All Questions
103
questions
0
votes
3
answers
118
views
Driving a P-channel MOSFET with high voltage input
I designed a buck converter as an MPPT charger using high side switching. It seems the signal on the gate of the MOSFET good. If a solar panel with low voltage like solar MPPT 18volt there isn't a ...
1
vote
2
answers
96
views
Question on Turn-off Snubber Operation
I'm struggling to understand how this snubber circuit reduces power loss during the off time for this buck converter. Anybody able to explain it's operation / what is happening for each component ...
- 13
0
votes
3
answers
115
views
Validate my 3V3 power system
My Power System, can someone validate it? I'm not familiar with using the TPS63060.
Datasheet can be found at: https://www.ti.com/product/TPS63060
I'm trying to power a ATMega328p-AU + 4 digit 7-...
1
vote
1
answer
156
views
Average Modelling of Buck Converter
I am doing Modelling of Buck Converter for LT3890 (Datasheet link attached) for Frequency response analysis .
I have some reference model of Buck converter ,please refer below image
Datasheet Link: ...
- 119
0
votes
0
answers
51
views
DC-DC boost Converter for a motor load
To give some context I have a 250 watt DC motor It is powering an electric race car for a school race my class is competing in. The rules say I have to use a specific unmodified motor supplied by 2, ...
1
vote
1
answer
187
views
Can I connect buck boost converters back to back?
I need to power a Bluetooth speaker (Beatbox Portable) with a battery pack while also allowing DC power in.
I also want to use the input DC power to charge the four cell lithoum ion battery pack.
Can ...
- 11
0
votes
1
answer
94
views
How to divide 12V/15A buck converter output into two outputs with the same specs? [closed]
I am currently working on a project to build a mini-atx pc for a rover. Heres a simple schematic of it :
The picoPSU Atx connector takes in 12V DC with a max of 15A peak and the zotac gpu 12V DC with ...
2
votes
0
answers
120
views
Power circuitry not coming up
I've created a PCB that has two buck/boost converters, the second one being connected to the output of first one. The enable pin of the second buck converter is connected to the PG pin of the first ...
- 163
0
votes
0
answers
50
views
Can a buck converter functioning in CCM have non-linear behaviour at light load currents?
I've been designing a Simulink/Simscape model of a TI buck converter launchpad (https://www.ti.com/tool/BOOSTXL-BUCKCONV) and I'm trying to have my model fit the behavior of the device.
The board can ...
- 1
0
votes
0
answers
41
views
Low Side N-Channel 75V to 12V Buck Converter with feedback
I want to design a buck converter for E-bike with 75V input and 12V, 20A (240W ideal case) output to drive the other components of E-bike using n-mosfet as a low side.
I also want to use a feedback ...
1
vote
1
answer
191
views
Buck converter simulation(Psim) always return the half value of the output voltage
I try to design a buck-converter in PSIM simulation program. Let me write the circuit's requirements:
Frequency = 80kHz
Ripple < 0.5%
\$V_{input}\$ = 30V
\$V_{out}\$ = 12V
\$R_{load}\$ = 10 \$\...
- 11
0
votes
1
answer
167
views
What extra components are necessary to bypass a boost converter when the input voltage exceeds its regulated output voltage?
I've made a USB-C power supply that's powered by a wind turbine. It contains a boost converter and a separate buck converter.
I'm aware that there are several buck/boost USB-C power supplies out there,...
- 313
0
votes
2
answers
366
views
Buck Converter Inductor Ripple Current and EMI
When attempting to reduce EMI at the schematic design stage of a buck converter it's often recommended that one minimize the output ripple voltage. It's clear why this would be useful.
Rarely is it ...
- 187
0
votes
0
answers
58
views
Using 2 LiPo Batteries via 2 Buck Converters for External Notebook Power Supply - will it work?
I have an old ThinkPad X220T notebook of which the internal battery is broken (and removed).
To get my notebook working on the go again I want to build an external portable power supply with 2 LiPo ...
1
vote
1
answer
48
views
Synchronous buck converter designing issue
what I'm recently occupied with is trying to create a model and later build a synchronous buck converter. I've been doing some troubleshooting to try to resolve my issue, but honestly I just got stuck....
- 11
1
vote
1
answer
121
views
24 V input, three 5 V outputs DC-DC buck converter design
I would like to make a DC-DC buck converter which has 24 V input and three 5 V outputs, but a typical buck converter circuits have only one output. How to change it to three outputs without an extra ...
