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Questions tagged [push-pull]

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LM358 Headphone Amplifier Oscillations

I'm trying to build a very simple headphone amplifier for my bass guitar. The bass has a built-in amplifier, meaning that unity-gain is sufficient for my amplifier, I essentially only need a voltage ...
0
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1answer
43 views

Does direct GPIO communication between 2 microcontrollers requires pull up/down

If I want to use GPIO pins of two microcontrolles as a mean of simple communication (e.g. reporting an event by sending 1 or 0), Do I need to enable internal pull up or pull down resistors on any of ...
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1answer
51 views

Push-pull output stage and driving circuit function

simulate this circuit – Schematic created using CircuitLab Hello, what is the exact purpose of the C3 and C4 capacitors, two diodes and R3 and R4 resistors in this circuit used to drive the ...
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0answers
40 views

Push-pull transistor - input current spikes and advantage over just an npn transistor

I have simulated the following circuitry in LTSpice: Input Voltage pulse characteristics: Questions: 1. What is the reason for the current spikes on the input resistor R2? Do I need to worry about ...
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2answers
80 views

push-pull explanation

I have this circuit on a board: That circuit is supposed to act as a push pull amplifier working as the following: In case it is not really visible the voltage connected to the collector of Q3 is 3....
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0answers
73 views

How to build a DC push-pull voltage amplifier with transistors?

I have a digital 3.3V PWM signal that I want to send to a speaker, i.e. amplify to higher voltage (e.g. 12V, but not sure) and remove DC offset with a capacitor. For the capacitor to work as ...
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0answers
57 views

Simple push-pull problem

I've made a circuit based on the schematics below, which works fine at simulation. The goal is to add some extra oomph on the output of a LT1210 opa (V1) to drive a piezo element at higher voltages ...
3
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1answer
143 views

Why is the square wave signal so distorted at the output of a push-pull pair?

I have this example circuit on my workbench: simulate this circuit – Schematic created using CircuitLab If I remove the RLOAD=1K resistor, then the output signal gets distorted. Yellow is ...
2
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1answer
155 views

Impedance matching for push-pull RF amplifier

I am working on the output matching network of a commercial push-pull class AB amplifier based on LDMOS BLF188. The output matching network consists of a 1:4 transformer and a Toroid with 8 turns The ...
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3answers
132 views

Why is the maximum efficiency of a push-pull amplifier 78.5%?

One of the practice questions for my upcoming test is this: After some googling, it seems like the correct answer is A. But why?
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2answers
126 views

Resistor between input and output for push-pull follower

I'm reading about push-pull output stages in The Art of Electronics, 3e. On page 107 he presents the following circuit: I'm confused about the function of the \$100\Omega\$ resistor used here. Below ...
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0answers
73 views

MOSFET burn down due to droping logic level voltage [duplicate]

I made 2 PCB, one is a logic driver with NAND Schmitt trigger (74HC132D & CD40106B) to drive FORWARD and BACKWARD of H-bridge channel, the other board is the H-bridge Power MOSFET, which used 4 P ...
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2answers
156 views

mosfets in h-bridge get hot on idle load

I'm trying to build cheap H-bridge driver to operate under 12-24 input voltage. I used 12v regulator as separated Vgs voltage driver, also to increase load current and I paralleled two MOSFET with ...
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3answers
380 views

pull-push gate driver for H bridge circuit

To drive power MOSFET following circuits with different pros and cons has been used type A type B type C type c which is called pull-pusher gate driver can used either P or N mosfet in h-...
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0answers
52 views

Behavior of an ECU Digital Output (0-24V) to another ECU (pull-up i guess) input

Recently i had to control a functionality of an ECU using a separate system (another ECU). ECU "A" provides an input pin which if measured in open circuit shows 12V, so i guess it is a pull-up input. ...
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2answers
293 views

MC34063 with external FET. Why?

Follow on from : earlier post Below is an LTSpice simulation of an MC34063 step up (5v to 9v) circuit. As you can see, this particular circuit is working correctly, and delivering about 300mA. The N-...
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2answers
342 views

GPIO push/pull and pull-up resistor?

