All Questions
Tagged with switch-mode-power-supply buck
312 questions
0
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99
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Buck converter (MAX5035D) regulation problem
I didn´t expect to be having issues with a buck converter, but here I am.
My design goal is a simple 15-60 V to 10 V buck converter. I settled with the following schmematic:
I designed a 2-layer ...
- 1
6
votes
2
answers
1k
views
How does a buck converter's output ripple waveform become sinusoidal?
Below image is from Fundamentals of Power Electronics.
The ripple component of the inductor current will be flowing through the capacitor as shown in the ic(t) graph. This one I understood.
May I ...
- 3,061
1
vote
2
answers
858
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How can I power an ESP32 with a 54V battery using a buck converter?
I need to power an ESP32 board from a 54 V battery. For that purpose, I understand that I need to step it down to 5 V so I need to design a step-down buck converter.
I tried the following circuit ...
- 133
3
votes
1
answer
483
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Simple SMPS power supply using buck converter
I'm a pretty new hobbist in this field. I wanted to try to create a simple and cheap power supply that transforms 220 V, 50 Hz AC into 15 V, 8 A DC, but I really can't understand how.
I've tried the ...
- 311
2
votes
1
answer
102
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Bare copper on buck converter PCB?
I am working on the design of dual 5V/3.3V power supply based on TI's TMZ12003EXT buck converter module. It's an older TI part, apparently intended for "rugged/military applications," but ...
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1
vote
0
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88
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Current-mode buck: get current from inductor winding
I was recently reading about current-mode control in switching converters.
When discussing the current sense signal, all sources I have read either show the current sense as some kind of additional ...
- 23.4k
2
votes
1
answer
432
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In MOSFET switching loss calculation, where does the 0.5 factor come from?
I am going through this material for calculating the switching loss of the mosfet.(https://www.monolithicpower.com/frequency-selection-in-switching-power-supply-designs-part-i)
The switching loss ...
- 3,061
0
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0
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59
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High ripple in the output
We have chosen the MCP16311 buck converter for 4 V @ 1 A output.
design specifications as below.
Input voltage range: 5 to 20 V (source - USB type C mobile, charging adapter)
Output Voltage : 4 V
...
user220456
6
votes
3
answers
669
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Why would you sense peak inductor current at the high-side PMOS transistor rather than at the NMOS?
I found this image for peak current mode sensing here.
Is there any reason that you sense the peak inductor current from the MP instead of theMN transistor? I know that ideally both should work but I ...
- 270
1
vote
1
answer
65
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Power supply connected to multiple buck converters, input current requirements
I have a 24V/40A power supply with a foldback current limiter. And I need to connect 76 buck converters of 5V and 2A each to it. Since the current of the power supply is limited and considering that ...
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1
vote
1
answer
213
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4-20mA loop energy harvester
I'm designing a board which is powered from 4-20 mA Hart loop. Only two wire.
Actually I had 19~20V due to the 250ohm resistor of the master side.
I would like to power two electronic stages 12V@4mA ...
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0
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0
answers
118
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Series capacitor buck converter small signal model
Does anyone know how to do the small signal model of the series capacitor buck converter?
I can't find a related paper talking about this one.
I think the small signal model is not the same as the ...
- 367
2
votes
1
answer
2k
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What is the function of the feedforward capacitor on the LM2596-ADJ?
I'm looking at the LM2596S datasheet and notice that on page 7 (figure 3) it recommends a "feedforward" capacitor for the adjustable variant.
The example schematic on page 9 shows a ...
- 11.1k
0
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2
answers
978
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What is the mode of MOSFET or BJT in buck converter?
I want to implement buck converter with conventional design (not synchronous etc) like below.
And I want to implement the converter for two cases. One is to use BJT as switching device and another is ...
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4
votes
1
answer
399
views
Peak current mode control question
I read two different figures about the peak current mode control block diagram, and I am confused about one thing, please see the below two figures.
In this figure, voltage loop output is connected to ...
- 367
1
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1
answer
44
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Range of transformer Q variation for UC3844B converter?
Here the UC3844B High Performance Current Mode Controller (at left, SO-8) is used with a custom transformer to step down bus voltage to 24V. The transformer is likely rated for about 40W, so ...
- 16.4k
1
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1
answer
354
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Power Supply Validation - What Matters?
