Questions tagged [switch-mode-power-supply]
A switch-mode power supply (SMPS) switches been fully-on and fully-off states quickly to maintain voltage regulation. They offer lower power dissipation and run cooler than linear regulators that continually dissipate power through a transistor.
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Generating a solid 5V output from a buck converter whose output varies from 4.8V to 5.2V
I have a buck converter whose output varies from 4.8V to 5.2V. This buck converter is present in my VCU. Input for the buck converter can vary from 8V to 14V.
The 5 volt rail is powering many IC's ...
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LLC convert design misunderstood
The question is addressed to those who have designed LLC converter.
As you you know during the design steps you come to graphs that looks like the uploaded one.
The intuitive view is when you ...
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LLC working above resonance
I am designing LLC Half-Bridge converter:
Pout = 500W, Out = 12V, Vin = 390V, Fr = 80kHz, Lr = 30 uH, Cr = 120nF, Lp = 190uH
The converter is working always above resonant frequency. The ...
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Placing feedback loop parts on PCB
I have one PCB for control circuitry and another for power parts (input caps, transformer, full bridge, output caps...).
I would like to ask if I can place some feedback parts (red square at picture) ...
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How do I calculate my buck-boost converter's duty cycle value given a minimum input of ~0V?
I am trying to create a buck-boost converter to convert the 9V from my battery to 5V. I am following a textbook to do so and it says first to calculate the Duty Cycle Value based on the minimum and ...
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Boost converter: using smaller inductance than "typical" application?
I need to boost 3.3V all the way up to 12.0V.
Current requirements are rather small, I only need to power an SSD1309 OLED driver ...
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Schottky diode for low-side GaN FET
I'm working with a GaN FET for a half bridge application. During reverse conduction of the GaN FET, to minimize losses, I have to use a Schottky diode in parallel to the low side of the GaN FET.
The ...
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Hissing SMPS after repair
I have a mixer with a TNY288 based SMPS which wasn't turning on. I've found the problem in a shorted schottky diode on the secondary going to the -12V regulator, unfortunately can't recall if I've had ...
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NCP1654 current Mirror
Regarding the NCP1654, there is a circuit in the IC block diagram that I don't fully understand. Could you please take a look at the figure below and help me understand the blue and red lines?
below ...
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Current regulation compensation SG3524 and right place to place sense resistor
What is the right place to place current sense resistor? As in picture we get traingular wave n position 1, sine wave with highest amplitude on pos 2, smaller sine wave on pos 3 and nearly flat line ...
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LED PSU for pulsed load
I've bought a cheap LED strip SMPS - 120 W / 24 V - with the intention to supply a couple of solenoids (15 W each) and an electronic device (around 4 W) with it. I'll never draw more than 80 W from it....
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Totem pole PFC control
I found a figure that discusses how to control S3 and S4 of the totem pole PFC.
Please refer to the image below.
However, I couldn't find any information regarding the control method used in this ...
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Buck Converter Gain Margin and Phase Margin Review
I am using this IC (MPQ4470) for designing a buck converter (12 to 5 V - 3 A). Below is my circuit.
I am checking the stability of this circuit. My phase gain plot is given below.
My PM is 92 degree ...
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What does float long and float short mean with respect to ferrite core transformer windings? [closed]
I have winding instructions for winding a EE13-06 ferrite core transformer, for secondary it's written 0.23 mm TIW,
no. of wire = 1,
no. of turns = 66,
start = float short,
finish = float long.
What ...
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Inductance of Two Primaries in Parallel
I need to verify the design of a prototype SMPS transformer. The transformer has two primary windings driven in parallel specced at the same inductance value (the transformer manufacturer suggested ...
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PI Controller or Type 2 compensator using SIMetrix/SIMPLIS
I have PI controller build around one OPAM (link:https://www.researchgate.net/figure/Schematic-diagram-for-PI-controller-using-operational-amplifier_fig2_338104251) and I want to simulate it in ...
