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Questions tagged [sepic]

For questions about single-ended primary-inductor converters (SEPICs), which are a type of DC/DC converter. Use with the "dc-dc-converter" tag.

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Circuit analysis for DC-DC convertor SEPIC architecture

I'm analyzing the following reference design from Texas instrument for making a variable dual output (+/-60V form 11V): What I'm curious to know is to understand the signal waveform for the following ...
Andromeda's user avatar
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3 answers
73 views

Filter on SEPIC architecture output for making +/- 60 V from 11 V input

I'm working on a LM5155 Boost/Flyback/SEPIC controller reference design PMP40488 from TI. The goal of the design is making variable output (maximum +/- 60 V) from 11 V input. My question is related to ...
Andromeda's user avatar
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1 answer
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DC-DC converter design simulation tools and Webench design tools to identify the best-suited IC and schematic

I did a research about what are the simulation tools and webench tools for major companies like AD and TI to find a effective tools for my design purpose: For example for Analog Devices, there is the ...
Andromeda's user avatar
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1 answer
53 views

DC-DC SEPIC convertor design

In a reference design form Texas instrument for a SEPIC architecture: I noticed there is a specific consideration for connection between HVGND and PGND for LM3488 as follows: At the same time that ...
Andromeda's user avatar
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1 answer
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DC-DC convertor-SEPIC architecture

I'm working on a SEPIC DC-DC convertor, in the reference design from Texas instrument there is MOSFECT which is derived by DR pin of the main controller (LM3488) as follows: There is an diode (D4), ...
Andromeda's user avatar
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1 vote
1 answer
88 views

LM3478 MOSFET and inductors overheating

I'm trying to design a SEPIC converter based on LM3478, with input voltage range 12-36 V, and output 24 V 2 A. I'm calculated all relevant values of components, according to "AN-1484 Designing A ...
Ihor's user avatar
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1 vote
1 answer
71 views

LTspice: SEPIC simulated output voltage does not match known output voltage

I am designing a SEPIC that meets the following criteria: ➢ Vin = 15 V-35 V ➢ Vout = 25 V ➢ Output voltage ripple 1% peak to peak ➢ Switching frequency 100 kHz ➢ Load 10 W-50 W Calculations have been ...
eutectic_codswallop's user avatar
1 vote
1 answer
69 views

How to calculate diode forward voltage (Vd) for a MOSFET within a SEPIC?

I am in the process of selecting a MOSFET for a SEPIC. I require Vd in order to calculate the peak currents across the inductors, which are ultimately needed to calculate the MOSFET peak current, with ...
eutectic_codswallop's user avatar
0 votes
0 answers
76 views

What's causing this ringing? GaN SEPIC Converter Gate Ringing

I'm designing a SEPIC converter using a HEMT GaN from EPC (EPC2204) and a dedicated GaN driver IC (1EDN71x6U). I've been in this loop (mind the pun) trying to mitigate gate ringing, and I'm having a ...
Alex Turner's user avatar
1 vote
1 answer
188 views

Not able to get enough current from buck boost (sepic) converter made using TL494

I am trying to build a buckboost converter for converting 5-40v input to 5-35V output at 3A max to use it for many purposes by usign TL494. I am using a SEPIC topology as i want a non inverting output....
Logesh-0304's user avatar
1 vote
1 answer
119 views

How can I achieve high efficiency in a SEPIC with AC inductor losses? Where's all my energy going and why?

I'm building an asynchronous SEPIC converter with a wide input range (10-60 V) and a 24 V 2 A output. This is based on an LM5022, and I'm trying to achieve high efficiency as its heat generation is a ...
Alex Turner's user avatar
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0 answers
193 views

Is it good idea to cascade SEPIC converters to extend the input voltage range of the XL6009?

I'm currently working on designing a current controlled SEPIC converter with a wider range of input voltage for a medium sized power application which can be powered by a lithium battery. The existing ...
Fatihy's user avatar
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2 answers
671 views

High power DC/DC step up or boost converter

From a wall power supply of 12V (I'm planning to use the PSU), I would like to boost the voltage to 22V at 9A to power some heating foil. These heating foil requires about 130W and I need at least a ...
stefyanna's user avatar
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1 answer
52 views

How to calculate components values for LM3421 in SEPIC mode

How can I calculate the components values for LM3421 in SEPIC mode? In the LM3421 datasheet, there is not much information about SEPIC topology. (Section 9.2.9.2 is labelled "Detailed Design ...
Goku's user avatar
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1 answer
173 views

Meaning of these inductor dot symbols

For the following circuit from the NCV5171 datasheet: What is the meaning of a solid dot on one inductor and an open dot on the other?
Sittin Hawk's user avatar
1 vote
1 answer
318 views

Beginner seeking feedback on circuit design: SEPIC with adjustable voltage

I recently got very interested in electrical engineering. After watching a bunch of YouTube videos on circuit and PCB design, I figured it's finally the time to get a bit hands on. I decided to start ...
NoSegfault's user avatar
3 votes
4 answers
196 views

