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 disspate power through a transistor.

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SMPS with two outputs ,12v 3A(max) , 24V 2A(max)

Hi all , I am new to designing circuits. I am building an SMPS using the fairchild Semi FSGM300N Power switch. here is the datasheet http://www.farnell.com/datasheets/1526530.pdf they have given a ...
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37 views

Switching Power Adapters dying, How to test them and can they be fixed? [closed]

I am hoping someone can help me solve a bit of strangeness with my power supplies and switches. I think I am asking a question that is relevant to this exchange if not please let me know. There is a ...
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4answers
183 views

What makes the transformer in a SMPS smaller?

I'm reading up on how SMPS's work, and all the videos says that after the high-volrage chopping stage, a smaller transformer can now be used, because of this high frequency. My question is, how does ...
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1answer
75 views

Is it possible that LED power supply is interfering with my webcams USB connection?

Not sure it is a right place to ask this question but I'm pretty out of options. I'm building DIY home-studio LED lights out of multiple 12V LED bulbs. I'm using a dedicated power supply connected to ...
1
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1answer
85 views

How does the PWM from MCU get translated into a output voltage as in Power Electronics [closed]

Background: I am preparing for a full-time employment starting in May. I am coming from a computer engineering background so I only have some working knowledge regarding EE. The job duty is Firmware ...
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1answer
52 views

SMPS --> TDA8920 | +V GND -V op-amp

I'm thinking about buying a TDA8920 audio amplifier and power supply and I need some help buying the right PSU. See edit below. So here's what I know. L (AC) = Live (Brown*) N (AC) = Neutral (Blue*) ...
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55 views

Why does this voltage error amplifier output always reach its saturation voltage?

Why does the voltage output of both amplifier (Vm1 and Vm2 as shown in picture) always reach its saturation voltage?
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62 views

High current SMPS transformer

I would like to have some tips concerning DIY winding of SMPS transformers. Let's consider the following example (for reference only): Input: rectified 230V AC (mean value: 310V DC on the DC-link ...
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2answers
54 views

Optimal PWM Frequency for EMI & EMC

I am planning to design a 65W power supply which will use a PWM frequency of around 100kHz. I am specifically concerned about conducted EMI (not as much about radiated for now). I am currently ...
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1answer
100 views

Simulating SMPS with ideal switch in LTSpice?

Yes, this in a portion of a homework assignment (hence the idealized and slightly asinine problem statement). Aside from solving the circuit (which I have done), I am supposed to simulate the ...
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0answers
48 views

Hold switch trigger delayed

I have a small battery driven, microchip controlled project where I use a rotary encoder for toggling/setting various settings. Mostly software based as that is what I'm more familiar with as of yet. ...
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2answers
183 views

How does power dissipation for surface mount components work?

I know that with usual through hole components we can attach heatsinks etc. But how does it work with surface mount components? Is having a copper plate around the component the way to go? How do we ...
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1answer
175 views

Clean DC power design for very high precision circuit

We have been designing a very high precision control circuit for quite a while. And we are thinking to make it much easier to use, which is to get rid of the Lab DC Sources and use AC to DC switching ...
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2answers
79 views

SMPS, output ringing?

I built an SMPS (see here for details), and so far it's been working good. But I noticed a strange oscillation (or ringing?) at the output. Here's what it looks like, with a 4 amps load: Now, ...
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2answers
201 views

How to filter out the mains power supply spikes?

I'm purposely dropping AC from its normal levels (230VAC @50Hz) just to analyse the behaviour of a DC motor drive board that I have. When the AC mains voltage falls below 180V, the 7 segment display ...
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2answers
194 views

Is this a good layout for a 5A buck converter?

