Questions tagged [buck]

A non-isolated DC-DC converter topology which outputs voltage less than or equal to the input voltage

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TI's bypass mode step-down converters

Texas Instruments encourages the use of the TPS62730 step-down converter with bypass mode along its RF devices. Does this mean : its noise is low enough not to affect RF ? Thus being a more efficient ...
3k views

Audible noise in DC-DC buck converter

In my design, I have a +3.3 V SMPS that provides power to digital circuits (microcontroller, EEPROM, etc.). The microcontroller allows applying a 100 Hz PWM signal with variable duty cycle and with an ...
1k views

Can I use digital pots for my feedback resistors to a buck-boost regulator?

I'm working on a design, and this will be my first attempt at a buck-boost regulator. I need the output to be variable because my application calls for different voltages under certain conditions. ...
348 views

Buck boost converter

I have noticed that some buck boost converters say "led driver", some have step down/up control and what looks like a display voltameter and ammeter, they are adjustable to 5 Amps/32v. Obviously these ...
3k views

What is the most efficient way to power a solar computer (5V) from a 12V lead acid battery?

My project: Power a Beaglebone Black (BBB) entirely from solar energy. Obviously energy efficiency is crucial here. My setup so far: PV panel connected to a deep-cycle lead acid battery. Now I need to ...
2k views

Maximum limit on the Buck converter inductance value

I found the minimum inductor required for a buck converter using the following formula - L_1 = \frac{V_{in\,max} - V_{out}}{I_o \times K_{ind}} \times \frac{V_{out}}{V_{in\,max} \times fsw}...
1k views

Current measurement in a Buck Converter

We have developed a prototype of a PID-regulated Buck converter made around the AVR XMega. 6-17V at the input, 5-10 on the output, 15A current limit, 500kHz PWM switching. The issue is, how to make ...
900 views

I was reading a chapter on Step down Choppers(Buck Converters). I had trouble understanding the operation of the circuit as it wasn't explained properly in the book. When I looked up on the internet , ...
2k views

Regarding Transient response of a Buck converter(Quantitative analysis…)

I want to know transient response of a Buck converter. I have seen in so many occasions, like when calculating Output capacitance, datasheets consider, say in a transient event, loop will be ...
4k views

Is it possible to run a Buck converter with rectified AC supply voltage?

I know that a standard Buck converter requires DC voltage as input. But if your primary input supply is a high AC voltage, it is not very easy to make a clear DC voltage out of it. For example, if I ...
430 views

What kind of capacitor should I use in Buck topology if the load is a lead-acid battery?

I'm using BQ2031 to charge lead-acid batteries. BQ2031 takes battery voltage as feed back and controls the switching element according to it. Now the load is not a passive element, instead it is a ...
281 views

Are Buck converters conceptually same in low/high power applications?

I am new to power supply circuits. I am studying datasheet of buck regulator LM22676 which generate 5V/3.3V dc for micro-controller supply in one of my system.The datasheet says it has a N-channel ...
2k views

Building a low-power solar/wind buck-boost converter

Using a 18V(max) solar panel, I'd like to charge a 12V lead-acid battery. I'm working from the basic inverting buck-boost circuit. My main question is, being a relatively low-power circuit, can I ...
385 views

Effect of duty ratio on buck converter with battery load

Will the battery charging circuit be able to supply charging current if the duty ratio is adjusted to 0.1?
4k views

Effect on output voltage for buck converter in discontinuous mode

In a dc-dc switch mode buck converter, why the output voltage is different from the desired value when the inductor current is discontinuous? How can the voltage be adjusted to the required value? ...
4k views

Resonant Frequency of LC Circuit in Switching Converter

Why do we set resonant frequency of LC circuit in a buck converter to be less than 10% of Fsw? For example, if Fsw is 300 kHz, why should resonant frequency be around 30KHZ. I am guessing it is due to ...
4k views

What is the purpose of using MOSFET instead of free-wheeling diode in Buck topology?

