All Questions
Tagged with smps or switch-mode-power-supply
3,228 questions
4
votes
4
answers
625
views
Inductor energy storing in buck converter
I am trying to understand inductor energy storing during ON time in buck converter.
Energy stored in inductor of buck converter is (Input Power -Output Power)*Ton
Lets say output power is 5 W and ...
- 119
8
votes
2
answers
1k
views
Is an LED driver IC just a boost conv with voltage across Rsense fed into FB?
There's these really cool things called power modules, but they are all marketed as normal dc-dc converters. Not many as "led drivers" for currents more than 1 A. The basis behind this ...
- 417
3
votes
1
answer
267
views
What does "Single-Ended Primary Inductor" mean?
SEPIC stands for Single-Ended Primary Inductor Converter. Could anyone explain what "Single-Ended Primary Inductor" means in this context?
(Image from schematic of SEPIC in wikipedia here)
- 270
2
votes
5
answers
460
views
What is the correct definition of a floating output DC-DC converter?
This is what Dave Tweed wrote in his post here about a floating power supply:
It simply means that the output side of the power supply is completely isolated from the input side, not even sharing a ...
- 270
1
vote
1
answer
55
views
Considerations for Output Capacitance in LDO and SMPS Circuits
In LDO or SMPS circuits, the maximum capacitive load is generally specified. Is the capacitance at the output of the LDO or SMPS circuit used after the SMPS LDO output also included in the output ...
- 772
1
vote
2
answers
146
views
DCM vs CCM Noise Spectrum
Will the noise spectrum (at the LISN) due to switching of a Synchronous Buck DC-DC converter be different (peaks) if the converter is operating in DCM (Inductor current) compared to CCM keeping the ...
- 295
1
vote
1
answer
126
views
LM3478 MOSFET and inductors overheating
I'm trying to design a SEPIC converter based on LM3478, with input voltage range 12-36 V, and output 24 V 2 A. I'm calculated all relevant values of components, according to "AN-1484 Designing A ...
- 13
0
votes
1
answer
42
views
In a PFC boost converter, would input current distortion happen during initial voltage build up- when input is higher than output?
It is said that "Boost DC voltage output must be higher than the maximum line peak voltage otherwise you will introduce distortion (harmonics)"
Shown below is the simulation output for a PFC ...
- 3,156
0
votes
0
answers
112
views
Can a common mode choke be used to filter a SMPS dual power supply?
I have a switched mode dual power supply with +12V, GND and -12V outputs. I'm seeing a lot of high frequency noise on the output of this power supply that I'd like to attempt to filter out. The noise ...
- 103
2
votes
3
answers
512
views
Current Rating in Common Mode Choke
What is the meaning of this current rating which says "unbalanced" current?
I know in common mode chokes the common mode current rating is given. Why here it is written as Iunbal.?
- 295
0
votes
0
answers
67
views
Pspice simulation not working
I am simulating the evaluation board LM5145EVM-HD-20A on Pspice.
(https://www.ti.com/tool/LM5145EVM-HD-20A)
LM5145 already has the Pspice model for the same but the switches used are not Pspice models ...
- 295
2
votes
2
answers
405
views
C2000 PWM skips a compare on synchronization
I found a mitigation for the problem that I couldn't post to e2e.ti.com because they demand a company email (University won't do). See my self-answer below.
I'm using a TI microcontroller ...
5
votes
2
answers
315
views
Non inverting buck boost transfer function
When considering the compensation of a non inverting buck boost (single inductor), the datasheet considers to take into account the worst transfer function between the buck transfer function and the ...
- 2,610
0
votes
0
answers
37
views
OnSemi NCV1076 Ltspice Model Lib
I am trying to desing a SMPS with LTSpice. There is a driver which ı can use in real.
It is NCV1076.
But ı could not find a .Lib Model to use in LTSpice.
There is a simulation model but it is only for ...
0
votes
1
answer
155
views
Switching power supply has high ripple voltage no matter how many capacitors are added
I'm designing a board that uses a Texas Instruments TLV62569DBVR (datasheet here) to convert 5V input from a USB power supply to 3.3 volts to be used to power an ESP32-WROOM-32D-N4. I am having lots ...
- 71
0
votes
2
answers
98
views
Minimum on-time does not depend on MOSFET
I would like to better understand this topic: Minimum ON time for a buck converter
One of the answers seems to say that the minimum on-time depends on the selected MOSFET. According to the datasheet ...
- 2,610
0
votes
0
answers
39
views
Switching Freq. and Output voltage error
Attached is the datasheet for the Synchronous Buck Controller: https://www.ti.com/lit/ds/snvsb32b/snvsb32b.pdf?ts=1711536038118&ref_url=https%253A%252F%252Fwww.ti.com%252Ftool%252FLM5145EVM-HD-20A
...