When it comes to validating a power supply (for example, a buck regulator), what parameters matter?
From the research I have done, I think that things such as ripple voltage, percentage overshoot ...
- 878
0
votes
2
answers
1k
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Would increasing the load resistance in a buck converter increase efficiency?
I was recently asked in an interview if the efficiency of a buck converter would change based on changing the load resistance (I assumed this meant constant input and output voltage).
I answered that ...
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10
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5
answers
957
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MOSFET failure in a high power AC-DC SMPS buck converter
I've made a AC-DC step down buck converter that converts 220 VAC to a variable 45 to 70 VDC at 5 to 10 A to charge a Li-Ion battery. I'm currently using ESP32 to drive a MOSFET driver (IR2110) to ...
- 101
1
vote
1
answer
519
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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 ...
- 3,156
2
votes
2
answers
1k
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Why use external compensation on a buck IC?
The AP64200, with block diagram of
says about loop compensation that
The goal of loop compensation design is to achieve:
High DC Gain
Gain Margin less than -10dB
Phase Margin greater than 45°
Loop ...
- 3,259
1
vote
3
answers
319
views
Buck converter simulation Vout lower than expected
I am trying to design a simple buck converter in LTSpice. Here are my parameters:
...
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1
vote
0
answers
443
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DC-DC converter/step down layout improvements/feedback
I'm designing a board with a 12V to 5V DC-DC converter circuit and I would like some feedback on how it can be improved. As it is the first time I have designed such a circuit, I'm not the most ...
- 159
2
votes
1
answer
685
views
Buck converter after boost converter -- what is an advantage?
I encountered a mass produced device that has a power circuit like this:
5V from USB ==[boost converter]==> 13V ==[buck converter]==> 12V
and it confused me. I don't see why you would need a ...
- 31
1
vote
0
answers
42
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Buck regulator thermals calculations
Schematic:
Specification:
Vin = 24V
Vout =5V
Iout max = 8A
Freq = 0.691 Mhz
Assumptions: Good layout and FETs mounted on 1-2 inch^2 of copper.
Calculations based on this doc: https://www.ti.com/lit/...
- 757
0
votes
2
answers
185
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I would like to drop a variable DC voltage from input 30Vdc to 200Vdc to output 5Vdc with a max 200mA
I am new to electronics and would like some help if possible.
The incoming voltage will be variable from 30Vdc to 200Vdc coming from a bank of solar panels. The output is 5vdc at a max of 200mA. I ...
- 11
6
votes
3
answers
2k
views
Switch mode power supply vs DC-DC converter
I have started learning about DC-DC converters and switch mode power supplies (SMPS.) I know that the standard SMPS (attached fig. below) has an input rectifier, DC link capacitor, inverter, output ...
- 87
3
votes
2
answers
900
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Frequency Response of Ideal and Real Type III Compensator
I'm trying to develop a Buck Converter with a Voltage-Mode Control, using a Type III Compensator, just like the one below.
So I calculated its transfer function, and then with the correct values of ...
0
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1
answer
87
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Buck converter: Additional circuitry working not clear
Saw the below schematic of a buck converter, but not able to figure out the working of the marked section. It is shown Node 1 is at 16 V.
Looks like sensing the differential voltage across inductor, ...
- 3,156
2
votes
0
answers
101
views
Is it true that power supply design is difficult when input voltage range is wider?
During power supply (buck converter) testing, I had seen the lowest efficiency values corresponding to highest input voltage. I thought if the design meets this worst case scenario, it should be ok no ...
- 3,156
2
votes
2
answers
218
views
MOSFET selection for buck regulator (SOA vs thermal dissipation)
I am trying to design a buck regulator with the following specification: Vin = 24V Vout = 5V I max = 8A Fsw=228k. The load is basically a long strip of RGB LED's. Which in certain cases would be all ...
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0
votes
0
answers
49
views
Integrated buck regulator capable of 12A
I was narrowing down design options on digikey for a buck regulator capable of 5v and 8A continuous currents when i came across the following part which integrates the FETs and is capable of wide ...
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1
vote
0
answers
433
views
Reverse recovery body diode in synchronous buck converter
I am building a synchronous buck converter from 72 V to 4.2 V 2 A. Is there a way to lower the losses of the lowside MOSFET’s body diode? I am using a switching frequency of 300 kHz and with the ...
