Questions tagged [step-down]
For questions about stepping down voltages. Consider using in conjunction with related tags such as "dc-dc-converter", "buck", "transformer", "ac-dc", etc., if applicable.
285
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What are the consequences of small bootstrap resistor (in DC-DC buck/step down specifically)?
If I understand it correctly, a bootstrap capacitor (CB) is used to store energy to turn on the high-side MOSFET (P-channel MOSFET). In DC-DC buck converters (which I use now) this happens several ...
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Check of PDN for RF Amplifier - Revised
This is an update to my previous post. I was recommended to post it again.
For optimal working conditions, HMC863ALC4TR needs Vdd = 5.5 V and Vgg = -0.75 V. I have tried to design such a network to ...
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The best way to step down 12V to 5V with at least 10A current from a PS3 power supply for a WS2812B LED strip
I am new to electronics. I had a PS3 Super Slim power supply lying around, which outputs 12V up to 13 amps. Recently, I bought a 5-meter strip of WS2812B LED strip, which needs 5V, and the recommended ...
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Calculation of Power Transformers
I'm calculating transformers very roughly, with some approximate equations that I found on the internet, they are working perfectly but I'm supposing that they are oversized... They are power ...
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3
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Unable to start and run 12 V DC pump, only jolts
I have a 12V 19 watt DC water pump (800LPH), A 12 V DC step down converter, and two Dewalt batteries.
One at 18 V 5 Ah, other 18-54 V 9 Ah.
I've connected pump to step down to battery correctly, but ...
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2
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66
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How does a starter transformer work?
I am searching about chargers that are specifically for starting forklifts and other things that require, say, 12V-24V and 20A-80A. They have lead-acid batteries.
These starters have a switch for 12V ...
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1
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5 V behaviour of Mikroe Feather click shield when powered from Feather only
The Mikroe Feather click shield supports a mode where the power comes from the Feather:
In this mode the Feather board will provide 5 V and 3.3 V labeled as P5V ...
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Are heating elements multi voltage? [closed]
I have a 110 volt crock pot but I live in a 220 volt country. It says it uses 270 watts.
Can I just use it anyways without modification or should I try to find the interal wiring and make the heating ...
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What is the range of the most powerful step down DC/DC converters nowadays?
The team in my lab's company, we want to start using high voltage DC to perform some tests. The electric company can supply us a line of 25kV DC but in reality we would need to chop it to get voltages ...
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2
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How to calculate bootstrap Resistor in MC33163 Buck configuration
I am designing a DC-DC buck converter with MC34163DWG. I try to understand what value of resistor RB must I use at the buck/step down configuration and I also have questions about the CB capacitor. ...
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5
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Shielding Buck Converter
I have a simple question, and I want to ensure that nothing unexpected happens. I'm currently working on a Raspberry Pi-based robot project with a Pi camera, and I plan to power it with a battery, ...
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2
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110
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How to decrease DC Voltage and Increase Current [closed]
I am using a buck converter to reduce source DC 12 V 1 A to 5 V. It does reduces the voltage but the problem is that it also reduces current i.e; less than 1 A. I want to keep the POWER same at all ...
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Variable Vout of Buck Converter [duplicate]
I have been trying to understand the working of buck converter (without the use of a dedicated IC). So, I used LTspice to test a circuit on the parameters:
Vin: 100 V
Vout: 50 V
Freq.: 10 kHz
I: 5 A
...
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Check of PDN for RF Amplifier
I would like to ask you for help with the power delivery network (PDN) design.
For optimal working conditions, HMC863ALC4TR needs Vdd = 5.5 V and Vgg = -0.75 V. I have tried to design such a network ...
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2
answers
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How can I replace a potentiometer with a fixed resistor on a buck converter?
I want to use a buck converter which steps down 12 V DC to 5 V constant DV output to power my custom PCB.
I came across a buck converter in market which can do it but there is potentiometer on it ...
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Reduce voltage ripple in wall power supply and buck converters
For my project I choose a wall AC/DC power supply (AEJ160PS12) with output voltage at 12V and intend to use some buck converters to step down from 12V to 6V and 3.3V. The chosed buck converters is ...