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Boost average current mode control
I have one question about the bode plot of boost average current mode control.
Below is my schematic, the circuit is stable.
My design is for CCM boost PFC, and the current loop crossover frequency ...
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Power dissipation of synchrononous buck converter cannot be reduced with gate drivers?
For this project, I had to want to reduce the power dissipation (< 2 mW) when the Rload is 54 Ω. These are the two circuits that I have employed.
When I sweep the pwm frequency vs Pdiss (power ...
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PSIM and LTspice Constant On Time Control
I am trying to control a converter with constant on time. I mean the off-time should be changed with the changing of the output voltage. How can I achieve this? I try many methods with using error ...
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Are the poles on the rocker switch placed correctly?
This is a Marquardt rocker switch that worked at first. But the parts where spring all over the floor, then put together again. Now, the switch is no longer functioning. When the wattmeter was used to ...
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Simulation of motor drive IC in SIMetrix/Simplis
I want to simulate a DC motor driver like MIC4606-1 in SIMetrix/SIMPLIS software. The microchip provided only the SIMetrix model of MIC4606-1( Transient model:
https://www.microchip.com/en-us/software-...
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Variable input 208V-600V AC to 24V DC without transformer
The Question:
How can I design a circuit for an automatic transfer switch that accepts 120V-600VAC and keeps some 24V batteries charged (long term trickle charge is fine). P.S. I would like to keep ...
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Buck Converter Output Is Coming To More Than The Designed Value After 3 Or 4 Months In Some Boards
I have a buck converter which converters 12V to 5V,3A. The output of this buck converter is going to a load switch and from the load switch it is going to a connector.
What we observed is that after 3 ...
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Checking the stability analysis of a buck converter using SIMPLIS where to keep POP Trigger
I need to check the stability of below buck converter circuit (12 V in, 5 V out,3A, FSW=500 kHz) using SIMPLIS.
For this I need to perform an AC analysis. During the AC analysis, I need to keep POP ...
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MPQ4470 12V to 5V, 3A output is not simulating as expected in SIMPLIS
I am new to SIMPLIS, simulating this IC for converting 12 V to 5 V.
My first SIMPLIS circuit diagram is given below. My input is 12 V and the required output is 5 V. The load will take a maximum ...
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ZVS loss calculation in SIMPLIS
Below is the Half-Bridge LLC Converter Example from SIMPLIS.
I would like to observe the loss from the low side MOSFET.
I want to compare the ZVS and Non-ZVS conditions.
I am curious about why the ...
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Burning of Resistor in the Clamp Circuit of an SMPS
This circuit has been designed and optimised. When implementing on PCB R3 resistor is burning up. Any reasons or suggestions for this to happen? Circuit is stable and safe when supplied with 190V and ...
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How would an SMPS made using a 555 timer compare with one made with a dedicated controller?
The SMPS uses some sort of PWM to charge and discharge a magnetic element. The controller IC achieves this by using a switching element along with capacitors. While one could theoretically use 555 ...
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Current transformer design guideline
I want to design current transformers with two secondary windings (one for control loop and another for monitoring.) It will be used in DC-DC converter. What are the guidelines to be followed for the ...
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LLC Gain Curve by using SIMPLIS
Is it possible to use SIMPLIS to draw the gain curve of the LLC converter?
Because FHA analysis is not very accurate when the operating frequency is above the resonant frequency.
If it can, what kind ...
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Wider width or more fingers for CMOS transistor to reduce conduction loss in syncrhonous buck converter?
For a project, I am trying to optimize my buck converter to obtain a power efficiency of 87 %. The non-optimized buck converter gives a power efficiency of 86 %.
I try to size my PMOS 'power' ...
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Connection and external components for STM32 SMPS
I have some questions about the connection and its external components for the SMPS step-down converter of the MCU.
The microcontroller I'm using is a STM32H745IIT6. On the datasheet I found this ...