I have updated this question with the suggestions in comments and answers. Make sure you read everything. I want to make a PCB for a switching regulator (buck converter). It's a TL5001-based ...
0
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2answers
88 views

Driving MOSFET of 3.3 V gate voltage with 1.8V PWM pulse [closed]

My micro-controller is giving a PWM output of 1.8V. I need to drive a MOSFET with typical gate voltage of 3.3V. I am planning to use two cascaded switches (NOT gate configuration). I have checked ...
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32 views

L4970a output oscillates when load is removed

I need the following: 24V vehicle input. Allow for 28V. 13.8V @ 10A output. I used an L4970a. My circuit delivers the load, no problem. On initial switch on with no load, the output is stable. ...
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2answers
76 views

Increase voltage output by connecting 2 PSU channels together

I have a 240W 24V switching power supply. It's a cheap chinese psu so there is no specification, only the info on the ebay page. It has 3 dc output channels and they seem to be individual channels ...
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0answers
27 views

How can I test a 3rd party Open Frame SMPS power supply for use in Industrial Environments?

I am building a PCB for use in industrial automation equipment. My PCB uses a 12V DC (500mA) input which I get from a 3rd party SMPS. The SMPS converts the 220V AC to 12V DC (rated at around 1 Amp). ...
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1answer
66 views

Discreet Opamp SMPS design

I'm an electronic eng student and for a design project I need to design a switch mode power supply. Catch is I can't use any off the shelf SMPS ICs, only opamps and logic. Rough specifications are ...
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2answers
73 views

What transistor or combination of transistors should I use to make a fully controllable AC switch?

Suppose I want to switch AC. I want to control (allow, prevent, or interrupt) current flow in either direction. SCRs won't do because I want to interrupt current, and I don't recall seeing many IGBTs ...
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1answer
150 views

How do I source an Audibly noiseless (< 3dBA) power supply?

This is not a shopping question; this is a "what is the best way to solve this problem" question. To power a medium-size project, I'm looking for a 15W/12V board mount power supply, taking mains AC ...
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1answer
76 views

What benefit is there in synchronizing my switching supply to the system clock

Working on a power supply design, some of these integrated buck/boost all-in-one dc/dc switching supplies have selectable switching frequency and some can synchronize to an external clock. What ...
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2answers
74 views

What PWM frequency to use on SMPS

Just to give a little back ground on the project - I am currently building a buck converter linked up to 2 * 250W solar panels in parallel, then use an MPPT algorithum to track the max power. I will ...
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68 views

Can switching step-down regulator loaded with idle LDO consume 6mA @ 6V?

I'm struggling to understand where 5.7mA may be leaking in this very simple circuit based on ST1S10 step-down regulator and LP2985IM5-3.3 LDO: Link to full size image Long story short: ST1S10 drops ...
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3answers
325 views

Switching 60V with 3.3V microcontroller at 50kHz - 1MHz

I'm playing around with some switching mode power supply things. For this reason, I'd like to switch the input voltage with a microcontroller, from the PWM output or other output pins. The specifics: ...
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1answer
97 views

Can the discharge when plugging a laptop to a power outlet can do any harm?

In this question the OP ask if (s)he should connect a power source into a power outlet first or into the laptop first. While the question has been closed, i think there is a very valid point to ...
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2answers
94 views

What are the effective power limitations of the flyback converter topology, and why?

Looking at several different isolated converter topologies, flyback looks like it's the simplest at first glance. There's only one switch, so there's only one driver, which (all other things being ...
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2answers
114 views

synchronous buck ls-FET switching losses and dead time minimization

I'm designing a Synchronous buck converter. I'm having doubts regarding the following: In the rectifying period of the converter, using a Schottky diode in parallel with the low side MOSFET will ...
7
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2answers
372 views

Help identifying pwm controller “67A”

I am repairing a battery charger that uses two power supplies. TH20594 (couldn't find any info on that either) controls the primary PSU, while the mysterious chip controls the bootstrap/standby supply ...
2
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2answers
165 views

3 SMPS in one board

I'm doing a PCB where there are 3 SMPS: one boost(12v to 48v, 1 amp max) and one buck converter(5v to 4v, 4 amps max) functioning at the same frequency(same timer in microcontroller). the other ...
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1answer
148 views

Why do capacitors across my FETs minimize ringing/distortion?

I'm designing a 24V to 350V DC-DC Converter based on a H-Bridge. The power requirement is 500W and the circuit operates at 20KHz. The design works fairly well and I've achieved about 90% efficiency at ...
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1answer
127 views

What is the hardware/device that can switch a 5V and 12V (simultaneously) PC power supply lines?

