Questions tagged [latch]
A latch or flip-flop is a circuit that has two stable states and can be used to store state information. However latch is normally used to describe a simple storage device while flip-flop is normally reserved for clocked devices.
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Master-Slave register with dynamic CMOS logic
I just cannot understand the operation of this circuit:
(there is an error in the transmission gate, the yellow "0" ... but whatever)
If the input (light blue) is 0 and the gate is closed (...
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RS Latch: Signal behavior during transition from invalid to valid state
I have read a few of the posts here regarding race conditions as they pertain to the RS Latch, but they don't answer my specific question. I understand that if the latch is given an invalid input like ...
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How do I connect cd4010b as inverter for IOWR signal
Following with the post Latch LS374 works for sometimes and doesn't work at all next clocks
I'm planning to use LS373 instead of LS374.
I need to invert the IOWR signal, I only have that inverter
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Latch LS374 works for sometimes and doesn't work at all next clocks
I'm trying to interface with an 8080bus, that's the schematic of the socket of it:
Image: Partial schematic by Akai of their MPC2000XL showing the LCD interface, hosted on Mediafire
I'm latching all ...
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A transistor latch in dual-supply
I need to build a few latches they are supplied from +rail and -rail.
When the latch is ON it should output strong +Vrail and -Vrail also (not through resistor).
A solution on picture comes to my mind....
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What is the point of two enable signals in PT6957 LED driver?
I have a 48 x 16 matrix LED display E-MOTIVE Q-B-069B (no datasheet), and during reverse engineering I found 4 off PT6957 there.
PT6957 is 16-bit shift register, latched with constant current drives. ...
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Why is my code implemented in latches?
I am starting to design in a HDL. So, I'm designing a simple test, where variable "var" is an and of each "partial" row. However, when I synthesize this, I see that the RTL ...
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how do I add turn-off to a latching circuit?
so, I made this latch circuit : Falstad Simulator
simulate this circuit – Schematic created using CircuitLab
It turns on and stays on. How do I add turning off using single momentary switch?
I ...
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Is there something wrong with this power-on latch circuit?
I am analyzing an electronic device that has an MCU and the following characteristics:
it is powered from a 3.7 V Li-ion battery
it has an on/off button that needs to be pressed 1 second to power-on ...
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What are the necessary conditions to prevent latch-up problem for Oscillators?
In his chapter on oscillator design, Razavi discusses the issue of latch-up and proposes several methods to eliminate it. However, he doesn't provide explanations for these methods. Could anyone ...
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Comparator Latch Initial state
I am working on a latching current limiter circuit and as part of it I'm using multiple LM139 comparators to implement a simple SR latch. This specific comparator has an open-drain output.
A latching ...
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D latch circuit not working
I have made the attached circuit, to make a on/off switch for a power circuit. I have made the set and reset pins high. Also shorted the Q' and D. After many trials, still stuck up with the output Q ...
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CML Latch simulation in LTSpice
I am trying to simulate a CML Latch in LTSpice (schematic below), but the simulation results do not seem right. I am using N_50n transistors from BSIM4 model. L = 60n for all transistors, W = 10u for ...
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Transistor latch circuit stays on and button is unresponsive
I'm using a 2n2222a and 2n3906 with a 2n3906 as a reset and a irf4905 mosfet to carry the load I've redone this circuit many times on the computer, and breadboard and it seems to work but as soon as I ...
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How to convert SR (NOR) latch into S'R' (NAND) latch
What is the general rule of thumb to convert SR (NOR) latch into S'R' (NAND) latch? I only know the two inputs (S,R) need to be inverted. What about outputs (Q)?
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Setup and hold time for pulsed latches
I am reading "CMOS VLSI Design A circuit and System Perspective". I didn't understand why the clock period needs to be larger than below formula. Can anyone help me to understand it?
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Modification on latching power circuit
I have built the following circuit to power my esp8266. And it works fine.
https://community.home-assistant.io/t/multiple-button-wifi-remote-no-deep-sleep-required-battery-lasts-forever/306233
When ...
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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 ...
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Comparator connection with SR latch v2
I designed a comparator that sets 12 V on the output whenever there is overvoltage on the input of the comparator (13 V from AC sin source). In my schematic, the output value of the SR latch reacts to ...
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Rising Edge Demux
I'm trying to create a demux for the YM2610 sound chip.
The sound chip selects whether to set the low bits or high bits of the address with a single pulse; the rising edge should trigger a latch for ...
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Explain schematic for one-shot trigger
Can you please help to explain following schematic:
How does this circuit work?
What is the purpose of the diode and the capacitor?
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The logic gate design of a positive edge triggered, master slave d flip flop with asynchronous inputs preset and clear?
I'm a computer science student who's trying to get a better understanding of the d flip-flop. My project assignment is to make a CMOS design of a positive edged d flip-flop using ff master slave and ...
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Dual Mosfet as a hard latch rather than soft?
I have built and tested the below circuit and it works well as a soft latch with a toggle function from the momentary switch.
How would I modify this circuit to latch once and not reset until either ...
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MCU not powering off completely
I implemented this on/off circuit that I use with a LiPo battery and a HT7833 voltage regulator. Since my MCU (ESP8266) can only handle 3.3v, I added a voltage divider for the MCU sense pin, just like ...
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On a method of clock gating with a latch
My textbook (CMOS VLSI Design: A Circuits and Systems Perspective, 4th edition, by Weste and Harris) gives the following discussion of a particular method of clock gating into some digital block.
