Dual Op Amp Bridge Audio Amplifier is analyzed and explained in this video. For more Circuit videos: Electric Guitar Amplifier to XLR Audio Signal ua-cam.com/video/X4y8cwZdGEk/v-deo.html Op Amp Amplifier with Electronic Gain Control ua-cam.com/video/NoNgQpbj77Y/v-deo.html Push-Pull Power Amplifier with Darlington Transistors ua-cam.com/video/866MYibo8yE/v-deo.html VCA Electronic Gain Control (Part 1): Voltage-Controlled Attenuator Overview ua-cam.com/video/cFzYZsPEtP0/v-deo.html Power Amplifier Design (Class A) with Transformer ua-cam.com/video/gKlJrqGqeCI/v-deo.html PhotoDiode Amplifier with Data Compression Explained ua-cam.com/video/hqrRx2ufAwg/v-deo.html Amplifier with -25 to 55 dB Attenuation-Gain range ua-cam.com/video/oyz6lTGd2Xo/v-deo.html Electronic Gain Control for Op Amp Amplifier ua-cam.com/video/NoNgQpbj77Y/v-deo.html Push-Pull Power Amplifier with Darlington Transistors ua-cam.com/video/866MYibo8yE/v-deo.html Thermometer Circuit Design with Op Amp & BJT transistor ua-cam.com/video/55YsraFE0rg/v-deo.html PhotoDiode Amplifier with Op Amp and MOSFET Explained ua-cam.com/video/1c3EJ2d4pVI/v-deo.html Instrumentation Amplifier with Electronic Gain Control ua-cam.com/video/C4tghZ-q6Zs/v-deo.html Voltage Regulator Op Amp Circuit with Foldback current limiting ua-cam.com/video/VN4_qF9DvBM/v-deo.html Push-Pull Power Amplifier Design with Op Amp, Sziklai Darlington Transistors ua-cam.com/video/8BFzsi7-Vbs/v-deo.html And the Analog Circuits Video playlist: ua-cam.com/play/PLrwXF7N522y4c7c-8KBjrwd7IyaZfWxyt.html I hope these Circuit design and analysis videos are interesting.
You're welcome! If you found the Dual Op Amp Bridge Audio Amplifier video helpful, you might also like the Electric Guitar Amplifier to XLR Audio Signal video ua-cam.com/video/X4y8cwZdGEk/v-deo.html, where I explain amplifying audio signals for instruments like electric guitars, and show how to properly interface with XLR outputs. If you're interested in learning about electronic gain control for amplifiers, I have a couple of videos that explain how to manage gain electronically. You might find Op Amp Amplifier with Electronic Gain Control ua-cam.com/video/NoNgQpbj77Y/v-deo.html and the VCA Voltage-Controlled Attenuator Overview video ua-cam.com/video/cFzYZsPEtP0/v-deo.html useful. These videos will provide you with further insight into amplifier design, signal control, and practical applications in audio systems. I hope you find them interesting as well.
That's a good question. In this analysis we are applying an input AC signal in differential mode with zero DC offset. I would suggest using AC decoupling capacitors at input so that we isolate input terminals of the Op Amps from any DC residual of the applied input signal. I hope this is helpful.
If we take a really good input opamp and reinforce the output with for instance BUF634 (number of them, I mean 30-60) we'll have an excellent hi-fi amplifier with power enough for a big room. If we provide a really good power supply, that will be considered a hi-end amplifier with no doubts.
Good points especially regarding using combination of Texas Instruments BUF634 High-Speed Buffers or its newer version BUF634A to provide high enough AC current to speaker. Alternatively newer Texas Instruments products like OPA2673 Dual, High Output Current Operational Amplifier might be an interesting choice for this circuit. 👍
@@STEMprof Yes, OPA2673 might be interesting for some applications, may be it will be enough for a headphone driver, however I don't see it inside a power amp with its +-6.5V supply range. May be with a floating rail this will be possible.
@sc0or Yes, good point regarding supply range. We can also use high-current power transistors at the output of Op Amp to defer power delivery to transistor so that we can have a wider choice for the type of op amp for this audio amplifier.
