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Questions tagged [linear-regulator]

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4answers
64 views

Too low efficiency with “0-30V 2mA-3A DC Regulated Power Supply unit with Continuously Adjustable Current Limiting Protection” PSU kit

I ordered and assembled the kit (link and image added below). Everything works fine. But as everybody knows, it requires a great heat sink for the regulator. The ordered unit costs less than $5, but ...
0
votes
0answers
33 views

high voltage input low output regulator [on hold]

I need to voltage regulator for supply of microcontroller.Regulator details should be as: input voltage range of regulator: 3v-200v output voltage range of regulator: 2.7v or 3v or 3.3v (for supply ...
0
votes
2answers
49 views

Is this a suitable Voltage Regulator to replace an old circuit on my board and is my logic correct?

I have 4 of these 2n3904 transistor setups on my board: A1 -- requires 5v on these 2 connected pins to be enabled. I control this by driving r2 high at 3.3v which should allow 5v to flow through the ...
0
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1answer
42 views

PI controlled linear voltage regulator with overcurrent protection

I designed a simple linear voltage regulator for high voltage application around 500V which is controlled by a PI controller. Schematic 1 shows the raw design using a bipolar transistor to control ...
1
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1answer
57 views

Can I use same LDO for two outputs?

Can I use same LDO for two or three outputs? Given that the LDO provides enough needed current for three devices.
1
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1answer
36 views

How to connect two LDOs in parallel?

I have two LDOs that convert different input voltages into the same voltage. I'm not sure how to safely connect the outputs together so they become the same signal and can be both be used to power the ...
-1
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0answers
41 views

How to get two outputs of 5 and 12 V from bench power supply using DC to DC converter

So i want to design 3 circuits which are similar in structure. Input of the first one is anywhere between 0-5V and i need 2 outputs 5v and 12v Input of the second one is anywhere between 5-12v and i ...
0
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2answers
138 views

LM317 Soft-start circuit

assuming the below circuit is functional. Can you tell me how soft-start part is working? Would the same setup be valid for Vin=~3V and Vo =~1.3V, or would I need to change the C1 and R3. Also how can ...
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0answers
32 views

Power supply for electro plating

Which DC power supply will be more suitable for electro plating? The PWM type or the normal adjustable V/I type? How many voltage and current will need to be applied. What parameter to decide how ...
2
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2answers
75 views

Any downside to feeding a buck regulator into a linear one?

I need to convert 12 V down to 5 V and 3.3 V. I am using linear regulators right now but they get pretty warm and eventually I would like to supply more current for it (around 500-700&...
0
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1answer
26 views

LM2940, 7808 and Multichannel PWM chip

I'm putting together a circuit board to power and dim 5 LED channels. The average voltages on the channels are 12.3V, 11V, 11.4V, 7.8V, 6.6V, and max current is 1A. So my current plan is: 12V ...
1
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1answer
180 views

High voltage linear regulator (with pre-regulator)

I need to build a linear voltage regulator like this: The problem with the usual linear regulators (LM317, LM337, ..) is the limited voltages they can withstand. I have taken inspiration from a ...
0
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1answer
91 views

PWM duty cycle RPM regulation via sensing DC motor current

I have a DC motor that needs to be RPM regulated, that is, it needs to turn at constant RPM regardless of the load. I've read this can be done by monitoring current thru the motor windings and ...
0
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1answer
112 views

Bad 100Hz ripple in linear regulator circuit

Background I'm a beginner trying to make a linear regulator and made some decent progress on a breadboard powering from a 20V laptop charger. After battling off the typical opamp instability issues I ...
1
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2answers
147 views

What is a simple voltage limiting circuit?

I am searching for a neat solution for an input voltage limiting circuit. Situation: I have a circuit with an input voltage range from 6 V to 20 V at 3 A peak (the load), however my source can be ...
1
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2answers
53 views

Use regulator when input voltage is above threshold other wise use direct input voltage

I don't have much practical knowledge of electronics. I am trying to operate esp12e with single Li-ion battery with charging circuit. I am planning to use a good LDO regulator because Li-ion battery ...
0
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2answers
86 views

Best power supply for a BLDC motor; linear or SMPS?

