Questions tagged [constant-current]

Questions regarding constant-current supplies, devices and applications, as opposed to constant-voltage supplies. The voltage can vary while the current remains the same. Common in LED lighting applications and battery charging.

Filter by
Sorted by
Tagged with
0 votes
1 answer
49 views

Constant current driver issue or misunderstanding

I want to learn how to use a constant current driver. After some research I ordered an NSI45030AT1G driver which delivers 30mA from 10V to 40V according to the datasheet. After a real testing, I am ...
SkePsis's user avatar
  • 67
6 votes
2 answers
1k views

Is an LED driver IC just a boost conv with voltage across Rsense fed into FB?

There's these really cool things called power modules, but they are all marketed as normal dc-dc converters. Not many as "led drivers" for currents more than 1 A. The basis behind this ...
roaibrain's user avatar
  • 279
0 votes
1 answer
41 views

Relay to read only pulse signal not constant signal

I am trying to find or create a relay that provides power when there is a 12v pulse signal that last less than 1-2 seconds but if it receives signal longer than 1-2 seconds then it should stop or not ...
BonezMedia's user avatar
-1 votes
1 answer
268 views

What is the basic idea behind the so-called "improved Howland current source"?

I dedicate my question and answer to Gordon Deboo - the inventor in the shadow of Howland. The motive The idea for this Q&A came about yesterday after a related question was closed. Original ...
Circuit fantasist's user avatar
1 vote
2 answers
151 views

Howland circuit gain factor [closed]

I do not understand how the gain of the Howland circuit can be derived on an operational amplifier. I am attaching a photo of the circuit
niobium04's user avatar
0 votes
0 answers
29 views

Does current mode control for dc/dc conv imply a constant current output?

I am getting very confused, I have read articles about current mode and voltage mode control, and it seems that most converters use current mode control - which seems has two nested control loops. The ...
roaibrain's user avatar
  • 279
1 vote
1 answer
71 views

Rds(on) value of MOSFET constant current LED driver IC

I am testing a non-isolated APFC buck constant-current LED driver IC (model no.: BP2362XH) in my LED driver circuit. It operates in critical conduction mode (according to the datasheet). There are a ...
Sanjaya Wijewardana's user avatar
0 votes
1 answer
64 views

Understanding lead-acid battery charge

I´m trying to understand how lead-acid batteries charging work. So far what I tested: If a 14 Vdc supply is connected in a 12 Vdc battery, the voltage will drop to the battery level, and start going ...
samuel mattio's user avatar
1 vote
1 answer
51 views

0V with Electronic Load and CC Buck

Why would an electronic load show 0 V and a big current when connected to a constant current source? The load is in constant current mode. Is that the culprit? Probably a constant impedance would be ...
TobiasPSP's user avatar
1 vote
1 answer
60 views

RGB LEDs indvidual brightness control [closed]

i want to make RGB LEDs panel using https://www.lcsc.com/product-detail/Light-Emitting-Diodes-LED_TCWIN-TC5050RGBF08-3CJH-P35C_C784539.html RGB LEDs. I will put 100 LEDs in tha panel and want to ...
Zunuran Nasrullah's user avatar
1 vote
4 answers
166 views

Collector current vs. collector-emitter voltage

Why is the collector current in an NPN transistor in CE mode almost independent of the collector-emitter voltage? Doesn't increasing the reverse bias voltage (Vce) decrease the width of the base (due ...
Vinay5101's user avatar
0 votes
0 answers
56 views

How can I sum the output of the two opamps and multiply the voltage swing to +2vcc and -vcc

I have a VtoI circuit that you can see in the figure below. According to this circuit, I can receive a maximum sin current of 4 mA with a maximum load of 5 kΩ. Considering that the supply voltage for ...
raha's user avatar
  • 1
0 votes
0 answers
23 views

Can I use BP2857 constant current LED driver IC with a PWM-controlled MOSFET for dimming and turning the lights on or off with an ESP8266/Arduino?

I am trying to build a remotely controllable aquarium LED light. I live in a country where DigiKey and Mouser are not a thing. Electronic components are hard or impossible to find in this country. So ...
ISHRAQ's user avatar
  • 23
1 vote
1 answer
50 views

Connecting multiple loads in self-balancing parallel [closed]

I have three (or 'n', where n=3 at the moment) large LED panels that I want to run in parallel. As we know (or should have known before the 'royal we' actually tried it!), just wiring them together in ...
jackisquizzical's user avatar
0 votes
1 answer
93 views

I don't have constant current in this circuit

I have problem with this circuit, which purpouse is to give constant circuit on R7 resistor. Why i can't get constant circuit? Is it problem with simulator?
Византија Исток's user avatar
0 votes
1 answer
48 views

Using E3640A as current source

There is a E3640A power supply need it to function as a current source. In regular power supplies we set the maximum limit current and the regular voltage we want to output. In the manual shown in the ...
Josh23's user avatar
  • 1
0 votes
1 answer
52 views