I have a question regarding the behaviour of a MCU's GPIO pins when configured in a certain way in hardware and software. In this case I am using a dsPIC33EP, but I believe this question is generally ...
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2answers
477 views

What is the purpose of diodes in parallel with transistors in a solid state relay?

I know the diodes facing each other are for ESD protection, but what do the diodes facing opposite do ? The circuit is basically a 24V (usually used in industry) digital output.
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2answers
366 views

connecting Open drain and Push pull outputs to drive the same pin

I am designing a circuit in which has a voltage supervisor (MCP121-33)with active low output nRST connected to RESET input of the microcontroller which is straightforward. Also, there is a another ...
0
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2answers
311 views

Ferrite core selection for boost converter using push-pull topology

I'm trying to build a boost converter with the following specifications. Switching Frequency: 100 kHz Maximum Input Voltage: 14 V Nominal Input Voltage: 12 V Cutoff Input voltage: 10.5 V Power ...
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1answer
120 views

Push-pull amplifier

The question is concerned the output current of push-pull amplifier once the over-current protection is activated. The resistor Rs(one between base and emitter of the over-current protection ...
1
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1answer
204 views

Push-pull MOSFET gate schematic

So I was looking through the MAX713 datasheet and came across the schematic below. In short, MAX713 is a NiCd battery charging IC and below is shown the schematic for it in the the switching mode. The ...
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1answer
41 views

L9110 output stage

Does L9110 have a push-pull or open-drain output stage? As I have measured the output voltage decayed slowly from High to Low when light load is attached and inputs inverted. I would expect a sharp ...
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0answers
645 views

Push-pull converter transformer calculation

every one, I am an automation engineer, not an electrical, but I have some knowledge about electricity (I hope). I am designing a power supply with input voltage of 3,1V and the output voltage of 175V ...
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1answer
275 views

level shifting 5V pulse to 12V pulse

When I search for level shifting 5V pulse to 12V, I came to know about the circuit given below. It is simply based on a push-pull amplifier configuration as you all know. And what I have understood ...
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3answers
646 views

Pull-down resistor confusion

I can't seem to find decent information on this topic as all articles only explain general concepts of pull-ups and pull-downs or only cover pull-ups in greater depth. I understand the general ...
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1answer
412 views

Unkown distortion in low power push-pull amplifier

I'm trying to make a small headphone amplifier, and I started out simple: I'm using a LM358 opamp to drive a push-pull stage with a pair of BD transistors. I started by trying a single channel (only ...
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0answers
129 views

How can I calculate the input capacitance required for a push-pull step up converter?

How can I calculate the input capacitance required for a push-pull step up converter? Vin - 12V (dc source) Accepted Vin ripple = 100mV Duty Cycle = 50% Switching frequency = 300kHz Vout = +12V and -...
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2answers
5k views

Difference between Push-Pull and Totem-Pole

I can't understand/see the difference between a push pull, for example a circuit like that: And a Totem-Pole: Have these circuit a transistor in the input so for get a thing like "double ...
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2answers
278 views

Push-pull amp in class A what it mean

I take next sample schematic. This is only an output stage of any real power amplifier. It's clear when it's work in B-class the every BJT amplify only one half of input signal. But what it means if ...
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2answers
616 views

What is the easiest way to reduce quiescent current in a AB power amp?

I'm trying to design an push-pull amplifier for a 4 ohm load, it works with a 48 V source. This is the latest design I did: (Input and output are in those two capacitors and the potentiometers are ...
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2answers
1k views

Difficulties in biasing MOSFET push-pull amplifier

Everything works perfectly well and following the expected in the simulations on MultiSim. This is what the test-version of my circuit project looks like: I made this version of the circuit to ...
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2answers
1k views

Problems in push-pull biasing

I'm trying to make a push-pull audio amplifier with a pair of power darlingtons (TIP142 and TIP147), but i'm having problems with the biasing. Here's the diagram of one of its configurations: Here i'...
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1answer
557 views

What is a common-emitter bjt push-pull output stage?

