Questions tagged [buck]

A non-isolated DC-DC converter topology which outputs voltage less than or equal to the input voltage

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Current and power analysis for DC Buck Converter simulation using PSpice

I have a simulation circuit in PSpice that I got from digikey for my part I ordered. I simulated and found my configuration outputs the correct voltage but I need to do further analysis on the current ...
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14 views

WARNING: Can't resolve .param in LTspice

I am going to simulate buck converter using current mode control. I followed the circuit 2-80 from book Switch-Mode Power Supplies: SPICE Simulations and Practical Designs, second edition written by ...
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35 views

synchronous buck - nmos current flow direction

As far as I know in nmos the current flow from the drain to the source, and the drain and source are determined by the pin with the higher voltage on it (such that the source is the pin with the lower ...
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1answer
53 views

Why LM2596 buck converter output current is low when used as a mobile charger?

I am having LM2596 buck converter which is capable of providing 3A current and my input source is capable of providing 5A which is a transformer. but when i used the buck converter to charge my ...
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71 views

Best option from 30–60V to 3V3

I need to take power from ebike's battery (30–60VDC) for a datalogger (3V3) based on STM32 with almost no consumption. My question is what is the most efective conversion from 60V to 3v3? Is it good ...
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53 views

What is this fluctuation I get when I use the DC electronic load?

I have a buck converter. I am loading the buck converter using an electronic load - EA-EL 9200-18T When I load 100mA at the output of the buck converter, I get this waveform: To try to find out what ...
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59 views

Why overshoot happens in Inductor voltage in an open loop DC-DC buck converter?

I am extremely confused about why this overshoot occurs in the Inductor voltage waveform in buck converter and also why the time to achieve steady state reduces on increasing the load resistance. ...
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57 views

Rectifier ripple on DC-DC buck converters

I'm using the LMZ36002 buck converter module, which is a 1 MHz 4.5-60 V 2 A buck module. This means there is already an integrated inductor in the chip package. This device will accept any voltage ...
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59 views

Glitches in inductor current waveform

I am using this DC-DC buck converter. Schematics : Buck converter specifications : Input voltage - 18V to 32V Switching frequency - 300kHz Output voltage 9V Load current - 0mA to 200mA maximum. ...
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1answer
25 views

Buck converter in pspice output value changes depending on the resistance. How do I correct this?

I am trying to design a buck converter and simulate in pspice, however I am running into trouble. The voltage on the load (R1), varies significantly when the load value changes. How do I correct this ...
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1answer
42 views

Common mode inductor and diode circuit (EMC filter?)

I found this Buck converter circuit online, but not so sure what's the purpose of the circuit marked in red box and how it works. Please come in and discuss if anyone has an idea of it. Thank you
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34 views

Synchronised Buck converter - Soft-Switching

I have a question regarding the synchronised buck converter. This topology is using two transistors instead of a transistor and a rectifier diode. The bottom switch is used to reduce conduction losses ...
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50 views

How do I step down my voltage and up my current for a tethered drone

I'm fairly new to this platform but would like your advice on one of the projects that I'm working on. I am currently working on adding a tethering system to the DJI S1000+ spreading wings octocopter ...
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27 views

Capacitor currents equations for Buck Converter with Input Filter

I am trying to analyze the capacitor currents for the below buck converter with an extra L-C input filter: Switch in Position 1 \$ i_1(t) = i_{c1}(t) + i_{τ}(t) \$ \$ i_2(t) = i_{c2}(t) + i_R(t) \$ \...
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62 views

Role of the output capacitor in buck converter in terms of frequency

I am using this DC-DC buck converter - buck converter. Schematics : Buck Converter Specifications : Input Voltage - 18V to 32V Switching Frequency - 300kHz Output Voltage 9V Load Current - 0mA to ...
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1answer
85 views

Why is zener heating so much with MOSFET in boost converter circit? [closed]

MOSFET and zener is heating when I add clamping diode circuit with gate to source of MOSFET, clamping circuit have two back to back connected diode. why is zener heating? why is MOSFET heating? how ...
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50 views