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1
vote
1
answer
343
views
What is the min and max input voltage range of a buck converter to maintain efficiency above 90% [closed]
I want to design a stepdown converter from 72V lithium ion battery to 12V, 5A. I am torn between using a flyback converter and a buck converter. Which topology will give me maximum efficiency at that ...
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0
votes
2
answers
143
views
How does current flow in this circuit with multiple power regulators?
I have the following circuit:
simulate this circuit – Schematic created using CircuitLab
U1 contains two voltage regulators (Vo1=+10V, Vo2=-10V, input Vin=5V). (These could be buck, boost etc. ...
- 1,332
0
votes
1
answer
189
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How can I achieve a 25V - 5V @10A buck circuit, and a 25V - 8V @6.5A buck circuit? [closed]
I'm a computer engineer major in my senior year.
My team and I are making a SmartKart, and I'm responsible for power management and power designing.
Right now, based on several components we will be ...
- 1
1
vote
1
answer
790
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
-1
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2
answers
137
views
What rating of SMPS is perfect input to buck converter for 10A output
I'm having a 10A DC-DC Step Down Buck Converter, suppose I want to get X volts and Y amps at output, so do I need to have input DC of rating more than X and Y ? or how to decide input rating?
Now let ...
0
votes
1
answer
107
views
Feedback loop design (buck converter): Output capacitance- effective value or nominal value to be considered?
In this TI datasheet of TPS62180, it was mentioned that the LC filter combination should be selected from a set of predefined values. I understand this is usually the case for an internally ...
- 3,156
3
votes
4
answers
848
views
How does the bottom resistor in feedback resistive divider impact noise sensitivity?
What does this line (underlined) mean?
Does the datasheet imply the loading effect due to error amplifier?
MPS datasheet
- 3,156
1
vote
1
answer
80
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Why is the input capacitor calculation different in TI datasheet?
Below is the input capacitor calculation from TI datasheet
Why is it different from standard buck calculation given below?
Another TI dcoument
- 3,156
0
votes
1
answer
663
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Switch node ringing: How does high-side MOSFET turn-on time affect the ringing amplitude?
I was trying to understand the ringing in buck converters during turn on. The following equivalent circuit model was found in a website link.
My doubt is:
How does the turn-on delay of the switch ...
- 3,156
3
votes
2
answers
651
views
Buck converter - Maximum VIN of IC vs Maximum clamping voltage of TVS diode
For the circuit below which uses a LMR14050SDDAR buck converter from Texas Instruments.
The absolute maximum VIN of the IC is 44V, and the capacitors are all of 50V. In practice VCC can be 36VDC ...
- 657
0
votes
2
answers
71
views
Is it true that buck converter FETs are driven from LDO?
As per the below document
https://www.onsemi.com/pub/Collateral/TND388-D.PDF
higher switching frequency has the drawbacks listed. Iam unable to understand
Is FET driver in a buck converter internally ...
- 3,156
0
votes
3
answers
413
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 ...
- 3,156
0
votes
2
answers
201
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Clarifications needed about buck converter output ripple voltage derivation
I have a question regarding buck converter output ripple. In the below figure, could you please tell me how the area shown in the red circle has a time duration of Ts/2?
- 3,061
0
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2
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258
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Buck regulator transient response explanation
I am using TPS5450 buck regulator and trying to measure the transient response but seem to see a weird triangular adjustment before it settles. I can't see anything in the datasheet that would explain ...
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0
votes
2
answers
111
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How can the output current be programmed in the LTC3649 step-down regulator?
I use Analog Devices' LTC3649 regulator as a step-down regulator. It is said that there is a programmable output current in the datasheet, but I have no idea how to do this. Does anyone have an idea ...
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5
votes
4
answers
2k
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Why do buck converters end up in steady state?
I'm studying buck converters such as the one in the following simulation:
I have learned that for buck converters that are in continuous conduction mode and at steady state, the following equation ...
- 543
1
vote
2
answers
189
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Closed loop control buck converter
I have a buck converter of 400 V input, 200 V output, 300 kHz switching frequency, power output 100 W. I am trying to put it into closed loop voltage mode control. It is working DCM mode. Modelling ...
- 430