I am coming into a design that uses a custom designed, 24V brush-less DC motor controller. I am wondering, is it better to power this type of system with a linear power supply, a switch mode power ...
0
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3answers
83 views

Will battery last longer with larger capacity but lower efficiency (high V through LDO) or vice versa?

Given a simple circuit of a draw around 28mA (when supplied 3.3v). I'm trying to maximize run time on a battery, but working with what I've got on hand... I have the following batteries: 5000mAh 3S ...
2
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1answer
59 views

Using a higher C than necessary in a voltage regulator circuit

I've two questions: If I've a voltage regulator that says in the datasheet to use electrolytic capacitors is it possible to use 'normal' capacitors with the same capacitance? I've the circuit drawn ...
1
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3answers
194 views

Negative input, negative output switching regulator?

I've got a component within a larger device that requires both +15 and -15V, drawing about 100mA per rail. In addition, the main power supply of the larger device is providing +/- 28V, with a common ...
10
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6answers
2k views

Best way to power a microcontroller, SMPS vs Linear Regulator

I'm using a 12V adapter and a 2S 7.4V Li-ion battery to power my electronics, and I would also like to power my MCU with it. To switch between the adapter and battery I'm using a BQ24133 from TI. I ...
0
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1answer
49 views

Any 12 or 14 v 100amp voltage regulator it? [closed]

I have searched the Internet but didn't find one, can anybody please suggest me any regulator ic that is 12 or 14 volts and can bear upto 100 amps.
0
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1answer
292 views

Explain adjustable 4A regulator

I cannot understand how this circuit works. https://imgur.com/a/OAQSF4Y I have found a basic explanation online but is not enought to make calculations. "Using three LM317-N devices in parallel ...
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0answers
61 views

MCU controlled adjusting LED current with current sensing regulators?

I'm really sorry for the noobly formulated question, if I knew how to formulate it I'd probably find what I need by searching, this has to have been asked and dealt with many times. I've been using ...
2
votes
1answer
120 views

Linear current driver with several BJTs in parallel

With the circuit setup shown below, if I have available a type of Q2 transistor with a certain maximum dissipated power and need that D1 withstands a large current that would lead Q2 in trouble, it is ...
0
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3answers
176 views

Lm317 input connected to output?

I am figuring out the schematic of an existing e-bike controller. Specifically I am trying to replace an lm317t with a custom made switch regulator that outputs the same voltage. But first I want to ...
1
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0answers
51 views

Stable 12V 1.5A

I'm in need of a stable 12V 1.5A power which I could carry with myself. One way of doing it would be to strap, say, 12x 1.2V rechargeable batteries and use LM317. But then I read about buck ...
2
votes
3answers
157 views

Driving a 12v LED, substituting a PWM chip for a linear regulator?

I'm trying to reverse engineer a broken control box for some dual intensity motorcycle LED spotlights, and I note on the circuit board there is an AX 3007-50 12V ...
2
votes
3answers
3k views

Connecting Voltage Regulators 7812 in Parallel for High Current [duplicate]

Could I use two L7812 voltage regulator ICs in parallel to get 12 volt and more current that with just one?
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votes
2answers
158 views

LM350 not reducing the ripple [closed]

I share the picture of the schematic of my circuit. I want to use the LM350 variable voltage regulator to reduce the 40mV p-p ripple i have in my bridge rectified DC. Though it has no effect at ...
0
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0answers
142 views

Linear mosfet driver floating supply

I've been trying to find ways to drive an N-Channel MOSFET gate higher than the power rail in order to make use of the full supply available. The MOSFET needs to operate in the linear region using an ...
1
vote
1answer
180 views

Why there is transistor on LM317 ADJ pin? [closed]

I would like to understand the meaning / function of the transistor on LM317 ADJ pin on the following circuit. Image source
1
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1answer
455 views

Designing a linear regulated dual-rail power supply

I'm building a dual-rail power supply and need to drop about 5-10 V from the rectification output. It's for powering an amp so I need low noise and about 2A therefore I opted for linear regulators. ...
1
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1answer
147 views

How many MOSFETs can a linear controller handle?