DC-DC buck converter low input voltage behavior

I am using this DC-DC buck converter. Schematics : Buck Converter Specifications : Input Voltage - 18V to 32V Switching Frequency - 300kHz Output Voltage 9V Load Current - 0mA to 200mA Maximum. I ...
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39 views

Buck converter with current and voltage regulators

I need to find scheme for Buck converter with adjustable output voltage from 0 up to 12V. Also it may have an adjustable current limit. Max current output is 10A or at least 5A. Actually I will need ...
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1answer
28 views

Control Circuitry in the Buck Converter Design

In this question, the last line of the accepted answer states that - That's why the text suggests using 1/5 or 1/10 of the switching frequency as an upper limit in terms of how fast you should design ...
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39 views

Capacitor voltage of Buck converter with LC input filter

What will be the voltages across capacitor C1 and inductor L1 in terms of Vg,D,R? From the amp charge balance equation, i1=-io *D because i2=io.From my observation, Vc1= Vg for 0<T<DTs and Vc1= ...
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49 views

Converter stability - bode plot

I referred this YouTube video for buck converter loop stability. In the image we can see that the gain of the control loop we are talking about is Vout / Vin. Vout and Vin are both measured across ...
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1answer
60 views

Buck converter using LC input filter

Can somebody explain me about the working and waveforms of Buck converter with LC input filter? I can't figure out the output voltage expression using Vg, R and D(duty cycle) and the dc voltage and ...
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4answers
220 views

Capacitor voltage in buck converter and how it steps down voltage

I am having an issue understanding how the a buck converter circuit actually steps down the input voltage. Specifically, my issue is regarding the capacitor charging and discharging. Let's consider ...
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1answer
48 views

Conducted EMI of buck converter is too low even without filter

I have simulated a 48 V to 12 V buck converter with LISN in LTspice. However, CM and DM EMI is way below CISPR limits. I want to simulate a real world converter. How can EMI be increased? [2]
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48 views

Buck Converter Feedback Loop - Stability Criteria

Question 1 : I am having some trouble understanding the Stability criteria of the Buck Converter Loop Stability which says, "The cross over frequency should be less than 1/8th or 1/10th of the ...
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1answer
55 views

Will 14.4 volts from my solar charge controller damage my 12v equipment?

My charge controller is set to recharge my battery bank and begin a float charge at 14.4 volts. If I use some of my 12 volt components during the day while the batteries are charging, will this high ...
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1answer
43 views

How to Increase Solar Charge Controller Output Amps

I am new to solar panel system set ups, and I'm trying to make an off-grid DC-DC solar panel system where in I will be running a bunch of 12v loads which are mainly DC Pumps cause its gonna be ...
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50 views

Buck Converter Supplying Boost Converter - Potential Problems?

This post asked a similar question to mine, but the problems that I have noticed are distinctly different. I have a PCB that uses a buck converter to supply 12V from a 24V source, and I am boosting ...
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4answers
217 views

Problem with Bode diagram in LTspice

I am working on a buck converter and I want to obtain the Bode diagrams of the open-loop circuit. The below circuit is what I made. However, the DC-gain is -96 dB while it should be very small around -...
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40 views

Buck converter input voltage lower than the designed output voltage

I have this buck converter which is designed to produce an output voltage of 9V for an input range of 18V-36V. The datasheet of the buck converter mentions that the minimum required input voltage is 4....
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1answer
51 views

input capacitor for buck converter

To calculate the input capacitor for buck converter, I follow TI Application Report SLTA055–FEBRUARY 2006 "Input and Output Capacitor Selection". It says to determine the input capacitor &...
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41 views

Multiple transformer windings vs a single winding with a buck converter for dual output power supply?

I have to create a power supply that has both a 5V output at 1A and a 3.3V output at 0.4A. I was wondering if I should add another winding to my transformer or just make a 5V 1.5A power supply, and ...
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31 views

Buck converter input/ output capacitance

For a typical Buck (Step down), synchronous converter please consider the given image: I have added numbers there representing the following: Input voltage Input capacitance Output Inductance Output ...
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40 views

Does adding a line impedance stabilisation network reduce the output of buck converter in simulation in LTSPICE?