Output voltage not changing with a constant current driver

If I attach a voltmeter to the output of this constant current driver and lower or raise the input voltage (100-230V,) the output voltage remains constant at 56V. Should it not fluctuate between 40-...
Guit4eva's user avatar
  • 115
1 vote
2 answers
76 views

Alternative method of high power constant current drive for LEDs

The only high power, constant current method I am aware of involves using a MOS switch in conjunction with an inductor to alternately power and disconnect the LED, achieving an average current flow. ...
Antron Mack's user avatar
0 votes
2 answers
187 views

How to understand current limiter circuit

Here the MOSFET IRF9530 works in linear mode of operation and transistor works in forward active. Load resistance is 5 Ω and up to 15 Ω I can keep this MOSFET is linear mode and on increasing further ...
Praveen Kumar's user avatar
1 vote
1 answer
61 views

Boost Current and Limit Voltage

I have a radar gun which has a serial interface. The gun reports the velocity out to the serial port. I want to attach a microcontroller (ESP8266/ESP32) to the serial interface and forward the ...
namarino41's user avatar
1 vote
1 answer
38 views

Using VOUT to Power Up a DC-DC Switching Regulator

I am trying to use LM5117 to convert 36V (VIN) to 32V (VOUT) for constant current constant voltage application. It seems the datasheet is saying if the VIN > 14.5V I can use VOUT with a Zener diode ...
nmr's user avatar
  • 123
0 votes
1 answer
98 views

Building a constant current circuit [closed]

The constant current output should be able to be set from 0.2 mA to 20 mA with a load of 3500 ohms ±50% from a 5V battery source and a PWM signal set by a microprocessor. Do I need a transformer or ...
Marc's user avatar
  • 1
0 votes
1 answer
86 views

Need cheap variable positive/negative switching bench power supply with CC

Just for fun I want to make a lightweight, cheap, adjustable positive/negative bench power supply. "Lightweight" means that using an old PC ATX power supply isn't suitable as a basis. ...
Mike S's user avatar
  • 153
3 votes
1 answer
176 views

Simplest voltage-controlled constant current source outputting 500 mA

I'm trying to design a very simple, beginner-friendly voltage controlled current source that will output 0.5 A through a load resistor. The load (some current-activated nitinol wire) will be about 10 ...
Bee's user avatar
  • 597
0 votes
0 answers
49 views

Calculating JFET stats for a constant current source [duplicate]

I need to find a constant current source for a variable LM317 current regulator (schematic below), and I would like to know which JFETs to use. Can somebody let me know how much current I need and ...
Klumpy7's user avatar
  • 382
2 votes
1 answer
283 views

Airport runway lighting: What is constant current in relation to alternating and direct current?

I’m an apprentice electrician currently replacing runway lights and pulling new wire at a small international airport. When I asked I was told they are 5kV direct current. Okay… simple enough. What ...
Incompetent Jim 's user avatar
0 votes
1 answer
105 views

Instructables DIY current limiter circuit [duplicate]

I found this inline and was hoping if that circuit is okay. Instead of a battery though, I want to use a dynamo (plenty of juice-wise). Output of dynamo is 18 V 200 mA. I wish I could adjust the ...
imran muhd's user avatar
0 votes
0 answers
33 views

1S Li-Ion BMS Design

I want to use AP6633 Protection IC along with MCP73833 Charging IC for 1S Lithium-Ion Battery. The issue is pinout of AP6633. I really dont have any idea how to connect AP6633 Pins to MCP73833, More ...
Zunuran Nasrullah's user avatar
1 vote
1 answer
89 views

Isolate current flow in Ltspice using switch

I am trying to control the flow of current by the switch SW, I have used an independent current source I. However the switch is ineffective to isolate the resistor R1, because the switch is basically ...
Avijit Das's user avatar
0 votes
4 answers
159 views

How will two parallel LEDs behave on a constant current source?

Another user made the following claim: You cannot [LEDs] in parallel and expect the current to magically divide in half. Of course, this is exactly what someone just starting in EE would expect to ...
Matthew's user avatar
  • 572
0 votes
2 answers
133 views

How to wire mixed-count groups of LEDs?

I have a bunch of LEDs (all the same part number / specification) that I want to light up using a shift register. The trouble is, each output bit should control a different number of LEDs (depending ...
Matthew's user avatar
  • 572
1 vote
0 answers
111 views

Constant current LED driver temperature issue

I am using a DC-DC step-down constant current LED driver to power up four high power LEDs in a series connection. The LEDs are drawing a 2 A current at 100% power and they have forward voltage about ...
Lime7's user avatar
  • 33
0 votes
1 answer
114 views

Buck converter not behaving as anticipated with new trim pot resistors

I recently purchased a 300W buck converter from amazon 1 which has two 3296W 100K trim pots to control the constant current and constant voltage output. My plan was to use them as bench power supply ...
Prashant's user avatar
  • 131
12 votes
5 answers
3k views

Is it recommended to set the current limit on a bench power supply by shorting it?