- 13
0
votes
2
answers
136
views
Buck converter and resistive wire
I'd like to ask about my circuit.
It is a variable buck converter operated by an Arduino. At the end the 22 Ω resistor is resistive wire supposed to get hot because of the current.
One thing that ...
- 13
0
votes
2
answers
801
views
What is the mode of MOSFET or BJT in buck converter?
I want to implement buck converter with conventional design (not synchronous etc) like below.
And I want to implement the converter for two cases. One is to use BJT as switching device and another is ...
- 11
2
votes
1
answer
238
views
Critical inductance for buck converter
I have this problem: -
The critical current must be \$P_{out} = V_{out}I_{crit} \Rightarrow I_{crit}=\dfrac{45\text{W}}{16\text{V}} = 2.8125 \text{A} \$
Using eq. 3.43 from Ned Mohan's book we have
$$...
- 4,145
0
votes
0
answers
247
views
How to design a filter for multiple buck converters
I am designing an electronic circuit with multiple buck converters on it. All bucks are supplied by a 12V DC input voltage from a converter which is on an other card. I want that my converters don't ...
- 1
0
votes
2
answers
1k
views
High Voltage PWM
I really hope someone can help me with this difficult issue:
I want to generate a PWM signal from a 170V DC input.
ok, so far I have an arduino that can generate a PWM signal and drive a MOSFET that ...
- 11
1
vote
2
answers
138
views
Buck converter output voltage dips and makes noise when connecting 1A load
I've designed a buck-converter board using a ROHM BD9F500QUZ-E2 for 12 V output. Input will be connected to a 4S battery.
On no-load conditions, the IC outputs 12 V, and when the IC is loaded with 500 ...
- 49
0
votes
0
answers
28
views
power available to a DC-DC step down atached to an ac power adapter
I have an AC-DC power adapter with output rated at 3.42A @ 19V and a Step Down Buck converter Xl4015 rated to manage up to 5A with 96% efficiency conected to the power adapter output.
What is the ...
-2
votes
1
answer
692
views
Why do I get these voltage spikes in my buck converter? [closed]
I want to make a buck converter with bidirectional GaN FETs, so each switch is made up of two back-to-back GaNs:
The problem that I encountered is that if I have a deadtime (DT) higher than 0 ns ...
- 11
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
vote
0
answers
243
views
Synchronous DC-DC buck converter body diode switching loss
I have a couple of questions regarding the body diode of MOSFET.
I was looking at the calculation of the switching losses in the synchronous buck converter.
For calculating the turn-off switching ...
- 43
-1
votes
1
answer
104
views
Understanding Buck Converters [closed]
I need a little help designing a buck converter. Basically I want to generate a 5V output that will stay the same regardless of load resistance and that will exist when the input varies between 12 and ...
- 1
0
votes
0
answers
111
views
Buck converter design review - updated
Last week I asked this question attempting to find a solution to efficiently converting higher voltage to lower voltage.
From the answers, I arrived at TI Power Designer and I ended up with this ...
- 360
0
votes
2
answers
2k
views
How does a boost converter allow for a gain in output voltage by just switching the positions of the inductor and switch?
I get that in a buck converter, a low pass LC circuit was attached and this effectively filters out high frequencies. If the bandwidth is configured so that it is lower than the switching frequency, a ...
- 469
1
vote
4
answers
154
views
Can a Buck converter operated at 200kHz be used to step down 230V DC input to 5V DC output?
I was wondering whether this type of converter is possible. Any clarification on it will be appreciated. Thanks.
1
vote
1
answer
114
views
Synchronous Buck Converter Mathematics
Ive been trying to find a mathematical explanation on how a Synchronous Buck converter maintains continuous operation under ideal steady state conditions. I understand the underlying concept but i ...
- 89
0
votes
1
answer
128
views
Wide Range Input DC DC Buck Convetrer Design
Im having trouble understanding how i can achieve a constant output voltage with a varied input voltage. I know how to design a buck converter with a constant output when the input voltage is fixed ...
- 89
0
votes
1
answer
45
views
High Current Buck Converter with wide input voltage [closed]
I'm currently building a powerbank with PD outputs that are capable of outputting 5 amps at 20 volts, but my battery pack is 33.6V (8S Li-ion). I've managed to find a possible buck converter IC (...
- 3
0
votes
1
answer
320
views
Question regarding chinese voltmeter ammeter module
I am new to this forum. I am a Diploma in Electronics from India and a passionate DIY hobbyist too.
