Questions tagged [tl494]

Anything related to the TL494 integrated circuit. The TL494 is a complete PWM control circuit specially designed for switched mode power supply (SMPS) applications.

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What is the most used bi-polar output SMPS topology in gate driver isolation?

I have some questions concerning this schematic: What is the topology used here? I am guessing flyback without feedback circuitry. Why is the TPS40211 utilized here? Is it to provide more current? ...
1 vote
3 answers
167 views

How to fix hot PWM and crack 6A High-Speed MOSFET Driver?

My boost converter boosted voltage for a few seconds but it made a crackling sound, probably burnt. It doesn't switch the MOSFET now and TL494 is getting hot from the upper side which is where error ...
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1 answer
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Power ratings of resistors for a buck converter using the TL494

I am working on a buck converter project where I am using the TL494 as a PWM controller IC. I am confused about the power ratings of the resistors that are used in the entire circuit. I have added the ...
3 votes
0 answers
74 views

Is this a right way to drive MOSFET driver

I've designed the boost converter below: Aside from the irrelevant voltmeter parts which are not connected, I'm asking if the way I'm driving the MOSFET is correct. Working is simple, when TL494 let'...
0 votes
0 answers
187 views

Tl494 with gate driver IC output voltage problem

Recently I've got my hands on some ETD42 ferrite cores and decided to make a 300W pure sine wave inverter. I chose the TL494 SMPS IC for driving the booster circuit (12 to 340V) and using the EG8010 ...
-1 votes
1 answer
67 views

High current flow in voltage regulation using TL494

I am using the given schematic for voltage regulation. When I’m not given the feedback, that is point A and B is not connected, then m getting a pulse of 35 % duty cycle of 0-12 V. But when I’m ...
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1 vote
0 answers
1k views

Operation of the generic ka7500(tl494) based boost board and soft start adaptation

I am examining the operation of a boost card found in many cheap inverters, with a KA7500, EG7500 or tl494 IC type. Here is the diagram that can be found everywhere: My question are: what is the ...
0 votes
1 answer
69 views

how to map 1V - 10V to 1.6V to 3.2V for voltage regulation using TL494

I am trying to design the given circuit where pin 1 is the non inverting terminal of comparator where I want to use a ref voltage of 1V - 10V but IC TL494 is accepting a voltage of 1.6V to 3.2V....and ...
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1 vote
0 answers
153 views

Voltage regulation using TL494

I want to use TL494 IC for voltage regulation. For this, I am giving a 2.5 V reference to the inverting pin of the error amplifier and wants to vary a voltage from 0- 5V at the non inverting terminal ...
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0 votes
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85 views

Boost converter shorts out the power supply under load

I'm building a DC-DC step-up (boost) converter using TL494. The schematic is attached Input voltage: 9V The resistive divider at the output sets the output voltage to about 14V Desired output current:...
1 vote
1 answer
493 views

Problems with TL494 boost converter

I'm building a DC-DC step-up (boost) converter using TL494. The schematic is attached Input voltage: 9V The resistive divider at the output sets the output voltage to about 14V Desired output current:...
1 vote
1 answer
189 views

TL494 error amplifier pin maximum voltage input

I'm designing a 60V SMPD for my CNC milling machine using a TL494. I've have successfully driven the gate drive transformer which can in turn drive the MOSFETs. I am able to get 60 up to 70V output ...
0 votes
1 answer
213 views

TL494 dynamic frequency changing

I am using a TL494. I can adjust the duty cycle whenever I want, but I am having trouble changing the frequency. The TL494 datasheet says that the IC is a fixed-frequency PWM control IC. I use push-...
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1 answer
2k views

TL494 duty cycle adjustment

I'm building a simple pulse generator with a TL494 in single ended configuration. My plan is to set the frequency between 20Hz to 1kHz and duty cycle between 0% to 45%. I will adjust that with a ...
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0 answers
85 views

PWM controller IC selection

I am working on a boost converter with analogue PI control. I want to make the PI controller using a separate Op-amp IC and giving its output to the PWM controller to generate proportional PWM signal. ...
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4 votes
2 answers
484 views

Why is there no frequency compensation required in TI's TL494 example buck regulator design?

