Questions tagged [class-d]

A class-D (amplifier) refers to an electronic amplifier that operates the output devices (usually MOSFETs) as binary switches (either ON or OFF).

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Active Speaker Hiss [closed]

I'm trying to figure out why my Mackie SRM350v3 has a lot of white noise and digital whine (100Khz) coming through. The hiss is not dependant on the volume knob and I can hear changing in the digital ...
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I2S slave communication without an MCU - how to generate the clocks?

I am designing an audio amplifier circuit which uses an I2S digital MEMS mic (INMP441) for picking up voice signals and an I2S class-D amplifier (MAX98357A) for amplification. I have attached the ...
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5 votes
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I2S communication

I am designing an audio amplifier circuit which consists of an I2S digital MEMS mic (INMP441) for picking up voice signals and an I2S class-D amplifier (MAX98357A) for amplification. Both these ICs ...
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2 votes
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Voltage at the Drain Terminal of a Switching MOSFET

I am attempting to drive an STP55NF06 N-Channel MOSFET with a TC4427 gate driver, switching at ~100kHz. The desired outcome is a higher current PWM square wave at the MOSFET's drain (Circuit in Figure ...
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3 votes
1 answer
398 views

H-bridge class D amplfier [closed]

i am trying to make a closed-loop class D amplifier for a dissertation. I have the basics: audio signal-->pwm modulator(LTC6992)-->gate drivers->H-bridge-->LC filter--> speaker but i ...
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248 views

SG3525A for modulating an audio signal for a class D audio amplifier

I am using the SG3525A IC to modulate an audio signal into PWM that is then used to drive MOSFETS for a class D audio amplifier. I have managed to design a circuit that outputs a 10kHz PWM signal. I ...
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4 votes
1 answer
847 views

I found this circuit in a class d amp, and have no clue of its function

It doesn't make any sense for me, why would someone use those very hi fidelity op amps with nothing connected on input and output
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Inputs to TDA7498E Audio Amplifier

I am planning to use TDA7498E in one of my projects and was going through the datasheet of the same and got confused at one point. In the absolute maximum ratings, it is written that the INPA, INNA, ...
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How to determine the power rating of an output LC filter

I am trying to design a Class-D Amplifier using the TPA3116D2 IC chip. Using the typical application circuit provided by the datasheet on Pg.26 Everything is going well with the support circuitry but ...
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Isolated gate driver for the Class D amplifer

I am trying to simulate the gate driver part for driving the MOSFETs in the class D amplifier with 4N25 optocoupler, not too sure if the connection between 4N25 and MOSFETs is correct.
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124 views

Oscillation in Class D amp design

I am building a class d amp circuit with base design from Great Scott's Class D amp which is found here. I am trying to build and simulate the circuit in LTSpice with difference being I won't be using ...
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167 views

Is it okay to have a ground plane with a Class D Amplifier?

I'm working on building a Class D Amplifier (TPA3122), and from what I understand, you want to connect the grounds of the amplifier using a star connection. On this circuit, I plan on using a DC-DC ...
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1 vote
2 answers
528 views

Recommendations for building a dedicated external speaker from an older computer

I'm super excited to jump in and learn more about building an external stereo speaker from an older salvaged macbook laptop. I loved using the laptop to reference how my music sounded to get a better ...
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1 vote
1 answer
69 views

Simulation of distortion from output inductor in class D amplifier, e.g. inductor non-linearities modelling

I'm new around here :) So, I am doing a university project regarding the effects of the output filter of a self-oscillating class D amplifier for low frequency audio signals, e.g. subwoofers. The ...
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Debugging a SA 90.4 800W class-D audio amplifier

I am using a Re-audio SA 90.4 800W 4-channel class D audio amplifier (https://www.amazon.com/REAudio-SA90-4-4-Channel-Digital-Amplifier/dp/B00RE9EO7K) for some underwater piezoacoustics experiment. ...
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135 views

Noise with TPA3110D2 amplifier on the same power supply as an USB HUB

I have a TPA3110D2-based, XH-A232 amplifier board powered by a 12V switching supply (S-120W-12V). The input is the headphone output of a monitor connected to a PC. I would like to power an USB HUB ...
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728 views