I have a question regarding cheap 10 amp ammeter and a voltmeter module I bought off aliexpress.
I ...
- 1
1
vote
2
answers
419
views
Drop input voltage for a boost converter
I have a 21V DC solar panel power source, that feeds a DC-DC boost converter. I set the output voltage of the boost converter to 19.5V to charge my laptop, but since the input voltage is higher than ...
- 111
1
vote
1
answer
193
views
I can't get the desired output voltage
This is a simulation of a buck boost converter. I want to get -12V as the
output voltage , but I get -1.148V.
I checked the PWM and the duty cycle and it is right.
I think that my problem in ...
2
votes
3
answers
6k
views
Is it better to have a higher Vgs than Vds on a MOSFET (n-channel)?
I've been studying MOSFET switching applications recently, and have been playing with the Circuit Simulator Applet here. In my diagram below, I have Vds usually set to either 12 or 14, as I am trying ...
2
votes
2
answers
129
views
In a buck boost inverting converter is there any difference exchanging the position of the diode from the positive to the negative rail?
In a buck boost inverting converter is there any difference exchanging the position of the diode from the positive to the negative rail keeping the same current rotational direction ?
- 152
6
votes
7
answers
8k
views
How to reduce MOSFET heating in Buck Converter
I have designed this Buck Converter which convert 60VDC to 12VDC at 10A.
Switching Freq 100KHz.
Facing MOSFET too much heating issue.
MOSFET ON time and OFF time is decided by a UC3845B based circuit. ...
- 97
0
votes
4
answers
108
views
LED DRIVER: Buck Converters output current ripple
I need to design a led driver of up to 1A, to drive some infrared and near infrared LEDs.
Due to the nature of my application, the intensity of the light should be as stable as possible, as ...
- 23
0
votes
0
answers
42
views
Step down converter stops regulating above 6V input
I'm currently using the following step down converter in a 4xAA battery powered design -> TPS62745
I have my Vselect pins configured as 3.3v out and using 4.7uH / 10uF combination on the output ...
- 143
2
votes
0
answers
329
views
Inconsistent Output Voltage in DC-DC Buck Converter
I'm trying to implement the following tps54302 DC-DC buck converter, for a 5V 3A output:
All resistor values 1% tolerance, capacitors 5% tolerance, inductor 20% tolerance.
I'm testing with a bench ...
- 21
0
votes
4
answers
241
views
Switching and non-switching period in buck converter
I am using TPS54260 buck converter to step down 10V to 3.3V. Load = 1A.
While measuring the output voltage and switching frequency using oscilloscope, I am observing this:
During no load condition ...
user220456
0
votes
1
answer
3k
views
What is Pass Transistor?
What is pass transistor?. How does it work?.
while reading about the DC-DC converter, I came across Pass Transistor.
2
votes
1
answer
96
views
Why do I get this waveform at the output after power down of Buck Converter
I am having a buck converter which steps down 8-16V input to 5V output. Load current = 0.6A
But upon removing the input power, I get the attached waveform.
My schematic circuit is similar to the one ...
user220456
0
votes
0
answers
210
views
DC/DC Buck Converter PCB Layout Help
Most examples I find are for buck converters on a PCB of their own with massive traces. I want to make sure this layout is fine with the planes I'm using(both top and bottom copper pour layers are GND)...
- 35
-1
votes
1
answer
203
views
Buck step down convertor uses a lot of current? [closed]
I have a DC-DC buck step down converter module LM2596 voltage regulator
set to supply 3.0 volts to an atomic clock using a 8 Ah 12 V battery. The clock normally uses 2 AA batteries.
https://www.ebay....
- 209
1
vote
1
answer
2k
views
LC ringing on synchronous buck converter
I am working on a board that uses LTC3891 as a buck converter to step down 24V to 12V. There is quite a significant oscillation at the switching node, upstream to the inductor which I am curious about....
- 367
0
votes
1
answer
2k
views
Buck converter MOSFET getting hot
I am building a solar charge controller. I have based the design on pwm5 by Julian illet (circuit diagram attached). I am trying to convert this PWM charge controller in to a mppt one.
The buck ...
1
vote
1
answer
735
views
Boost Capacitor of Step-down converter
I'm working on the LT8607 Step-down converter to convert from 12V to 5V/500mA output.
The circuit schematic is as below.
What is the purpose of using the BST capacitor as shown in the schematic.