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Need help with high current step up DC
I need to design external battery for my flash.
I have checked it works with 4-6v DC with ~6a current to charge the capacitor in 2-3 second.
I have 18650 battery planning to use in 1S configuration. ...
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1
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46
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Calculation of step-up / step-down output voltage
I am trying to build a step-up and step-down circuit from a DC-DC converter IC.
This is from the datasheet:
I have two questions in relation to this:
The value of the resistor in the red box. It ...
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Separating 5v and 12v circuits using diodes, converters, and switches
I have drawn out a project with multiple power options.
I am wondering if any of these reverse current protection diodes can be left out.
If the double pole double throw switch can be replaced by a ...
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129
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High to Low logic level converter with MOSFET
I'm designing a sniffer circuit to tap input signals from various machines. The type of signal varies from input pulses and UART communication, the voltage varies from 5V to 12V.
These are the ...
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2
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Reducing a constant voltage source from 24 V to 12 V [closed]
I currently have a constant voltage source powering a PLC which outputs 24 V DC. I need to drop the voltage from 24 V to 12 V. Is there a way to do this without buying a $100+ DC-DC converter? The ...
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Desigining a 3S battery charger step-down buck converter
I'm a hobbyist, so my electrical engineering skills are not top notch.
I'm service tech and I'm working on modifying portable coolers (thermoelectric and compressor based) where we add batteries to ...
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AP64501 problem
I have a big problem with the AP64501. I used the reference layout from the datasheet for my own PCB (5V output (without C4 and C6)).
As soon as I put 24V on the input, the AP64501 burns out ...
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3
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350
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Using resistor to drop voltage in circuit with changing current [duplicate]
I have no problem calculating and understanding how to drop voltage using resistor for circuits with purely resistive loads - for example look at much current will an LED draw, subtract source and LED ...
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2
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147
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Can I use a buck converter and a 12 V adaptor to create a 5 V and a 12 V circuit?
I have a microcontroller that is powered by 5 V and some solenoids that need 12 V. At the moment I power the solenoids using a 12 V adapter and switch them on and off through MOSFETs which are in turn ...
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How is this stepping down 12 V? [closed]
I'm positive that the microcontroller (U3) in the picture can only receive a 5 V input. I just want to know how those components (the two resistors and the capacitor by In1) are stepping down the 12 V ...
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1
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Are there any step-down regulators without capacitors for a vacuum environment?
I'm trying to find step-down DC-DC regulators that would take input voltages of ~30V and convert it to 5V and ~24V.
I was originally looking at linear regulators such as the 7805T, but the specific ...
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MOSFET + voltage regulator usage, pull downs, common ground, schematics
As a continuation of my previous question about what type of part I'd need to control a circuit with a higher voltage, I put together schematics for what I hope would achieve what I am looking for ...
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Step-down chopper with RL load
I am studying a step-down chopper with RL load. I see that the output current waveform starts at a non-zero value (say Imin).
Shouldn't it start from zero? When the switch is closed, how does the ...
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Why is my circuit powered by a 24 VAC -> 5 VDC stepdown module releasing the magic smoke?
I have a Carrier HVAC system in which device controls are all powered by a 24 VAC pair and communicate via an RS485 differential pair.
In the past I've communicated with the bus by using USB to RS485 ...
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2
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Calculating of the maximum output current of a 12 V to 3.3 V step-down converter
I am planning to use the AP3211 step-down converter to go from 12 V to 3.3 V. The maximum current at 12 V that I can supply to the input of the step-down converter is 0.3 A. Assuming the efficiency of ...
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Disabling Two Step-Down Converters Together
I have a circuit using two step-down converters (RT8299) which take in 24V and output 12V to power a 12V, up to 6A resistive load. Each converter is rated for 3A, testing has shown the current circuit ...
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Why does my buck converter output 6.55 V instead of 5 V?
I'm trying to use the LMR51420 Simple Switcher IC to step down my 20 V DC to 5 V DC.
I have this circuit which is the typical application circuit from the datasheet:
When I measure the voltage on the ...
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Stepping down automotive 12V to logic 3.3V
I'm building a kind of CAN bus IO module with an ESP32. This module will control the taillights of my electric conversion project.
