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.
55
questions with no upvoted or accepted answers
2
votes
0
answers
55
views
How to understand this combinational cyclic circuit made of interconnected SR latches?
I'm trying to understand the following circuit, or better said, what must be the approach to analyze other similar ones:
What I'm doing for now is forget about the clock signal and the ...
- 1,191
2
votes
0
answers
58
views
Turning on a latch circuit with a piezo sensor?
I am trying to build a relatively 'simple' circuit with a piezo sensor that turns on an LED for ~10-20 seconds after it has been tapped.
In the off-state the circuit should use zero current to ...
- 21
2
votes
1
answer
300
views
CD4043 latch breadboard VS PCB
I am working on a circuit that contains CD4043 R/S latch. The design on the breadboard works and everything is great, as soon as the PCB was manufactured and components were soldered, an issue with ...
- 31
2
votes
1
answer
415
views
Shift register SPI control: cascading but individual latch
I would like to connect several boards to the microcontroller and send data to shift registers placed on the boards. I'm cascading all the shift registers for the data sending from the SPI. But I ...
1
vote
1
answer
662
views
Hold-on-hold-off soft latch power switch circuit
I'm trying to make a "hold-on-hold-off" type soft latch switch circuit, but I'm having a little trouble. I've found tons of "press-on-hold-off" types, but I haven't been able to ...
- 403
1
vote
0
answers
72
views
Equivalent time sampling with an ADC
ETS can be used to sample repetitive signals with a high virtual resolution.
Lets say we have repititive 1MHz signal we want to sample. This signal can be sampled with ETS.
For example a comparator ...
- 353
1
vote
0
answers
134
views
Nano Power Soft Latch
I need to latch an INT output with a time width of 7 ms. This signal is generated by an RTC clock and I need to enable an LDO with it. The LDO powers an MCU, which at the end of its program should be ...
1
vote
0
answers
53
views
A bus routing puzzle, does it ring a bell?
I am breaking my head over a puzzling bus routing puzzle, and I wonder if this sort of problem rings a bell. I have 4 memory cell ports, let's call them EE, OE, EO, and OO, that are being mapped to 4 ...
- 1,441
1
vote
0
answers
46
views
Problem based on Latches (Sequential Circuits)
I am trying to solve the following question:
I want to know:
If the truth table for \$ Q_{n+1}\$ and \$\bar Q_{n+1}\$ is correct.
I have found out the Reset and \$Q_{n}\$ conditions. However, I see ...
- 175
1
vote
0
answers
183
views
Jellybean Radio Button logic Chip
Below is an LTSpice simulation of a 'radio button' circuilt.
Ignore the bottom button, I am working on a 'reset' mechanism to unlatch any of the other buttons.
The idea is that the button you push, ...
- 289
1
vote
0
answers
117
views
Photocoupler to Latch Microcontroller Power Supply
I'm revising my custom arduino circuit which involves powering an atmega328p. I am using a 9V battery connected to a BS170 MOSFET. Without any voltage applied to the gate of my BS170, the battery is ...
1
vote
0
answers
282
views
Latching and Momentary Combo Switch
I am looking to recreate a switch circuit I have seen on an intercom system. The switch allowed for two functions, while using one momentary switch.
When the switch was pressed and emetily released, ...
1
vote
0
answers
91
views
Find high current latch or use Darlington array?
Looking for best practices here. I'm building a common-anode LED matrix. I've got a current sink LED driver, and I'm looking for a latch that will provide enough current to drive an array of LEDs. All ...
0
votes
0
answers
63
views
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 ...
- 101
0
votes
0
answers
36
views
How does a D-latch work in this condition?
I think that in a D-latch the Q+ (the next state) and Q'+ (the next state and prime) must be different.
But when the {Enable D Q} = {1 0 1}, the result is ...
- 11
0
votes
0
answers
76
views
How can SR-Latches store data over time?
My understanding is that the storing part of SR-latches boils down to having a wire loop. Ostensibly, the idea is that if there was current in the loop a second ago, there will still be current in the ...
- 101
0
votes
1
answer
58
views
WS2813 LED data permanently latching on power-on
I'm running into a problem where WS2813 LEDs 'latch' data permanently on start-up sometimes. The issue is sporadic, and random data is latched (RGB segments are enabled at random brightness levels on ...
