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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26 views

TPS54260 DC-DC Buck Regulator BOOT and PH pin voltage drop

I am using TPS54260 Buck converter which steps down 16V to 5V output. Load current is 600mA max. To the inrush current through the output inductor, I did some rework. But after some rework, my 5V ...
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43 views

Considering the inductor in a buck DC-DC converter, how to compute the current through it?

I've been stuck for a few days to the very first point of a lab in which we analyse the behaviour of buck and boost converters. The circuit is built by the university I study in, so there is no acutal ...
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67 views

Is it OK for capacitor voltage rate for this circuit?

I have a DC-DC buck converter circuit. C5 capacitor in this circuit is 10uF with a voltage rating 10V(only available for me ). is this circuit work as normal with 24V input?? or damaging c5(when ...
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86 views

Can I decrease voltage in a battery to get higher amp hour rating?

I am willing to use my 7.4 volts 1000mAh lithium polymer battery to power a motor that works with 3.7 volts, so I will input the 7.4 volt to a high efficiency buck converter to get an output of 3.7 ...
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77 views

Poor Buck Converter Current Limiting?

I am planning on using the XL7026 buck converter IC in an upcoming project because of its dirt cheap cost, small package and wide input voltage range. However, there is one concerning aspect of the ...
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69 views

Getting 12Amps of 0-12VDC from relatively low frequency PWM

I am trying to drive 4 parallel TEC elements. (TEC1-12706) I intend to run them together up to 12A (or 3A each.) I am using an ATMega328p (in the form of an Arduino Uno Board) to control the system, ...
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76 views

MCP16301 fail on power up - Vin shorted to Vout

I have designed a step-down converter PCB (4-layer) with MCP16301. It converts voltage from 24V to 5V. When I connect it to power source and then connect a 100ohm resistor (50mA@5V) it works normally....
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41 views

Do IC step-down/buck converters generally boost voltage when the input falls below the desired output?

I’m trying to select a buck convertor to regulate the output of a LiPo battery so I can use it to replace two AA batteries. Ideally I want the regulation to happen only when the battery is above 3 V. ...
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373 views

How to replace a potentiometer with a digital solution in a buck feedback loop?

I have a simple pre-made buck converter that looks something like this: The output voltage can be easily adjusted, by turning the R2 trimpot, which adjusts the voltage the feedback pin is getting. ...
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122 views

Is the zeta DC-DC converter topology scalable to 50kW / hundreds of amps?

Question The task at hand is to build a 50kW (e.g. say 125VDC 400A out) DC-DC converter that charges a large lead-acid stack with said 400A and accepts a somewhat wide input voltage range. With that ...
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3answers
111 views

Redundant DC-DC converter (parallel)

I am building a flight computer for a sounding rocket. I want to include redundant power supplies - in other words: parallel DC-DC converters. What do I need to consider in order to do this? (is my ...
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6answers
163 views

Buck converter MOSFET (IRF4905) heating up

I tried to build a buck converter without any ICs, just transistors, a diode and passive components. Its purpose is to convert 12V to 5V at 2 Amps. It works, but the switching MOSFET (IRF4905) heats ...
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131 views

Limiting output current of a Buck Converter

I am trying to power a 4S-ESC to drive a BLDC motor using a buck converter and 24V,10A SMPS. However, my buck converter can only handle 10 Amps of current (safely) at 15V through its output side. ...
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1answer
68 views

Placing multiple inductors (buck) close to each other on PCB

I have three buck converters on my PCB. 12V to 0.82V @ 25A -FP1308-R21-R, Fsw = 650 kHz, TPS548D21 12V to 1V @ 8A - IHLP2525CZERR47M01, Fsw = 1 MHz, TPS548A20 12V to 5V @ 3A - Inductor is XAL5030-...
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1answer
51 views

Constant Offset Floating Supply

What circuits can be used to provide a voltage supply capable of sinking around 1A of current that will always float 10ish volts below a given supply, that could be from 12 to 200 volts? I have ...
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37 views

Buck Converter - Calculating Line and Load Regulation

I have a buck converter with a PWM circuit and Control Circuit in LTSpice. I'm wondering, how do I simulate values for load regulation and line regulation? I was thinking for line regulation I could ...
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2answers
28 views

