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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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Oscillation criterium of UcD (Universal Class D) amplifier

This Paper written by Bruno Putzeys describes the operation of an Ncore/UcD amplifier. On page 2 the author presents the following formula, which he previously used to determine the approximate ...
thebear8's user avatar
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Class D Amplifier: MOSFET Gate Driver and Power MOSFET Confusion

So at the output of the comparator stage is a modulated PWM signal. I saw in some designs that the modulated PWM signal goes to one input of the MOSFET driver and the same PWM signal but inverted, ...
Tim Caleb's user avatar
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Can I connect two speakers to a mono analog input Class-D audio amplifier

I am using LM4670SD/NOPB in my design. The chip supply voltage is 5 V. My question can I connect two speakers to this amplifier as shown below. If yes what are the things to be taken care.
Confused's user avatar
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Coupling class-D output to audio input of another device

I have a MAX98357 with a class-D output stage that I want to use as the audio input to another device. The other device has a high-impedance (around 2.2 kΩ) input and ground connection. I was thinking ...
Acuario's user avatar
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2 votes
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Class-D amplifier output rings when connected to LC filter

I made a class-D amplifier with an output transformer, as you can see in the simplified schematic. Gate resistors are actually 10 Ω, not 2.2 Ω. The supply is 24 V, the PWM signal has a frequency of ...
mtx4's user avatar
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4 votes
2 answers
2k views

Understanding a Class D amplifier design

I've been trying to build a simple class D amplifier. I've seen through the block diagrams and design considerations online, but recently came across an amplifier design which doesn't seems to fit the ...
chethanRaj's user avatar
1 vote
2 answers
110 views

Poor efficiency of an H-bridge

I am simulating an H-bridge/class-D amplifier based on four GaN transistors with integrated gate drivers (NV6113 from Navitas). I am driving the gates via PWM signals where the PWM frequency is about ...
Charly's user avatar
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Class D amplifier safety

This is my first time I had success in doing a class D amplifier. Earlier attempts was on prototype boards with bad layouts. This time I made a good layout considering parasitics and it works good ...
acho's user avatar
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H-Bridge Class D Amplifier with transformer

I'm working on a H bridge amplifier capable to deliver 200 W into a 50 ohm load. Supply is limited to 24/28 V, unipolar. So I need a transformer in the output. You don't see a filter because I only ...
mtx4's user avatar
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1 answer
108 views

100 kHz Class D Amplifier with out Transfomer

I have to design a class D power amplifier, able to deliver 200 W on 50 ohm load at 100 kHz. Power supply should be 14 or 24V, I don't know at the moment so I need an output trasformer. I did few ...
mtx4's user avatar
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2 votes
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Can the differential output signal of a DAC be AC coupled directly to the differential input pins of a class D audio amplifier?

The datasheet of the audio codec I'm using (CS4272-CZZ) suggest a filter on the differential output pins. Their suggested configuration also combines the signals into a single ended output. I want to ...
Bennaman's user avatar
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Class-d Amplifier board not working after capacitor is placed in parallel at dc input while running

Noob here. I did a dumb thing few days ago that destroyed my TPA3110 amplifier board which is running on 24V 15A Lithium battery pack with BMS. I placed a 35V 4700uF capacitor across the 24V output of ...
Warriorrev6300's user avatar
1 vote
1 answer
78 views

How ca I match a class AB amplifier to voltage multiplier through a transformer?

So here it goes, I will keep this issue as simple as possible. I have this Class AB amplifier over here, that brings me a 60 Hz sinusoidal signal up to aprox 15Vp. Must be said that the sinusoidal ...
García Morales Kevin's user avatar
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How does this gate drive circuit work?

This circuit is taken from page 6 of this paper by Bruno Putzeys. It is used as a gate drive circuit in a self-oscillating class D amplifier. I am having a hard time wrapping my head around how it is ...
thebear8's user avatar
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Class D Amplifier Design Producing Lots of EMI

I recently completed a class D amplifier PCB design based around the TPA3118D2. It's been working very well for me and sounds clean on the output, but it appears to be producing a noticeable amount of ...
Emmett Palaima's user avatar
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1 answer
87 views

Power amplification of pulse signal using Class D power amplifier

I want to amplify the power of a pulse signal with 55% duty cycle, generated using 555 timer, to 40 W. I am planning to use a class D amplifier. But I have the following doubts: Can I directly apply ...
Vinita's user avatar
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Fix for poorly designed class-D amplifier mute circuit

I recently made a PCB for a project with several class-D amplifier channels to drive small speakers for audio feedback. I included a mute switch which connected or disconnected one end of these ...
Emmett Palaima's user avatar
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249 views

D-class audio amplifier like MAX98357A output for headset

The MAX98357A/MAX98357B PCM Input Class D Audio Power Amplifiers as used in Adafruit I2S 3W Class D Amplifier Breakout - MAX98357A specify 4 or 8 Ohm speaker resistance, with 33 or 68 uH inductance. I ...
Øyvind Teig's user avatar
1 vote
2 answers
332 views

How to make a MAX98357A class-D amplifier work with an Arduino (ATmega32) to play an audio file?

