Questions tagged [level-shifting]

Level shifting is the process of converting between different logic levels. E.g. from 0-3.3 V logic to 0-5 V logic

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1answer
116k views

Step up 3.3V to 5V for digital I/O

I normally use an Arduino for my projects because it has 5V inputs and outputs and has 5V Vin so that makes life very easy when interfacing with 5V components. For this project I want to use a ...
28
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8answers
8k views

Can I reduce voltage from 3.3V to 1.8V using a 1.5V battery?

I am interfacing to an EEPROM that works via SPI at 1.8V; unfortunately I do not have a 1.8V power source around and being this a weekend project, I wanted to complete it without going to the shop. I ...
24
votes
1answer
22k views

Is my MOSFET-based bidirectional level shifter insane?

In a moment of cheapness, I decided not to order a 5v to 3.3v level shifter from Sparkfun, but instead to put it together myself. The original schematic used a BSS138 MOSFET, but since I enjoy ...
20
votes
3answers
48k views

Single transistor level up shifter

I need a simple, single directionnal level shifter for 3.3V -> 5V conversion. There are many options on the internet, some using a logic ic and some using 2 NPN transistors (converter and inverter), ...
17
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2answers
50k views

Level shifting a +/- 2.5V signal to 0 - 5V

I have a front end module that generates an (ECG) signal that varies from +/-2.5 V. I want to shift this signal to 0 - 5V. What is the best way to do this? Would a summing amplifier like the below ...
15
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5answers
3k views

Are BJTs suitable for level-shifters? It seems FETs are more common,how do they compare?

I'm a hobbyist, and never got past the datasheets/tutorials for FET transistors; I'm a BJT man. I never found discussions dealing with BJT vs. FET and specific applications best suited for each type. ...
14
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4answers
22k views

Shutdown Controller for Raspberry Pi in a car

Following on from my previous question I'm trying to create a shutdown controller for my Raspberry Pi. The Raspberry Pi needs to be powered from the battery, but should power-down after the Pi ...
12
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3answers
18k views

I2C: 3.3V and 5V devices without level-shifting on 3.3V-bus?

do I really need a level-shifter if I use 5V-powered devices on an I2C-bus that has pull-ups to 3.3V? In my understanding the devices will only pull the lines (SDA, SCL) low (to ground) and never ...
12
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1answer
4k views

How is this circuit for level converting (5V<>3.3V) working?

Does anybody know, how is this circuit exactly working? It is level converter between 5V and 3.3V logic and it is bi-directional. I have some theory, but I am not sure with it (I never worked with ...
11
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2answers
795 views

I2C level shifting

I am currently designing a circuit that can record data from a sensor and save the data recorded into an EEPROM. My two devices (EEPROM and for testing purpose a RTC) are connected via an I2C bus to a ...
10
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3answers
3k views

How do you shift a square wave down?

I have a square wave the oscilates at 25khz from 0 to 30v. I would like it to oscillate from -15v to +15v. Is there a SUPER DUPER SIMPLE circuit to do this? Keep in mind it's going up and down at ...
9
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6answers
14k views

Increasing Voltage

I have a binary signal, 0V to 1.4V, which I can't change directly. What circuitry, (on a PCB) can I use to increase 1.4V to at least 2.5V. Do I need a transistor? I guess I'm looking for a switch ...
9
votes
2answers
4k views

What is the best way to convert 1.8 V to 5 V?

I connected HC-SR04 ultrasonic sensor, to single-board computer BeagleBoard-xM. Trigger pin requires 5 V DC. However, control pins of BeagleBoard-xM can provide only 1.8 V DC. What is the best way to ...
9
votes
3answers
42k views

Analog voltage level conversion (level shift)

I have a joystick that puts out analog voltage somewhere between 1.5V and 3.5V. I want to transform this range of voltage to control a motor controller that takes analog voltage between 0V and 5V. ...
9
votes
1answer
674 views

What's the purpose of this diode in this level-shifter?

look at this circuit: I don't get that what's the usage/purpose of the BAS316 in this circuit?
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2answers
8k views

How do I get an Arduino (5 V) and MPR121 (3.3 V) to talk?