13-48 V SEPIC - > 19.5 Vout; 0.5 A

I am trying to design a SEPIC converter with the parameters stated above and have already drawn a schematic using the LM5022 IC. I have built the system and noticed a few things: The output voltage ...
Yordan Aleksandrov's user avatar
2 votes
1 answer
494 views

Ceramic output capacitor selection for ripple current (SEPIC)

I'm designing a SEPIC converter based on a wide input voltage range SMPS controller (LTC3758). The requirement is for a wide input voltage (10-60V) with a fixed output of 28V @ 1.5A. I'm trying to ...
Alex Turner's user avatar
1 vote
0 answers
560 views

Confusion of the working principle of Isolated SEPIC converter

I am a bit confused about the current flowing in the magnetizing inductance L_m when the switch is off. I am reading a book(Erickson & Maksimovic, Fundamentals of Power Electronics, 2020), ...
Martineo Pang's user avatar
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1 answer
356 views

Why does this SEPIC buck-boost oscillate so much?

I've made this SEPIC regulator based on this design, using a MT3608 boost regulator, which has the same oscillation (ripple) as this question: I've made these changes: C1=100uF, C2=470uF R2(bottom ...
Tirdad Sadri Nejad's user avatar
0 votes
1 answer
242 views

Is a SEPIC converter truly isolated?

I have been in two separate design reviews where the SEPIC topology was rejected for an isolated < 40W application. These meetings were at 2 different companies and with different principal ...
Carlo B's user avatar
1 vote
2 answers
124 views

Calculating ripple voltage across sense resistor (SEPIC DC-DC Converter)

I am designing a SEPIC DC-DC converter based on the LT3758 (Analog Devices). In the data sheet the maximum switch ripple current percentage is calculated using the ripple voltage across the sense ...
soup's user avatar
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1 answer
118 views

Coupled Inductor for DC-DC Converter ~50W

I'm designing a DC-DC Flyback or SEPIC converter, not decided yet. The converter is used to source some power LED's. The output voltage up to 60V and 1A with an input of 12-24V. The switching ...
Matthias Waelti's user avatar
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0 answers
116 views

Powering a 12 V Relay and a 3.3 V Microcontroller with one Power Supply

I'm trying to power the LN298 motor driver in order to use a 12V linear actuator. This motor driver comes with a 5V voltage regulator, so you can power a microcontroller with one power supply. The ...
Ishaan Kohli's user avatar
1 vote
0 answers
63 views

Secondry side pulse by pulse current limit

Coupled inductor SEPIC converter using UC3843. Vin nominal = 14 V Vout max = 30 V Iout max = 2 A According calculations based on many resources the MOSFET's current will be Peak = 7.62 A RMS = 5.3 ...
Deron Felix's user avatar
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0 answers
146 views

Buck converter after SEPIC converter

I have designed a SEPIC and Buck converter using the TI power designer tool, which I have individually tested, and proved to be working correctly. They are both of the non-isolated type, but when I ...
wardn's user avatar
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1 vote
1 answer
186 views

SEPIC converter : why average secondary inductor is the output current?

I can't get the reason the why the average secondary inductor current is the output current. Simulation confirms it's true, as well as documentation. But I haven't found any clear explanation. Sorry ...
inico's user avatar
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-1 votes
2 answers
359 views

Selecting capacitor for SEPIC converter

I'm looking for an advice how to select capacitors for my SEPIC converter. I have done calculations, but I haven't find Cin, Cs and Cout yet. What seems like a problem is that there are few work ...
Marc Paul's user avatar
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0 answers
194 views

sepic converter using lm3478

Is it possible to make a sepic converter of 120 W using LM3478 ? I am trying to make the circuit in TI web bench but it is not supporting over 12V 3A in LM3478.
Pradeep Gusain's user avatar
4 votes
1 answer
465 views

Is there a problem using electrolytic (polarized) capacitor as coupling capacitor in SEPIC converter?

I found this circuit from here and have been thinking about to build it: The author present it as Ćuk converter but I understand it as SEPIC, after reading this and this. Q: My main concern is, ...
Junaid's user avatar
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1 vote
0 answers
143 views

building real simulation in multisim(NI company) of dc-dc SEPIC convertor

hi I am trying to build real simulationin multisim of dc-dc SEPIC convertor how ever in my output voltage i get a lot of RIPPLE . the problem is that I get a lot of spikes in my capacitor current . ...
Tomer Polski's user avatar
4 votes
1 answer
554 views

SEPIC vs. ZETA feedback

When I was reading through the RECOM book of knowledge DC-DC, I found out that the SEPIC converter has more chance of having resonance feedback than the ZETA converter. They mention that the SEPIC has ...
J. Joly's user avatar
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1 vote
0 answers
252 views

How to limit starting current of a SEPIC based LED driver?