I designed a circuit for a high current linear regulator (20A peak, 16.4V (max) input regulated to 13.8V) using a Micrel MIC5158 together with a BUK9575-55A. The 20 A peaks are short, since the use is ...
0
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3answers
1k views

What causes a faulty Linear Voltage regulator to output wrong voltage [closed]

I made a circuit where I needed DC 8v supply. I was using a KA7808 to regulate the voltage. While testing the voltage regulator unit, I identified that the Regulator IC might be faulty because I was ...
0
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2answers
1k views

Would this circuit work on AMS1117?

Just a quick question. is this a correct circuit? would it drive 500mA device? given using AMS1117 as the regulator? Do we need to add heatsink? any alternative to step down the 12V to 3.3V without ...
1
vote
1answer
128 views

Connection between PID, Pole placement and LQR

I am trying to control a wheeled inverted pendulum with a PID controller. I already designed a linear quadratic regulator (LQR) and a pole placement regulator (PPR). I would like to design a PID ...
0
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0answers
121 views

Is this regulator circuit safe to use?

A friend asked me to make a simple regulator for a high current load: a 13.8+-15% V, 20 A (a radio). The input is a 13.5-16.8 V LiPo 4S pack. Obviously, the pack cannot be discharged completely. Still,...
0
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0answers
46 views

employing a series resistor to mitigate an absolute maximum voltage rating

I am trying to run an IC with an absolute maximum voltage spec of 3.6 V. The linear voltage regulator that feeds the whole board specifies a maximum output voltage of 3.63 V. For a given input current ...
0
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0answers
123 views

analog voltage minimum for preregulator

I try to design a lab power supply with a DC/DC preregulator(for now LTC3646), and linear regulator(LT3080). I found a really clever hack that sets voltage produced on the preregulator to voltage set ...
2
votes
1answer
159 views

LT3080 Set pin voltage

LT3080 documentation states under absolute maximum ratings: SET Pin Voltage (Relative to OUT) ±0.3V (http://cds.linear.com/docs/en/datasheet/3080fc.pdf page 2) In the documentation there's also ...
1
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1answer
379 views

100 mA current sink with LM317 does not work above 25V

I needed a current sink for something and I arranged one with LM317T: simulate this circuit – Schematic created using CircuitLab It has a switch to select whether I want to sink 100mA or 500mA ...
0
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1answer
108 views

Linear behavior from 0-10V and steady at 3.3V from 10-24V

Apologies as I have very basic electronics background, and after searching for a whole afternoon I couldn't find out how to implement a circuitry that has this behavior as shown in the graph. If ...
1
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3answers
89 views

Linear regulator loop dynamics

Given a step change in the input voltage of a standard op-amp based linear regulator, a finite amount of time is needed for the op-amp to sense the voltage difference at its input and do whatever it ...
2
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2answers
73 views

Solar voltage waivering

Folks, Hopefully this is the right place to ask this. I'm a software engineer with VERY limited EE experience and am trying to learn. At the moment, I've got a project that I'm trying to power using a ...
2
votes
2answers
793 views

Switching pre regulator and linear regulators

I need to have a 5v supply with around an amp of current draw max, and a 6v supply with around a 4amps current draw max. I was thinking: instead of having two switching regulator circuits, just having ...
0
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4answers
557 views

Linear regulator using emitter follower and operational amplifier

I have understood that you can create a linear regulator using a high-current BJT power transistor in the emitter follower configuration and one operational amplifier (and a voltage reference, which ...
1
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3answers
557 views

5 volt regulator not getting desired output

I have been trying to assemble a simple 5V regulator circuit using the L7805CV and have had no luck at all getting the output to 5V. I have tried many circuits and multiple L7805CV regulators, ...
0
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1answer
239 views

78xx switching regulator question

I would like to know how a 78xx series linear regulator can be used in a switching application. I have found a circuit that shows such a use, but I have trouble understanding how the circuit ...
0
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2answers
112 views

Voltage regulation for Atmega328p

I am designing a circuit containing two Atmega328p. First chip will drive TFT screen with 3.3 V linear voltage reg. Second one will drive BT module, couple of relays, two sensors, SD card module, and ...