- 295
6
votes
3
answers
604
views
Modified output voltage range of laptop power brick? (TL431)
So here I have a standard 19V noname laptop power brick rated at say 4A output. Inside is a typical SMPS regulated by a TL431 and an optocoupler.
I added in a potentiometer to the reference resistors ...
- 857
1
vote
2
answers
135
views
Low power toggle switch
I have used a 555 to toggle output on/off from a push button pulse and was wondering to use something similar to TTP223 due to its low consume once with 555 have more than 10mA in standby, anyway ...
2
votes
1
answer
178
views
Ferrite bead on input EMI filter
Here is the schematic of a demoboard :
It is a buck converter with an input EMI filter. As you can see it there is an inductor and a lot of capacitors which make an LC filter with a cutting frequency ...
- 2,610
0
votes
0
answers
41
views
GPIO and LDO voltage slightly increases when other GPIO enables load
I have a circuit in that GPIO_1 (yellow trace) is generating repeating signals to control an NMOS and GPIO_2 (green trace) is controlling an LED driver (buck DC/DC) load via an NMOS switch.
When a ...
- 251
0
votes
1
answer
80
views
Where can I buy high current smps transformers? [closed]
I am designing a 48V/30A power supply from 230VAC using 2 switch forward topology, I am in need of a transformer for this purpose, I have searched all the possible websites for it(DigiKey, Mouser, ...
- 11
0
votes
0
answers
88
views
Positive and Negative Dual Power Supply
I want to build a dual power supply board that works with 12V DC from the power adapter and gives +/-15V at its output. I came across a schematic in LT3094 datasheet on pg 30.
I am trying to simulate ...
- 187
0
votes
0
answers
71
views
Generating LLC Tank Gain Curves within Open Loop Simulation - SIMPLIS
I'm using the half bridge LLC open loop circuit mr. basso very kindly gave to the world, but I am having troubles generating the tank gain curves. I'm somewhat of a novice when it comes to SIMPLIS and ...
- 180
1
vote
1
answer
67
views
TPS564247 switching voltage regulator problem
I have been working on a 12 V to 3.3 V DCDC converter that uses the TPS564247 switching regulator IC. Here is the schematic:
The problem is that the IC keeps resetting itself once a second. At first, ...
3
votes
1
answer
137
views
In LTspice, is there any way I can obtain the frequency response of power converter alone?
I am aware of the following methods. But my intention is to understand the behavior of power converter alone, before adding the controller and feedback loop.
FRA analysis: Provides the open loop ...
- 3,156
1
vote
1
answer
98
views
Slow simulation on LTspice
What could be the reason for the slow simulation speed for this converter circuit I have emulated from Fig 9-5: https://www.ti.com/lit/ds/symlink/lm5145.pdf?ts=1710376974553
- 295
0
votes
0
answers
34
views
Injection point for stability analysis
According to the application note from OMICRON, for making good stability analysis of a converter, it is necessary to place the injection point at a certain place on the board :
Does anyone know why ...
- 2,610
0
votes
3
answers
169
views
Positioning of Inductor and Capacitor for Mains Voltage Noise Filtering
In the datasheet of this power supply, it is recommended to place the capacitor before the inductor for the mains voltage filtering circuitry, as it is shown on this image featured on the datasheet:
...
- 51
1
vote
1
answer
41
views
Measurement of small signal voltage of switched capacitor dc-dc converter
I have a short question. I have a Switched capacitor dc-dc converter which I want to obtain the magnitude bodeplot in dB manually rather than using AC_analysis in the simulation (To understand how to ...
- 113
0
votes
1
answer
377
views
Power Supply for VFD Display
I recently ordered a GP1294AI VFD display from Aliexpress. Unfortunately it did not contain the necessary power supply to power the display, but the datasheet did include the necessary schematics for ...
- 43
0
votes
1
answer
175
views
Understanding lead-acid battery charge
I´m trying to understand how lead-acid batteries charging work.
So far what I tested:
If a 14 Vdc supply is connected in a 12 Vdc battery, the voltage will drop to the battery level, and start going ...
- 155
5
votes
4
answers
3k
views
Is it safe to connect AC earth to DC negative?
I'm going to use a switching mode power supply in a product. When I use no earth connection in the input, the metallic body of the PSU gives a little electric shock. (it has ~70V AC with reference ...
- 71
4
votes
2
answers
161
views
MOSFET SOA relevant for switching power supply design?