I have modelled a 48v to 12v buck converter in Ltspice.When I added a LISN the output reduced from 11v to 6.3v but EMI remains the same.Is it okay if output voltage is reduced?
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2answers
63 views

Advantages of consequent buck converters

Lets assume we have a 12V source (i.e. an external PSU). We need to go down to 1V8 to supply some load. Leaving the costs behind and using only synchronous buck converters, what are the advantages and ...
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177 views

Equation 20.16 Proof

In studying the Fundamentals of power electronics by Robert Erickson I do not understand how they arrived at the equations for current and voltage Link to Book, page 772 is where I am at https://...
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43 views

Parallel Usage of Buck Converters | LM2596 Module

For my application, I need three voltages +5V, +15V, -15V Initially, I was using wall socket plugs to connect two 15 volt adaptors, in which I connected the + and - together and considered it as ...
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Is it possible (feasible) to use a synchronous buck regulator for balancing batteries?

I need to build for a hobby project, a active balancing circuit for large number of LiIon series cells (90 cells). So it needs to be cheap but efficient :) (ie. not resistive dup). After lot of ...
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1answer
33 views

Synchronous Buck Converter Mathematics

Ive been trying to find a mathematical explanation on how a Synchronous Buck converter maintains continuous operation under ideal steady state conditions. I understand the underlying concept but i ...
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46 views

Buck converter suggetion [closed]

I want to design buck converter Vin 12V V out 9V I out 400mA. any suitable part / switching frequency I want to use very low like 65KHz
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44 views

EMC (radiated emission test) issue in buck converter

i am designing CV smps 12V 1A (with EMC design) post that output side i will use dc to dc buck (Vin-12V Vout-9V, 400mA) or Boost convreter (Vin- 12V VOut-36v, 100mA). which configuration will be more ...
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2answers
95 views

Inconsistent voltage on buck converter (TPS54240)

I'm currently facing a weird issue. For one of my project I had to design a buck converter circuit in order to step down the voltage of three LiIon batteries to 3.3V so I can power a microcontroller. ...
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1answer
32 views

Wide Range Input DC DC Buck Convetrer Design

Im having trouble understanding how i can achieve a constant output voltage with a varied input voltage. I know how to design a buck converter with a constant output when the input voltage is fixed ...
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1answer
38 views

Synchronous Buck Converter - Current sourced by the NCH mosfet

I am trying to understand the basic operation of a synchronous switching-mode buck converter. I a continuous-mode operation the inductor current is always positive, hence from the mosfets to the load. ...
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1answer
89 views

DC/DC Switching Converters: Is it possible to run a current-mode converter in voltage-mode only?

DC/DC Switching Converters: Is it possible to run a current-mode converter in voltage-mode only? If so, is there an example using a buck converter? In particular, I'd like to use UC3843 (LT1243) in ...
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47 views

reverse voltage polarity protection

I'm thinking about making a reverse polarity protection for a buck converter AOZ1284, and I've found this article design-guide-pmos-mosfet-for-reverse-voltage-polarity-protection I didn't find the ...
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65 views

Building a buck converter using CMOS 555 with mosfet driver

Can I use ICM7555 IC to generate 300 KHz PWM signal and feed that PWM to IRL2104 mosfet driver to build a non-isolated DC to DC buck converter? I'm asking this question because I couldn't find any ...
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2answers
34 views

Two MP1584 voltage converters in parallel

I have a circuit that will need to power different loads at different voltage levels (because they are LEDs of different colors). Can I use several cheap MP1584 modules in parallel (as in: same input, ...
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1answer
32 views

How does the buck regulator soft start condition reduce the unwanted voltage drops from high impedance power sources?

I have been studying the functionality of the soft start function. I understood how it will help to reduce the overshoot of the output voltage as well. Here, my intention is to understand the meaning ...
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2answers
103 views

Is this voltage division equation correct?

I am trying to study the significance of resister divider feedback circuit in buck regulator. This is the TI document I am referring to. As per TI doc, voltage at the feedback pin is as follows, When ...

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