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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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0answers
31 views

Buck converter design using MCP1630V

I have already designed a buck converter with the following specifications using an MCP19035: Vin=14V, Vout=1.8V, Fc=63kHz(Crossover frequency), Vref=0.6V, Iout=10A step load High IOH=7.5A step ...
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42 views

MCP19035 buck converter controller

I'd like to design a buck converter using MCP19035, I've gone through the datasheet of this component and and the design procedure using it. In the datasheet, it says that the component provides Two ...
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0answers
35 views

How do voltage and frequency fluctuations affect switch mode power supplies?

I have a high power (6000W) sub-woofer amplifier which has a switch mode power supply. This amplifier only worked few hours before it stopped working and it looks like an issue in the power supply. ...
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37 views

Solar panel voltage with buck converter and mosfets?

If the input voltage of the solar panel as Vin in the picture below. if Vin is in the range of 10 V to 37V.The average voltage value in the node in yellow during switch 1 is on and switch 2 is off is ...
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1answer
51 views

COB lights using 4 aaa batteries

I bought a few COB lights from Harbor Freight, they look like light switches. I would like to hook them up to a wall mount power supply, I think they are wired in series. Also, I would like any ...
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1answer
121 views

RT6224D-based step down circuit yields 0V - why?

We received a set of prototype boards. They have a DC power supply input feeding into a step-down converter, which is built around an RT6224D. It is supposed to deliver 5.0V. The circuit is almost ...
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1answer
51 views

Gain deficit and phase margin at crossover

I went through an exercise of the following specifications: A voltage mode buck converter working in CCM mode works with: \$V_{in}\$ min = 10V, \$V_{in}\$ max = 20V \$R_{load}\$ min = 2.5 ohm \$R_{...
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1answer
32 views

Switching Regulator[AP65211A] Issues: Higher Voltage then expected at minimal load, drops to 0 with small load

I normally just use linear regulators in my designs and this is why... Switching Regulator in question: https://www.diodes.com/assets/Datasheets/AP65211A.pdf Circuit: Board Layout: The problem I ...
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2answers
135 views

Does polarity of scope probe matter when measuring ripple of the power supply module?

Measuring ripple of 28V/12V power supply module across +/- output pins. Does the probe tip have to be placed at +pin and probe gnd to -pin, or it can be reversed? Having inverted readings when ...
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0answers
38 views

SMPS mains hum on guitar rig

My guitar rig consists of Guitar -> Audio Interface (Steinberg UR22) -> Laptop (via USB). I listen to the (processed) audio using headphones connected to the audio interface. ISSUE: When the ...
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2answers
60 views

Direct connection or using capacitor when shorting PSU's DC negative terminal to earth terminal?

I have read and then observed that for reducing the 50Hz related noise, tying the -DC terminal of an SMPS supply to the earth terminal woks well in some cases when. Below shows a direct path by a wire ...
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0answers
41 views

Ripple in output voltage

I am working on an Active Clamp Forward converter. Schematic is given here: Specs: Output voltage-5V Input voltage 26..42V frequency=500KHz Output power=10W It is working fine in open loop, but in ...
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1answer
83 views

SMPS electrical noise issue

1I'm using class 2 medical graded SMPS in our device. So earth connection not recommended. When connecting SMPS to load (contains capacitive touch LCD), touch function is affected by SMPS noise. When ...
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1answer
35 views

Is there a minimum current drain to use LM25011 of TI?

Using LM25011 as switching voltage regulator to power a board with wide range of current drain rates. Input of 24v; Output of 5V; Drain current between 5mA and 1A. Is this component suitable to this ...
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1answer
79 views

Topology choice for wide-output-voltage-range SMPS

I'm intending on building a off line (230VAC), 50W, isolated, constant-current switch mode power supply. This by itself is not a big challenge with the plethora of application notes and examples ...
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1answer
225 views

how to switch to backup battery when power fail?

