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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isolated voltage

I am looking to add an isolated 10-12V supply capable of producing ~200mA to an existing circuit which has 5V and 12V rails available on the board. I would prefer to use the latter (12V) as it can ...
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26 views

Can a joule thief circuit be made to both boost or buck an input voltage?

In the normal run of things I would use a 555 or something similar to generate a PWM signal as the base for my power supply. The caveat is that for my application I need continuous operation from an ...
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34 views

diode protection for output of smps [on hold]

I have been asked for a diode protection in the output of SMPS. Can someone explain how tom connect the diode and the specifications of the diode to be connected. I am using 24VDC, 20 Amp SMPS Thanks ...
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58 views

Can I use a TVS diode to remove spikes in SMPS?

I have an almost working Half-Bridge SMPS that has some ringing in the output like this (not the real output, just and image I found): I have eliminated almost all the oscillation using a snubber ...
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23 views

Switching Power Supply Not Working TI TPS54331

Let me preface this by saying this is my first switching power supply design. With that said I used TI's online tool to auto generate the schematic / values of the resistors, caps etc.. What could ...
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53 views

12V -> 110V@0.11A DC/DC. what topology?

I need to design a step-up converter with following specs: vin = 12V +/- 10% vout = 110V iout = 0.11A non-isolated The most problematic constraint is that the converter must be very compact. ...
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3answers
107 views

Coiled Nichrome wire 220 volt

I want build a furnace using firebricks and coiled nichrome wire. The dimensions of the furnace are 1×1×1 m. I need temperature inside the furnace to be 650°c. I have 220 VAC mains. ...
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1answer
47 views

Can a CM choke be used to suppress common mode current in a DC circuit?

I have a setup with a DC/DC converter like in the figure below. I need to minimize common mode current on the supply input. There are no other connections besides Vsupply + and - and Rload + and -. ...
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19 views

What are the switching frequency and inductance implications of IEEE 519?

A simple power supply composed of a diode rectifier and filter caps has significant harmonic content. The line distortions caused by such equipment can have impact on other power utility customers and ...
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21 views

Unregulated Forward Converter for Galvanic Isolation

It seems to me that I could use an unregulated forward converter to provide galvanic isolation and then use a DC-DC converter to provide the voltage regulation. I'd use a two switch forward converter ...
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1answer
44 views

AP5002 step-down switching regulator loop stability

Problem, parameters I have an 5V output power supply, with 2S LiPo input (6-8.4V), implemented with AP5002 (PWM control 2A step-down switching regulator, docsheet), and for the life of me, I can't ...
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4answers
2k views

Spacecraft Power Supply Frequency

I know that aircraft sometimes employ a 400Hz AC system to save weight on transformers, so I'd imagine that spacecraft might employ a similar technique. I'm wondering if anyone in the aerospace field ...
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1answer
87 views

Choosing a linear regulator vs. switching regulator for low-power application?

I have a 3.6 V battery that I want to regulate down to 3.3 V and 1.8 V rails. I have already asked about the configuration of the two rails here. My question here however is whether I should use a ...
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2answers
55 views

Create a Time-Variable Dc Power Source

For some reason, I need a Time-Variable DC power source that changes it's value according to time. I need this changing of value to be controllable. I'll put it this way : Say I have a 12 volt DC ...
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1answer
71 views

Driving a low resistance load with PWM

I have been trying to build a simple PWM power supply to use a 3.7v battery to drive a small heating element with a DC resistance of about 1 ohm. I have built a slightly modified version of the ...
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2answers
44 views

Buck Converter vs plain PWM Power modulation

I have a dc load that I'll be controlling with a fixed voltage DC source. The output of the load is proportional to the average power delivered (it's a heating element). Since the element is a fixed ...
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3answers
77 views

MLCC as SMPS filter caps

This question is out of curiosity. I know fairly well that mains SMPS can suffer from bad electrolytic caps. Now I wonder if replacing all electrolytics with MLCCs work? Will it make a more durable ...
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8 views

