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6 votes
Accepted

Zener instead of resistor divider on dc-dc converter feedback pin

The zener changes the nature of the feedback signal. It is the result of a subtraction rather than a division. This enlarges output errors as seen by the FB input. To see how, consider this. If ...
AnalogKid's user avatar
  • 21.4k
6 votes
Accepted

SEPIC DC-DC converter

Does this help you understand: -
Andy aka's user avatar
  • 465k
5 votes
Accepted

How does MPPT maintain a constant voltage?

MPPT is not a specific "algorithm", it's a concept. When you pull more current from a solar panel, the panel voltage drops; if you pull too much current, the voltage collapses and you get ...
Boann's user avatar
  • 474
4 votes

Applying a voltage by DAC to a Feedback pin of a DC-DC controller

A most convenient way of adjusting the voltage digitally is to use a current source/sink DAC. Maxim (now Analog Devices) make a family of devices, such as the DS4424 which is controlled by I2C. It’s ...
hacktastical's user avatar
4 votes

Applying a voltage by DAC to a Feedback pin of a DC-DC controller

Here's a way to get a 0-60V output using a DAC input. The output is 60V for a DAC voltage of 0V, 30V for a DAC voltage of 1V and 0V for a DAC voltage of 2V. Note that the output voltage increases as ...
Carl Rutschow's user avatar
4 votes
Accepted

Applying a voltage by DAC to a Feedback pin of a DC-DC controller

The FB input will see the external circuitry like this: simulate this circuit – Schematic created using CircuitLab So as you can see, assuming the input ...
Rohat Kılıç's user avatar
3 votes

Limiting voltage on voltage monitoring pin

An N channel JFET in combination with a zener diode can be used here. To avoid excessive power dissipation and high voltages across the JFET I splitted the voltage and power using two FETs in series. ...
Jens's user avatar
  • 7,357
3 votes

Limiting voltage on voltage monitoring pin

Try a low drop-out voltage linear regulator set to the maximum voltage you want to monitor, 28V. This can be made up with discrete parts, the schematic below shows the idea. This circuit will force [...
Fabio Barone's user avatar
  • 5,452
3 votes

Applying a voltage by DAC to a Feedback pin of a DC-DC controller

The 5515 will adjust its operation to maintain 1.001 V on the FB pin. This means the FB pin 'looks like' a zero impedance when the 5515 is operating properly, as whatever current you feed into it, the ...
Neil_UK's user avatar
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3 votes
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Level shift a digital 1.8V signal to split supply rail, using BJT

One tiny (2.2 x 2.2 mm) SOT363 IC DCX114YU from DIODES will solve this: simulate this circuit – Schematic created using CircuitLab
Jens's user avatar
  • 7,357
3 votes

Does this DC-DC converter model require an external switching signal?

Please read the datasheet for this device. The "SW" pin connects to the switching inductor. The datasheet provides this information, along with all the other information needed to use this ...
Dwayne Reid's user avatar
2 votes
Accepted

RCD snubber loss in flyback converter

In ics waveform below, that is current in snubber cap is -Vcs/Rs. Since the diode is reverse biased how does this current appear? You should read the article more carefully: - ...
Andy aka's user avatar
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2 votes
Accepted

DC-DC SEPIC convertor design

This only makes sense when looking at the copper pour, not at the schematic. The point of this is to keep the power ground isolated from the regular ground, so that the pour areas are only connected ...
Lundin's user avatar
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2 votes
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DC-DC convertor-SEPIC architecture

The resistor is there so that you can slow down the turn-on of the FET if you want to, by changing the value from zero to something else. The turn off would be faster since the diode would conduct on ...
John D's user avatar
  • 24.1k
2 votes

Need help opamp or optocoupler?

If you trust the 5.8V signal to never exceed +5.8V, and to never fall below 0V, then you could employ a simple resistor potential divider: simulate this circuit – Schematic created using ...
Simon Fitch's user avatar
  • 39.1k
2 votes

Need help opamp or optocoupler?

If only level needs to be changed and no isolation is needed, you can just use a voltage divider (2x resistor). The signal is slow enough for that. You can also use opamp with gain lower then 1 to ...
ursusd8's user avatar
  • 450
2 votes
Accepted

Maximizing power transfer from 50Hz AC line via toroidal current transformer

Minimum line current 50A means we need to drop maximum 20V to deliver 1kW. I assume we have no way of looping a wire around (power lines are generally solid wire, coated with rigid insulation, and ...
Tim Williams's user avatar
  • 39.8k
2 votes

Does this DC-DC converter model require an external switching signal?

The SW node is a power output, not a signal input. It's the node that gets switched by the switching transistors and/or diode. It's where you attach the inductor and, if applicable, the bootstrap ...
Hearth's user avatar
  • 35.3k
1 vote

Applying a voltage by DAC to a Feedback pin of a DC-DC controller

Carl's answer is the canonically correct way to do this - I was about to write that up but he beat me to it. The feedback pin becomes a "summing node" for the output voltage and the DAC ...
Alex I's user avatar
  • 3,501
1 vote

Current spike through bootstrap circuitry during turn-on and off of HS FET (GaN FET half bridge dc-dc)

Yes, these are typical issues in bootstrap circuits, when loose layouts and fast switching are involved. 8nH is wild large for GaN; with DFN types, that should be down in the <5nH range for the ...
Tim Williams's user avatar
  • 39.8k
1 vote
Accepted

Filter on SEPIC architecture output for making +/- 60 V from 11 V input

I see you've already accepted an answer, but there's a detail missing. the positive voltage is fed back to the feedback pin. Assuming proper regulation, this will never exceed the feedback voltage of ...
rohmeooo's user avatar
  • 153
1 vote

Filter on SEPIC architecture output for making +/- 60 V from 11 V input

I want to know what is the role of R4 and R10 in this circuit? They are there to provide a light load when no real load is connected. If you didn't have these resistors and you disconnected your load,...
Andy aka's user avatar
  • 465k
1 vote
Accepted

Constant output voltage in buck-boost converters

I've tried to understand why the voltage across the inductor is constant. I think it is thanks to the generator to which the inductor is connected in parallel, and which provides constant voltage, so ...
RussellH's user avatar
  • 17k
1 vote
Accepted

DC-DC converter design simulation tools and Webench design tools to identify the best-suited IC and schematic

These tools, are nothing more than that: tools. They can offer suggestions (sometimes even complete designs!), but there will never be a substitute for using your noggin'. Particularly for the wide ...
Tim Williams's user avatar
  • 39.8k
1 vote

DC DC boost giving high voltage , minimum quiescent current

This circuit works well. It's not pretty, but it works superbly. You could adapt the shown regulator to suit your own system, or could create a simpler one based on the same principle. Example only: A ...
Russell McMahon's user avatar
  • 151k

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