All Questions
90
questions
3
votes
6
answers
1k
views
What is an intuitive explanation on how a buck and boost converter transfer energy?
I can understand how a buck converter can step down the voltage but only with the formulas. I am struggling to understand intuitively how the inductor stores energy and releases it in a way so that ...
- 31
0
votes
0
answers
29
views
Using a coupled inductor in a multi phase buck converter - how to set the inductor dot notation and converter PWM for best ripple reduction
Based on these Charles Sullivan papers, we can use a coupled inductor in a multi phase converter to reduce inductor ripple current.
https://www.princeton.edu/~minjie/files/sullivan-CICC-2021.pdf
http:/...
3
votes
1
answer
204
views
Inductor magnetic field collapses during switching?
SEE EDITS BELOW
I'm running into some problems with my Buck converter design. During the switching period the inductors magnetic field seems to collapse, which generates some large voltage peaks. That'...
- 33
0
votes
1
answer
97
views
Should I limit inrush current of this MOSFET buck regulator?
I am building a digitally controlled constant current switching power supply. This circuit will deliver no more than 105 Watts at around 20V from an AC-DC DIN rail SMPS of 250W.
You can see and ...
0
votes
1
answer
172
views
Audible Noise in MC34063-Based Buck/Boost Converter Circuit
I am trying to make a hotplate with an ESP32 and I use MC34063 for buck/boost converters. The hotplate itself require 12-30V to operate and the ESP32 and LEDs need 3.3V.
Here is the circuit:
When the ...
- 355
7
votes
2
answers
748
views
How do buck regulator modules with integrated inductors manage to be so small?
This 20 A buck regulator module from TI is 6.5x7.5x4 mm and has an internal 330 nH inductor.
This 6.5x6.5x3.1 mm 330 nH inductor from Coilcraft has an RMS current rating of 18.8 A and is the smallest ...
- 95
2
votes
1
answer
56
views
Buck converter inductor waveform having high ripple and slow charging and fast discharging [closed]
The following shows the voltage (green) and current waveform (yellow) across an inductor in a buck converter designed to step down 30 V to 15 V with 0.2 A output current.
The inductor values according ...
2
votes
3
answers
135
views
High voltage buck converter inductor voltage rating
We‘re designing a buck converter that should convert 600VDC down to 20V. For that purpose we use the ST VIPer26k.
We’re currently looking for an inductor (L2). The inductance is 1mH, but we‘re not ...
- 378
0
votes
1
answer
87
views
Sign conventions of inductors in circuit analysis
Here's what I know about inductors:
As per Lenz's law, inductors sort of maintain the direction of current passing through an inductor. So whenever there is an interruption on the source from which ...
2
votes
3
answers
260
views
Inductor in buck converter
I have a couple of questions regarding the switching inductor in a buck converter.
Is it normal for the switching inductor in a buck converter to heat up?
In my circuit, it reaches around 65 Celsius. ...
- 345
0
votes
1
answer
75
views
Buck and boost converter inductor confusion
I have seen that a boost converter uses the spikes of an inductor to step up the capacitor voltage as this spike is stored on the capacitor.
Why don't we get a similar effect in the buck converter? A ...
- 671
1
vote
1
answer
185
views
How to choose the right inductor current limit for buck converter?
While learning and trying to make my first two-phase buck converter to power some servos, I found 2 x 3.3 uH inductors are needed for an application that will draw 30A (15A each). The problem is that ...
- 411
2
votes
1
answer
114
views
How to choose the right inductor for buck converter with LM5143A-Q1? (from TI)
While working on my first voltage regulator circuit I got stuck at calculating the inductor value... The IC is LM5143A-Q1 from Texas Instruments, and according to the datasheet, the formulas for ...
- 411
0
votes
2
answers
363
views
Buck Converter Inductor Ripple Current and EMI
When attempting to reduce EMI at the schematic design stage of a buck converter it's often recommended that one minimize the output ripple voltage. It's clear why this would be useful.
Rarely is it ...
- 187
1
vote
2
answers
1k
views
Minimum Inductance for Buck converter to maintain CCM
In a buck converter, consider all components to be ideal; the
output voltage is kept constant at 5 V by controlling the duty
cycle. The input voltage varies between 10 V to 40 V, the
output power is ...