Application of SIMPLIS POP analysis to converters with AC input

Is there any restrictions on switching frequency of the converter? SIMPLIS help says: Converters with AC inputs will only POP under very specific circumstances. These requirements are: ...
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3answers
478 views

555 timer boost converter doesn't meet spec

I've been messing around with nixie tubes lately which requires a high voltage source (~150V-200V) to turn on. I searched around for a simple high voltage generator and found this circuit which uses ...
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60 views

Power regulation circuit's voltage dips

Solution: A LiPo pack showing 7.4V, or even 8V is not a charged pack. In fact mine was just shipped and hence discharged for "storage". There is nothing wrong with my circuit. I made a power ...
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2answers
37 views

Which Power Management implementation to use and the differences therein

Upon using an 'RF to DC converter', DC power management is needed. There is a dilemma in the approach as there are a number available. From the storage capacitor, there is the 'Switched-mode power ...
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1answer
82 views

How to calculate the ratings when a mains-rated transformer is used in a SMPS?

I have a mains-rated transformer that is a leftover part from my previous project. Now since I am experimenting with the idea of SMPS, I am wondering how it would behave when handling the higher ...
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140 views

How to bypass DC-DC converter with N-channel high side MOSFET

I have a DC-DC SMPS converter which is used as a pre-regulator in the power supply with linear post-regulator. A specific requirement is to provide mode of operation when pre-regulator is bypassed. ...
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45 views

H-Bridge Power Supply Erratic Behavior

Description: I have built a copper plating tank to plate circuit boards and am using a technique called Reverse Pulse Current plating to help aide in the copper plating process. What that involves is ...
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5answers
403 views

What does a buck converter do with the energy that a linear regulator would otherwise waste as heat?

I've been reading for hours about how switching regulators work but I'm still unable to understand what it does to keep the power equity between the input and the output (ignoring internal losses). ...
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4answers
367 views

Determining amplitude of a 2 MHz sine wave

I'm designing a class E resonant inverter at a switching frequency of approx. 2 MHz. I need to control the inverter so as to maintain a constant current at the load. My strategy would be to put a ...
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1answer
54 views

Can I cross the output inductor trace with input power line?

I'm attempting to learn a little more about SMPS design while referring to existing designs and posts such as this one: SMPS PCB Design Critic I'm implementing an AL8805 based constant current buck ...
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64 views

What power supply topology should I use?

I need to design a power supply capable of providing a maximum of 1800V at 0.02mA. The input voltage ranges from 135 to 250V DC. What topology is recommended for this voltage? Flyback, buck?
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450 views

Boost SMPS getting very hot. Why?

I tried to experiment with boost SMPS with multiple supply rails and I almost burned myself when touching parts when running. Here is the circuit and the part getting hot: simulate this ...
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2answers
76 views

SMPS transformer orientation with respect to PCB: what's best for EMC?

I have the option of either using a vertical or horizontal bobbin for a flyback SMPS transformer, and I can't conclusively decide which would be best for minimal radiated interference to be picked up ...
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1answer
72 views

DC-DC power supply module help needed [closed]

I have purchased this little brick (link below) that I though would allow me to input for example 12V DC and output a lower output voltage, for example 5V DC, but I'm now testing it and it seems to ...
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38 views

High Voltage AC&DC transition on PCB

I'm designing a SMPS and drawing layout onto double-sided PCB. Due to mechanical features of design, both AC and DC current should have transition through vertically attached board. For example, input ...
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3answers
172 views

Will this zero-cross detection circuit work?

