use pin 16 for short circuit protection and it never adjusted the current Just turn off the pwm output I try using 5k ohm potentiometer to try and see if it adjusted the output current and no current was turning down it just turn off, the same thing when I try using pin 1 for voltage controller i don’t get a voltage trimming it just turn off why is this, for months now I am having this issue with tl494 and ka7005b
Same thing happened to me when I was making the circuit that's why I uses1K resistor connected to pin 1 and voltage divider output and don't forget to connect 10k resistor between pin 3 & 2. See the circuit diagram properly I mentioned all details
@@innovationic I get the voltage to work already I need the current control i use a 5k potentiometer so i will need to by some 10 timmer
for input 40v-45v, ...?
separate auxiliary coil needed for 40v or above
I don't understand about separate auxiliary coil circuit. but I tried to provide a 40v input coil voltage, and I removed the in4148 diode pin which goes to pin 12 of the IC along with the main VCC line. and I replaced it with a 12v external voltage. Do you want to make the separate auxiliary coil you mean?
yes, its just like the smps which have auxiliary coil for PWM controller IC. And for 40v increase the number of turns in transformer.
One more thing, if we parallel 4 MOSFETs, does the 4.7k resistor from the IC output (pin 9,10) which goes to ground need to be added more?
single 4.7k is enough
What is the resister and jumper wire in the back of the pcb ? Not exist in your diagram !!!
the resistor is shown just as jumper wire between two joints
@@innovationic so the schematic diagram is correct and you updated ?
yes
Hello, can you give me the number of turns of the inductor?
15 turns for both coils
@@innovationic Thank you very much
Awesome
Transformer details please?
transformer is from ATX supply filter inductor and without any modification use the two coils and use in this circuit
What is the value of inductor in micro henry uH ? Can use 2 irfz44n in parallel for increasing out current i want 10A
as I have calculated the inductor is 100uH with 16 turns and for more current use more irfz44n in parallel, make sure have a proper totem pole driver circuit for IrfZ44n
@@innovationic thanks, can you draw a diagram of totome pole drive for more mosfets i’m new in electronics
ok
Hello , i made inductor 22 turn give me 33uH !!??? My core from atx 2cm inner diameter 3.8cm outer diameter color is green-blue
how do i get higher current? thanks
use bigger core and multiple Mosfets to increase the current
apprecited@@innovationic
Thanks
Great, the module have CC & CV fed back?
yes voltage and current both can be adjusted
@@innovationic i know have cc and cv mode but circuite have feedback for both current and voltage when increase output power ?
The output current is sense through 0.1ohm resistor connected at output, you can control output power
@@innovationic thanks what about adding more mosfets can you draw circuite diagram for driving more mosfets ?
Hello ... there are two 1n4148 zener diode in pcb but in the circuite diagram only one ? And 100nF and 10nF cap number are different between pcb and circuite diagram .... it’s a big difference between pcb and circuite diagram over all ???!!!! So which one is correct?????
circuit is correct
@@innovationic can you check it ? I want to make the circute and i want to be sure the circuite you uploaded is correct.
Circuit diagram is correct, in the PCB 1N4148 are shown but not written and the 100nF & 10nF cap are shown in both circuit & PCB
@@innovationic number of cap difference between pcb and circuite, in circuite one 10nF but in pcb two 10nF ??!!! And one 1n4148 in circuite but two in pcb ??!!
Here is the updated Circuit & PCB -
drive.google.com/drive/folders/1WXCR5QHfJqvhz5jM4JN-NcD6NHfZu7ho?usp=sharing