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Absolute minimum current drawn from a DC power supply
I am using a Keithley PWS2721 DC supply to power an ICM7555 timer IC. The datasheet for the IC indicates a typical current draw between 30 - 250 µA (for a voltage range 2 - 16.5 V). The datasheet for ...
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Connecting more than one device to a SMPS or battery or DC supply
Thank you for thinking to answer my question.
First of all what I have.
SMPS, (output 24 V 2.5 A)
Four devices which requires 24 V 1-2.5 A as input to operate.
Note: current drawn from each device ...
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LLC ZVS deadtime calculation
According to the TI LLC document, I can use eq 32 to calculate the dead time to achieve the ZVS in the half-bridge LLC Converter.
below is my spec of half bridge of LLC converter.
the deadtime I ...
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How is an RCD snubber different from an RC low pass filter?
The RCD snubber is used in flyback SMPS designs where AC-DC conversion is carried out. I know that a snubber circuit is used; its purpose is to filter transients. According to my understanding, the ...
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How can switched capacitor converter be useful when its output is not regulated?
The charge-pump converter also known as switched capacitor converter and flying capacitor converter is a type of inductorless switching voltage source i.e SMPS. It can generate a voltage higher than ...
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What happens if input voltage to switching regulator is outside of its specifications?
A switching regulator e.g buck, boost e.t.c requires that the input voltage be in a certain range. Then, it shall use feedback to generate the required output voltage. Fair enough.
What will happen if ...
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LLC SMPS Problem
I faced with a problem in a LLC SMPS which I designed,
The mentioned PS is a 200 W/6.3 VDC, Input is 85-240 VAC (including PFC),
For the output rectifying, I used 4 MOSFETs (IRL8113) as active ...
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How are multiple power rails controlled in sequence for a multi-voltage PCB?
Lets take an example of an FPGA that has these voltage rails:
...
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SMPS for AC-DC conversion
The question is related to datasheet of part DK1203.
The datasheet description is as follows:
The DK1203 is a secondary side flyback type AC-DC Switch Mode Power Controlling IC. With integrated 700V ...
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Switched mode power supply design (II)
The switched mode power supply controller IC contains a feedback loop. The output voltage goes into a voltage divider resistor circuit and the output from this voltage divider goes into the controller ...
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Switched mode power supply design (I)
Using switched mode power supply on a PCB seems to be quite a lot of work since we need to choose so many components and make sure that the PCB layout is done correctly.
This brings me to specific ...
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Why two EMI Y-capacitors in series between primary and secondary?
Y-capacitors between primary and secondary are often used to reduce common mode noise in flyback SMPS, as explained also here.
I have read that two Y-capacitors in series are needed to be compliant ...
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LTspice Frequency Response Analyzer (FRA)
This post is a continuation of this question.
LTspice recently introduced a new feature called frequency response analyzer, see the image below.
The green box shows the symbol for FRA. If you click ...
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Generating an analog sawtooth ramp for PWM
I came across the circuit below:
Source
I can't seem to understand how the circuit works. They even say that one can set the maximum duty cycle. Kindly explain to me how the circuit works. I would ...
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Buck converter inductor selection: maximum switch current limit vs output current
I need to select an inductor for this buck converter. Its output current is 3 A and maximum switch current limit is 6 A. As far as I know, I need to select an inductor whose current ratings (both DC ...
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How to measure the stability of a buck converter using LTspice
Below is my buck converter circuit. How can I check its stability using LTspice?
I need to measure GM and PM.
Is this true that a 30–60 degrees phase margin and a gain margin of 2–10 dB are desirable ...
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CRM PFC frequency drop
When designing CRM PFC, I encountered an issue with the switching frequency. In theory, the frequency waveform appears as expected.
However, during simulation using a tool, I observed a drop in ...
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What are the advantages and disadvantages of feeding DC into an SMPS?
Can I feed DC into an SMPS to get a regulated output? If yes, why? and What are the advantages and disadvantages?
For example, I would like to input 200VDC to an SMPS with an input range of 100-230VAC....
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