- 89
0
votes
0
answers
40
views
Weird waveform of a digital latch
I am simulating on ADS.
As you can see, the V1 goes high at 9n sec.The clk has first rising edge at 10n sec.
Why does output V2 not go up at the 10n seconds? It goes up at 20n seconds at the second ...
user314455
0
votes
0
answers
87
views
24V input shutdown-latch - is it a good idea?
I want to protect my circuit by adding the ability to the MCU, to turn-off the power supply (and by this also turn itself off), in case of certain failure conditions are met. One of it would be ...
- 1,772
0
votes
0
answers
70
views
Toggle latching IC to replace relay
I need an IC on which pins stays in same state after power reset. How it's called? I don't want to use relays.
0
votes
0
answers
132
views
Does an eFuse exist that latches off immediately (and does not reactivate) in case of a short-circuit?
I've just discovered eFuses (from Texas Instruments + Toshiba + STMicro).
In case of a short-circuit on the output, MOS can be disabled in 150-500 ns by detecting a surge of current (called "fast-...
- 37
0
votes
1
answer
83
views
Latch the values generated by a 4-16 line decoder
I am using a 4 to 16 line decoder to convert a 4 bit number from arduino/seeed/ESP32 to drive circuits like RGB leds which would otherwise use up all my pins. There are some problems with this ...
- 101
0
votes
0
answers
59
views
To turn a ratioed circuit into non-ratioed circuit, what should be the transistor sizes for proper operation of this circuit?
The circuit is at the bottom. I know it is a ratioed circuit however, how can I convert it to a non-ratioed circuit without adding two more PMOS transistors between Vdd and the other PMOSs. Also, what ...
- 173
0
votes
0
answers
65
views
How to stabilize this CV triggered toggle (555 timer latching switch) when fed with two gates?
I created the prototype for a modular synthesizer module. The project goal is an AND gate that is fed with two control voltage inputs (A and B with an Vpp around 5V). There will be two outputs: the ...
0
votes
1
answer
138
views
Why is my latch circuit not toggling?
While I am waiting on some parts I made this circuit in a simulator. When S1 is pressed it should toggle the relay K1 and latch in that state, turning on the other LED. When I press the switch, though,...
- 11
0
votes
0
answers
233
views
Cycle-by-cycle current limiting with latching comparator
I am attempting to design a cycle-by-cycle current limiting circuit for a motor driver.
Here is my circuit along with some notes to explain its intended operation:
The latching comparator I plan on ...
- 63
0
votes
0
answers
97
views
Need help in Latching ON/OFF switch
I am working on a latching on/off switch, There are many ways to do it by using discrete components. But I want to use an IC to perform that task. I found MAX16054 IC which is similar to my ...
- 41
0
votes
3
answers
226
views
Difference between latches and flip-flops in datasheet
At university and several online searches (Difference between latch and flip-flop) I have been taught that the difference between a latch and a flip-flop is that the latch is level triggered while the ...
0
votes
1
answer
303
views
Glitches in clock gating cell
how exactly does glitch happen for rising-edge and falling-edge ICG ?
Why for the top version of rising-edge ICG, there is no X at the MSB of the latch output ?
Note: TE signal is asynchronous to CLK,...
- 393
0
votes
0
answers
46
views
Random latch period of 555
I've designed a dice circuit, simulated it in Proteus (which worked) and got the PCBs manufactured. A problem I'm facing on the real thing is that if the button is pressed normally (e.g. for as long ...
- 110
0
votes
1
answer
28
views
Input / output behaviour of dynamic latch
I'm studying this dynamic latch and I wonder why, when the switch closes the second time, in doesn't go up to high as well.
When I consider only the switch and out, ...
- 585
0
votes
0
answers
239
views
Latching Priority Encoder, circuit works but I don't trust it
I added a schematic even though the question is actually too simple for it. The datasheets for the devices are likely to be more revealing.
The circuit is super simple. I have a 74HC148 priority ...
- 178
0
votes
0
answers
70
views
How to latch a signal rise and low on the next signal rise
My input signal is a pulsing 35Hz with a top at 5 volts. The pulses itself are short.
