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Questions tagged [negative-voltage]

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DC-DC converter to make variable output +/-70V from 5V input

This is a SEPIC DC-DC architecture from Texas Instruments to make a variable output from +/-5V to +/-70V. Iwould like to understand the principle of how the negative voltage is being made from the ...
Andromeda's user avatar
  • 473
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1 answer
48 views

Delay in discharging of the capacitor for sequencing purpose

Our aim is to sequence 2 different power supplies i.e. 5 V and -48 V. On sequence is first "5 V is generated" and then "-48 V is generated" with 120 ms delay. Off sequence is first ...
Sahasra Vaiishnavi's user avatar
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0 answers
37 views

Multiplexing Solar Cells with a Common Positive

I am trying to switch between 6 pixels of a Perovskite Solar cell that exist on a single slide. I hope this would allow me to measure their voltage and current with one four-wire measurement ...
Kerry Tang's user avatar
1 vote
3 answers
78 views

More current draw from a power supply based on a voltage divider

I've built a circuit that needs a power supply that can provide -12V, 5V and 12V. I've built the circuit below as a proof of concept, being aware that I might need to build something that allows for ...
Peter Lenkefi's user avatar
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0 answers
52 views

Generate 200MHz Phase-Shifted Voltage Sine Waves

I'm looking into a way to construct a circuit that can generate ~200MHz negative voltage sine waves (8 channels), where there is 11 degrees of phase offset between the channels (0 deg, 11 deg, 22 deg, ...
Hikikomori's user avatar
1 vote
1 answer
34 views

How do the switches and level translator work in the LMC7660 Switched Capacitor Voltage Converter [closed]

This is the block diagram of Texas Instruments LMC7660: Here 4 switches are used S1 to S4. The diagram shows source connection of only two transistors S1 and S2, and leaves out the S3 and S4 switch. ...
Newbie_Programmer's user avatar
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0 answers
34 views

STM32L432KC used for negative voltage?

My TIA circuit's opamp needs a negative supply in order to get a output with a 2V dc bias and ac signal that the stm adc can sample. This is needed since the opamp needs a ~3V difference between input ...
Visje999's user avatar
0 votes
1 answer
64 views

TIA needs negative voltage supply

My TIA (figure 1) needs due to its op amp at least a negative voltage supply. There is needed a 3V difference (datasheet op amp). But how can I create this negative supply, I have a 12V dc power ...
Visje999's user avatar
5 votes
4 answers
469 views

Ground in differential opamp situation

I have a setup like such in the provided schematic. The idea is that I do have a -2.5 to 2.5V signal which I'd like to convert to a signal between 0 and 5V. How should I connect my opamp? Should the ...
Mart's user avatar
  • 376
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0 answers
75 views

Protecting negative power rail

I don't trust my power supply and want to protect my circuitry from over(under)-voltage, but cannot find a clear path of going forward with negative power rail. LDO which I use (LT3094) is rated for ...
Andrejs Cainikovs's user avatar
1 vote
0 answers
72 views

Is it possible to use an Efuse for protection with negative voltage?

Following to this question, is it possible to use an efuse with a negative voltage power, to eliminate the need of the required big heatsinks?
Shamooooot's user avatar
1 vote
2 answers
100 views

Isolated negative Vdg on MOSFET

This is probably crazy, but: What would happen if I apply a negative voltage between the drain and the gate of a MOSFET (or positive from gate to drain), assuming that this voltage comes from an ...
Valentin Richard's user avatar
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0 answers
54 views

High negative voltage cut-off for op-amp from dual-rail power supply

In the picture I have a circuit that prevents reverse polarity and cuts the voltage with respect to the Zener diode (15 V) as a voltage reference for positive voltage output. How do I apply the same ...
HuracanWind's user avatar
1 vote
2 answers
159 views

Voltage comparator approach

I am building a self biased tube amp. It has an adjustable negative bias of about -32 to -67 Vdc for various tubes. The power supply side has some bult in safeties to make sure there's always a ...
Hoops's user avatar
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4 votes
3 answers
980 views

How does this negative voltage rail work?

Rod Elliot has a dual bench power supply project on his web site (project 223, see schematic below). I'm trying to understand his method for adding a low voltage negative rail without using an ...
RobT's user avatar
  • 115
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1 answer
58 views

Which MCU ADC configuration works best for bipolar input measurement [closed]

The jumper pads can be set to configure the input pins connected to an MCU. Which configuration would work best to enable reading negative voltages?
Dustin LaRoche's user avatar
1 vote
1 answer
105 views

Is negative voltage going to cause trouble?

I'm trying to design a circuit that will allow me to set and reset an SR-latch with a single input. My idea is that when the input is driven high, the latch immediately resets, and if it persists for ...
php_nub_qq's user avatar
2 votes
2 answers
633 views

µA723 output Zener diode: why is it as high as 6.2 V?