I have designed a SEPIC based LED driver which gives 60 V, 350 mA constant output with a good power factor. It is connected with 220 V AC source.Then I have used full-wave rectifier.After ...
Fouzia Ferdous's user avatar
0 votes
0 answers
119 views

High voltage drop over output diode sepic converter

I made a SEPIC converter please see the wiki for the scematic: https://en.wikipedia.org/wiki/Single-ended_primary-inductor_converter Observation: The output is 12V 2A max. When I use a scope I see ...
Want2Know's user avatar
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0 votes
1 answer
809 views

LTspice XVII problem simulating SEPIC converter

This is the second time I'm trying to simulate a SEPIC converter today. First I went with LT3959, but after hours of trying to make it work, I assumed there is something wrong with the component and ...
Lazyboy's user avatar
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0 votes
1 answer
276 views

TI LM3488 SEPIC, adjustable power supply down to 0 volts

I decided to make an adjustable power supply with input voltages from 3 to 6 volts (4A), and output voltages from 2 to 12 volts. But I had a thought, that as long as I'm making it, I should make it go ...
Lazyboy's user avatar
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2 votes
1 answer
232 views

Lossless Resistor model in PSpice?

Is it possible to make a lossless resistor model in spice? I want to test the large signal model of my DCM SEPIC converter (without linearizing it). OrCad's PSpice library doesn't seem to have it, but ...
Filip Cvejic's user avatar
3 votes
2 answers
11k views

SEPIC vs Cuk vs Zeta Converter

My understanding is that SEPICs, Cuks, and Zeta converters all provide a stable output voltage despite an input voltage that can vary either above or below what is desired. The SEPIC and Zeta ...
CraigC's user avatar
  • 147
3 votes
1 answer
1k views

SEPIC converter capacitors calculation

I have got a SEPIC converter design see here: http://www.linear.com/docs/27994 The calculation of the SEPIC converter starts at page 21. For the input capacitance on page 17 they tell you need: \$I_{...
Want2Know's user avatar
  • 111
1 vote
0 answers
178 views

SEPIC converter working in BURST mode without having one

I designed a SEPIC using the LT3467 with coupled inductors. It supply 17V starting from a 12V input. On the simulator (LTSPICE) everything works, but on the test board there is a problem. With 70mA ...
Alecoglia's user avatar
2 votes
1 answer
261 views

Sepic based charger

I have acquired a LT1512 Sepic based controller which is a controller for charging purposes. I have followed the datasheet as much as can, read few articles on how to set it up for my purposes, ...
mnemonic's user avatar
1 vote
1 answer
2k views

Compensation Capacitor and Resistor Values

I'm currently working on a Power Electronics project which I will convert 10-28V input DC voltage to 12V DC output voltage. I've deciced to use LM3481/3488 configured as SEPIC in my project. I've ...
Pyro's user avatar
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7 votes
1 answer
498 views

Vin: 2-36, Vout: 4.2. Should I use step-up, followed by step-down, or SEPIC?

My application has a small device, which draws about a watt, and is powered through a small dynamo, backed by a battery: The dynamo generates 33 volts at maximum speed, close to L6902's max input ...
anrieff's user avatar
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1 vote
2 answers
1k views

Low voltage DC UPS - confirm specs

I've looked at the other answers here regarding building a low voltage UPS and have come up with the following design. Requirements: 1) At least a couple of hours of up time; 2) USB power 5V @500mA, ...
Mr Banana's user avatar
9 votes
4 answers
4k views

Can I use a common mode choke as a coupled inductor in a SEPIC converter

I do not really understand the difference between common mode chokes and coupled inductors. They are both 2 coils wrap around the same core but I know they have different purposes. I want to design a ...
Sonia's user avatar
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7 votes
3 answers
3k views

Isolated DC/DC flyback/SEPIC

As far as I understand the flyback topology, it can be used in both buck and boost converters. What I am not sure about is: Does it also work for the case where buck-boost is needed, i.e. \$V_{\text{...
Junius's user avatar
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2 votes
0 answers
211 views

Why does my SEPIC converter output more power at higher temperatures? What are the implications of this behavior?

I have a Pololu S18V20ALV SEPIC voltage regulator board that is wired to a high-amperage 5V USB power source on the input and a DC brushless fan on the output. The output is set to about 5.5V. ...
bwDraco's user avatar
  • 1,421
1 vote
1 answer
2k views

LTSpice SEPIC simulation current spikes

I am designing a SEPIC power supply using the LT3758. I have simulated the circuit in LTSpice and all the waveforms are as expected except the L1 current. Here I see massive overshoots when the MOSFET ...
David G's user avatar
  • 433
0 votes
2 answers
154 views

How to choose V_out resistors for LT8494 SEPIC

I am in the middle of a project where i want to use a mcu (ST32F3028U6 with DAC of 2.4V - 3.6V) to control the V_out voltage of a LT8494 SEPIC DC/DC Converter. I understand the basic operation of the ...
Martin1's user avatar
11 votes
2 answers
4k views

How do I size the coupling capacitance for a SEPIC converter?

The app notes I've seen for a SEPIC converter1 all tell me to size the coupling capacitor for ripple currents and voltages. I haven't seen one that tells me how to size the capacitance. Obviously ...
Stephen Collings's user avatar