I have a project running with MCU supplied with a 24V power supply regulated via an SMPS to 9V also, I have Li-ion battery pack 9V how to connector these two sources to run the MCU with battery pack ...
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70 views

500v generation with 24V

I want to generate 500V @100mA from a source of 24V @2.4A. My question is that would it be possible to maintain this current? Any clues please.
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2answers
131 views

How do I connect an LED with floating DC voltage?

I want to connected an LED at the output of 500V DC. This DC power supply is made by 3phase DC rectifier and is floating. I would like to have a display on the front panel of the supply which will ...
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2answers
54 views

Use of the same transformer with a replacement offline SMPS controller?

We have an SMPS that was designed by a third party. The controller, VIPER100, has gone obsolete. ST don't do any sort of direct replacement, but other manufacturers do similar devices or at least ...
2
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1answer
82 views

Relay+SMPS = Noise in RS-485 bus

I designed a board with a microcontroller (Atmega328), 3 relays and a RS485 transceiver. The relays control SMPS LED drivers (Meanwell LPF series). The system consists of 10 boards, each one ...
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1answer
92 views

How to select current for power supply? [duplicate]

I've two step motors with 12V-0.4A each, A4988 as stepper motor driver and CNC shield on Arduino. As I know I should use at least 2x voltage for stepper motors and I would like to know, if I use 24V-4....
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1answer
126 views

Current sensing techniques in SMPS

I have gone through the following circuit provided by microchip technology and I get trouble in understanding the circuit circled in red the the image!! As I understood, this circuit is used as a ...
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1answer
110 views

Ceramic Capacitor whistle in DC-DC Converter

I have designed a 24V Input, 5V and 30W output DC-DC converter (TPS40170) which is working fine under normal conditions. This was approved with an evalboard. But my load is being switched with a ...
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2answers
98 views

AC “chopping” power supply inrush current problem

I've made a simple AC to DC chopping/switching power supply circuit (I'm not sure if it's called that) as shown below. in the left part of circuit (which is the gating/chopping part) when the ...
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2answers
129 views

Problem in IR2112 use

What is wrong in this connection diagram. I had provided pwm with 20kHz and 5volts. But at the R3 I am not getting results
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2answers
111 views

Power Supply : How to keep SMPS always above the post-regulator that follows it

I'm trying to find a way of building a new power supply for my workshop, in order to keep it small and not so hot I will be using a spare xformer to step down mains to 24v and then a variable buck ...
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1answer
60 views

Buck converter design issue

I want to design buck converter for 385VDC to 48VDC for that I calculated the values of component and simulated it with proteus but I am not getting the desired output. What is wrong? PWM has a 20v ...
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1answer
104 views

explain the working of this circuit [closed]

I'm basically trying to understand how this Dc to Dc step-up converter work. please help me.[![dc-dc step-up voltage converter 1v-9v][2]][2] I need to design a DC DC step up converter using bjts. ...
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2answers
75 views

What's a safe method for determining the switching frequency of a blackbox ACDC converter?

My project uses an off-the-shelf ACDC converter that conceals design details from such as switching frequency (or SF range). It's 24 V output rated to 5 Amps. I want to measure it's switching ...
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1answer
110 views

Dysfunctional IRF9540

simulate this circuit – Schematic created using CircuitLab I am trying to build my own SMPS and I was intending on using a P-Channel MOSFET for high side driving the main circuit. The MOSFET in ...
3
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2answers
75 views

What capacitors are proper to use for input of AC DC converter?

I am trying to build an 120 AC to 15 DC @ 200 mA converter using a Power Integrations LNK3206P. Using the full bridge rectifier setup on Table 10 from application note AN-70, Cin1 and Cin2 should each ...
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2answers
123 views

Fixing conmutation for high voltage switching with power MOSFET

I have an issue with a charge circuit for a capacitor as load. I want to switch approximately 400 V DC to charge a 1000 µF 600 V capacitor. I'm using a power MOSFET for this application. I need it to ...
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4answers
110 views

How to Turn off a PIC Microcontroller in high capacitance circuit?

