28
votes
Accepted
Why are boost/buck converters never fully integrated/all-in-one?
It has to do with the limitations of silicon.
You can easily make lots of transistors in silicon, and connect them together.
Resistors and capacitors, particularly ones with any precision, are ...
- 47.1k
15
votes
Accepted
Idea behind current mode control in DC-DC converter
It is a vast subject to discuss but, basically, with voltage-mode control, the error voltage delivered by the compensator directly sets the duty ratio \$D\$. By doing so, you adjust the output power ...
- 23.5k
13
votes
Accepted
Why is buck-boost efficiency not specified for ultra light loads (μA)?
Why is buck-boost efficiency not specified for ultra light loads (uA)?
Buck devices first
You need to dig a tad deeper and find devices like this one: -
A closer look at the efficiency curve on the ...
- 473k
11
votes
Getting a +5 V supply from a negative 48 V , non-isolated (Telecom)
A small isolating DC-DC converter module, with 36V-72V input range, and 5V 1A output is the easiest approach. -48V to negative input, 0V to positive input. Then connect the 0V output to 0V input, and ...
- 8,271
9
votes
Why doesn't a boost converter help overcome USB cable resistance?
You have discovered the negative resistance feature that occurs with switch mode regulators.
This is a very simplified explanation of what is going on. For all intents and purposes and assuming a ...
- 24.1k
9
votes
Accepted
What will happen if the input voltage of the buck-boost converter goes below the recommended input?
Most DC-DC chips have an input undervoltage lockout, so if the input voltage drops too low, it's probably going to shut down.
Then, since it is no longer drawing current, the input voltage will rise, ...
- 81.6k
9
votes
High-power, high-efficiency boost converter design
I have used one of my ready-made free templates with a 200-kHz interleaved boost converter operated in CM and I can deliver 100 W from a 3-V source. The inductor current peaks to 19 A and the rms ...
- 23.5k
8
votes
Cheap way to power blue LED on coin cell
Connect the led to the coin cell. Nothing simpler than that. The high Equivilant Series resistance of the coin cell, as well as a lower voltage than the nominal 3.3-3.6V @ 20 ma, means that it's self ...
- 73.4k
8
votes
Accepted
How to prevent "Def Con" and simulation running at femtoseconds / second (running forever) for 1,600-run simulation
Try this: for all sources add Rser=0.1, and for the 3V one add Cpar=1m, and for both ...
- 21.8k
8
votes
Supercapacitor to prevent temporary power supply voids
Capacitors follow I=C*dV/dt. Your 1 F is good for 1 A for 1 s in you allow voltage to fall 1 V. Or in your case, 100 ms at 10 A and drop to 4 V. 4 V too low, try 50 ms at 4.5 V or 25 ms at 4.75 V. You ...
- 16.8k
8
votes
Accepted
Identification of IC used in Pololu 5V, 5A Buck Converter (my2101 330)
The "M" symbol looks like Micrel's logo before they got bought up my Microchip. Example: -
Above right-side image from here. Left-side from question.
So, I guess the device might be a ...
- 473k
7
votes
Accepted
Is it possible to get a high efficiency buck-boost converter by switching between the two?
Consider the most efficient type of buck controller; a synchronous type: -
Then, in order to turn it off when the parallel boost section becomes active you need a MOSFET on the output like this: -
...
- 473k
7
votes
Accepted
is a voltage regulator required for atmega328p when powering from boost converter at a set voltage?
is a voltage regulator required for atmega328p when powering from boost converter at a set voltage?
No it is not.
The ATMega is "just" some logic circuits in a chip.
So is the CPU in your PC and in ...
- 81.4k
7
votes
Cheap way to power blue LED on coin cell
Your most important decision is which LED.
You want the most photons per watt at the lowest cost.
Comparison of LEDs in the selection process is not as easy as it may appear.
Low power blue LEDs ...
- 7,517
7
votes
Why are boost/buck converters never fully integrated/all-in-one?
There are also this compact micoModules available, for example from Analog Devices [Linear Technology].
It integrates controller, inductor and capacitors inside one package:
The reasons for using ...
