All Questions
59
questions
0
votes
1
answer
95
views
What is the "best" way to make a diy 7v rechargeable battery?
I have a device (the wii "sensor" bar, basically an IR LED array) that the literature says takes 7v. I can't find any battery offerings that come in 7v, but many that are 3.7v, so I am stuck ...
- 141
0
votes
1
answer
574
views
TL494 step-down converter high voltage LTSpice
I have tried to make LTSpice of step down DC-DC converter, however I cannot get it to work. I suspect the schematic is good however either LTSpice model is not correct or I made some critical mistake.
...
- 145
1
vote
1
answer
125
views
Burning sound from the PSU
I am trying to make a bench power supply from an old 350W PC PSU
that provides 4 lines
3.3V 8A
5V 9A
12V 11A
-12V 1.5A
Here is the connections diagram:
I used this step down module to be able the ...
1
vote
1
answer
233
views
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 ...
- 3,404
1
vote
0
answers
105
views
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 ...
1
vote
3
answers
113
views
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 ...
- 23
1
vote
2
answers
203
views
How to calculate bootstrap Resistor in MC34163 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. ...
- 3,404
0
votes
5
answers
397
views
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, ...
- 53
0
votes
1
answer
50
views
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
...
- 117
2
votes
2
answers
319
views
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 ...
- 99
0
votes
0
answers
59
views
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 ...
- 29
2
votes
2
answers
209
views
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 ...
- 345
3
votes
1
answer
183
views
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 ...
- 31
1
vote
1
answer
121
views
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 ...
2
votes
3
answers
1k
views
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 ...
- 21
-1
votes
1
answer
143
views
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 ...
- 103
0
votes
1
answer
1k
views
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 ...
- 11
1
vote
2
answers
76
views
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 ...
- 1,235
0
votes
1
answer
596
views
Step down buck converter - lower input voltage than output - LM2596
I want to power 5v leds from a 12v source in my car using a "DC-DC Adjustable Step-down Buck Converter LM2596 3A". The source has a dimmer switch which can regulate the voltage from 12v to 1....
- 1
3
votes
0
answers
180
views
LM3150 Webench not matching with LTSpice?
I'm trying to implement this design from Webench (5V @ 10A):
I'm using LTspice to simulate this design, but my results are bizarre, as shown here:
I have looked into this thread: TI Webench and ...
- 31
0
votes
1
answer
365
views
Step-down converter in an ATX PSU, why?
I was recently looking at a 500W PSU schematic, and found out they used step-down converters on 12v and 5v output. Schematic is attached(pls see hi-res at https://ibb.co/nbDRJPq)
The D2 diode charges ...
- 392
-1
votes
2
answers
273
views
Buck / step down voltage in limited space
I am designing a small PCB. The supply voltage is 12V, but I also need 5V with supply of maximum 250mA.
The most obvious solution is to use voltage regulator - there are plenty of them and some like ...
- 555
2
votes
1
answer
704
views
Switching regulator vs converter
Is there any difference between switching regulators and converters? I have read about step-down voltage regulator and buck converters and they seem to be the same. So, can I use the term converter ...
- 37
1
vote
1
answer
1k
views
What is the difference between buck and step-down converter
I always thought "buck" and "step-down" are synonyms. But now I'm looking at two datasheets:
CAT4201
CAV4201
They seem very similar, but the first is described as "350 mA ...
- 1,235
1
vote
0
answers
101
views
How to select external components for a buck converter?
I design a simple circuit activates fan when processor heats up and then control rotation speed. The fan has a brushless motor with an internal motor controller. So I got the idea to create a buck-...
- 21
1
vote
0
answers
658
views
Buck converter (TPS54331) oscillating
I have designed and built a buck converter based on the TPS54331 which oscillates at 5.4kHz with an amplitude of 700mV peak-to-peak under a 1A load. I want to remove these oscillations.
Here is a ...
0
votes
1
answer
1k
views
Understanding Power Good Signal in TPS54719
I'm using TI TPS54719 DC-DC and I'm trying to understand the PWRGD signal functionality.
Definition of PWRGD pin in datasheet: An open drain output, asserts low if output voltage is low due to thermal ...
- 1,067
0
votes
1
answer
130
views
Converting 12 Volt Lipo to 5V with Buck Convertor
I'm trying to power a large bank of LEDs that require 5V at 5 amps. I plan to use a 12v hobby Lipo attached to a buck convertor to step that down. I also need to power a teensy microcontroller with ...
1
vote
2
answers
322
views
Do I need to include overhead when picking a power supply?
I need to power 40 Raspberry Pis, each requiring a 5V input and have a maximum current draw is 2.5A.
This would mean:
5 x 2.5 = 12.5W
12.5W x 40 = 500W
That I ...
- 408
0
votes
0
answers
166
views
How to reduce noise Buck converter at constant current mode ACT4088
Hello i am using a ACT4088US-T (datasheet here) Buck converter and i made it to run in constant current mode 500[mA] through a Diode (D5):
Everything works fine. It draws 500mA no matter the load i ...
- 3,404
1
vote
1
answer
524
views
Buck Converter design, which is better? 48V->12V direct conversion or 48V->24V->12V conversion for 12V application
I am designing a 1KW DC-DC buck converter with Vin(51V battery pack with Vnom = 48V) for driving four 250W motors. Is it advisable to step down the voltage directly from 48V to 12V or should I first ...