0
votes
2
answers
219
views
use of capacitors and inductors in buck converter [closed]
For stepping down voltages, why can't we use a simple resistive circuit and the voltage division rule for the output? Why do we use a buck converter instead? What role do a capacitor and an inductor ...
- 33
0
votes
3
answers
64
views
Current and voltage value before inductor pin in buck converter
In buck converter we know that pure DC current will be after inductor pin. But what will be the current/voltage value before it.
Let’s take an example, the buck converter circuit with 12 V input to 3....
- 543
1
vote
2
answers
190
views
Selecting capacitor and inductor for adjustable buck converter
I'm trying to understand how to choose the right inductor for a buck converter that can produce different output voltages.
When using an LM2596 I can add a potentiometer into feedback loop to produce ...
4
votes
2
answers
899
views
What is this ringing in the inductor current?
I am working on a buck-boost converter and I see this ringing in the inductor current. It happens on turn on of the high side FET (See attached Image). First of all is this ringing normal?
Is there ...
1
vote
1
answer
127
views
Buck converter coil selection (Coilcraft vs Bourns)
I am using the SCT2331 (a clone of the Diodes AP63200, with 400KHz switching frequency instead of 500KHz). The design works with an inductor from Coilcraft (LPS3314-103), but when I try a different, ...
- 7,600
1
vote
1
answer
429
views
Coupled inductors for multi-output buck
I see coupled inductors are generally used in multi-phase design to take advantage of current ripple cancellation.
What is really the advantage of coupled inductor in multi-output buck or multi-output ...
- 3,032
0
votes
1
answer
160
views
Inductor and specs for a buck converter at low currents - high r
I'm currently designing a buck converter using the AP64501. This issue/question is not specific to that buck however. I have a python script that I wrote that uses the formula's in TI's appnote: AN-...
- 736
1
vote
1
answer
512
views
How to reduce inductor heating in buck converter?
I am designing a simple buck converter to drive 9 V, 3 A LED. Supply can vary between 20 and 30 V. I used the TI Power Designer Tool to calculate the inductance value and other parameters. Here is the ...
- 83
2
votes
3
answers
164
views
Buck Converter Theory Confusion
For a buck converter, I'm having a hard time conceptually understanding what is happening.
Here's my thought process: When the switch is closed, their is a positive voltage across the inductor equal ...
- 393
1
vote
0
answers
125
views
Inductor saturation current
I'm trying to determine an inductor's saturation current, I use a PWM with a gate driver (TLP250) and a 0.4Ω sense resistor at the source which I probe across to capture the current waveform.
I ...
- 41
1
vote
0
answers
263
views
Can an air core inductor cause a buck converter to malfunction because of EMI?
I am trying to build a buck converter circuit using the LM2596T.
While reading its datasheet, it came to my attention that EMI is a potential problem one should not ignore while designing a buck ...
- 633
1
vote
1
answer
489
views
How do I stop buck converter voltage from dropping whenever current increases?
I built this buck converter circuit using the LM2596T-5 (5 V OUTPUT, 12 V INPUT) using the exact components mentioned in the datasheet's first page (schematic below), except for the diode.
I used the ...
- 633
0
votes
3
answers
379
views
Multi-phase buck converter inductor selection
This question is regarding the inductor design (uncoupled) in a multiphase buck converter.
In a multiphase converter, the inductance per phase requirement is higher than the corresponding single phase ...
- 3,032
0
votes
2
answers
1k
views
Buck converter waveform
It became very hard for me to understand the concepts associated with buck converter waveform. What is the role of capacitor in its output terminal? Is it used for smoothing the voltage ripple? Why ...
0
votes
2
answers
504
views
Why am I getting a sinewave output from a buck converter with an input of square wave?
I was expecting the output to stay at 1V which is the average value of (2V, 1MHz, 50%) input.
It seems the capacitor is slowly charging to the input peak, and the inductor current is changing based on ...
- 1,150
0
votes
1
answer
2k
views
Inductors: Saturation Current or Rated Current?
I am designing a 5V, 5A buck converter, and I am trying to spec my output inductor.
The datasheet specifically mentions that my inductor should have an appropriate current rating, but
I also wonder ...
- 161
0
votes
0
answers
141
views
Disadvantages of routing inductor in Buck Converter on opposite layer?