(Source) I usually see Buck circuit models in which a MOSFET is used instead of a free-wheeling diode. What I understand from the Buck topology is, when the upper MOSFET is off, it doesn't matter ...
262 views

Is something wrong with my frequency selections for a buck converter controller? [closed]

I'm designing a processor-controlled buck converter. I'm seeing some instabilities, which I suspect may be due to improper frequency selection at different points in my system. I'm trying to regulate ...
2k views

Buck converter with op-amp, inductor issues when load changes

I'm looking at the designs for a simple buck converter which has the P mosfet, inductor, capacitor and reverse based diode. Instead of PWM, I'm trying out to use an op-amp to switch the P mosfet but ...
974 views

Any qualitative analysis saying RC snubber required or not for High current Buck converters

I have a design where i am using TPS53355 from TI to generate 0.9V @ 15A from 12V(10V-14V). For this design, i want to know whether RC Snubber required or not? as far as i know, Generally in High ...
666 views

Extending a switch mode power supply controller IC to work under higher input voltages

I have a AP6502 IC, which is a cheap DC-DC buck converter. It converts a DC voltage in the level of 4.7V-18V to a DC voltage of 0.925V-16V. I works under 2A current maximum. Example Usage of AP6502 ...
4k views

Role of Capacitor when switch is open in Buck Converter?

in a buck converter, initially, when switch is closed, then capacitor charges and stores energy. But when the switch is opened, then Inductor current flows through thr free wheeling diode, but what ...
7k views

LC Low Pass FIlter in Buck Converter

Hi In this circuit below: What role is the LC Low Pass filter playing? The switch is switching ON-OFF alternatively, at a frequency which determines the Duty cycle, and we get an average output at ...
4k views

Step-Down DC-DC converter question

I want to use Power over Ethernet (48V, 30W best case) to power something that's going to require up to 15W at 10V. That means I need to step down the PoE voltage but step UP the max current. As I ...
1k views

Buck converter operation

I have been reading about the buck converter and have also referred to the various online resources like here. In the above circuit, as I understand, when the switch closes, current starts to ...
1k views

Step down switching regulator heating up with light loads

I built a step down switching regulator based on a Diodes AP5100 using the datasheet example circuit with this layout. The voltage is being stepped down from 15V to 12V and the AP5100 is heating up ...
1k views

Is this a bidirectional buck/boost converter

I found this interesting IC on Linear Technologies site, but I don't understand if it, or its development board, can both boost input voltage to output and buck output voltage back to input. http://...
1k views

Buck regulator frequency requirements (transient response)

Looking at the frequency choices for buck regulators, is there a defined "good" range for a particular context? Looking at datasheets, manufacturers extoll the virtues of "better transient response". ...
2k views

Convert 320VDC to 220VAC or 48VDC voltage using 220VAC (UK) UPS?

I've got access to 12 flexible Solar Panels - 320VDC each Main voltage is 220VAC (here in the UK) and also might buy an electric engine running at 48VDC. Would a 220VAC Uninterruptable Power Supply ...
586 views

Can a synchronous regulator “chirp” in burst mode?

I'm looking at (the millions of) buck regulators available for a project where the board will be a host board for a Gumstix Dual Cortex A9. This can pull quite a bit of current at maximum so I was ...
915 views

I am planning to use a Diodes AP5100 switching regulator to go from ~22V to 12V in my circuit, which will have a max current draw of about 1A. This is my first attempt at laying out a switching power ...
3k views

12V -> 3.3V DC step down at low current

For a project that I've been working on, I want to drive a couple of ICs and several LEDs from an ~12V supply (lead-acid battery). I think the whole thing should draw about 100mA, so I didn't really ...
2k views

Routing a buck/boost DC/DC converter

I need some help with the layout of a power supply. I botched the first two iterations as I do not have the necessary experience, and I would like to avoid another costly run. For the sake of ...
3k views