What is a robust (reverse polarity protection, overvoltage protection ...
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Powering a 5V solenoid with a 24V digital output
I feel like I have seen many varieties of this question going in the other direction (powering a 24V solenoid with a 3V3 or 5V logic signal) but I'm having issues with finding answers about going in ...
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1
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139
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Is it safe to connect HDMI from a 110 V device with a 220 V device? [closed]
I have a PC powered by a 110 V outlet (220 V-110 V step-down transformer) and a monitor powered by a 220 V outlet. Would it be safe to output my display to the monitor via HDMI?
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1
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Three-phase mains AC/DC conversion to 12 V
I am trying to power an Arduino for a DIY power quality/meter project. It has to work in scenarios without neutral (three-phase delta) so it can still work in case of neutral loss or for applications ...
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Can very high voltage and very low current AC produce strong magnetic flux in the coil?
I have done some research and also conducted some experiments and found that the magnetic flux in a transformer or a coil mainly depends on the number of turns and current flowing in it and not the ...
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1
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Step down 100 V to 26 V with some specific requirements [closed]
I'm trying to repair an HP 8555A spectrum analyzer module which shows problems in the step-down power module.
I'd like to replace the module which steps down the 100 VDC coming from the mainframe unit ...
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2
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Does this phone charger circuit meet the USB port's 1 A current rating safely?
Vp = 170 V; Vrms= 120 V.
I'm using a 9-0-9 1 A step-down transformer, a full-wave bridge rectifier, a 1000 μF capacitor, and an 800 Ω resistance to convert the input voltage to 7.4 V approximately.
...
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1
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Where does the Step-Down Convertor used as compare to RECOM DC/DC converter?
I am reading Step-Down converter and given the circuit below, which is a step down converter. It consists of a MOSFET, inductor, diode, capacitor
And if I compare it with RECOM component DC/DC ...
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54 V input on one, or two 40 V linear regulators? (LM317)
Before I explain the situation I am in, please bear in mind that I am completely new to electronics, and I want to spend as little money as possible on my current project because of outrageous pricing....
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1
answer
129
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Using an open drain buffer as a logic level step down converter
I'm trying to convert a 3V3 UART to 1V8 UART with an open drain buffer, but the output of the buffer is always high.
See the schematic below for the circuit. On the input to the buffer, there is a 0V -...
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3
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Buck converter adjustable output-voltage using digital potentiometer [closed]
I am trying to design a buck converter using an LM2576HV (Vref: 1.23 V) and a digital potentiometer (input: 48 V, output: 0 to 48 V, Imax= 3 A).
The digital potentiometer with the highest supply ...
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1
answer
114
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Buck converter load voltage drop
I'm creating a buck converter from a NE555 and LM358 (feedback loop) for powering a tablet motherboard. (This is a learning experience for me, don't want to use an off-the-shelf board.)
Here is the ...
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1
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711
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24V to 5V step down voltage regulator with LM2678 [closed]
Reference: https://www.ti.com/lit/ds/symlink/lm2678.pdf
I have constructed the circuit above attempting to step down the DC voltage from 24V to 5V. But I keep getting 8.3V as the output voltage. It is ...
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Calculating watt usage from an input/output electronics spec for step-down transformer's minimum watt limit
I'm trying to calculate the minimum watt limit needed for a step-down transformer that convert 220 V to 120V from source (220V) to 125V smart plug then to an electronic appliance with the following ...
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Can this Raspberry Pi UPS circuit work?
I created following UPS circuit to shutdown my Raspberry Pi 3A+ properly:
I would really appreciate if somebody can review my circuit. I know it's a little bit hard to read, but I'm sorry. I'm a ...
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Can I trust a variable voltage step down converter to hold at a fixed voltage
I need a 70 watt capable 76 volt DC-DC supply. I cannot seem to find any readily available on the market, so I considering buying a step down converter such as the one pictured below and setting it to ...
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2
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Improve thermal effeciency of buck LED driver with fixed supply rail
I have this driver circuit that uses an ILD8150:
There are two identical sections of this module on my PCB.
One powers 6 LEDs the other powers only 2 LED. The Vf of the LEDs is 2.85V @ 350 mA.
So the ...
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