- 983
7
votes
Where does the negative inductor current go during CCM at no load in synchronous converters?
There are several reasons why ensuring the buck converter remains in continuous conduction mode (CCM) in light- or no-load conditions:
the duty ratio is the same regardless of the load: when the buck ...
- 23.5k
6
votes
Accepted
How to calculate how long a supercap can provide power
Hold up time is
T= \$\frac{C(V_s - V_f)}{I}\$
where I is the current, C is the capacitance, Vs is initial voltage on the capacitor, Vf is final voltage on the capacitor (perhaps the minimum ...
6
votes
Accepted
How to pick a capacitor to adjust loop compensation caused by reactive load?
If you ran your supply with the load and it proved to be unstable, then you can consider compensation. Also, given your input, this is about the most precise answer I can give.
If all you need is ...
- 21.8k
6
votes
Accepted
How does a boost converter allow for a gain in output voltage by just switching the positions of the inductor and switch?
Consider this simplified schematic of a boost converter: -
In the first half of the switching cycle the MOSFET is activated and the inductor is placed directly across the incoming supply \$V_{IN}\$: -...
- 473k
6
votes
Accepted
Why is my boost converter output lower than expected?
The likely problem here is that the MBRS1100 diode you have used is only rated for a reverse voltage of 100 volts and you are expecting it to block 135 volts (output voltage minus input voltage). OK, ...
- 473k
6
votes
What technical progress enabled high-efficiency charge pumps?
Don't believe everything you read on the internet. Even with passive switching, well-designed Cockroft-Walton circuits can be very efficient, and have been since Cockroft and Walton used the idea to ...
- 4,987
6
votes
Accepted
What technical progress enabled high-efficiency charge pumps?
The electrical efficiency of charging a capacitor from a constant voltage source through a resistance is given by
$$\eta = \frac{\text{energy transferred to capacitor}}{\text{energy transferred to ...
- 27.8k
6
votes
What is an intuitive explanation on how a buck and boost converter transfer energy?
I am struggling to understand intuitively how the inductor stores
energy and releases it in a way so that the voltage is stepped down
A buck converter needs to be controlled by a "system" ...
- 473k
6
votes
Accepted
Undersupplied LM2576 buck-boost converter: Prevention, and where is all the power going?
I'm suspecting that your 1N4007 is causing issues. The datasheet of your LM2576 specifically says not to use it. According to the 1N4007's datasheet, the forward voltage is 1V at 1A, which is causing ...
- 1,861
6
votes
How to Keep a Constant Output Voltage While Using MPPT?
The whole point of MPPT is that you have a load that can accept variable amounts of current. In other words, you can't charge a battery at constant voltage or constant current if you want to use MPPT -...
- 178k
5
votes
Accepted
MC34063ADR overheats and burns
1B-13F, 1N400x are inappropriate for SMPS designs- too long recovery time even for a pig of a chip like 34063- and not even specified so the specs can be met yet the diodes can be very different.
Use ...
5
votes
How to prevent "Def Con" and simulation running at femtoseconds / second (running forever) for 1,600-run simulation
When a simulation descends to machine limit calculation it is a sign that the simulation sees or expects chaotic output.
This can be due to a divergent solution (e..g runaway positive feedback, ...
- 5,908
5
votes
Accepted
Buck-Boost polarity
Why can't we just place the load rotated? Wouldn't it solve the
problem?
For a simple load yes, you can do exactly that but, for more complex loads that require a common 0 volt line with other ...
- 473k
5
votes
Accepted
Why specifically use a MOSFET and Schottky diode on a buck or boost converter and not other transistors or diodes?
MOSFET's are used because the voltage drop across the MOSFET, when on, is lower than the voltage drop across a BJT. This makes the MOSFET more efficient as a switching device.
Schottky diodes are used ...
- 29.5k
5
votes
Accepted
the sound from the coil when the current is drawn
I think you've shot yourself in the foot with your layout. You've got a high-power package, and three of your highest-current traces are long and thin.
When a switching supply IC vendor gives you a ...
- 47.1k
Only top scored, non community-wiki answers of a minimum length are eligible