Noise problem with buck/boost switching regulator

I am designing a electrical device for a research project (I'm a PhD student, but unfortunately not EE!). More info on the device can be found at http://iridia.ulb.ac.be/supp/IridiaSupp2012-002/ The ...
473 views

Driving LEDs with Specific drivers or buck/boost regulation

I have a circuit that is driving 3 x LED rings and an Arduino/ATmega @ 5v through a standard 5v regulator. Each LED ring draws 11v @ 300mA and is PwM switched using a 2n7000 Mosfet from the ATmega's ...
268 views

Choosing SMPS, buck regulator or controller [closed]

There are thousands of buck regulators I can choose but I can use some good advices. I need fixed 7...8V output, 10...15V input and 2A maximum. The problem is I can't decide because I need smallest ...
6k views

How step-down voltage regulators behave when their input drops below their output voltage?

How do the common low-dropout LP2950 and buck LM2596 regulators behave when their input voltage drops below their output voltage? I'm driving a micro-controller board rated for 3.7-5.5 V with a 4.8V ...
368 views

buck converter for high current LED

My first question here: I want to make a simple adjustable current supply for some LEDs I have (approx 3 V and up to 3 amps). I've decided against just using a single FET to control current as it ...
3k views

Multiple buck converters on the same PCB, should switching frequency be the same?

I have a question regarding dc-dc buck converters. I need to supply multiple different voltages on my board and I am very limitted with power this is why I need to use high efficiency converters. If ...
2k views

Cheap Step-Down converter as Solar Charge controller

Instead of buying in an expensive MTTP-Charger I want to buy a cheap module only. You get these small 2A/40V Buck-converters at eBay for 2-3 USD or the bigger 10-12A /40V from 9-11 USD. Setup: ...
6k views

Why does this buck converter output such low current?

I'm making my first attempt at building a buck converter, as a constant-current supply for a 700ma LED, from a 5V or 12V supply. I have it working with the parts I had on hand, at about 88% ...
945 views

DC-DC Buck Regulator: Embedded or External MOSFET

What are benefits and drawbacks of using Buck Regulator with external MOSFET compared to Buck with embedded MOSFET? Is there some general rule? In my case I need 5V 3A from 9V-30V supply.
2k views

Enable pin current limiting resistor?

I was looking at the AOZ1280CI DC-DC buck converter, and I'm having trouble properly interpreting the datasheet concerning the enable pin. In the pinout description, it states: Enable pin. The ...
20k views

Is it ok to connect the output of buck regulator in parallel?

I am using MCP16322 buck regulator powered from 12V and outputs 5V and 2A. Is it ok to connect the output of two of these in parallel? Does connecting the outputs in parallel mess up the maximum ...
10k views

How do I select the correct inductor value for the following buck regulator?

First of all, I suck a bit at math, and I'm no electronics genius, so the stuff I do is for fun and for learning purposes... I'm working on a buck converter circuit to convert my USB Vbus 5V to 3.3V. ...
847 views

Is there a reason to use smps regulators over modules

I'm just discovering that TI have switch mode power modules as well as regulators. For example they have the LMZ12001 which would be significantly easier to use than the TPS62150 regulator. Elektor ...
2k views

A basic buck converter circuit to power 3W LEDs from PC power supply?

I'm just finishing up my first electronics course (edx.org), and I want to build some LED grow lights for starting seedlings in the winter. I have high power LEDs, like this one here, and I have a PC ...
993 views

Help on MPPT for solar panels

I am studying maximum power point tracking (MPPT), and I have found many setups using buck converter. Since buck converters step down the voltage, how can you have the maximum power at load if you ...
5k views

Buck switching regulator based on ATtiny84a — please critique!

Here is an attempt at designing a buck regulator based on a ATtiny84a as the PWM controller. It should go from a 4S LiPo battery (12.8 - 16.8 volts in) to a reasonably regulated 12V output, used to ...