@@STEMprof Sure, but even mid power bjts mostly are not fast enough. I can remember KSC2690 and 2SC3503 with a bandwidth to 150MHz. High power transistors are not an option at all. And this is why buf634 with a bandwidth to 250MHz is unique (relatively unique due to high current output). I listened to an amplifier built with buf634 which was able to amplify PAL signal -) It sounded as a hi-end device. However it didn't use a bridge architecture and was limited with 20W@8Ohm
@@sc0or Great points regarding the importance of monitoring the max speed that power transistor is able to achieve. But I think there are Power Transistors that can easily handle Audio frequencies with 20 to 40A Collector current. Few examples are OnSemi 25 Ampere 200W 2N6338, 2N6341 High-Power NPN Silicon Transistors www.digikey.com/en/products/detail/onsemi/2N6338G/1475307 and possibly Fairchild FGH20N6S2, FGP20N6S2, FGB20N6S2 600V 125W N-Channel IGBT www.digikey.com/en/products/detail/rochester-electronics-llc/FGP20N6S2/11508896
LOL,I fail to understand how this works, but configured s non inverting opamp, so both raise and fall a the same time. I simulated the circuit, i even put a 8 ohm resistor between both opamps as analog for the speaker, the current was like u amps over the 8 ohm resistor. I even rotated one of the opamps like it would seem logical, one pushing and the other pulling, but the behavior was the same. I'm curious how this Bridge mode works, my car amp has this.
Thanks for your interest in this circuit and sharing your thoughts/observations. As explained starting in minute 8:30 , It is like a differential amplifier for AC input signal that is applied between the non-inverting terminals of the two op amps. As the input AC voltage increases, it pushes up the positive input terminal of say the left op amp higher than the other one's. As a result an AC current flows from left to right through the resistor R1 (C1 impedance is practically zero in the frequency range of interest).
@@STEMprof Hey, i made a pcb of my class AB amp, now i wanna make a pcb for the power side, bridge rectifier, etc. I wanna add a soft start to prevent inrush current of the capacitors, using mosfets. for the positive rail it's not so hard, but applying the same voltage of the gate of mosfet of the positive rail on the negative's gate doesn't work, since there is like 40 Volt difference. the negative rail moves much faster if you use caps as time delay. I tried various sources, like stack exchange. You happen to know a method of moving 2 mosfets a the same time on 2 voltage extremes?
![Band-Gap Voltage Reference Diode [Temperature Compensated Circuit]](http://i.ytimg.com/vi/qYOe7JOidHk/mqdefault.jpg)
![Band-Gap Voltage Reference Diode [Temperature Compensated Circuit]](/img/tr.png)
Dual Op Amp Bridge Audio Amplifier is analyzed and explained in this video. For more Circuit videos:
Electric Guitar Amplifier to XLR Audio Signal ua-cam.com/video/X4y8cwZdGEk/v-deo.html
Op Amp Amplifier with Electronic Gain Control ua-cam.com/video/NoNgQpbj77Y/v-deo.html
Push-Pull Power Amplifier with Darlington Transistors ua-cam.com/video/866MYibo8yE/v-deo.html
VCA Electronic Gain Control (Part 1): Voltage-Controlled Attenuator Overview ua-cam.com/video/cFzYZsPEtP0/v-deo.html
Power Amplifier Design (Class A) with Transformer ua-cam.com/video/gKlJrqGqeCI/v-deo.html
PhotoDiode Amplifier with Data Compression Explained ua-cam.com/video/hqrRx2ufAwg/v-deo.html
Amplifier with -25 to 55 dB Attenuation-Gain range ua-cam.com/video/oyz6lTGd2Xo/v-deo.html
Electronic Gain Control for Op Amp Amplifier ua-cam.com/video/NoNgQpbj77Y/v-deo.html
Push-Pull Power Amplifier with Darlington Transistors ua-cam.com/video/866MYibo8yE/v-deo.html
Thermometer Circuit Design with Op Amp & BJT transistor ua-cam.com/video/55YsraFE0rg/v-deo.html
PhotoDiode Amplifier with Op Amp and MOSFET Explained ua-cam.com/video/1c3EJ2d4pVI/v-deo.html
Instrumentation Amplifier with Electronic Gain Control ua-cam.com/video/C4tghZ-q6Zs/v-deo.html
Voltage Regulator Op Amp Circuit with Foldback current limiting ua-cam.com/video/VN4_qF9DvBM/v-deo.html
Push-Pull Power Amplifier Design with Op Amp, Sziklai Darlington Transistors ua-cam.com/video/8BFzsi7-Vbs/v-deo.html
And the Analog Circuits Video playlist: ua-cam.com/play/PLrwXF7N522y4c7c-8KBjrwd7IyaZfWxyt.html I hope these Circuit design and analysis videos are interesting.
I like learning audio power amplifier design. Thank you very much.