I have the Sparkfun MPR121 I2C Capacitive touch sensor breakout board I have read that it uses 3.3 V, I know that I can't just connect up the 3.3 V power supply output from the Arduino as the ...
8
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2answers
501 views

Level shifter using BJT schematic

I was reading the book Analogue electronic circuits and systems, by Amitava Basak, when I stumbled in this level shifter circuit that uses BJTs instead of the usual mosfets. See the below picture. ...
8
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3answers
2k views

Differential amplifier with differential output and common-mode shift

Summary: I would like to build a differential amplifier with differential output, but shift the common mode to a different level from the original. My current knowledge takes me this far: Take the ...
7
votes
1answer
9k views

How to convert a digital signal from 24V to 5V

I have an industrial automaton that gives me a digital signal (24V or 0V) on its outputs and I want this signal to control an integrated circuit, but the integrated circuit only takes a TTL signal in ...
7
votes
3answers
17k views

Level Shifting 1.8V to 5V with N-channel FET

I am using BeagleBoard-xM GPIO outputs to drive some DC motors with the help of L293D IC. The problem is that there is a difference between voltage levels. The GPIO outputs only supply 1.8V while ...
7
votes
1answer
867 views

Capacitors in MAX 232

Out of curiosity, can I replace the electrolytic capacitors in the circuit with non-polar ceramic capacitors? Will I get the shifting in level? MAX232 datasheet: LINK
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1answer
1k views

How to blink LED with 1.8V?

I am experimenting with an Intel Edison mini breakout board with pinout like here: http://fab-lab.eu/wp-content/uploads/2014/10/Edison_IO_LED.jpg Now, I soldered header pins to plug the board into a ...
7
votes
1answer
10k views

TTL voltage shift from 5 to 3.3 Volts “UART”

I want to make serial communication with a device which works on 0-5 Volt TTL level. But my serial chip uses 3.3 Volt logic. (this is an UART communication) I know that I need a step down at least ...
7
votes
1answer
806 views

Open collectors & 74LVC245

I am trying to interface a PS/2 keyboard to a MSP430 for a toy. The PS/2 keyboard runs off 5V, but the MSP430 microcontroller runs off 3.3V. So I have a 74LVC245 level shifter to convert between the ...
6
votes
3answers
11k views

Bidirectional level swiching 5V <-> 3.3V

I am looking to interface a 3.3V device with a 5V one. This will require the shifting of the logic levels between the two devices. Doing this in one direction is a trivial matter, but I need to do ...
5
votes
2answers
3k views

Level shift circuit MCU to MOSFET

I have a H-bridge that is being supplied by 12V and using around 10A. I am turning it on/off with a microcontroller that has an output of 0V-5V. The switching frequency is "super low" so the gate ...
5
votes
5answers
18k views

Simplest uni-directional level shifter (3.3V -> 5V)

I want to drive a WS2801 LED strip from a Raspberry Pi GPIO. I have connected the MOSI and CLK pins directly to drive the LED but it is not working as the WS2801 datasheet says that a high level is \$...
5
votes
1answer
1k views

Can a level shifting circuit shift voltage the other way around?

I'm working on a project where I use an FPGA and connect it to multiple servos (called AX-12), which are connected in a daisy chain. Each servos has a unique ID so them being connected in a daisy ...
5
votes
3answers
344 views

How did this simple nmos level shifter break my STM32?

I'm trying to read some 12V square wave signals from an old car with an STM32. I built some level shifters like shown below to down-shift (and invert) the signal so I can hook it up to an GPIO. ...
5
votes
2answers
528 views

Level shifting in HV CMOS processes

I'm working on a project for which custom ICs are being designed by another person on the project. The process being used is a mixed voltage CMOS process which uses a \$1.8\mathrm{V}/5\mathrm{V}\$ ...
5
votes
1answer
3k views

Can I use a voltage divider for shifing logic levels?

I'm trying to drive a 3.3V IC from an Arduino which has 5V logic pins, so I need to shift that 5V down. There's no data from the 3.3V device to the Arduino so I don't need to shift back up. Can I use ...
5
votes
2answers
679 views

How do I interface with OBD-II?

I've been tasked with interfacing with the on-board diagnostics of a vehicle. Some systems use 7V signalling, some use 5V signalling, some signal up to the battery voltage (which can be as high as ...
5
votes
1answer
2k views

i2c over gpio - level shifter

I'm quite new to this. I have just basic background in electronics. So I would appreciate an advice from someone more experienced. I would like to connect an i2c display to my tp-link wr703n (ar9331) ...
5
votes
2answers
562 views

Is a 40109 fit for 3V3 <=> 5V level shifting?