This example circuit is given in Texas Instrument's application note SLVA001: "Designing Switching Voltage Regulators With the TL494": They use a 140 μH inductor and a 220 μF electrolytic ...
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0 votes
0 answers
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confusing with tl494 application circuit

According to tl494 datasheet on application section. For buck converter, they use error amplifier with 101x gain to control swithching duty cycle and then for curent limit, they use high gain error ...
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1 vote
0 answers
1k views

Tl494 converter powerend kind of oscillation / buzzing

I'm in trouble with designing and testing tl494 halfbridge converter (schematic based on atx power supply and this one: https://www.hobbyelektro.eu/spinany-zdroj-0-30v-0-6a/) Converter wasnt quite ...
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0 votes
1 answer
283 views

TL494 output signal slopes

I'm designing a buck converter based on TL494. And I have to drive high side mosfet, i want to use a gate drive transformer, switched by totem pole driver. The problem is that slopes of signal coming ...
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1 vote
1 answer
212 views

Limiting the pulse width of a PWM by using voltage divider and a single power supply

I'm using a Tl494 PWM and I want to limit the pulse width from 0% to 80% of the signal as maximum. How can I achieve this using a SINGLE 5v reference supply (I know it can be achieved by using two ...
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1 vote
1 answer
257 views

PCB ground plane noise

I have designed PCB for my buck converter. When designing the PCB I've created, I have made one ground plane as shown. I received the PCBs and there was noise in the TL494 affecting fixed 5V Vref ...
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2 votes
2 answers
667 views

TL494/TL594 measure current with grounded load

Multiple examples of current limiting with TL494/TL594 suggest to use current sensing resistor between load(-) and GND. But I want load to be grounded. Can current sense resistor be placed above load(+...
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11 votes
2 answers
2k views

Buck converter, squeaking/whining inductor

I have a problem with my homemade buck converter. It is based on a TL494 control chip with my discrete MOSFET driver. The problem is that my inductor squeaks and whines, when the output current ...
0 votes
1 answer
259 views

Two PWM signals from TL494

I need to generate two open-loop PWM signals with different duty cycles for my converter. The frequency is 20kHz. I did generate one signal. Should I use another TL494 and connect it to the same ...
2 votes
2 answers
339 views

TL494 minimum operating voltage VCC

Has anyone operated TL494 on +5VDC practically as it works in simulation software ? minimum operating voltage indicated in datasheet is +7VDC . please confirm.
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3 votes
4 answers
1k views

Compensating for voltage drop across current-sensing resistor in a TL494-based SMPS

I'm trying to wrap my head around this reference design from this TI document. This is a 5V power supply that is rated at 10A. ...
1 vote
1 answer
7k views

Current limiting using P-CH MOSFET

I am currently building variable voltage/variable current (lab) power supply out of an ATX switching power supply. I have done voltage regulation tweak of the TL494 so now it gave me variable voltage ...
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5 votes
4 answers
3k views

Full bridge HVDC to modfied square sine - random half side MOSFET burn

I am trying to make a step-down 350V to 220V voltage converter. I decided to go with rather simple circuit of full bridge MOSFET inverter since my loads are only resistive or switched. I had built it ...
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1 vote
1 answer
645 views

Can I measure inductor current by adding a secondary winding?

I have a buck converter and I want to add a current loop to it. I don't want to use a hall-effect sensor or something expensive like that. I think it is not practical to use a sensing resistor since ...
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-1 votes
1 answer
220 views

How do I use one feedback pin with two error amplifiers?

I know there is a similar question asked: TL494CN and error amplifier. However, that link does not answer my question. If I need one current loop and one voltage loop on the power supply, how should ...
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3 votes
1 answer
170 views

Transfer function of this opamp circuit

(Source: Designing Switching Voltage Regulators With the TL494, Page 25) What does the output of this opamp give? Use approximated values if necessary. The reference voltage is \$V_R = 5V\$. Denote ...
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