Trying to understand this Class D amp (using IR2113) circuit

I understand the concept of the Class D amp and this circuit, but in this particular case there is one part I just don't get. What I don't understand is how the low side of the signal should work at ...
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Replace amplifier IC with a class D amplifier (AN7133N with TPA3116 board)

Today I received this nice 90's Panasonic RX-CT900 boombox in the mail. The specs claims it is 2x60W PMPO (PMPO b**llsh*t throw-of- a-cliff specification) but in fact it is just 2x5.5W RMS (Panasonic ...
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Efficient current drive with arbitrary waveform

I need to drive a defined, arbitrary current waveform into an output with a load impedance that may not be constant. Currently, I am using this: The 100V is created from 9V dc using a standard boost ...
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7 votes
3 answers
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Audio signal on oscilloscope

I am exploring the mainboard of an Epson 3010 projector. This particular projector has internal speakers but does not have an audio out and - as I have built my own external audio amplifier - I wanted ...
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Class D amps ALWAYS ON?

May I just ask if Class D amplifiers are expected to stay continuously on, flat out, at full power and never have the volume reduced?! I’ve recently obtained this: http://www.amplifier.co.uk/images/...
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Why is this opamp PWM circuit not giving a PWM output?

I thought I'd see a PWM rectangular wave at opamp output, but the simulation gives a constant +Vsat. Why am I not getting PWM ? simulate this circuit – Schematic created using CircuitLab EDIT: ...
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Class D Amplifier Design: Simulation(/Practical Design?) Issues

For a college project my project group needs to make a speaker amplifier. We need to use a +-15V PSU for the whole system and the amp must at least provide 15W to an 8 Ohm speaker. One of the ...
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-1 votes
1 answer
265 views

Class D amplifier with +-70V rails

I'm trying to design a class D amplifier with rails that have +70V and -70V. Most designs I find online switch at the mosfets between the +rails and ground. Is it possible to get the mosfets to switch ...
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Peak Power Vs Rated Power

I wish to understand more on power parameter needed to design the power supply of audio amplifier. Which power parameter should we use when designing the SMPS? Is it peak power or rated power? Lets ...
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4 votes
4 answers
3k views

In a Class-C power amplifier, what does the resistor in the base do?

Look at the picture, which shows a Class C power amplifier (source). What is the role of the resistance in the base of the transistor, and what happens if it's removed?
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396 views

Split Audio lineout into two different amps

I am using a 3116d with a lpf and a 7498 for the mid range. The audio signal comes from a common source. The cables are split and soldered, so that both amps receive the same input. However, doing so ...
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Constant current source for an alternating magnetic field of varying frequency and constant amplitude from a solenoid

The project I am working on requires me to oscillate my sensor. I am doing this by coating a ferromagnetic material on the sensor and applying a sinusoidally varying magnetic field. I was applying the ...
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2 votes
0 answers
78 views

PCB design in class D amplifiers [closed]

in the process of building a class D amplifier I am now stuck at the point in which I have a lot of audible noise and I don't know where this is coming from. I know there could be a lot of causes but ...
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-1 votes
1 answer
94 views

Class D Amplifier with Inverting Logic [closed]

If a class D amplifier had an additional logic input which was used to indicate that the amplifier's output should be inverted, could one use this signal to swap the logic of amplifier's switches so ...
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177 views

Can I use BTL audio amplifier IC in single-ended output configuration?

I am designing a widget that has to have a speaker output (low power, between 1W and 2W, 8 Ohms, low-quality) with the limitation that one end of the speaker must be grounded. There are lots of audio ...
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How to calculate error amplifier output in amplifiers

I'm trying to derive an accurate formula for the output of an error amplifier in the class D amplifier I'm simulating. Most literature on the error amplifier/integrator in class D amplifiers glosses ...
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3 votes
2 answers
492 views

What causes those oscillations in a comparator circuit

I designed a simple class D amplifier based on theory (output stage not pictured): Layout(ish, the board was modified in a few places, the whole top part is a separate PCB soldered into where some ...
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2 answers
874 views

Class D amplifier - equation for peak current?