I have checked couple of datasheets for 40109 and although they specify "Supply Voltage Range" as min: 3V, max: 18V, none of the other tables specify values for < 5V. Can I safely order these ...
5
votes
2answers
11k views

Solution for level-translation (3.3V Arduino Due <-> 5V shield)

The new Arduino Due board has its microcontroller running at 3.3V, but unfortunately most standard Arduino add-on shields (boards) run at 5V, thus their I/O signals are at different logic levels. The ...
5
votes
1answer
102 views

How to speed up level shifter?

I have a level shifter that uses a transistor to control the gate of a high voltage P-channel MOSFET, like this: simulate this circuit – Schematic created using CircuitLab This is designed to ...
5
votes
1answer
800 views

I2C device doesn't sink enough current

Im working on a display project and have run into some I2C issues. The display is of 3.3V design, so I figured, no big deal, ill use a level shifter and be on my merry way. Well, sure enough the level ...
5
votes
1answer
1k views

Odroid XU4 and Olimex MOD-IO by I2C via level converter

Long version Like some of you, I do electronics as a hobby and I'm relatively now to this, so I have a few questions regarding the communication between my Odroid XU4 and a nice I2C module from ...
4
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3answers
4k views

Voltage level shifter

I need to make a voltage level shifter. It needs to translate a TTL logic level into a 12 V logic level. I have applied the 5 V at the base and 12 V Vcc and took the output from the ...
4
votes
2answers
1k views

How can a Switching diode act as a level shifter?

I am following a schematic about a one-way logic 3.3->2.8 level shifting circuit. The hardware in question is a MCU output that drives 3.3V and the input of the UART interface of a SIM800 GSM Module....
4
votes
3answers
1k views

How can I know if I'm safe from burning out my robot with more voltage?

I have a Wowwee animatronic robot that I've been tinkering with, with the goal of hooking my arduino up to it so that I can control it from my computer. The problem is, using a multimeter, I've ...
4
votes
5answers
7k views

How can I switch a high-side transistor from logic referenced to ground?

Problem: I have a logic signal (represented by SW1), say from a microcontroller, that is either 0V or some low voltage, maybe 5V or 3.3V. I have a higher voltage supply (V1) and a switching device (M1)...
4
votes
2answers
5k views

Is a N-Channel Mosfet save/reliable for level shifting UART from 3V3 to 5V?

I am busy with a design that needs to connect a Raspberry Pi to an Arduino via UART. Previously I have designed a circuit that worked okay. Prev Design http://blog.protoneer.co.nz/wp-content/uploads/...
4
votes
1answer
3k views

What is the difference between a voltage-level translator and a logic-level translator?

(This is a follow-up to an earlier question of mine.) I would like to use the GTL2000 bi-directional translator IC to facilitate level translation between a 3.3V circuit and a 5V circuit (including ...
4
votes
2answers
1k views

Understanding 74LVC245 datasheet and current source/sink

I'm using a SN74LVC245A (datasheet) to shift 5V TTL down to 3.3V so I can read the signals with a Raspberry Pi. However I am getting really weird results (a 60Hz input signal is picked up by the Pi ...
4
votes
1answer
762 views

MOSFET on Arduino Uno

What is wrong with this circuit? I've performed the following tests in my circuit: When I set the controller output pin PD7 to HIGH, the source/drain voltage is 0V (measured with oscilloscope). ...
4
votes
1answer
762 views

Clock conversion from 3.3v CMOS to 2.5v

I need to convert a bunch of data signals from an FPGA coming out at 3.3V CMOS into 2.5V for an LCD display. I've found the SN74CB3T16210 and the SN74AVCBH164245 and they both seem like they'll do the ...
4
votes
2answers
5k views

How does a bidirectional level shifter work?

I have the following circuit with an NPN HEXFET Q1 (BS170) Correct me if I'm wrong: When the TX-3V3 microcontroller is 3.3V i.e. logical 1, the TX-5V is a ...
4
votes
2answers
296 views

Voltage shifter distorts signal

I am trying to downshift a 5V TTL signal to 3V logic signal using NTB0102 level shifter. The connection is described below: However, my oscilloscope measurements are distorted. Even the input signal (...
4
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2answers
1k views

Common Gate Level Shifter

I am in the need for a high-side load switch and came up with the following schematic. High-Side voltage levels and current vary between 5-12V / 2 A max. The high-side PMOS (SI5509DC) is rated for 20V ...