What I want to do is to switch the power supply lines (5V and 12V) for a hard drive. The 5V line is meant for data transmission, and the 12V is for the spinning disk DC motor. I would like to control ...
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1answer
58 views

Power rail design from Li-Polymer battery chip output

Case: I am building a battery driven device and so far it seems like I will be using the MCP73871 to provide my device with battery power and charging via USB. I need to regulate the output from the ...
2
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1answer
159 views

Audible noise in DC-DC buck converter

In my design, I have a +3.3V SMPS that provides power to digital circuits (microcontroller, EEPROM, etc.). The microcontroller allows applying a 100Hz PWM signal with variable duty cycle and with an ...
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2answers
112 views

Reducing Voltage Ripple in a Switching Converter.

I used TI's workbench to design a simple 24 to 12V @ 6A. I have it built in a PCB board, but I started doing some power measurements and notice the output voltage ripple is quite high at loads bigger ...
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0answers
70 views

Hobby King 30A ESC 3A UBEC AS a voltage regulator

I wanted to efficiently step down 11.1V into 5v for my raspberry pi so i ordered (after reading many forums suggesting) this 5V UBEC thinking it would be simple switching regulator with two wires ...
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3answers
527 views

What is wrong with this simple SMPS?

I've been reading up on power electronics lately and as a challenge (and also a learning exercise), designed my first switching power supply - a buck converter in this case. It is intended to ...
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1answer
91 views

Cheap homebrew lab PS; need verification of magnetics for toroid

A sixteen state state machine made with an sram and max7004 cpld is a 200khz osc that drives the FETs for the chopper in four switchers. A low end PIC can modify the contents of the SRAM to change ...
2
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2answers
89 views

What is the need for an inductor coil in a smps-buck converter?

Here is the figure: All tutorials have an inductor in smsp-buck. But when I simulate without an inductor I see a similar plot. Why not use only a capacitor?
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3answers
195 views

Using an OEM power supply

I am trying to use an 12V OEM type power supply to supply 12V to stepper motors through an L293 h bridge in an Arduino powered circuit but my current setup starts burning all the negative wires and ...
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2answers
223 views

Convert 48V battery bank to 12V for boat appliances - Inefficient?

I need a 48V bank for an electric motor on my boat. I also need 12V for my appliances. Obviously keeping both a 48V and 12V bank would be most efficient but the space required and cost of maintaining ...
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2answers
136 views

Paralleling of 2 power supplies with different voltages

I have 2 full bridge dc-dc converter from 12 to nearly 170 volts. each one are designed to 250 watts... I am designing the transformers and is very complicated to make exactly equals by homemade and ...
3
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2answers
200 views

Why have atx power supplies need selector voltage?

I am studying various ATX power supplies schematics and don't understand the need of the voltage selector as switching power supplies work at range of voltages. In most schematics i see the 110V line ...
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1answer
83 views

How to vary the supply voltage for Xilinx Virtex-5 FPGA ML501, ML506, and ML510 boards?

I'm trying to do an experiment to see how different supply voltages affect the frequency of ring oscillator and the reliability of SRAM cells. I have access to a couple of Xilinx Virtex-5 boards, ...
5
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4answers
281 views

Cause of diode failure in step-down switching mode power supply

In a basic switching step-down voltage regulator design (as shown in the picture below), what could possibly be the main cause of a short-circuited diode failure (D1 in the picture)? A little ...
2
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5answers
464 views

1.2V, 3.3V, and 5V small power supply design

Problem: I'm attempting to develop a power supply for a system that needs 1.2V, 3.3V, and 5V from mains 120V 60Hz. I have never ran into needing all three at once and am curious if anyone knows of a ...
0
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1answer
152 views

0-24V 0-47A DC-DC Converter

I have built a 12/24V 47A DC Power supply following this guide. It works well for running my battery chargers, but I'd like to make it a CCCV supply from it for my projects. What would it take to ...
0
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2answers
110 views

Switching power supply -V

As you could see from the image below i want to understand what is the -V in a switching power supply unit and where i can use it?