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 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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1answer
107 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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2answers
207 views
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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4answers
2k 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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61 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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51 views
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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66 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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1answer
61 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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76 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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1answer
270 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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2answers
125 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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2answers
243 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
107 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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2answers
312 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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1answer
53 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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1answer
279 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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99 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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52 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
221 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
1k 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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1answer
525 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
163 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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1answer
320 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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1answer
81 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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1answer
85 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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2answers
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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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1answer
261 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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789 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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1answer
71 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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2answers
932 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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3answers
2k 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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75 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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1answer
4k 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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105 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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522 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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2answers
236 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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1answer
986 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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2answers
599 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
114 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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105 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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1answer
244 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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1answer
338 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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800 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
729 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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343 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
179 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
76 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
4k 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
656 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 ...