The µA723 voltage regulator has a 6.2 V Zener diode on its output. I am trying to understand why the Zener voltage is as high as 6.2 V. (LM723 or LM723C are more or less equivalent parts, raising ...
Tony's user avatar
  • 168
2 votes
6 answers
2k views

How come negative power supply has negative voltage only

So I have seen power supplies that produce e.g. -48V DC (used e.g. in telecom but probably not only). For sure, that power supply is floating and in no way is negative terminal connected to earth. So, ...
seeker's user avatar
  • 476
2 votes
0 answers
87 views

LT1054 wrong output

I'm using a LT1054 to generate a negative voltage to power my OpAmp's. I used the circuit described in figure TA03 of the datasheet. My Vin is 15 V and my R1 and R2 are 20k and 220k respectively. With ...
Cícero Zanette's user avatar
2 votes
4 answers
484 views

Summing Amplifier Supply Voltage

Consider the case that I have a standard inverting summing amplifier with two inputs: 0.5V DC and 1V DC. Therefore, the output of the amplifier should be -1.5V related to GND. However, If I connect ...
Aurora7979's user avatar
1 vote
1 answer
108 views

How to obtain negative voltage for op-amp?

How to setup negative -10 V for an op-amp to be designed on a PCB? I read that -10 V can be obtained from a power supply by connecting positive to ground and negative of the supply to the node where ...
negative_feedback's user avatar
1 vote
1 answer
275 views

Using a DCDC buck converter for negative supply

I am still fairly new to DC/DC converters and was wondering how to generate negative output supply with a positive input supply. I don't know what the general requirements and limitations are but here'...
Hansel's user avatar
  • 333
3 votes
1 answer
2k views

Op-amp dual supply methods

To power an op-amp with a dual supply (+Vcc and -Vcc) you can use two power supplies connected in series. I would like to find an alternative and less expensive way to do this as (in my project) the ...
philfs's user avatar
  • 73
1 vote
1 answer
133 views

Creating -5V supply from a AC/DC adapter

I want to use a Friwo FOX12-XM 5.9V adapter from RS with a -5V LDO to create a -5V supply which I draw as follows: Would this be fine and is the adapter isolated?
user1245's user avatar
  • 4,301
1 vote
2 answers
265 views

What is the most used bi-polar output SMPS topology in gate driver isolation?

I have some questions concerning this schematic: What is the topology used here? I am guessing flyback without feedback circuitry. Why is the TPS40211 utilized here? Is it to provide more current? ...
Younes Thabet's user avatar
4 votes
3 answers
3k views

How to generate -5 V from +5 V and GND?

I have an Arduino providing +5 V and GND. I have a component that requires +5 V, common GND, and -5 V connections. Is it possible to generate -5 V? If not, what input voltage do I need? I am driving a ...
Power_tile's user avatar
2 votes
2 answers
368 views

Is it possible to use one voltage source for an op-amp?

This is a typical to op-amp for a non-inverting amplifier. I have tried to google this before I asked this question. Unfortunately, all circuit diagrams seem to require two voltage sources. In real ...
kile's user avatar
  • 877
0 votes
2 answers
162 views

±50 V from two 50 V DC-DC boost converters

I am having trouble building a power supply for my car audio amplifier board. The board needs a ±50 V, 250 W RMS PSU, which is why I bought two switch-mode power supplies, each 50 V, to connect them ...
LL 23's user avatar
  • 1
3 votes
4 answers
2k views

How can I supply −5 V to an op-amp?

This is the circuit that I intend to implement on a breadboard. I only have an ESP32 microcontroller, so I can supply the +5 V, but I have no idea how to supply the −5 V. If I change Vee to 0 V (GND ...
Scipio's user avatar
  • 803
0 votes
3 answers
363 views

Biasing a low AC voltage for input to an ADS1115 ADC

I have an AC signal from a position sensor that changes between -200 mV and 200 mV, something like 400mV peak-to-peak. I have ordered an ADS1115 breadboard and I use an STM32 microcontroller. I'm not ...
Knowledge's user avatar
  • 441
0 votes
1 answer
61 views

Use GND as V- in voltage regulator

For a circuit sensor, I need +15 V/GND/-15 V. My supply voltage is a single +5 V rail from a standard switching PSU. I looked at different voltage regulators and found, besides others, the ITA series ...
Sacharon's user avatar
2 votes
1 answer
936 views

Negative voltage from a positive LDO

I came across this design which generates +1.5V and 1.5V from https://simple-circuit.com/arduino-ac-current-measurement-current-transformer/) My question is: with the same DC/DC isolated transformer, ...
Julien's user avatar
  • 489
-1 votes
1 answer
160 views