My professor mentioned it briefly in class, and I've been googling it and all I find is the CC output stage. Can anyone show me a picture of this configuration and maybe describe how it works? Can you ...
0
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3answers
166 views

What is the meaning of “ground” and “-V” in a simple push-pull circuit?

In this simple "push-pull" circuit, there are +V, -V and ground connections. up until now, i always considered ground to be the minus side of the battery. but that is also the way i understand -V, so ...
5
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1answer
197 views

MHz gate switching: choosing BJTs

I'm trying to build a discrete driver to switch a power transistor (Qg=12nC, Vg=0->6V). I want to push the limits to see what is possible with discrete components (so no driver IC) so I'd like it to ...
0
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2answers
371 views

High-side switch Vs Complete mosfet push-pull configuration to drive an inductive load

In my application, a microcontroller with 5V logic needs to drive two 12V DC fans in voltage. The microcontroller will use a PWM drive signal with a carrier frequency of 32 kHZ. For several reasons, I ...
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2answers
405 views

Pull-up resistors needed for quasi-bidirectional push-pull PCF8575/PCF8574(A)

I wonder if I need pull-up resistors when using the PCF8575 I/O extender. It's not directly mentioned in the datasheet (http://www.ti.com/lit/ds/symlink/pcf8575.pdf). The datasheet does remark that ...
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0answers
91 views

Push-pull mechanism

I'm new here and I'm sorry if this question is inappropriate. I'm trying to build refreshable braille display that will be placed inside of a desk, so I have a lot of vertical space. To build display ...
2
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4answers
2k views

How to keep the bias current constant in class AB output stage?

I am working on a hobby project to build a small audio amplifier. Actually the idea behind the circuit is to build a 0.5W-1W audio amplifier that can be powered from a single 9V battery and have ...
0
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2answers
551 views

Basic questions regarding Push Pull stage

I am confused as to how the following circuit will work(????) Lets assume that there is no AC signal and only a DC signal is applied. According to the books this is a voltage follower stage i.e Vo ...
3
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1answer
163 views

Synchronous buck using BJT's in stead of MOSFETS

Recently I came across a schematic of a synchronous buck converter using normal transistors in stead of MOSFETS, like this: I was always under the impression that when the top switching device turns ...
1
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4answers
463 views

Noisy BTL Audio Amplifier Circuit

I designed and breadboarded a simple audio amplifier circuit and when I play audio through the speaker, it is pretty noisy and very quiet. The +5V is being supplied from a USB port. I'm still probing ...
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3answers
776 views

Push-pull amplifier oscillation

I try to build simple unitary push-pull amplifier which amplifies also DC. Here is a result of my work: Unfortunately high frequency oscillation effect occured due to strong negative feedback: My ...
0
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1answer
1k views

Push-pull configuration using ZXMC4559DN8TC

I'm testing this circuit and I found some issues in driving ZXMC4559DN8TC n-p channel MOSFET. simulate this circuit – Schematic created using CircuitLab I have some problem in driving ...
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3answers
980 views

Optimal design choices for mosfet driver for DC-DC step-down converter

I'm dealing with an application in which a DC-DC converter is used to transform an input voltage of 15V DC into lower voltages. The current configuration makes use of an LM27222 with two mosfets in ...
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1answer
96 views

Amplifier output goes haywire with load attached

I'm trying to create an op amp using FETs and BJTs. I need the gain to be over 500, currently without a load attached I have the gain about 1000. The input is a 0.05V sine wave, the output is ...
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2answers
255 views

bjt audio amp push pull “super complimentary” [closed]

I found here this super complimentary design: http://www.valveradio.net/audio/super-complementary-stage.html To improve the symmetry of a complementary push-pull output stage, a special "super ...
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1answer
469 views

How can inductance affect push pull converter?

I'm trying to figure out the effect of adding inductance to a push pull topolgy but there are many parameters and I got confused. First of all, considering the previous basic circuit, What limits the ...
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3answers
133 views

When two transistors connected which one is on and which one is in cutoff from given circuit condition?

here in this question's solution, given that upper BJT is on while lower one is in cutoff region for Vbb = 2.7 V and viceversa for Vbb = -2.7 V and both will be in cutoff for 0 V. While in other ...