Below image is the input voltage VDD to PIC16F18326. I am turning off (Switching off the mains supply) my circuit at point A (see image). Due to large capacitance at load, which is required in my ...
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1answer
66 views

What is the operating frequency of this IC?

It is the LT3751 High Voltage Capacitor Charge Controller, datasheet. I am trying to calculate the required value for the input capacitor for my application, but the datasheet does not clearly ...
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0answers
247 views

Large negative current spike in N-Channel MOSFET source when turn-off

I am working on repairing a power supply board of a LCD TV (200W power), more specifically, the PFC section (active power factor correction). See schematic (adapted from here): I've replaced some ...
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0answers
47 views

SMPS: Current Mode Control [Sub-Harmonic oscillation] - How to determine ramp when capacitor is unknown?

Currently I am working to charge an DC-link capacitor to prevend inrush currents. I want to charge the capacitor from 0 to 700V using with an Vin of 700V. I want to do this by using an SMPS and found ...
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1answer
97 views

Reactive vs Real Power in DC-DC Converters

I don't understand which form of power, reactive or real, should be dominant in a maximally efficient DC-DC boost converter. As the circuit charges the inductor, the current and voltage will be out ...
1
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1answer
138 views

5V Switching Regulator Problems

I have a circuit with two supplies. A 19v supply for stepper motors, and a 5v supply for driving the ATMEGA644, 3 stepper motor driver daughter boards, a bluetooth LE daughter board, and 2 ws2812b rgb ...
3
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2answers
321 views

LM22678 Unstable output

I am building a voltage regulator with the LM22678-5. I used TI WE-Bench designer to get the component values needed for the regulator: The regulator outputs 5V when there is no load however it ...
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0answers
33 views

Flyback, primary inductance selection for wide output current changes

I would build my first flyback converter. Converter would be designed for 2A max and load device would draw about 100-200mA for most of the time with 1.8A peaks. Peaks would take a little longer so I ...
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1answer
88 views

What does the ripple frequency of a buck converter indicate and how does it affect the DC device connected to its output?

What is the desired ripple frequency for buck converters connected to computers, networking device as power supplies? Can we judge the quality of power supply from ripple frequency? (buck converter ...
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0answers
57 views

Cant recognise a Damaged component of switched-mode power supply

I was repairing an smps ATX power supply I found a damaged component that I could not it recognise. I thought it's a power switch since it was mounted to a heat sink along with tow D13007 NPN power ...
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5answers
181 views

Spec says 7-24V, can I use 25V?

I'm building an IoT device with a Wemos D1 Mini. It should control a relay, and also measure the temperature. The thing is, my only practical power source comes from my garage door opener which I ...
2
votes
1answer
131 views

What could cause my boost converter to output below its nominal voltage?

I'm very new to electronics and I'm building things and experimenting as a learning opportunity. I've put together a boost converter circuit and it works OK, but I've noticed that under larger loads ...
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1answer
33 views

SMPS Transformer - Different Current Densities for Primary and Secondary

I've seen a design sheet of an isolated off-line 5V/2A flyback converter. In the "Calculating Wire Sizes" step the designer uses 4A/mm2 for primary and 10A/mm2 for secondary. This seems quite ...
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0answers
183 views

Make a constant current source using a 700VDC supply at 4A

Goal: Charging a capacitor to 700V I want to charge a capacitor(any value) to 700V using an SMPS (buck converter.) to prevend inrush current. It's important that the system could charge the ...
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1answer
149 views

Boost converter drawing too much current

I am trying to play around with some SMPS boost converters, in order to power my Nixie tubes at around 170V (boosting from 20V to 170V). Yes, I know that there are already existing power supplies that ...
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0answers
45 views

Slope of the Inductor current

this forum is very helpful in the term of power-electronics. I got a question about LT-spice simulation. I want to compare the slope of the inductor current in two circuits.The only difference between ...
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1answer
69 views

Cordless dremel hard wire [closed]

4.8 v cordless dremel. I've got a bunch of different supplies laying around all different volts none exactly right what would be most comparable battery = 4.8v-.7Ah. Supplies I have close maybe ...