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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How to pimp a cheap power supply

I'm building a small class D amplifier: some op amp circuits for pre-amplification, a pwm modulator based on a dsPIC, some power buffers for controlling the gates of an h-bridge power stage, and a LC ...
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132 views

Inexpensive circuit architecture for power supply voltage adjustment?

This is not a sourcing question; I don't need part numbers or manufacturers. Most DC/DC converters (LDO, buck, etc) with an adjustable output voltage have you set that voltage using a resistor ...
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can switching regulators cause interference on wifi based circuits?

I read that buck and boost converter due its switching mode produces too many noises compared with linear regulators but it is more efficient. Can those those noises cause interference on boards with ...
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45 views

Measuring switched mode power supply efficiency accurately for high currents

I hade implemented a switched mode power supply: * 1.2 kW * Input: 12 VDC, 100 A * Output 5 VDC, 240 A I need to measure it's efficiency (power loss/total power) by accuracy of 1%. In other words: I ...
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99 views

Transistor PWM Generator (No ICs) for practical application

I want to produce a good quality PWM signal with transistors(BJTs, FETS, etc..). I do not want to use an IC at all(learning to use transistors properly). I'm currently using a BJT Astable Mutivibrator ...
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75 views

Use of relay 5V instead of 3.3V

We are currently designing a system which will use a relay, a MCU and a sensor (powered in 3.3V with 100mA max current consumption) + a few LED (2.2V type). it will be powered by a 9V battery After ...
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46 views

Mini Workbench Adjustable Power Supply

I'm trying to design a mini workbench power supply to use for small electronics that is powered from the 12V rail of an old ATX power supply. I want it to be able to provide an adjustable voltage of ...
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59 views

Is this a good layout for BQ40Z60-based battery management unit?

Could you please take a look at board layout and tell is there some stupid mistakes. I tried to accomplish the following characteristics: Max discharge current: 10A Max charge current: 5A Charge ...
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39 views

Using 1:1 Transformer for High Side Switching

I'm working on a 2-sw Forward Converter with isolated input and output. The design is complete on paper, but I still have a problem in my head: High side switching. The question is, can I drive the ...
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60 views

schematic symbol from power supply, two triangles pointing together

What does the symbol marked Z1 (two triangles pointing towards line) represent in this schematic?: This is coming from the reference design on page 10 of the LD7550-B pulse width modulator ...
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95 views

Snubbing DCM (nonsynchronous) Buck converter

FINAL UPDATE: I've posted an outcome report below. I'm very satisfied with how this has come out and I learned a lot in the process. More details and before/after shots in the answer below. Thanks to ...
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75 views

Determining the input capacitance for a SMPS [closed]

I'm attempting to layout a SMPS using the LTC3703 chip, however the datasheet doesn't talk about the AMOUNT of input capacitance, just that it be low esr. However, it does talk about "bulk ...
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82 views

What's wrong with my SMPS circuit?

I've proto-typed a switch mode power supply with variable voltage and current control using a MAX1763 IC. I've powered it on and for the most part it works great, I can control the voltage using the ...
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1answer
44 views

LM2596 random shutdown

I'm using a LM2596S-12 to regulate 36v DC input to 12v with custom PCB. I've made 12 boards and all seems to work initial. Out of the 12 boards, 3 of them have random shutdown. During shutdown, the ...
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134 views

How practical are these land patterns for connecting components in a SMPS?

Was reading this app note from Linear Technology: PCB Layout Considerations for Non-Isolated Switching Power Supplies and on page 7, there is the following image. Are the desired connections ...
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81 views

Step up SMPS with unrealistic voltage output with a 100W LED COB load

I got some 100W LEDs to make a lamp, realized with a boost converter I could use an old ATX power supply and bingo I'd be fine. It worked at first, until I didn't like the color so I decided to ...
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2answers
43 views

Sizing of and Type of Power-loss / Brown-Out Protection Capacitor

I found a few resources and this question here: power-loss protection I'm using an MCP16301 step down regulator to turn 12v to 3.3v I'm having trouble determining I in this equation: C=I×t/ΔV with ...
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91 views

SMPS PCB Layout

I am using a couple of SMPSs (MPM3610) on a 4 or 6 layer PCB. The recommended PCB layout seems to use solid copper regions to connect the design together. Should thermal-reliefs be used on the ...
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79 views

Voltage Divider?