I'm trying to spec a power supply for a class D amplifier IC. I have figured out the maximum RMS current draw by taking the RMS power rating of the amp, increasing that to compensate for efficiency ...
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1 answer
161 views

Not functioning Class-D Stereo Amplifier circuit

I am connecting a circuit for Texas Instruments TPA3125D2 Class-D Aplifier. Datasheet here: http://www.ti.com/lit/gpn/tpa3125d2 The circuit design is here: The circuit that was tested is not on ...
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3 votes
3 answers
1k views

Output Filter Components Breaking Class D Amplifier Chip

Hi I am designing a class D amplifier PCB using the TPA3122D2 amplifier chip. I am planning to base my circuit on the schematic from the evaluation board: I bought components of the same values given ...
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How to Choose Proper Components for Class D Amplifier Circuit

Hi I am designing a class B amplifier PCB using the TPA3122D2 amplifier chip. I am planning to base my circuit on the schematic from the evaluation board (see below). I have tried building out this ...
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2 votes
1 answer
724 views

Why would this Class D Audio Amplifier have low current draw?

Disclaimer: Saying I have very little knowledge of electrical engineering theory is an understatement. I very much appreciate your help and patience. I'm not finding any questions similar to mine, but ...
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3 votes
0 answers
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Audio PWM over Radio [closed]

I'm working on a project in which I must send audio over RF such that remote speakers can pick up the signal around a house/apartment. The goal is to broadcast music from a single device somewhere in ...
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Three level PWM modulator circuit feedback simulation

I'm trying to design a three level PWM circuit with feedback and i'm struggling to understand the feedback aspect. The design is based on this design by Texas instruments and modified to suit three ...
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1 answer
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How would a mains transformer react to unfiltered "Class D" PWM sinewave on its primary?

Somewhat related to this question: How do I apply PWM signal to the primary side of a transformer to get synthesized sine wave at the secondary side? - specifically "Choice 1": However in my case I ...
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1 vote
2 answers
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IR2110 driver output causing shoothrough despite deadtime

I'm having trouble with the ir2110 output. I'm working on a class d full bridge amplifier and I use 2 ir2110 to drive 4 irf540N mosfets. The switching frequency I use to generate the PWM is 240kHz and ...
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MOSFET driver circuit configuration for half bridge MOSFETs for power amplifier

I am making a class D audio amplifier and I am using a MOSFET driver to control two MOSFETs in a half bridge configuration as shown in the circuit below When I connected the circuit without the ...
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PWM Comparator types for Class D

I've started simulating a Class D amp, but it seems the MAX999 (I saw recommended elsewhere on this site) isn't working. Could anyone point me in the direction of why? I swapped in an LM311 which ...
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How do you model differential inductor in LTspice?

I wonder how I can model a differential inductor in LTspice? I've an inductor that has half the turns on one side and the other half on the other side. It's intended to be used in a bridge tied ...
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1 answer
208 views

Removing switching artifacts from a commercial audio amplifier

I got an audio amplifier but I have problems with it. How can I remove switching noise (artifact) from the output of a Behringer iNUKE NU1000 Power Amplifier audio amplifier? I got from ...
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1 answer
128 views

High Frequency Excitation on Class D Amplifier

I'm building a discretized class D audio amplifier that's running at 250kHz that's designed to run on a single ended 80V supply. I was seeing very high amplitude, high frequency excitations on the ...
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3 votes
2 answers
224 views

How can I see if my filterless class-D audio amplifier is clipping or not?

So I'm using MAX98357A, which is a filterless class D audio amplifier. I'm running it using Vcc = 5 V. Looking at the page 28 of the datasheet, I see the folliwing formula for output voltage: Output (...
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Resistor values for class D amplifier

I haven't done a bad job for this amplifier circuit since I got it to work with 470K for RV and 10K for RG but what I'd like to do is create a better quality sound output. Maybe my 1/2 watt 8-ohm ...
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1 vote
0 answers
1k views

Unfiltered square-wave as feedback in class D amplifier

I found this little circuit that (ab)uses a TL494 SMPS PWM controller as PWM driver for a class D audio amplifier: (Source article @ Geekcircuits.com ) It uses the unfiltered, but constant amplitude ...
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