Is it possible to make a MAX98357A class-D amplifier work with a normal Arduino? I've only found solutions based on an ESP32. If not, why not, and is there a solution or an alternative solution?
playmobox's user avatar
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Can I amplify a PWM signal via a class-D amplifier without any input capacitors?

In the datasheet of a PAM8302A, which is a class-D amplifier, the recommended circuit is as follows: I have seen many people also use a variable resistor (potentiometer) at the input. I do not ...
ar2015's user avatar
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Class-D audio amplifier produces a sawtooth wave on the output, not sine

I am using a MAX9744 Class-D amplifier and want to get a sine wave in the output. Someone suggests using an LC low-pass filter for this, and in the datasheet of the amplifier, the values for inductors ...
mangozu's user avatar
9 votes
3 answers
3k views

Why can't I get rid of shoot-through in my half-bridge circuit?

I am building a class D amplifer and I have getting shoot-through despite my best efforts to mitigate them using dead-time, miller clamping, and using high V_GS_threshold MOSFETs. Here is the circuit ...
Random Burnout's user avatar
3 votes
3 answers
150 views

Can Class D output capacitors be placed towards both rails?

Please consider the simplified Class D output stage below. Depending on the half-bridge duty cycle, different output voltages (within the power supply range) can be applied to the load. simulate this ...
tobalt's user avatar
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Solving buzzing issue using audio isolation transformers

I've had a problem with an unearthed Class II SMPS amp that would buzz when connected to an earthed audio source. The issue seems to be leakage current from the amp's ground to the earth through the ...
Alex P's user avatar
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1 answer
173 views

Ground loop hum with Class I/II connections

I've recently revived a pair of speakers by replacing the class D amp with a new separate module (plus a simple opamp active EQ) and keeping the stock SMPS which seems to be working fine. The unit is ...
Alex P's user avatar
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-1 votes
1 answer
142 views

How to create a microphone preamplifier [closed]

I am quite new to audio electronics, but also to electronics in general. I have tried to do quite a lot of research, but still cannot find enough information to make a proper amplifier for a mono ...
Jakub Folejtar's user avatar
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2 answers
219 views

How to power a class D amplifier with rechargeable batteries?

I am using a TPA3136AD2PWPR to provide 5~6 W to an 8 ohm speakers. According to the datasheet, I'll need to provide around 10~12V to the supply pins. I was hoping to use a rechargeable Li-Po battery ...
Khaled Matloub's user avatar
0 votes
2 answers
118 views

Powering two 12 V amplifiers wired in series from a single 24 V supply

Given: Two XY-AP50L D-class audio amplifiers (or any other similar boards for that matter). I want to make them work from a non-stabilized 24 V DC supply (bus alternator + 24 V batteries). At the ...
esteewhy's user avatar
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1 answer
77 views

How to calculate power dissipation of LDMOS-device for arbitrary waveforms

I am currently simulating a current mode class D PA and would like calculate the dissipated power in the LDMOS-transistors I am using. I am currently doing this by calculating the RMS value of both ...
electronoob's user avatar
1 vote
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197 views

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 ...
Sri's user avatar
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5 votes
3 answers
2k views

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 ...
Sri's user avatar
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2 votes
1 answer
317 views

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 ...
SctKwl's user avatar
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3 votes
1 answer
825 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 ...
Frantisek Balaz's user avatar
0 votes
2 answers
1k 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 ...
Frantisek Balaz's user avatar
4 votes
1 answer
927 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
Hiro Ishida's user avatar
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1 answer
108 views

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, ...
DodZi's user avatar
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0 votes
1 answer
526 views

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 ...
Leoc's user avatar
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0 votes
0 answers
239 views

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.
Thomas Li's user avatar
1 vote
1 answer
521 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 ...
Saksham gupta's user avatar
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2 answers
487 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 ...
Jayvin Street's user avatar
1 vote
2 answers
567 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 ...
Sable Vesti's user avatar
1 vote
1 answer
130 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 ...
David skovgaard hansen's user avatar
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1 answer
139 views

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. ...
Swapnil Saha's user avatar
-1 votes
1 answer
219 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 ...
ivaradi's user avatar
0 votes
2 answers
2k 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 ...
Isty001's user avatar
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1 vote
1 answer
895 views

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 ...
Codebeat's user avatar
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0 votes
2 answers
60 views

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 ...
ARF's user avatar
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7 votes
3 answers
2k views

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 ...
Alessio Sangalli's user avatar
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3 answers
224 views

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/...
merseymale's user avatar
0 votes
1 answer
129 views

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: ...
across's user avatar
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