0
votes
1
answer
57
views
Determining \$I_{peak}\$ and \$f_{min}\$ and \$f_{max}\$ for MP4569 buck IC
Trying to figure out what inductance value is needed for my application of MP4569.
They give the minimum inductance value in terms of \$I_{peak}\$ (page 12):
\$L_{MIN}={{V_{IN(MAX)}{\times}t_{ON(MIN)}}...
- 825
0
votes
0
answers
34
views
Constant Voltage Power Supply
I’m working on a project were I need to power to some 24V 4-20mA sensors, a 3.3V ESP32 and a 5V SIM808 module.
To accomplish this I’m using a step-down buck converter to reduce a 12V electrolytic ...
- 11
2
votes
2
answers
593
views
Limiting input voltage for buck converter
I want to power some micro controllers and a couple of leds on my electric bike, counting up towards 5 Amps.
Power supply is a 36V battery, with a range of about 42V to 33V. This voltage is to be ...
- 43
1
vote
2
answers
265
views
MCP16301 fail on power up - Vin shorted to Vout
I have designed a step-down converter PCB (4-layer) with MCP16301. It converts voltage from 24V to 5V.
When I connect it to power source and then connect a 100ohm resistor (50mA@5V) it works normally....
- 13
3
votes
2
answers
199
views
One step-down regulator 24 V to 1V or two step-down regulators with lower steps?
I am trying to design a working principle scheme to step-down the input voltage from 24Vdc ---> different low voltages (1.8 V, 1 V, 1.5 V, 3.3 V with ripples ~ 1%).
Could you kindly explain me the ...
- 59
1
vote
2
answers
875
views
Using LM2596 step-down with Li-po
I'm doing a project with an ESP32 (3.3 V), a DHT11(3-5 V), a soil sensor (3.3-5 V, the cheapest Chinese), NRF24L01 (2.6-3.6 V).
I'm using LiFePO4 right now (3.32 V), but when the battery voltage drops ...
2
votes
1
answer
1k
views
Will a buck converter allow current to pass through if Vin is less than the configured output voltage?
In general, will a buck converter allow current to pass through if Vin is less than the configured output voltage?
Specifically, I'm reading the TPS54308 datasheet and I'm not seeing an answer to my ...
- 245
2
votes
2
answers
2k
views
Is it possible to convert 19.5V 3.33A to 12V 5.5A?
I have a laptop charger which has 19.5 V 3.33 A output. I want to use it for raspberry, which needs 5V and 2.5A and for monitor which needs 12V 3A. Is that charger strong enough to run the whole ...
1
vote
0
answers
207
views
DC-DC buck output voltage
I am designing a DC-DC step-down converter (asynchronous) and I would like to achieve a Li-Po charging with it (18 - 22 V input voltage). My goal is the CC/CV charging but to do this, I need constant ...
- 31
0
votes
1
answer
107
views
Correct power supply for my project
I am making an autonomous bot where i need to power a few sensors (IR, PIR, sonic,etc) and an arduino. In total the sensors draw about 300 mA current(max).
My power supply is a LIPO of 12 V (11.1 V),...
- 151
0
votes
2
answers
328
views
Current relationships across a voltage step down convertor
This question arose from a conversation over the weekend and we tied ourselves in knots trying to get to the bottom of it. I didn’t have time to put a simple circuit together so it would be great to ...
- 105
0
votes
3
answers
4k
views
high current buck converter?
I am in the process of building a power bank with 18650 batteries for a trolling motor. The nominal voltage for this battery is 14.8 V. The motor specs are 12 VDC - 45 A max current draw.
Now the ...
- 61
2
votes
3
answers
2k
views
How does using a DC-DC step down converter save power?
I understand how DC-DC buck converters save power when compared with a linear regulator, but do they save power when compared to not using power conversion all together? In my specific case, I have a ...
- 639
0
votes
2
answers
641
views
Step down from USB (5 V) to 4.3 V for battery dummy
I have a camera for which I bought a dummy battery to connect it with power bank or other power source. Original battery is 3.6 V Li-ion so I need around 4.3 V but the USB (from powerbanks) is 5.1 V ...
-1
votes
2
answers
455
views
build or buy buck converter
Hi I am looking to step down a 10 volt DC to 5 DC with low output current (less then 1 amp)
Is it the best to build a buck converter or to buy it ready ?
thank you
Actually I am using an arduino,
I ...
- 29
0
votes
2
answers
1k
views
Using parallel inductors on LM2596
In the datasheet of LM2596, 33uH or 47uH inductors are recommended for 5V output. I can't find any high amperage inductors of those values. So that if I use 100uH of 2 inductors in paralell(they will ...
- 71
3
votes
3
answers
2k
views
Step-Down/Buck-Converter: How to replace feedback voltage reistor divider to electronically control the regulator output voltage
Most today used switching regulator ICs that I've seen have some kind of feedback voltage pins. I think I've pretty understood the way it works:
A resistor divider from output to ground is created to ...
- 288
2
votes
2
answers
2k
views
Cooling buck converter mosfets by placing on bottom layer of PCB - a problem?
I have a design and layout for a buck converter which currently sits on one layer of a 2 layer PCB. I would like to force-cool the heat generating components of the board by placing them directly onto ...
- 133
1
vote
2
answers
429
views
What is the equivalent of a buck converter for AC voltage?
A have researched and found that a buck converter is used for stepping down voltage in DC applications.
However, my application uses AC current. I have christmas lights that plug into the wall and I ...
- 506