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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UC3845 Soft start circuitry
I do not really understand how the soft start circuitry of the UC3845 is really working.
Here is what is explaining:
Here is the architecture of the chip:
I understand that we need a transistor as ...
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Flyback converter simulation in LTspice: discrepancy between Switching model and Averaged Swicht model
I´m trying to make a Averaged Switch Model of a flyback converter for transient and AC simulation in LTspice. I´m following the document "Advances in Averaged Switch Modeling and Simulation" ...
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Tiny Switch TNY289 current limit and di/dt question
I want to ask about how the Integrated circuit decides the proper (di/dt) for next cycle , the voltage across an inductor/transformer is L*(di/dt) the Integrated circuit TNY289 as I understand
it ...
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Output Stage Double LC Filter of a buck converter
I am trying to design a double LC output filter on a buck topology.
I want to set the bandwidth of my converter to be at 20 kHz. The swithing frequency would be equal to 250 kHz. The first resonnance ...
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Phase shift at half the switching frequency of a dc-dc converter
I would like to know if, regardless of the control loop used (Voltage mode control, average current mode control, peak/valley current mode control), there is always a 90-degree phase drop at FSW/2 due ...
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Microcontroller mosfet switch
There are three different processors in my circuit. These are STM32F401RCT6, ATmega328P and ESP32. I want to turn these processors on and off with the switch whenever I want. The circuit I created for ...
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Using VOUT to Power Up a DC-DC Switching Regulator
I am trying to use LM5117 to convert 36V (VIN) to 32V (VOUT) for constant current constant voltage application. It seems the datasheet is saying if the VIN > 14.5V I can use VOUT with a Zener diode ...
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Sampling gain effect in buck converter
I recently learned that there is a phenomena called sampling gain effect in dc-dc converter and I am struggling to understand what this phenomena really is. Could someone enlighten me?
And I have seen ...
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How is clearance and creepage considered in this case? [duplicate]
I'm making a high voltage PCB where there are 2 grounds - one is HV ground (HV-) and the other is the microcontroller ground which is isolated. HV+ is at 100VDC. How do I consider the clearances and ...
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What is the use of additional CC-CV circuitry in an Isolated SMPS(LLC converter) when feedback is already present? [closed]
I was designing an LLC converter which has an output of 16V and 20A (320W). The chip manufacturer said that the particular chip (chip has both half bridge primary control and magnetic coupled feedback ...
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Clearance and Creepage for the Nets
I have made the schematic of the double pulse test setup and have also highlighted the NETS for the PCB layout. Test will be done at 100VDC (HV+) and current ~ 30A.
Please suggest where the clearance ...
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Output stage filter of a buck regulator and ESR
I am trying to design a two LC stage output filter on a buck converter. And as the needed peak to peak ripple has to be pretty low ~ 1 mV, the overshoot and undershoot need also to be pretty low, I ...
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How to decide the number of layers? [duplicate]
I am new to PCB design and I want to understand how exactly we should select the number of layers. I just know more layers helps us with making the routing easy but I don't understand what is power ...
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How to decide number of layers?
I am new to PCB design and I want to understand to understand how many layers to choose. I just know more layers helps to make the routing easy but I don't understand what is power plane, ground plane ...
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BD8306MUV and idle current
I need to generate 3.3 V from a 3.6 V battery to power a sensor. I choose the Rohm buck-boost converter BD8306MUV for that, but I discovered that it consumes nearly 5 mA of current in idle mode ...
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How is voltage regulated on the output of this supply? [duplicate]
This lil' piece of eye candy is a portion of an SMPS schematic. How do the TL431 and optocoupler work together to regulate the output voltage? Moreover, and I'm assuming this plays a role in it too, ...
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Direction of current flow in SMPS flyback converter doesn't make sense
I'm analyzing this Astrodyne TDI 15W SMPS and I'm confused as to why the dot on the secondary is on top. I calculated the secondary voltage to be 120*(3/70) = 5.1V and this made sense given the ...