Battery emulator based on an array of buck converters for BMS testing

Problem: How to quickly and cheaply test if a given BMS (Brand: Daly / Tiny BMS / etc) or battery-powered system behaves as intended for various cell voltage combinations without waiting for actual ...
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1answer
51 views

ASIC Solution for Digital Closed loop Buck Converter Control

I am implementing a Closed loop Current Mode Control Buck Converter on a dsPIC Microcontroller which has an output of 3.3V and unregulated input of 5V. I am doing digital control, so I implemented ...
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2answers
59 views

Why do some switching regulator ICs have single VCC pin but multiple PGND pins?

This is a follow up question to Reason of multiple GND and VCC on an IC I found a switching regulator IC (buck) that has multiple PGND pins and one analog ground (AGND). It has only one VCC pin. (...
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48 views

Buck inductor current ratings

we are designing a buck using MIC23350 to generate 1.8V @ 2A. Input - 2.5 to 5.5V - typical is 3.3V or 5V. Switching frequency- ~1100khz. Nominal current is ~0.5A, Max current can be 30% higher. ...
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156 views

Buck converter drops only keeps Vout if no traces are connected

I wanted to try to use a buck converter to get 3.3V from a LiPo battery and found the Analog Devices ADP2108. Exact part number: ADP2108AUJZ-3.3-R7. Farnell/Element 14/AVNet link. I've populated the ...
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1answer
42 views

DC-DC PCB power plane on inner layer

I am currently designing a 6 layer board that has a couple of DC-DC converters on it. The largest one is a buck that transforms 12V to 5V with an ouput current of max 7A. Layer 2 would be GND, layer ...
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48 views

Noise on probe while measuring Switching Frequency of Buck Converter

I have a buck converter and I am measuring the voltage ripple at the output capacitor along with that I am measuring the switching frequency at the cathode of the diode. Please refer the below image. ...
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34 views

Step down converter stops regulating above 6V input

I'm currently using the following step down converter in a 4xAA battery powered design -> TPS62745 I have my Vselect pins configured as 3.3v out and using 4.7uH / 10uF combination on the output ...
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47 views

Relationship between switching frequency and controller's crossover frequency in DC-DC converters

I am reading some answers related to my questions based on control loop stability of SMPS. I came across this question. The accepted answer states: A switch mode power supply is essentially a ...
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11 views

4PPoE PD cost reduction

My current project is designing a PD circuit for use with 4PPoE/802.3bt (up to 60W), powering 24V stepper motors/drivers. I've found a couple of different chip combinations - I quite like this diode ...
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1answer
53 views

Control Loop Stability of DC-DC Converters

I am performing a control loop stability test on my 5V DC-DC Buck Converter with the help of this Keysight App Note I understand that we are injecting a noise signal on the feedback network of this ...
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1answer
47 views

Control current to one of two loads on PCB

I am currently working on a project where 2 batteries powers multiple components on a board. A raspberry pi, 2 thrusters and a winch. Each device is powered via the battery and a buck converter. The ...
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2answers
80 views

One step-down regulator 24 V to 1V or two step-down regulators with lower steps?

I am trying to design a working principle scheme to step-down the input voltage from 24Vdc ---> different low voltages (1.8 V, 1 V, 1.5 V, 3.3 V with ripples ~ 1%). Could you kindly explain me the ...
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40 views

Measuring output voltage (Single ended probe vs differential ended probe)

I have a SMPS buck 3.3V output. I am trying to measure the output voltage at the output capcacitor using Oscilloscope. I am using a single ended probe with spring ground tip to measure the output ...
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38 views

Need help designing power distribution system

I need help designing the power distribution system for a rocket test stand. I am new to power electronics so I am confused about how to go about it. I have to supply power to 8 solenoid valves that ...
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1k views

Why are boost/buck converters never fully integrated/all-in-one?