I am routing a TPS562202S buck regulator, using a 4.7 uH inductor. Due to space and assembly constraints, I cannot place the inductor on the same layer as the regulator. The regulator will be on the ...
- 325
1
vote
1
answer
169
views
Bulk capacitance equation derivation from appnote
I am looking at SLTA055 by Texas Instruments. It discusses, among other items, how to determine the bulk capacitance required for a buck regulator if a LC filter is used. Since the "L" will ...
- 736
6
votes
1
answer
856
views
What are the issues with using multiple inductors for a DC/DC converter?
I'm going to be designing a Buck Converter that will supply a max of 10A of current to an LED Strip (9V to 20V in, 5V out). Since I want to minimize the amount of EMI in the circuit, I want to use ...
- 1,195
0
votes
0
answers
184
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.
...
user220456
0
votes
3
answers
450
views
Buck converter without inductor in a NiMH charger (Zilog AN0259 application note)
After doing some reading online, it seems that you can't really build a step-down converter with only a filtering capacitor and without an inductor, because the losses occuring during charging of the ...
- 13
5
votes
2
answers
1k
views
Where does the inductor energy go in a buck converter when the load is suddenly disconnected?
It is known that inductors resist a change in current. So, my question is that in a buck converter, what prevents the output voltage from going all the way up due to inductor resisting a current ...
- 109
1
vote
2
answers
193
views
Power inductor's staturation current for buck converter
Is it correct that when selecting an inductor for a buck converter I should be choosing an inductor with the saturation current higher than the converter's peak current?
How much of a margin should it ...
- 825
2
votes
2
answers
175
views
Buck Converter Capacitor and Inductor Characteristics
I'm trying to make a buck converter with this mickey-mouse MC34063A chip that will step-down +5V to +3V3 up to 500 milliamps. I've gone through the calculations by hand and validated them with an ...
- 187
1
vote
1
answer
836
views
In Buck Converter, when the ESR and EPR of Inductor increases then what is the its effect on output voltages and why?
I have done LTSpice simulation. I have seen that by increasing ESR of inductor, the output voltages decreases and by increasing EPR of inductor the output voltages and ripple in output current and ...
- 23
1
vote
1
answer
373
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-...
- 1,398
2
votes
2
answers
1k
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.
...
- 1,398
1
vote
1
answer
561
views
Buck Converter - Inductor CCM and DCM
I have a doubt while selecting the inductor for a buck converter.
TI App Note
In This app note, in the abstract itself, they mention that this :
This application report gives the formulas to ...
user220456
2
votes
1
answer
267
views
LM2596T, Inductor selection
I'm trying to build a simple low voltage 0-12 adjustable PSU and the simplest way i could think of was using a LM2596T ADJ.
In page 16 of the Datasheet there's a inductor selection selection guide, ...
- 2,396
6
votes
3
answers
2k
views
Buck Converter dies unpredictably upon connecting power
I made a PCB for an ESP32-based solenoid controller that is powered by a 24V DC Jack. I'm using an AP63205 Buck Converter to step that input down to 5V DC, and then a linear 3V3 LDO to power the ESP32....
0
votes
1
answer
185
views
Buck Converter - Closed Loop - Effect of decreasing inductance and increasing capacitance
Output voltage as a function of output current is plotted from oscilloscope data for a closed loop buck converter.
Switching frequency is kept the same in both the cases.
CASE 1 : Inductance = 2....
- 13
12
votes
2
answers
3k
views
Buck converter, squeaking/whining inductor
I have a problem with my homemade buck converter. It is based on a TL494 control chip with my discrete MOSFET driver. The problem is that my inductor squeaks and whines, when the output current ...
- 199
1
vote
1
answer
226
views
Questions on Inductor Selection guide from TI [closed]
I have been researching on Selecting inductors for Buck Application and came across an Application report from TI.
I have few questions which are listed below:
On ...
- 962
0
votes
2
answers
195
views
buck converter inductor lm2576
I was curious and looking at the datasheet of the buck converter IC LM2576, looking at the inductor selection guide it feels counter intuitive to me.
Why is the inductor value needed reducing as we ...
- 79
1
vote
1
answer
92
views
Buck converter inductor calculation doesn't agree with typical application schematic
Im trying to play around with some buck converters and have found one that I might want to make a circuit with. The IC I want to use is the the TPS53125 in QFN package. It's a dual output buck ...
- 127