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Double Pulse Test setup layout consideration
I am new into PCB Design and wanted some suggestions for the layout for double pulse test.
Regarding placements of the components (inductors, capacitors, gate driver, MOSFETs)
How many layers? 2? ...
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What is the difference between voltage mode control and current mode control for SMPS? [closed]
What is the difference between voltage mode control and current mode control for SMPS? I also wanted to know what kind of modelling techniques are used model these controls (i.e. average models... etc....
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Which is the more important switching parameter in MOSFET datasheet? Turn on/off/delay times or Input/Output/Reverse capacitances?
I see both capacitance and timing details mentioned in the MOSFET datasheets.(Ref:)
Which one should be considered for comparing the MOSFET switching performance between 2 MOSFET part numbers?
Note: ...
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Is it a good idea to place SMPS output capacitor close to inductor?
Is it okay to bend the output electrolytic filter capacitor right next to my SMPS inductor?
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How to choose the value of the slope compensation?
I do not understand how RICHTEK as chosen its slope compensation. The article is here. The parameters of the buck are the following:
Vin = 12 V
Iout = 3 A
Lout = 10 uH
Fsw = 340 kHz
Vout = 3.3 V
The ...
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How can I separate the switched-mode power supply from the RF PCB to avoid interference?
I want to construct an autonomous RF PCB module powered by a solar panel. To achieve this, I have obtained solar harvester and battery charger integrated circuits (ICs) designed to charge a Li-Po ...
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Circuit to convert 14.8v battery with max 4a discharge current into 12v, 9v and 5v output?
I am making a robot with multiple devices mounted on top. I am planning to buy either a 14.8v or 11.1v Li-ion battery which has internal BMS limiting maximum discharge current to 4A. Now I need 9v for ...
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Identifying SMPS transformer
I have a SMPS acting weirdly and I believe to be caused by its transformer. I need to find a replacement but I'm having trouble identifying it.
The marking has too lines: 1st containing the VDE logo ...
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Why should I route the feedback trace under the output capacitor?
I'm looking at the TI TPS5430DDAR. In the reference circuit, it has a note to route the feedback trace under the output filter capacitor.
It feels like it would be much more simple/direct to not do ...
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TNY268 switch when connecting HV then stop switching, not sure of EN/UV correct operation
I am trying to design a simple power supply using TNY268, I connected the circuit as follows:
Where the input of the attached schematic is connected to the output of a bridge and smoothing capacitor, ...
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SIMPLIS - Buck CM from C. Basso Website
I took from the website of Christophe Basso a simplis simulation. I have some questions about it to be sure to understand it. Here is the schematic of the simulation:
It is a current mode buck ...
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SIMPLIS - Pop trigger and evolve pop trigger
I am new on SIMPLIS but it appears to be the best simulations tool for smps.
I just have a question : What the difference between this two POP trigger ?
I found it on the RICHTEK Website. But this is ...
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Simple forward converter - strange demagnetisation
I am trying to build a simple forward converter. After MOSFET turns off I am demagnetising to 100 µF cap on secondary side. There is about 1 µs core doing nothing and after that demagnetisation starts ...
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Voltage spikes on switch-mode power supply Vout when disconnecting barrel jack
I have a fairly simple circuit that uses a DC/DC converter (Traco TSR 1-2450E) to generate 5V for my microcontroller board (D1 mini or similar) from a 12V wall wart. I used the TSR 1-2450E because I ...
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Confusion in number of turns and strands in flyback transformer
I am designing my own discontinuous mode flyback transformer and am following the book Transfomers and Inductors Design Handbook by Colonel. Wm. T. Mclyman. I have used all the equations of the ...
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Can someone please explain this circuit? SMPS, Bridge Rectifier, Transformer
What do these optional components do?
