Levelshifting is the process of converting between different logic levels.
1
vote
2answers
86 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 ...
2
votes
1answer
66 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 ...
0
votes
2answers
93 views
How does a hex level shifter works?
My LCD screen operational pins are driven by 5V whereas my STM32 MCU outputs 3.3V maximum.
I would like to shift 3.3V to 5V for about 6 pins. I could use opamps to amplify the input, but in my ...
1
vote
3answers
86 views
Use 74LCX245 level transeiver for SPI / I2C
I'm needing to convert the levels of the SPI and I2C busses of a 5v microntroller to a 3.3v card reader and epprom memory so I choosed to use the 74LCX245 since its a bidirectional transeiver.
But ...
10
votes
2answers
154 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 ...
1
vote
0answers
87 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 try to measure voltage. There is 5V on HV and TX_HV but 4,7V on LV / TX_LV.
Putting TX to LOW ...
6
votes
4answers
1k 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 ...
0
votes
1answer
65 views
newbie: comparator adjustable level shift
I'm trying to build a simple fpga logic analyser and wondering how to best design the input circuit.
I would like to support 8 channels, voltage between 0-5V, with a adjustable threshold range (lets ...
5
votes
1answer
143 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 ...
1
vote
1answer
65 views
Converting logic and sign
I have an interesting project and I could use a little help. I'm using a microcontroller who's input to the ADC and output on the GPIO and DAC pins are all within a 3.3V range, and I have to interface ...
1
vote
3answers
224 views
controlling SPI devices using the Arduino - different voltages
My arduino board uses 5v to power the atmega chip. I was wondering is there any thing wrong with powering my atmega at 5v but say I power my MCP4922 dac at 3.3v does it matter? It just that I've seen ...
1
vote
2answers
561 views
Negative Voltage Level Shifting to an ADC
I am currently building a project that uses an AD595 analog devices chip to linearize the output of the Thermocouple sensor to 10mv/deg C. This output is to be connected to the ADC input of a Zigbee ...
4
votes
1answer
93 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 ...
2
votes
4answers
336 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 ...
5
votes
1answer
144 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 ...
0
votes
0answers
70 views
Working with arbitrary CMOS signals (2.5V - 5.5V)
I am trying to build a simple CMOS-RS232 convertor for my uC boards to be interfaced to a PC. I am using a MAX232. The board has to be able to be hooked to any uC board. I use AVR-s, ant they work at ...
3
votes
1answer
224 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 ...
6
votes
2answers
2k 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 ...
0
votes
1answer
381 views
I2C level shifting and protection
I am interfacing an MCU (CC1110) with Vdd of 3.3 V to a battery gauge IC (BQ27510-G2) with Vdd of 2.5 V. Currently, I am pulling the bus up to 3.3 V with a circuit that I blindly copied from a ...
3
votes
1answer
1k 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 ...
5
votes
2answers
1k 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 ...
0
votes
1answer
239 views
How to reduce voltage from a high speed buffer?
I am using this buffer to connect signal between 2.5 V and 5.5 V to a 3.3 V microcontroller.
The problem is I will get a 5 V output and my microcontroller doesn't have 5 V tolerant inputs so I have ...
3
votes
1answer
728 views
Arduino / Raspberry Pi: Voltage Converters and IO-Pins
I want to drive an LCD that needs 6V from a RaspberryPi. The Pi has a 3.3V logic power-pin, and a 5V power-pin that's directly connected to the MicroUSB-PowerSupply.
Am i right in the assumption ...
3
votes
3answers
1k 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 ...
0
votes
2answers
172 views
Camera circuit with different voltage requirements on arduino
First off - i'm an EE noob, but i've muddled my way through a number of arduino projects, so have some experience there.
I'm building a breakout board for a CMOS camera sensor for use with an arduino ...
2
votes
3answers
277 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 ...
1
vote
2answers
552 views
How to communicate to ATmega328 with a PC
I need to connect the ATmega328 to a PC to show the datas that are gathered from the microcontroller, in Visual Basic .Net.
I have done it successfully using the Arduino board with USB cable.
But ...
4
votes
3answers
4k 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.
...
0
votes
2answers
123 views
Automatic ranging level convertor?
I'm designing a PCB based on an ATxmega microcontroller (max. 3.6v tolerant). I plan to connect a range of external 3.3v devices. However, I do have a few 5v devices that I want to connect.
There are ...
4
votes
3answers
613 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 ...
1
vote
2answers
124 views
Flipping a signal
I've an input of two input lines, one being connected to ground and one carrying the signal (measured to ground). The output should be three lines with one being ground and the others measured in ...
3
votes
2answers
894 views
1.8V to 5V, still not comfortable with transistors
I have a H-bridge IC L293DNE that needs 5V input signals to operate, however my available outputs are only 1.8V from a Gumstix Overo GPIO pin. I have a power supply that supplies me with +5V 1A.
I've ...
3
votes
3answers
4k 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 ...
0
votes
1answer
387 views
Square Wave Voltage Level Shifting (Take 2)
After my question before, I tried to design a circuit with zener diodes and transistors for this issue.
It seems to work in simulation. Am I overdoing it? Are there any other simpler ways to do this, ...
2
votes
2answers
276 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 ...
0
votes
0answers
278 views
Is this buffer for protecting 3.3v logic from 9v power sane?
there. I'm playing with the idea of making a multi-interface for classic game controllers. I realize this is foolish, but I'm doing it anyway.
The interface connector between the system and the ...
6
votes
1answer
816 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 ...
9
votes
1answer
3k 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 ...
3
votes
3answers
2k 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 ...
2
votes
3answers
427 views
Level shift + amplify
Let's say I have a signal where 1v is digital 0, and 4v is digital 1.
I am a little lost how can I use PNP+NPN transistor to have +11..12(for 1) or -11..12V(for 0) output, provided that I have ...
5
votes
6answers
2k 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 ...
1
vote
3answers
537 views
Arduino Serial TX to iPhone RX voltage drop?
Articles I read about this tell me to hook up a 1KOhm resistor between the Arduino's TX and the iPhone's RX. I understand this is because Arduino's signal is 5V and I want 3.3V going to the iPhone.
...
2
votes
2answers
821 views
Logic Level Converter, Arduino and Cellphone
I am trying to interface a 6150 Nokia cellphone with an Arduino Duemilanove board, as some have already done through the FBUS protocol (see here for example).
The FBUS protocol uses 2.8V logic, so I ...
6
votes
2answers
3k 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 ...
1
vote
1answer
432 views
Shift 0-5V logic to ±2.5V logic
What's the simplest way at low speeds (sub 100 Hz) to shift 0-5V to ±2.5V? I was thinking of using a comparator or op-amp, but there must be a simpler / cheaper way. I wanted to avoid a dedicated ...
2
votes
3answers
4k views
How do I shift voltage levels?
I want to use an RF12B to communicate over radio with an arduino, but the transceiver is rated at 3.3v. I hear I need to use a voltage level shifter, but what do these look like and where can I find a ...
4
votes
2answers
304 views
How do I interface with ODB-II?
I've been tasked with interfacing with the on-board diagnostics of a vehicle.
Some systems use 7 V signalling, some use 5 V signalling, some signal up to the battery voltage (which can be as high as ...
2
votes
3answers
546 views
I²C level shifter pulls low side up
I am using the well-known I²C level shifter from that appnote from Philips.
The 3V side is supplied by an LP2950-3.0 regulator and is loaded only moderate (a few quite lazy 74's).
The problem I'm ...
4
votes
3answers
2k 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 ...