I have a Rapid 85-1901 switching mode 0-20V 0-5A bench power supply: Without a load attached the current shows 0A no matter how you turn the dial. After searching how to set the current limit online, ...
Danny Beckett's user avatar
0 votes
1 answer
43 views

Relationship between RMS-current and energy stored in a solenoid

Regarding the formula for energy stored in the magnetic field of a solenoid (U=1/2LI^2), I presume that the RMS value for an alternating current could be used for the I-value. Is this correct?
proton's user avatar
  • 1
2 votes
0 answers
69 views

Constant current controller for a 5V, 400A supply [closed]

I'm a grad student with some practical experience in electronics but very little foundational understanding. I have a new project that requires a low voltage and high current (5V, 400A) and I've ...
king_geedorah's user avatar
0 votes
1 answer
100 views

Constant current near to maximum load current

Following on from my last question where I asked about dual purposing a PFET used for reverse polarity prevention for current limiting to a load (spoiler, that doesn't work for my application), I have ...
learnvst's user avatar
  • 1,281
3 votes
1 answer
119 views

How to make fast CV/CC transition in linear NMOS regulator?

I want to design a linear regulator based on NMOS with CC/CV capability. I made a circuit with two separate loops (CC and CV), each of which is stable. The problem is in the transition moment when the ...
Vasiliy's user avatar
  • 85
0 votes
0 answers
103 views

Difference between DM13A and TLC59281 Constant Current LED sink Drivers

I was using DM13A driver in my old PCB designs and it was working perfectly using Arduino Mega. Due to parts shortage at JLCPCB I had to use TLC59281 driver for my new PCB. But TLC59281 is not working ...
Zunuran Nasrullah's user avatar
0 votes
2 answers
210 views

Replica Board of Samsung Horticulture Gen2 Module

I want to make Replica board of Samsung Horticulture Gen2 Module but with smaller form factor. I am using 42× LM301H (Full spectrum) and 8× LM351H LEDs. IF of LM301H is 65 mA and IF of LH351H is 350 ...
Zunuran Nasrullah's user avatar
3 votes
1 answer
138 views

Keep frying constant-current LED drivers and LED PCB modules

This has happened twice and I'm hoping someone can tell me what I'm doing wrong so that I don't fry another set of drivers and LEDs. I have an array of high-intensity LEDs for a crop imaging ...
Tim Keller's user avatar
1 vote
0 answers
44 views

How to provide a low response time <1µs constant current source up to 1.5A

I need to provide a constant current source that can provide up to 1.5A current and a compliant voltage of 0-40V, with a low response time of <1µs. How should I approach this problem? Common bench ...
hailstone's user avatar
4 votes
5 answers
716 views

In the circuit below, assume ideal op-amp, find Vx?

Assuming ideal op-amp, I have this question that asks to find Vx: Here is my solution, how can I verify my solution? Can anyone check please? Ok, after seeing the comments, I tried again and got ...
Yousef Zerini's user avatar
0 votes
0 answers
45 views

How do I power an inverter using a combination of a car and an external battery but limit the current taken from the car to only 100A?

The car in question is a Nissan Leaf, whose 12V "starter" battery is replenished by an onboard DC-DC converter with a maximum safe output of about 100A (this is used as a handy way to tap ...
LMF5000's user avatar
1 vote
0 answers
65 views

LED circuit with an AL1793

I'm currently making my own light fixture, a multicolor Par light to be exact (and a few other types once this is successful). Now I'm trying to control a string of 6 multicolor LEDs. The circuit will ...
RektByMemes's user avatar
1 vote
3 answers
173 views

Op-amp as constant current sink

The red circled part is acting as a constant current sink circuit but I can't understand how. If someone can share the calculations or formula or even explain what is happening?
Rachit Juthani's user avatar
0 votes
1 answer
63 views

Constant current LED driver replacement [closed]

I have a LED lamp fixture with a constant current driver that I need to replace. The old driver has a set of DIP switches to select the output current and is currently set to 29W and 650mA constant ...
allu's user avatar
  • 101
0 votes
1 answer
126 views

High power constant current source [closed]

I want to make a high power flashlight with a 10 W (3.3 V 3 A white) LED in it, its a single LED and 2 Li-ion batteries in series. The problem is that I can't find a good LED driver to have a ...
aref niki's user avatar
1 vote
4 answers
329 views

Issues driving 3W RGB LED (common anode): Can't light all 3 colors at once

I hate asking advice somewhere that I can contribute little so trust when I say that I have logged many, many hours researching this.. have watched every relevant video on YouTube I can find, every ...
Outbak Jak's user avatar
0 votes
0 answers
141 views

Charging a Li-ion battery using both constant current and constant voltage circuit

I was developing a wireless charging circuit and have a made the receiver circuit. the circuit is meant to charge a Li-ion battery (Makita). I have a voltage regulator in the receiver circuit that ...
EmeraldMonk's user avatar

1
2 3 4 5
13