I am designing a piezo micropump driver that feeds into a piezo electric transducer that mists a liquid. Both of these designs have been testedindependently and now its time to integrate. BST of ...
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70 views

External capacitor sizing on power supply

First off, please excuse my electrical ignorance as I am a mechanical engineer stepping outside of my boundaries. I am designing and building a servo motor (~180W rated power, PMDC) driven arm system....
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41 views

SMPS acceptable output ripple voltage - standard

After I received many suggestions in my last question to use a SMPS instead of an LDO I looked further into this matter. While checking different options (cost is my main concern) I checked some IC's ...
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27 views

What are SD/SS, delay, and flag pins on LM2596?

I'm studying the TI datasheet for an LM2596. On page 4, at the top left in section 7.1 Absolute Maximum Ratings, it mentions: \$\overline{\mathrm{SD}}/\mathrm{SS}\$ pin input voltage (6V) Delay pin ...
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95 views

low pass filter

I am working on a data acquisition system and i wish to get data from a pressure sensor . I have designed an analog circuit based on information i have collected which consists of an Instrumentation ...
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1answer
67 views

Is possible to implement this op-amp split power supply design? [closed]

Hi all, I have a op-amp charge pump circuit that could produce up to 3A 1000Hz AC current regardless of load. This current is used to test a battery (V1 in the image). The weird part is that I have ...
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23 views

Achieving PWM wattage control w/o causing overcurrent fault?

I'm working on a project where I need to create a very compact PCB for a vaporizer. The target maximum power output is 15W. Currently I'm planning to use a TI TPS61088 boost regulator to boost a ...
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3answers
299 views

What is a clamped inductive load?

As I'm reading about switch-mode power supplies (SMPS) I keep coming across the term clamped inductive load. You'd think there would be a clear definition that would pop up as the first Google hit, ...
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41 views

When do I need separate MLCC (input) and AL-ELEC (bulk) capacitors on my SMPS design?

I've been studying the specification of input capacitance for switching converters. I have a related question here that provides more background. In my research into the topic I came across TI ...
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1answer
60 views

Is it useful to think of SMPS input capacitance as part of an LC filter?

I'm at the stage of learning about switched-mode power supplies that I'm focused on understanding the role of input capacitance. Just for background, I'm working with a buck topology for this ...
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37 views

Voltage regulator bypass capacitor placement

At both the input and output (especially the output), I need to place several bypass capacitors (all MLCC). The datasheet for the voltage regulator seems to suggest that using a 10uF on both the ...
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430 views

Is “catch diode” the correct term to use in SMPS context?

UPDATE: Ok, two good answers, I've chosen the one with more votes as the "right" answer, leaving it to the wisdom of crowds to choose between two fine choices. For anyone who cares, I think I'll ...
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1answer
61 views

Step-up converter for 20 mV input

For an experimental thermo-electric generator (TEG), developed by a colleague for low-power energy harvesting, it is possible to achieve an output power of 400 uW at the maximum power point. The ...
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122 views

What is the principle of operation of this power supply?

I bought this power supply off Amazon, it is described as 5 Volts DC 60 ampere. I was able to adjust the output so it produces 5 volts at its terminals. Here is a link to where I purchaed it from: ...
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What causes this knee in my MOSFET drain voltage drop?