I ...
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Working of edge-triggered flip flop
The above circuit is a master slave flip flop. Edge triggered. The working should be:
During positive cycle, master is enabled by clock, storing data.
At the negative edge (transition), slave takes ...
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What's the difference between a latch and a flip flop? I found multiple answers
So I was checking out sequential logic and I found two different circuits for flip flops (or latches, or both). Let's take D flip flop for my quesiton.
There's one circuit here, showing a D flip flop:
...
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How to calculate the time constant of a simple cross coupled diff pair latch circuit
I have a circuit, which is given below.
Now I want to find the time constant of the circuit, considering there are equal caps placed at node X and Y.
For a small signal model I can easily find the ...
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Confusion about Synthesis Results of Verilog Code: DATAIN has no connection
I am quite puzzled about the synthesis results of the following code.
Here is the code:
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SR latch with both inputs at 0
I know questions on SR latch and FF has come up fairly often and I've already seen answers that made me understand better how this device work.
However, I still have a doubt when both input S and R ...
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Is there any such thing as a tristable, quadristable, etc. multivibrator?
The title says it all.
Is there a discrete circuit that can produce 4 different outputs based on a single tactile switch click?
I'd like to do this with either a discrete design or a 74373 since ...
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Difference between DM13A and TLC59281 Constant Current LED sink Drivers
I was using DM13A driver in my old PCB designs and it was working perfectly using Arduino Mega. Due to parts shortage at JLCPCB I had to use TLC59281 driver for my new PCB. But TLC59281 is not working ...
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Capacitor function in a flip flop circuit
I'm new to electronics and I'm trying to figure out the following circuit.
The circuit turns on one of the leds when one button is clicked, if the other is clicked then the current light is turned off ...
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Latching with MOSFET
I am struggling to have the circuit below working on LTspice. Indeed, as I understand it when the switch is pressed the LED should change it's state (turn on if off / turn off if on). The switch is ...
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Blue UV LED Timer Circuit
I have designed a PCB for mouth guard device and also its enclosure is ready in which PCB will be placed when its not in use. I want to use a UV blue light for UV sterilization inside the box. Now the ...
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Replacing pushbutton with sensor in 555 timer latch circuit
I want to make a circuit where there will be a photodiode which when receives infra red light from the IR LED for the first time, produces a high output and when it receives the light for the second ...
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Why would an intermediate voltage level cause a metastability in a SR-latch
Transistors and logic gates are actually analog in nature they aren't digital they don't turn on or off at certain voltages.
Image source: All About Circuits - Voltage Tolerance of CMOS Gate Inputs
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Astable multivibrator and latch in one
I am trying to design a combined function of oscillator and latch in one circuit to spare parts.
Seems it is working but anyway do you think it is OK or did you see somewhere this circuit?:
simulate ...
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Tie an input of an AND gate to its output
Let's say we have an AND gate and we give 1 as one of its inputs and we tie the other input to the gate's output.
What will happen?
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Triggering an SR Latch with multiple reset lines
Ok, so I'm relatively new to electrical engineering having worked on the software side of life in the past. I'm trying to work a simple SR Latch where only one output is enabled at once. To do this, I'...
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Latch is stable with competing capacitors?
I inherited the attached design as part of a work project. This is a latch which is meant to hold the high-voltage side of the system in the powered on state when a momentary power button attached to ...
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Is this circuit correct and safe to bypass my latch circuit, turning on the load every time I connect it to 5V?
I have this working on/off latch circuit below that works on a 8.4V battery.
I can charge and bypass the battery when I connect the circuit to a 5V charger, while still providing supply to the load ...
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First time designing an SR latch; I'm using it to control the enable pin on my eFuse IC. Just want to know if I'm overlooking anything
I just finished designing my rectifier module that has a built-in voltage monitor IC and an eFuse IC.
Its purpose is to convert the 3-phase AC output from my wind turbine and use it to power my USB ...
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Transistors falsely latch with EMI
I have a very basic NPN - PNP latching circuit:
[Sorry for the upside down image]
The latch initially is off, and when the op_amp_Signal_and_latch turns on, the ...
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ESP32 power latch circuit react on low and high (reed switch)
I am currently building a door sensor with an ESP32 and a reed switch.
My code is working with the deep sleep functionalities of the ESP32. With its help I can detect a falling/rising edge and wake ...
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Push button latch circuit - switch issue
I have built a single push on/off latching circuit as per the diagram. It runs from 12 V.
It works, but the issues I have is that first, it is already on when I connect power, it should start off, ...
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D-type LATCH output when minimum clock/enable pulse width is violated and input/output are the same [closed]
Can the output of a D-type latch go metastable when:
There is a minimum CLK/ENable pulse width violation
The input and the output of the latch have the same value?
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How to make a D-type latch not start in SET condition by itself?
I have this schematic to digitally start and stop a power supply of a Raspberry Pi, and I want to be assured that the latch doesn't start by itself in the ON state when I apply power.
Of course, if it'...
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Question about T flip-flop
I am trying to implement a switch that works like the description in the picture. In my research I came across the T flip-flop, however a T flip-flop requires a clock signal. I don't have that.
Is ...
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How do I model switches in Matlab/Simulink?
I am trying to model different types of switches in Matlab/Simulink. There is this type of switch that I can't find a name for or design. I am not an expert in digital logic, I only have the basics ...
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