Schematics: https://crtdatabase.com/crts/jvc/jvc-bm-h1300su
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What transformer should I use for high power switching? [closed]
I'd like to build a high power switch mode power supply. I'm still not entirely sure how to do this, but I am playing around with some circuits for now.
My thoughts was to have input voltage (wall ...
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How to generate 0-150V adjustable DC output? [closed]
I wish to generate a voltage range of 0 - 150V output @ 2A Max to drive an actuator, and I don't really have a lot of great ideas at this point.
I have 2 power sources available, one is 220V AC, ...
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EMI filter attenuation requirement for a buck converter given EMI compliant AC-DC converter
In my application I have an off the shelf 600W 72V AC-DC converter that generates the main DC bus that powers a custom board that houses a 72V input, 9A output buck converter switching at 330kHz. A ...
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Connecting secondary ground with primary ground
My system must be made of 2 DC/DC converters and a battery (safe voltage level). I already have a DC/DC converter that I bought on internet. It is the following. It is an isolated DC DC converter. I ...
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How can I boot a switching power supply driver/oscillator IC?
I am trying to design a simple switching power supply. The idea is to produce a square wave using an NE555 then through MOSFET or BJT provide the pulse to switching step down transformer. My problem ...
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What connector pin header can I use for high voltage?
I am making a PCB for a double pulse test setup. What connector pin can I use on my PCB to connect a high voltage DC supply for the HV+ and HV- connections?
Voltage ratings: 100VDC and 800VDC.
The ...
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Right SMPS for gate drive in power mosfet
I am building a 48v, 2kw sinewave inverter based on EGS002, in order to drive spwm & control circuitry, I need to step down 48v to 12v.
Interestingly I found Hilink's 3w (0.25a) and 10w (0.83a) ...
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Balloon inflator rocker or micro switch stops working
I designed a balloon inflator that uses a 120v, 6.6A, 800w motor with a power load of 700 and unload of 772 and it uses two types of switches one is a micro switch (10A, 125v)used on the nozzles for ...
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Generating a biphasic pulse
I was trying to generate a biphasic pulse for TMS application. I was referring to this website.
The waveform is given below.My circuit implementation is described as follows.
I am making a flyback ...
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Diagnosing submersible 24 VDC pump on SMPS
I connected a submersible 24 VDC, 1.2A water pump to a constant voltage 24 VDC 100W LED Power Supply (SMPS). As my user name shows, I have many of these LED power supplies in store. That's why I used ...
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Parasitic inductance when probing high frequency signals with MMCX connectors?
I am using an oscilloscope to probe some high-frequency circuits (a SMPS). On my circuit board, I have installed some MMCX connectors to connect my probes to. These MMCX connectors have a short ...
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Isolation Topology in SMPS
I have been researching SMPS designs as a hobby recently and finally have the courage to build one for theoretical and practical understanding. I have chosen an isolated design looking at several ...
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RCC SMPS Regulation
Could someone explain how the auxiliary winding controls the output voltage on the secondary winding?
For instance,
How do the zener diodes function?
How do you calculate the output voltage as a ...
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Continuous and discontinuous mode flyback Confusion
I was looking at the construction of the flyback transformers and found its two types the continuous and discontinuous mode. I have slight confusion regarding that:
Is the circuit designing of the ...
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Flyback transformer with no load situation confusion
I am having a slight confusion in the no load situation of the flyback transformer. Consider the high pulse at the gate of the mosfet turning on the switch. At this case the current will increase ...
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Suggestion on core calculation with air gaps
I was working with the SMPS transformers and found a transformer that had a small air gap already there and was used in charging system of a battery. I wanted the ferrite core for my own transformer ...
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Switch Mode Power Supply / GPS - Filtering+Shielding
I'm working on my first RF PCB, for GPS/ GNSS and am particularly concerned about Noise/ Interference. Hopefully someone can shed some light, or point me toward a similar thread?
It's worth noting ...
