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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157 views

When is voltage level shifting needed/unneeded?

I know the question sounds simple, but I am facing an edge case here. I have a microcontroller with 3.3V on the GPIO's. I want to use it with this LCD panel. Adafruit creates their own breakout board, ...
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2answers
3k views

Microcontroller PWM to bipolar push-pull amplifier issues. (level shifting)

I'm trying to design a circuit that allows a micro controller (arduino) to control a voltage to a load. The load voltage needs to be bipolar in nature (+- 3 to 5 V) for use in controlling a TEC. My ...
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1answer
495 views

Why would a 5V input to a 74HC04 pull it's V_CC from 3.3V to about 4V

I have the following circuit: simulate this circuit – Schematic created using CircuitLab The SN74HC00 (from TI) has input clamps, so I am expecting the 5V logic input to be clamped to about 3....
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2answers
138 views

mosfet capacitance charging question

Can someone please explain to me why the output of this level-shifting circuit starts charging from around 2.8V to 5V, and NOT from 3.3V to 5V. At the time where the output is at 5V there is a 3.3V ...
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2answers
818 views

3.3V step up to 5V using BJT

I'm using an Arduino Blend Micro with outputs that provide only 3.3V and I need to control a MOSFET that needs 5V on its gate. Can I step up the voltage from 3.3V to 5V using a single BJT?
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2answers
350 views

Is this a reasonable design for a high-speed level shifter?

I wanted to try designing a device that will use an RS-232 interface. RS-232 works at +12/-12V - I know I can use a MAX232 as a level converter, but I wanted to try designing my own (this is a ...
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2answers
552 views

Level shifting of 125 MHz clock signal

I have 3.3V 125MHz clock signal which need to be translated down to have an amplitude of 1.8V. My first idea was to use some logic inverter, run it on 1.8V, and since it probably has protection diodes ...
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3answers
993 views

Level shifting a clock signal

I need to step-up a clock signal of 8 MHz from 3.3V to 5V, I was wondering if this type of level shifter would work : The BSD840N as rise and fall time fast enough for my application but I'm not sure ...
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1answer
224 views

Large range input single level shifter

I have an application where I will be taking serial signals will need to level shift the signal to 3.3V. The input signal will be from 15 to 5V for a high input and I need them all shifted down to 3....
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2answers
333 views

USB to multiple RS485

I'm trying to create a device that will control a few independent RS485 lines using single USB port. My first idea was to use GL850G usb hub controller (4 downstream ports), 4x FT232R, 4x MAX485. I ...
2
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1answer
2k views

Arduino <-> BBB UART issues using bi-directional level converter (5v to 3.3v)

I am having a strange issue interfacing between an Arduino and BeagleBoneBlack over UART. The Arduino is 5v logic, and the BBB is 3.3v logic, so I'm using a bi-directional logic level converter from ...
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3answers
138 views

Connecting devices with different logic levels

The following figure is taken from this link, where the author explains how NOT to connect devices having different logic levels He says that: Directly connecting the devices together (see above)...
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4answers
2k views

How to shift differential signal to read with single ended adc?

I'm using a current sense resistor (0.02 ohms) for a high current battery monitor for a hobby project. I'd like to shift this to a 0-5 V range to monitor using an ADC input (single ended.) I ...
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2answers
793 views

Square Wave Voltage Level Shifting

I have a square wave signal of 300 KHz which is 0.2 V to 1 V. It is the output of FP5138 Non-Sync PWM Controller IC. I want to drive a PMOS with this square wave but with the levels shifted to (Vin-12)...
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1answer
73 views

is this level shifter a dud or am i doing something silly?

i am very new to hardware circuitry and am attempting to connect a wiegand rfid and pin code reader to a raspberry pi for door access control logic. more details at: https://gist.github.com/grenade/...
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2answers
94 views

Increase Rise and Fall Time of this Schematic

The following cirucit converts a 3.3V PWM signal into a +-12V PWM signal and works as expected. I want to increase the rise and fall time of the ouput signal to approx 2us. How can this be done? ...
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1answer
435 views

Level shifter default high problem

I recently bought a logic level converter for interfacing Arduino Uno with ESP8266. I had decided to use SPI communications between the two but after making all connections correctly it failed. ...
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2answers
147 views

Can I, Bi-Directional Level Shifter as Motor(3V) controller with Arduino Lilypad (3.3V)?