Moving from small arduino applications to higher-power applications for work, I've had to switch from using simple linear regulators to switching boost/buck converters any time a different voltage to ...
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1answer
40 views

DC/DC converter with LM25085A and FDC5614P is not converting voltage

Guys I designed a DC / DC converter from 12V-34V IN to 3.3V-OUT and I used the Power Designer from TI to help me in the designer of this converter in the website simulate everything went well. the ...
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1answer
47 views

Ripple current at output capacitors

I was reading about the selection of output capacitors at the output of buck converters and found this Link The accepted answer states that before I select an output capacitor, we must fix the ...
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46 views

Buck regulator load regulation voltage drop

I've built a switched buck regulator using a TPS40057, schematic below, I followed the instructions in the datasheet and used the TI provided spreadsheet to calculate the loop compensation network (...
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38 views

Does Buck Converter offer a protection against inrush current

Let's say I have a 1000W "true sine" inverter linked to a 12V lead-acid battery. Note my inverter will allow 2 kW peak load for a short period of time (for example to start an inductive load) I ...
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2answers
63 views

Bead on buck regulator circuit

I came across a DC-DC converter schematic and I notice that they use a bead on the schematic. I would like to know the purpose of this chip on this circuit and what the effect of removing it.
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1answer
59 views

The best way to bring drop 700VDC to 12VDC?

I am currently working on a PCB design that will be using 12VDC to power all of its components. It will be mounted on a vehicle, which is powered by an external power supply, which supplies the ...
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65 views

PWM-Switch Model of a Cascaded-Buck-Boost

Im trying to develop the PWM-Switch Model of a Cascaded-Buck-Boost. First of all i want to extract the Large-Signal Transfer function for the Buck-Mode. I'm working through the book "Switch-Mode ...
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55 views

Modelling DC/DC-Converter

i want to model a cascaded Buck/Boost-Converter with FAST like mentioned here: https://cbasso.pagesperso-orange.fr/Downloads/PPTs/Chris%20Basso%20APEC%20seminar%202013.pdf. The goal is to implement a ...
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57 views

State-Space Model of a Buck-Converter in DCM

I have a problem getting the State-Space Representation of an Buck-Converter in DCM. There are 2-Switch Cycles between one Period. If the Switch is closed the Circuit looks like: after applying ...
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59 views

PWM signal to “real” analog signal with low load dependency

I am designing a circuit that allows me to regulate an Arduino PWM output to a stable voltage reference (PWM to 0-5V ideally) dependent on the duty cycle. So far my approach has been to attach a low ...
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1answer
48 views

Maximum input voltage in buck converter

Consider the following simple buck converter It consists of an NMOS input device, a diode, inductor and capacitor and a load. If we are limited to a gate voltage on the NMOS device of 12 volts peak-...
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25 views

Bad Waveform on Output of Buck Converter

I have designed a buck converter (poorly) and have been getting terrible noise. I made a post here where I was given suggestions on how to do a proper layout for my buck converter. This post also ...
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63 views

Techniques for Filtering a Noisy Buck Converter

I have built a buck converter on the TS30011. Unfortunately, I am getting terrible noise on the output. External Parts Used: Inductor Output Capacitors I have been analyzing my design and have ...
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124 views

Can I decrease voltage to get higher amperage?

If I have for example a battery that outputs 10 V but with a maximum of 0.5 A. If I took the output of the battery and entered it in a buck converter to get 5 V will I get the same 0.5 A at 5 V or I ...
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1answer
53 views

Buck converter step response

I am simulating a current step in a buck converter with a resistive load that I designed. I am measuring the response while stepping the current up from 5A to 10A and stepping the current down from ...
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261 views

What is this SMD for on a SZBK07?

I purchased a SZBK07 CCCV Step Down Buck Converter and I was hoping to remove the TRIMPOT and replace with a potentiometer how ever there was a Orange SMD thing bridged between the 2 and 1 pin's on ...
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1answer
91 views

PCB ground plane noise

I have designed PCB for my buck converter. When designing the PCB I've created, I have made one ground plane as shown. I received the PCBs and there was noise in the TL494 affecting fixed 5V Vref ...
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1answer
34 views

How to measure correctly efficiency at high load with LT8646

i'm trying to measure efficiency of a LT Part LT8646 at high load with the attached schematic. i'm using a dynamic load and a power supply to give 12V. I'm using a digital multimeter to read the ...