Using 12V output as ground in 24V power supply to form +/-12V rails

I have a power supply which outputs both +12V and +24V, Here's a photo: Can I use the +12V as ground in my circuit to have a -12V(from 0V)/+12V(from 24V) output? The load on the -12V output will be ~...
a12's user avatar
  • 1
1 vote
1 answer
1k views

Positive and negative voltage level shifter + inverter

I am looking for a level shifter/inverter that not only changes the high-state to another voltage but also generates a negative low-state voltage. The output of Inverter 1 is fixed to (0V … 600 mV), ...
Paul M's user avatar
  • 45
0 votes
1 answer
394 views

How to get negative voltage on PWM signal

I'm researching EV charging stations. Looking at the SAE J1772 communication protocol, I see that there is a +12 to -12 volt 1 kHz PWM signal on the control pilot, which indicates the charging station'...
php_nub_qq's user avatar
0 votes
0 answers
50 views

Using negative supply rail instead of ground in SMPS IC

I'm working on a solar power inverter I noticed that all PWM ICs using negative 12 rail as a gnd... As an example a PWM IC SG3524 which is used to convert batteries voltage to high dc bus voltage used ...
Abdullah Bitar's user avatar
0 votes
1 answer
219 views

low voltage cutoff for negative voltages

I've been trying to design a simple low voltage cut-off circuit for my dual supply +-9V circuit. The positive side works as intended with the LM431 and a PMOS, but the negative side not so much. The ...
Kaiser F's user avatar
0 votes
1 answer
67 views

Positive and negative voltage readings across a rig simulating bearing contact, supplied with a DC source

I recently ran a few experiments to simulate the effects of shaft voltages on motor bearings through using a simplified experimental rig. The rig simulates bearing contact. I applied a DC source ...
Mrcemify's user avatar
0 votes
1 answer
116 views

Powering nixie tube from negative voltage?

I've built a photomultiplier tube supply; it takes +100VDC from a boost converter, which then goes through an inverting (in the sense of postive->negative rather than DC->AC) charge pump to give ...
T.S's user avatar
  • 107
0 votes
0 answers
170 views

Using NMOSFET for driving negative voltage

I want to use NMOSFEts for driving negative voltage. Is it possible to use it?
Farzaneh's user avatar
  • 159
1 vote
1 answer
217 views

Philips PE1535 bench power supply - reason for design choice?

Just a little question about the Philips power supply PE1535. Link to original manual : http://bee.mif.pg.gda.pl/ciasteczkowypotwor/Philips/PE1535%20-%20PE1545.pdf Why the negative power supply ...
maher471's user avatar
1 vote
0 answers
252 views

How to safely read +-5V with an Arduino

I have a -5V +5V binary signal coming from a CNC controller that I want to read with an Arduino. This is the way I have it setup: The resistors are actually 10K. The left voltage source would be the ...
hellvetica's user avatar
1 vote
1 answer
229 views

Does the negative voltage regulator emit noise into ground

I am designing an inverting voltage regulator using a LT3758 controller to generate -15 V from a 12 V / 5 V input. This is a non-isolated regulator. My biggest concern implementing the design is if ...
Voldemort's user avatar
  • 167
1 vote
1 answer
353 views

Contrast voltage for display from PWM with negative rail

I want to control the contrast of this display using a well-filtered PWM output. They recommend a potentiometer between Vdd and Vee (negative built-in rail): With my MCU I can generate a filtered PWM ...
Mark's user avatar
  • 1,225
1 vote
4 answers
3k views

If you source a negative voltage from a power supply, should the current be negative also?

I am clear that negative currents are simply currents that flow in the opposite direction. I am unsure as to how to apply this information to the real world. (relating to positive and negative leads) ...
Andyon98's user avatar
-1 votes
2 answers
60 views

DC to DC converter connection [closed]

I am fairly new to electronics and I started to have some doubts. I am going to use a DC to DC converter R1SE-0505/H2-R (5V to 5V) to have an isolated power supply for the audio components. I have ...
dobowicz's user avatar
0 votes
1 answer
245 views

Negative voltage value for AD620 amplifier

I am using AD620 to amplify the signal of a pressure sensor, and a negative supply voltage must be added to V- pin. should the negative voltage value be the same as the positive supply voltage? or any ...
Ayman hussien's user avatar
0 votes
2 answers
86 views

OP2177 opamp with single supply

Does anyone know if I can use "OP2177" with a single supply without a negative voltage on V- ?
mehrad aghaei's user avatar
11 votes
5 answers
3k views

Is it OK to create a negative rail just by dividing voltage with resistors?

I want to build some circuits to learn about op-amps, and so I would like to set up a negative rail. Are there any problems in creating a negative rail by using an 18 V bench supply and then simply ...
JohnnieL's user avatar
  • 215