I am picking the low and high side MOSFET switches for a 2 amp output buck converter, simplified schematic shown here. Vin = 20 V and Vout = 15 V.
The IC manufacturer has a spreadsheet for ...
4
votes
2
answers
253
views
Inductor - Voltage rating and Saturation
An inductor has rated operating voltage (across inductor) = 75 V. Suppose 100 V comes across it for some microseconds (~ less than 1 us). What will happen? Is the operation dangerous in such cases? I ...
- 295
2
votes
0
answers
133
views
Buck Converter Current Mode Control Simulation
I have downloaded LTspice PWM switch from christophe basso website http://powersimtof.com/Spice.htm file name PWM-CM2-MD2 by Mark Dimattina
I am doing 5.1V converter based on LTC3890 IC so I tried to ...
- 119
0
votes
0
answers
45
views
Current Mode Control
I am referring the doc https://www.venableinstruments.com/current-mode-control-wp and trying to understand behavior of current mode control but unable to understand following things
1.
What is the ...
- 119
0
votes
0
answers
40
views
Synchronous SMPS Enabling with Charged Output
When using standard slow-start circuits that slew the 'comp' net for topologies like synchronous buck and boost converters, there can be reverse current events if the supply attempts to enable when ...
- 73
0
votes
2
answers
333
views
Ferrite bead on a SMPS output [closed]
Suppose I have an instrument which needs a very clean power supply line. I have an SMPS which outputs 24 V at 3.2 A, which is then cleaned via a LM1084 linear regulator.
Given that the output of a ...
- 650
15
votes
3
answers
2k
views
Why did my DC/DC Buck Circuit fail?
I'm in the process of debugging a PCB I made. On this board, a 24V input feeds through a DC/DC buck circuit (based around the TI TPS54202DDC) to output 11V, then an LDO to output 9V (to ensure a very ...
- 671
0
votes
3
answers
95
views
Charge "something" over a 10 second interval then dump the charge on a load. (Alternative to battery?)
I'm getting a limited current of about 10 mA from a 12 V DC source. I would like to charge "something" (anything but a battery) with this energy over 10 seconds, and then dump it to a 12V ...
- 137
1
vote
1
answer
100
views
Choosing an adequate op-amp for shunt resistor sensing in SMPS applications
I would like to get some industry experts / design engineers opinion about potential methods to improve the proposed shunt resistor current sensing method below. The intention is to improve this ...
- 45
1
vote
1
answer
291
views
Average Modelling of Buck Converter
I am doing Modelling of Buck Converter for LT3890 (Datasheet link attached) for Frequency response analysis .
I have some reference model of Buck converter ,please refer below image
Datasheet Link: ...
- 119
0
votes
1
answer
103
views
Enabled LDO based on the input voltage
I need to power a microcontroller (ATTINY826-SU) from a USBC port that supports Power Delivery (I'll use a battery back for that). For the sake of simplicity I'll omit the circuite to negotiate the ...
- 53
0
votes
2
answers
38
views
Gate driver input
I am giving a pulse input (from a microcontroller) to the INA/INB pin of the Gate Driver IC: https://www.ti.com/lit/ds/symlink/ucc21222-q1.pdf?ts=1708945816410&ref_url=https%253A%252F%252Fwww.ti....
- 295
0
votes
3
answers
157
views
Copper wire for high frequency converters
Designers use Litz copper wire for high frequency windings. That rapidly increases the diameter of wire needed and decreases the stacking factor.
Should’t it be possible to make a copper wire with ...
- 2,901
0
votes
0
answers
61
views
How can a power converter small signal model predict transient behaviour during a load step which is a large signal disturbance?
I see small signal model being used to predict the Overshoot/Undershoot of output voltage due to a load step.
How do we justify this approach, since the basic assumption of small signal modelling is ...
- 3,156
0
votes
0
answers
86
views
Could DC-DC isolated power supply switching noise harm the input of an instrumentation preamplifier?
I am looking for a noiseless protection against 100ms pulse of 1kV of an input of ultralow noise instrumentation preamplifier (eight AD8428 connected in parallel, fixed gain of 2000) to measure very ...
- 103
1
vote
0
answers
101
views
Get power for driver circuitry in an inverter
Planning to build an inverter based on egs002, I got high voltage high frequency side (ferrite core transformer including N-MOS and high speed rectifier) from old UPS board which I will drive using ...
- 624
1
vote
0
answers
83
views
Why does this pulse generator have a voltage inverter?
I am designing a fast pulse generator, inspired by Leo Bodnar's pulse generator, using the ADCMP572 ultra fast comparator.
It looks like a pretty simple device, using a PIC microcontroller to drive ...
- 27.6k