Basically this could be easily done by using a BJT NPN, but since I want to control two motors(3 V, 45-60mA) and 5 LEDs was thinking of using a Bi directional level shifter instead of using ...
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2answers
5k views

GY-521 MPU-6050 + Arduino nano - Logic converter or not?

I bought this MPU-6050: link (marked as "GY-521" on the board) According to the manufacturers' site, the sensor logic level is 3.3V (though the eBay page says ...
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3answers
2k views

Connecting a 3.3V circuit to a 5V bus

I would like to connect a 3.3V (not 5V-tolerant) circuit (a Xilinx XC3S200 FPGA) to a TTL-level 5V asynchronous 16-bit bus (very similar to qbus) with about 30 mostly bidirectional lines. (The bus ...
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0answers
116 views

Convert analog piezo “transition” to digital signal

I'm trying to get what amounts to a knock indication into a microcontroller input from a piezo sensor. It's looking fairly good now at the fifth iteration, and about ready to provide digital levels ...
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0answers
92 views

Buffer-cum-Level shifter using dual MOSFET

I am putting together a Buffer-cum-Level shifter using dual MOSFET to deal with PWM signal for display backlight control. This 3.3V PWM signal is driven by MSP430G2452 and would be reaching the ...
2
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1answer
73 views

Voltage shifter 0-30VDC

I am required to generate and measure squared signal (PWM like). I should cover a 0-30VDC amplitude. High level of the signal is 30 VDC, low level is 0VDC. The bandwith to be covered is 0-20kHz. I ...
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0answers
106 views

Which mosfets can be used for level shifting [duplicate]

I would like to build a 5v circuit that uses an sd card and a 3.3v SPI screen and for the level shifting I would like to use the common mosfet circuit, but all versions I have seen use a BSS138 which ...
2
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1answer
829 views

raspberry pi 3.3 to 5v level shift for led rgb strip

I'm working on my first electronics project. Basically I'm trying to control an rgb led strip from a raspberry pi's gpio pins. I'm trying to convert the raspberry pi's 3.3v up to the 5v required for ...
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0answers
113 views

Upward Voltage Level Translation

I need to up-translate two complementary 2.5 V signals to 5 V. I am looking for a circuit which can do this and which consumes ultra-low static power. I tried to design one, using 4 MOSFETs as shown ...
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0answers
2k views

Level shifting with BSS138 - weird values

I need to connect 5V and 3.3V devices via I2C as follows: I've connected 3.3V and 5V pull-ups and tried to measure the voltage. There is 5V on HV and TX_HV but 4,7V on LV / TX_LV. Putting TX to LOW ...
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3answers
1k views

Which 74xx logic families are overvoltage tolerant on their outputs?

Here's my dilemma: I have a 3.3v active-low logic line, and I want to use it to drive a 5v active-low logic line. The 5v line already has a pullup, so my plan was to use an open-collector buffer IC ...
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5answers
2k views

Level shift 0/5V to -10V/+10V

Can anyone show me a simple circuit to shift a 0V/5V square wave (low freq, under 10Hz) to a square wave -10V (when was 0) to +10V (when was +5V). Can it be done with some transistor or do I need an ...
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3answers
6k views

What can I replace a BSS138 N-Channel MOSFET with?

I'm replicating this level shifter by Sparkfun but they use a transistor that I don't have. Frankly, I know next to nothing about transistors so reading the specs is way over my head at this point. ...
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3answers
894 views

Power Supply Issue, Voltage Drop Under Load

I have the Ardupilot Mega flight control board (APM), which outputs 4.8V. I want to power CC3200 MCU with it, which needs at least 3V for stable operation. I power APM using a power module connected ...
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3answers
1k views

Logic level shifting from 5v to 2.8v and vice versa

I need to use a logic level shifter in my circuit which translates 2.8V logic level into 5V and the other way round. I found this document. The device itself is presented on the page 10. It is very ...
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3answers
208 views

How does an auto bidirectional voltage translator work?

I'm trying to understand how the auto bi-directional voltage translators work. Background: I have to choose a part that can translate signals in both ...
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1answer
238 views

Why is this considered a slow logic level shifter?

I'm working on a project where I have to do some unidirectional logic level shifting. I'm not able to get any chip to do it at this moment (it's late at night) so I looked up some DIY solutions and ...
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2answers
104 views

Convert CMOS-level signal to microphone-level (0..3V --> -1..+1V)?