I have a 10W SMPS circuit powering a home appliance like this: I need to extract a zero-crossing pulse from this circuit which would then be fed to a micro-controller. To this end, I am considering ...
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1answer
127 views

SMPS Design Transformer Core Selection

I'm trying to construct an SMPS power supply with 230VAC at 50 Hz input and 5.6V/2.5A output. Here is the schematic: The design was optimized with EE19 core selected and I am expected to optimize ...
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62 views

Power supply noise measurements

Im working on a project where I need characterise the noise from a power supply so I can then design some filters. The power supply provides 5V, 12V and -12V to a set of analogue sensors (hence the ...
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3answers
169 views

Measure voltage difference between ground and DC floating power supply lines

110/220V AC to 12V DC switching mode power supply (metal enclosed, input is 220V with separate L,N and ground.) Measured voltage difference with a multimeter between V- and V+ 12V DC as expected ...
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2answers
172 views

Bench DC power supply output

I recently purchased a ATTEN APS3005D Regulated DC power supply from eBay and I'm having some odd and potentially alarming results that I'm trying to get my head around. Note: I'm testing this ...
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1answer
91 views

Surge protection for SMPS

Can an NTC (Negative Temperature Coefficient) thermistor be placed before a MOV (Metal Oxide Varistor) for protecting an SMPS from inrush current and voltage spikes? Here is a drawing to clarify my ...
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96 views

Detecting transient voltages in a wall wart

Background I have now three smartphones (SGS3 [neo], max 77686 or so) lying around, all more or less dead due to a broken voltage regulator. Since I am not a fan of coincidences, I suspect a broken ...
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3answers
122 views

How is U1 powered in this schematic

This is taken from an app-note on the ONSemi NCP1014. Pin 1 of the NCP1014 is Vcc, and I don't understand how it is powered in this configuration. The datasheet linked above mentioned a dynamic self ...
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1answer
78 views

Can varnish affect the performance of the air gap in an SMPS transformer?

In the past I have built several switched-mode supplies using off-the-shelf transformers just using the datasheet properties without having to worry too much about their construction, however I am ...
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39 views

EMI/EMC filters for different frequency sub-circuits

I am designing a PWM based solenoid controller. The PWM controller works at 23kHz with an average circuit consumption of 23-45mA. The PWM controller is powered by a non-isolated SMPS with 12V output ...
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1answer
103 views

SMPS Transformer - Secondary voltage rating

I am designing isolated flyback converter with input voltage range 40VDC-110VDC, 5V/6A output. I am struggling with finding appropriate transformer since each and every one I found have lower primary ...
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1answer
70 views

does 0,7V supply on 5V devices damage the device?

In a certain state of my circuit there will be 0,7V on the supply pins of certain IC's (comparator & current sensor). Of course the IC's won't work on this voltage but does this damage the IC's or ...
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1answer
103 views

Microcontroller-based SMPS designing

Is it feasible to construct a variable voltage SMPS using one of each of the following: ATtiny84 microcontroller IRF4905 power PMOS 2N7000 signal NMOS 4.7mF cap 220uF cap AD5280BRUZ100 100kOhm ...
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2answers
61 views

Parallel transformer outputs

If I fed in ~140 volts at 100kHz to This transformer what is the most power I could get out of it? The data sheet rates it at 36 volts DC 3 amps on one of its three outputs but I am confused by this. ...
3
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2answers
97 views

Using a transformer with 400 volt rated primary side with a 120 volt line

Is it possible to use a transformer rated for 360 to 400 volts on its primary side on a 120 volt line? Will it still perform adequately? And I would assume the turns ratios still apply? This is the ...
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2answers
54 views

Arduino detects voltage on ground

I've been having a hard time finding a solution to this problem. I recently ordered a 5 Volt 2Amp AC to DC switching power supply from adafruit.cc When I connect my Arduino's analog sensor to the ...
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2answers
275 views

Relay not switching immediately from switching power supply to battery backup

WARNING This project as currently described is badly flawed in a number of ways that are liable to lead to complete failure of the equipment. As it is stated that it is intended to be used in a life ...
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2answers
90 views

switch mode power supply capacitors

If I am laying out two switch mode power supplies right next to one another from the same supply(24V), one is switching to 5V and the other to 12V then do I need both of the input capacitors? Thanks