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I need a Power amplifier which amplifies a 0-5V Arduino-generated PWM Signal to a 0-12V Signal with 120W, for powering a ZVS induction heater.

Linearity is not important because i can correct the error in software. Maybe it will be useful to convert the pwm signal to a analog signal to amplify it.

I thought about one of these Solutions: Step-up converter or a Class AB Amplifier. I'm not sure what i should do. What would be your solution and why?

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    \$\begingroup\$ Class AB amplifiers amplify analog signals, not digital. Step-up converters are voltage regulators which also do not apply. If this is for a motor, what kind of motor? Brushed? And unidirectional or bidirectional? \$\endgroup\$
    – DKNguyen
    Oct 29, 2019 at 21:01
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    \$\begingroup\$ Do you want PWM at 12V/10A or do you want a low-pass filtered 0-12V? \$\endgroup\$ Oct 29, 2019 at 22:00
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    \$\begingroup\$ You should provide a lot more information if available. For designing an amplifier it is vital to know as much as possible on the load to be driven. Is it ohmic or inductive or capacitive? Is it linear or non-linear? Also the type of signal (bandwidth, linearity) is of interest. \$\endgroup\$
    – Ariser
    Oct 29, 2019 at 22:35
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    \$\begingroup\$ It is unusual to amplify a PWM signal. Are you filtering the PWM ot create an Analog signal before you amplify? What is the bandwidth of the signal? \$\endgroup\$ Oct 30, 2019 at 0:20
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    \$\begingroup\$ If you are looking for a "digital" 12V PWM output, google half-bridge driver. \$\endgroup\$
    – sstobbe
    Oct 30, 2019 at 3:18

2 Answers 2

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Step up converters don't have a gain and most of them are built to operate within specific input\output ranges. Variable voltage step ups may be difficult to control.

I think the best thing would be to find an off the shelf AB amplifier if you wanted to 'amplify' PWM

Another option would be to parallel op amps. Paralleling op amps, like the LT1210 (1.2A of current) or the OPA548T (~2A of current). The drawback would be some loss in power and you would need at least 5 opamps.

The best thing would be to drive an H-bridge or mosfet with the arudino as H-bridges are great for PWM and have low loss. The other nice thing about mosfets is they have almost any power limit through paralleling.

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  • \$\begingroup\$ Your are right, Step up converter are not the right thing. Do opamps have a positive or a Negative temperautre coefficient? because if its negative i have to couple the temperature of the opamps very good. H-bridges with 120w are very expensive, if i use parallel H-bridges, do i have to couple them thermally? \$\endgroup\$
    – Salmjak
    Oct 30, 2019 at 8:29
  • \$\begingroup\$ +1 for for the half H-bridge option. This is exactly what I recommend in my answer here too, despite it receiving criticism from some folks there who claim H bridges can't work with PWM (I'm not sure why they would claim that, but see comments under the question and my answer there). I've used H-bridges for PWM many times. Glad to see someone else (you in this case) also has experience with H-bridges and knows they are good for this application. \$\endgroup\$ Oct 14, 2020 at 18:59
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    \$\begingroup\$ @GabrielStaples If both FET's turn on then it is a problem, I'm willing to bet some people may have a problem with preventing this from happening in all cases or don't understand some of the frequency effects from loads they are driving. If using 2 Nch FET's it can be challaning to meet the gate drive requirement. \$\endgroup\$
    – Voltage Spike
    Oct 14, 2020 at 19:22
  • \$\begingroup\$ If using 2 Nch FET's it can be challaning to meet the gate drive requirement. That's true. I've heard using a capacitor-based charge pump works well for this so you can use an N-Channel high-side switch too, not just on the low-side. Then, you get the benefits of the higher current and power capability of the N-Channel vs P-Channel MOSFET. \$\endgroup\$ Oct 14, 2020 at 19:33
  • \$\begingroup\$ Honestly, I think the person is just confused/mistaken/misinformed--take your pick, but it's become a contentious issue and I fear the misinformation is spreading faster than the truth, and the Arduino Stack Exchange community may not have enough members experienced in EE to pick out the truth and help settle the issue. \$\endgroup\$ Oct 14, 2020 at 19:36
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you just need a high output current circuit with gain of 2.4

schematic

simulate this circuit – Schematic created using CircuitLab

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  • \$\begingroup\$ I'm not sure if i can provide a Voltage source of 15V. But i will have 12V \$\endgroup\$
    – Salmjak
    Oct 30, 2019 at 8:11

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