You're welcome! If you found the Dual Op Amp Bridge Audio Amplifier video helpful, you might also like the Electric Guitar Amplifier to XLR Audio Signal video ua-cam.com/video/X4y8cwZdGEk/v-deo.html, where I explain amplifying audio signals for instruments like electric guitars, and show how to properly interface with XLR outputs. If you're interested in learning about electronic gain control for amplifiers, I have a couple of videos that explain how to manage gain electronically. You might find Op Amp Amplifier with Electronic Gain Control ua-cam.com/video/NoNgQpbj77Y/v-deo.html and the VCA Voltage-Controlled Attenuator Overview video ua-cam.com/video/cFzYZsPEtP0/v-deo.html useful. These videos will provide you with further insight into amplifier design, signal control, and practical applications in audio systems. I hope you find them interesting as well.
How will the workload be distributed between the amps if the input signal has a slight unintended offset?
That's a good question. In this analysis we are applying an input AC signal in differential mode with zero DC offset. I would suggest using AC decoupling capacitors at input so that we isolate input terminals of the Op Amps from any DC residual of the applied input signal. I hope this is helpful.
If we take a really good input opamp and reinforce the output with for instance BUF634 (number of them, I mean 30-60) we'll have an excellent hi-fi amplifier with power enough for a big room. If we provide a really good power supply, that will be considered a hi-end amplifier with no doubts.
Good points especially regarding using combination of Texas Instruments BUF634 High-Speed Buffers or its newer version BUF634A to provide high enough AC current to speaker. Alternatively newer Texas Instruments products like OPA2673 Dual, High Output Current Operational Amplifier might be an interesting choice for this circuit. 👍
@@STEMprof Yes, OPA2673 might be interesting for some applications, may be it will be enough for a headphone driver, however I don't see it inside a power amp with its +-6.5V supply range. May be with a floating rail this will be possible.
@sc0or Yes, good point regarding supply range. We can also use high-current power transistors at the output of Op Amp to defer power delivery to transistor so that we can have a wider choice for the type of op amp for this audio amplifier.
@@STEMprof Sure, but even mid power bjts mostly are not fast enough. I can remember KSC2690 and 2SC3503 with a bandwidth to 150MHz. High power transistors are not an option at all. And this is why buf634 with a bandwidth to 250MHz is unique (relatively unique due to high current output). I listened to an amplifier built with buf634 which was able to amplify PAL signal -) It sounded as a hi-end device. However it didn't use a bridge architecture and was limited with 20W@8Ohm
@@sc0or Great points regarding the importance of monitoring the max speed that power transistor is able to achieve. But I think there are Power Transistors that can easily handle Audio frequencies with 20 to 40A Collector current. Few examples are OnSemi 25 Ampere 200W 2N6338, 2N6341 High-Power NPN Silicon
Transistors www.digikey.com/en/products/detail/onsemi/2N6338G/1475307 and possibly Fairchild FGH20N6S2, FGP20N6S2, FGB20N6S2 600V 125W N-Channel IGBT www.digikey.com/en/products/detail/rochester-electronics-llc/FGP20N6S2/11508896
LOL,I fail to understand how this works, but configured s non inverting opamp, so both raise and fall a the same time.
I simulated the circuit, i even put a 8 ohm resistor between both opamps as analog for the speaker, the current was like u amps over the 8 ohm resistor.
I even rotated one of the opamps like it would seem logical, one pushing and the other pulling, but the behavior was the same.
I'm curious how this Bridge mode works, my car amp has this.
Thanks for your interest in this circuit and sharing your thoughts/observations. As explained starting in minute 8:30 , It is like a differential amplifier for AC input signal that is applied between the non-inverting terminals of the two op amps. As the input AC voltage increases, it pushes up the positive input terminal of say the left op amp higher than the other one's. As a result an AC current flows from left to right through the resistor R1 (C1 impedance is practically zero in the frequency range of interest).
@@STEMprof Hey, i made a pcb of my class AB amp, now i wanna make a pcb for the power side, bridge rectifier, etc.
I wanna add a soft start to prevent inrush current of the capacitors, using mosfets.
for the positive rail it's not so hard, but applying the same voltage of the gate of mosfet of the positive rail on the negative's gate doesn't work, since there is like 40 Volt difference. the negative rail moves much faster if you use caps as time delay.
I tried various sources, like stack exchange.
You happen to know a method of moving 2 mosfets a the same time on 2 voltage extremes?
Beautiful bridge audio amplifier work balance input and tone control ?
Thank you. Glad that you liked this dual op amp audio amplifier video.