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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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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36 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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63 views

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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79 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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45 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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1answer
93 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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101 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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32 views

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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104 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 overstatement. I very much appreciate your help and patience. I'm not finding any questions similar to mine, but ...
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61 views

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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40 views

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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1answer
168 views

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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1answer
583 views

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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60 views

High frequency PWM methods

I have a few questions regarding generating PWM waveforms in audio and motor driving applications. I want to mess around a bit more with switching, gate driving circuitry and motor control/ ...
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1answer
223 views

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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1answer
87 views

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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202 views

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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70 views

Removing switching artifacts from commercial audio amplifier

I got an audio amplifier but I have problems with that. How to remove switching noise(artifact) from the output of Behringer iNUKE NU1000 Power Amplifier ,Audio amplifier? please find I got from ...
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78 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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98 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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199 views

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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569 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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70 views

How to achieve digitally adjustable supply rail sover a wide range (low up to 300V)?

I need to be able to vary the supply rail over a wide range (low voltage up to 300V DC). Current consumption will be from 1 mA up to 40mA. The thing will be powered by AC mains 120V. I am wondering ...
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759 views

low pass filter class d amplifier

I am designing a Class D audio amplifier. Im using a 40Khz triangular wave to modulate my input audio signal of 1Khz. However when I designed my low pass filter(cut-off frequency=20Khz), I still get ...
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1k views

Using a NE555 for 12V boost to 24V to power an amplifier

I'm trying to draw a supply scheme for a class D integrated amplifier. It requires 21V to 24V power supply and about 6/7A of current at 24V. The input is a car battery: 10V to 14.4V. I found this ...
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69 views

Audio Amplifier

We are using WM8960 Audio CODEC which has internal Class D Amplifier with up to 1W output for speakers. I plan to provide external Class D amplifier as optional which boost up the output power to 2W ...
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3k views

Put a resistor in series between amp and speaker

I use a PAM8403 class-D amplifier module (~ 2$ on ebay), which is very good, and stereo. The output volume is too loud. If I lower the amp's input volume (via software), then obvisouly the output ...
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93 views

Class - D Amplification Problem

I am trying to make some amplifier circuit like Class - D type. Below is the circuit; Input is sinusoidal @2500Hz. I couldn't make gate driver circuit. Thats why i use voltage dependent voltage ...
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461 views

Stereo to mono amp solution with mono bridge

I have these stereo amplifiers - Adafruit 20W and Sure Electronics 15W. If I connect this passive stereo to mono bridge at its output, will it technically be a good solution? Will the amps work ...
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200 views

How can I avoid saturation in current source amplifier?

I'm designing a class d amplifier with current feedback as in figure below with the following features: Vbus=50V Iout programmable from 100mA to 1A rms Vout=35Vrms max When the load overcomes the ...
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817 views

Calculation and measurement of input and output impedances of a Class-D amplifier

How would I calculate, from datasheet information or elsewhere, the input and output impedances of a Class D power amplifier, in general or for say a chip like the LM4670 or the TPA2000D1? {Note that ...
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472 views

Can I use a Class D amplifier as a summing amplifier?

Context: I'm creating a mono, battery powered speaker. I'd like to sum the left and right channels of a stereo input signal into a mono output signal, which I feed into a Class-D Mono Audio Amplifier ...
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1answer
110 views

Audio AMP Datasheet help

Disclaimer: I know you aren't supposed to ask about specific IC's as it is not helpful to the community in general, but I am at my wit's end here so I will try to make this as relevant as possible. ...
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104 views

Calculating real part of a square wave

i'm trying to understand how Bruno putzey in Globally Modulated Self-Oscillating Amplifier with Improved Linearity in section 4.2 Analysis comes to the equation in presented in (2), see snapshot below....
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220 views

Can a MOSFET h-bridge class-D amplifier be used as a digital-to-analog converter?

They are used as de facto DACs for low power audio systems and in power inverters. But how common are they for high frequency D/A conversion(or broadband)?
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289 views

Using AND gate as a comparator

I amb trying to desing a very simple Gate Driver for a Class-D audio amplifier. In order to introduce the Dead Time my first thought was to use a RC conected to a comparator as an imput of an AND gate....
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665 views

Input filter for class d amplifier

I have built a ~50W class d amplifier powered by a 12V SMPS. My problem is that the output of the SMPS has high frequency noise. I know that the noise is not audible but I would like to remove all of ...
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2answers
610 views

Using an audio amplifier with differential outputs with headphones

I'm planning to use TPA2012D2 (http://www.ti.com/lit/ds/symlink/tpa2012d2.pdf) audio amplifier from TI from my headphone audio project. This amplifier has a differential outputs for left and right ...
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315 views

Switching problems in class D amplifier

I'm building a class D amplifier with a dsPIC as PWM modulator. The part of the schematic that I want to talk about is the interaction between the microcontroller output (pwm signal) and the gate of ...
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1answer
163 views

Calculation of Breakdown Voltage

How can we calculate the breakdown voltage of a BJT in ADS? Is it Possible or not in ADS? Problem:- I have a ADS BJT model. I am using that to generate high voltage output. For that i need to bias ...
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1answer
74 views

analog shut down whilst turning on an LED

I am a EE student from Denmark, in the middle of making a class D audio amplifier. In this matter, I have stumpled across a needed circuitry. I need a way to shut off my gate driver (essentially the ...
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2answers
1k views

Using a LM311n in a class D amplifier as comparator

I'm making a class D amplifier as a school project, and we are currently at a stage where we simply need to add the comparator. But the comparator (LM311n) does not seem to run as intended. My ...
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2answers
3k views

Am I using IR2104 correctly?

simulate this circuit – Schematic created using CircuitLab I am using the following circuit with given component values. I am not getting a proper level of output from Ho or Lo pin to drive the ...
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2answers
528 views

Class-D Amplifier working outside audio range frequencies?

I've been wondering what could possibly limit the use of class-D amplifier to audio range frequencies. When I look at some class-d amplifier specs, it seems that a lot of them can't reach great ...
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3answers
2k views

Trying to remove distortion of speakers seems impossible

I'm working in a project with the goal of make a portable bluetooth speakers without distortion. When I try to turn up the volume, the speakers start to make a distorsion, like when rhe radio can't ...
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2answers
532 views

Circuit to put digital amplifier into standby when no audio is at inputs?

I am putting together a battery powered audio amplifier using the PAM8403 class D chip. http://www.diodes.com/datasheets/PAM8403.pdf It has an active low STANDBY pin which turns off the circuits ...
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1answer
189 views

Dual passive low-pass filter

I am building a class D amplifier and need to design passive low-pass filters for H-bridge with cut off frequencies at about 400 Hz. However, I am unsure about few things, this is the simplified ...
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1answer
115 views

Ballpark achievable switching frequency for 100mW D-class amplifier

The background for this question is a Master level university group project, we're designing a class D sigma delta modulated amplifier which is part of a MIDI synthesizer on a large FPGA. We're ...
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1k views

Purpose of gate driver in Class D amplifier

Can somebody explain to me why we need MOSFET gate driver in class D amplifier like in the picture below(common class D schematics)? What I don't understand is if we for example have 9V rails, then ...
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2answers
818 views

Class D amplifier woofer filter designs

I am working on a 140W class D amplifier for my subwoofer. I am familiar with its topology but have few questions. The music source is a radio that ouputs 200mV peak-to-peak signal containing all ...