FINAL UPDATE: Understand a previously mysterious power MOSFET switching waveform wiggle! @Mario uncovered the root cause here below, distinctive to so-called VDMOS devices, typical of many power ...
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46 views

Battery Charge and Discharge time for constant voltage charge battery, and how to know if its fully charged

In my Project I used below battery and a battery back SMPS. Battery Type:- Sealed Lead acid , Volt:- 12V, Ah:-7AH Charge parameters:- Constant voltage charge with voltage regulation Standby use 13.6V-...
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1answer
43 views

Efficient low current buck controller topology

In SMPS there are two sources of loss: parasitics, and the controller. Usually, the load consumes more power than the controller, and the parasitic losses dominate. I have the opposite situation. I ...
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66 views

Universal 3.3V & 5V power source for small device

I'm working on a hobby project which combines two modules that require 3.3V @ 130mA and 5V @ 100mA power sources. I want to make my device work at wide range of power sources - from single 3.7V ...
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89 views

What determines the output voltage of this SMPS?

This website http://danyk.cz/impulz4_en.html says that the output voltage is due to the zener diode that has a forward voltage drop of 18V. But zener diode is just a clipper that regulates the output ...
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41 views

CV or CC battery charging via SMPS module

I am using attached SMPS module, it has battery back up UPS function. I read the datasheet and I couldn't find information what type of battery charge scheme I need to use. Should I use constant ...
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101 views

switch off on 5v, on on 0v [closed]

i have a 2.4 tft lcd shield for arduino. I want to turn backlight off and to light it using the reset button from shield. This button outputs 5v when not pressed and 0v when pressed and led backlight ...
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62 views

What SMPS topology is this?

I came across this SMPS topology that I don't recognize. It looks sort of like a combination of a buck converter and a boost converter, but I can't quite figure it out. I haven't been able to find ...
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38 views

Considerations for switch mode power supply with microcontroller and sensors [closed]

I'm fairly new to this forum and the entire field of electrical engineering. I have a microcontroller (Atmega328P) project that includes a current sensor and several radios (900Mhz-2.4ghz). It is ...
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1answer
55 views

Modifying switching power supply to produce any voltage(s)

I have few units of 24V 3A output smps power bricks. I'm planning to mod one of this to generate 12V at least at 5A for my LED strips. My idea is to tap two wires from the secondary winding of the ...
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138 views

Two 12v Power supplies in series?

Is it possible to use my (3d printers 12V 20A power supply) in series with 12V unknown amperage pc power supply to gain at least 24V 20A for my printers new hotend?
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85 views

Does a switching supply always need load

I'm looking to use a switching supply from an old computer for a project. The project runs a motor that turns on and off based on a timer, powered by the switching supply. Do I run any risk running ...
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1answer
46 views

SMPS Short Circuit

I am using an ATX SMPS to power my Orange Pi Plus 2 via 5V supply. It worked fine for a couple of days without problem until yesterday. I happend to connect my audio amplifier TPA3116 which worked ...
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1answer
80 views

Battery Charger using a buck converter

I'm designing a Lead Acid battery charger with 3 stages. For the 2nd stage (constant voltage stage) as it is written in literature: the voltage applied on the battery must be dependent on temperature. ...
2
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1answer
64 views

How to stop leakage of mains adaptor [closed]

For the past year or so I have been using a mains to 5VDC adaptor to charge various devices. Everything is working perfectly fine but this charger I think, has a noticable leak to the low voltage side ...
4
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3answers
188 views

Benchtop power supply current limit on MC34063 switched-mode power supply

I'm currently building a power supply using a MC34063 IC. I have used an external n-channel MOSFET for switching the high current used to drive an LED pair. simulate this circuit – ...
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42 views

LT3680 switcher output doesn't have regulation under no load

I have a switcher circuit based on LT3680. I implemented the typical circuit shown in the datasheet in a well laid out 4-layer PCB. However, I find that the input voltage is present at the output at ...
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1answer
47 views

Need help identifying power transistor 11SL60H

Hopefully someone can help me identify what these two transistor are. I believe they're toast as the y open across all pins. Normally I can google parts like these but this one I get absolutely ...