I'm building a microcontroller circuit that feeds its output into a microphone input of an audio recorder. The output is a square wave. (Think old-style 3.5mm Square credit card readers). What can I ...
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4answers
465 views

Shifting a 2.7V digital signal to Arduino logical levels?

I'm pretty much a beginner in electronics and I'm currently working on a personal project, where I have a device, that is putting out a digital signal (square wave) that goes from 0V - 2.7V and I need ...
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3answers
1k views

voltage of input(+5V) is greater than the supply(+3.3V) provided for 74HC245 buffer

In my design I am using 74HC245 buffers between a input signal of +5v and controller pins of +3.3V. What is the supply value I have to use for buffer (74HC245). I want to use +3.3V as the supply, but ...
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4answers
8k views

What is the simplest op amp level shifter?

What is the simplest op amp level shifter? That is, no gain and both inverting and non inverting configurations, for AC coupling
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1answer
2k views

5V to 3.3V Level shifting circuit

I am interfacing an SD card to the Z80, one of which uses 5 V logic (Z80) and the other uses 3.3 V logic (SD). I believe the 3.3 V to 5 V level shifting will be taken care ...
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3answers
641 views

Looking for a level translator for single duplex serial bus

I have a 3.3V UART (two pins) plus a direction selector pin (also 3.3V.) I need to talk to and listen on a single duplex serial bus at 5V with 20 mA drive strength. The signaling rate is 3 Mbit/s, ...
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3answers
388 views

Protecting a 3.3V circuit from 5V power supply

I'm designing a dev board for 3.3V parts. On the dev board, I will have a header for an "FTDI Friend" USB-to-Serial converter. The FTDI part can supply Vcc to the target board. However, FTDI parts ...
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1answer
716 views

Using 2N2222 as level shifter for TIP127: simulation works, circuit does not [closed]

I'm building an H-bridge with complementary Darlingtons, TIP122 and TIP127, as they are cheap and the nearby shop has them (i know about the high power dissipation, it doesn't matter), and i found ...
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5answers
4k views

convert 12V PWM circuit to 5V PWM using opamp [closed]

I can convert a 12 V PWM signal into 5V signal, by using voltage divider on 12 volt signal , then directing it to base of NPN common emitter transistor with collector connected to 5V simulate this ...
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3answers
1k views

Operational Amplifier Circuit - +/- Signal to 0 … 5 V

I know that this question has been ask in similiar ways already. Since I am rather new to Electrical Engineering and I don't want to waste material I wanted to ask you guys first if my approach is ...
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1answer
191 views

Translating a 1.8 V FPGA pulse to 24 V pulse to power a solenoid

I am designing a board that will interface between a FPGA board and solenoid that powers a pneumatic system. The signal coming from the FPGA is a LVCMOS 1.8 V signal. Current from the FPGA signal is ...
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3answers
90 views

Levelshift distorts when freq is higher than 4kHz

I 'designed' this circuit to shift a level coming from an arduino to -5/+5v signal. It simulates well in EASYEDA. I also built it on a breadboard with a symmetrical powersupply and signalgen giving ...
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1answer
128 views

Weak output from TXB0104 at 1.5MHz

I'm driving a TXB0104 translator from 3.3V logic on the B side, VccB is 3.3V, VccA is 2.5V, OE is on VccA. Both supplies are solid. It's on a breadboard. (https://www.sparkfun.com/products/11771). The ...
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2answers
250 views

What is wrong with this voltage shifter?

I need to do voltage shifting (3.3V Papilio FPGA <--> 5V RAM chip). Most of the pins are output 3.3V -> input 5V, and 3.3V qualifies as "high" to a 5V device, so I can connect them directly. The ...
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3answers
7k views

1.8V UART with 3.3V UART

I have Quectel EC25 module comes with GPRS and GNSS in built, this module needs supply of 3.3V and it's UART works at 1.8V (default Baudrate is 115200) - But i have a processor ATMEGA2560V running at ...
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1answer
126 views

Is it safe to leave floating the low voltage supply of a logic level shifter?

I need to interface two devices, one runs at 5V and the other at 3.3V. In order to safely interface them, I'm using a simple logic level shifter (LLS) of this kind: It's a pretty straightforward ...

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