The first pulse (5v) should trigger a latch at 5v high. And the next pulse should reset the latch to low.
Added a ...
- 121
0
votes
1
answer
122
views
Outputting correct data on shift register with clocks tied from microcontroller
I want to be able to output correct data from the microcontroller to the 74HC595 shift register without using the clock lines separately. This schematic matches my ideas for 16 bits of data:
The ...
0
votes
0
answers
64
views
Is there a one trigger latch for AC?
SCR is good for latching DC source, one trigger will turn on the source indefinitely. But how about AC source?
Latching mechanical relays is good but it is too big for me. Triac is designed for AC ...
- 1,044
0
votes
2
answers
129
views
Modification to the D flip-flop
When we take a clock and a signal, the D flip flop output always gives "clock edge" AND, and the state will be high unto to the next clock cycle.
Now I want my output like like a latch, but timing ...
- 101
0
votes
0
answers
339
views
TTL "radio-button" using priority encoder and latch
I'm liking this site and I am not always using it to just throw a question but to develop ideas all the way. First time I did that was on StackOverflow I need JSZip and gzip for my web page, and JSZip ...
- 1,441
0
votes
0
answers
560
views
Understanding complements on inputs
I've got a problem understanding formal writing down of complements on inputs.
During my laboratory exercise I was working with a device that had D flip flop embedded in it. The goal was to ...
- 179
0
votes
0
answers
172
views
BJT Latching Circuit Help
I have build a latching circuit using both a NPN & PNP BJT to turn on and off an LED, as shown below:
simulate this circuit – Schematic created using CircuitLab
When I built the circuit ...
- 1,506
0
votes
0
answers
60
views
Capacitor life hours
Working on an existing product which has had field failures. Design is a short (60ms) pulse is sent via microcontroller to activate / deactivate a latching switch. I have determined failure is due to ...
- 251
0
votes
1
answer
447
views
Latching power circuit with short-to-ground switch
I'm trying to build a circuit around an existing switch that allows another component to override the switch state. (Our component is a computer and the feature we're trying to build is remote-...
- 125
0
votes
0
answers
149
views
Latch with no Vout
I'm working with the WiPy expansion board at
https://github.com/wipy/wipy/blob/master/hardware/ExpansionBoard-v1.2/ExpansionBoard-v1.2_Schematics.pdf
On sheet 3, there is what appears to be a latch ...
- 69
0
votes
0
answers
248
views
Strange output from latch connected to comparator
I'm trying to make a latch (in ltspice), so if the comparator output (A) goes low, the latch will trigger and C will go high. C should stay high, irrespective of whether A goes high or low after that. ...
- 2,107
0
votes
2
answers
1k
views
Soft-latch auto-reset OFF (hold) / ON (press) button, is the schematic correct?
I'm looking to make a soft-latching interface with a single momentary push button.
Required features for my build are (edited, sorry for bad description) :
Circuit should always start in OFF ...
- 1
0
votes
0
answers
173
views
Soft latch on/off button simulation
I am trying to simulated in pspice a soft latch on/off circuit but it is not working as expected, even if I double check the implementation. Can someone explain to me why the voltage on the probe is 0....
0
votes
0
answers
491
views
Lowest power way to latch power supply after input pulse
Background
Right now I have a circuit consisting of a Adafruit Huzzah Feather (ESP8266 board), an ADXL345 accelerometer, and an ATTiny85 (bare chip). The circuit is powered by a lipo battery plugged ...
- 33
0
votes
1
answer
113
views
Memory in sequential circuit
In sequential circuit block diagram ,it is said that some outputs are again feedbacked to inputs,after storing them in memory.
But,where is that memory in sr latch.In sr latch ,it is seen that the ...
0
votes
1
answer
615
views
Building a D flip-flop with two D inputs using 3 S-R latches
"Use three clocked SR latches to build a D flip-flop with two D inputs (D1 and D2 ) and two clock inputs C1 and C2 . Clock C1 takes data D1 and clock C2 takes data D2 ."
Any hints how to start?
- 157
0
votes
1
answer
52
views
What protection measures to consider when switching many loads at the same time with shift registrers?
I'm developping a programmable load board with many of these load steps to test LDO or DC/DC converter Output.
As you can see, what changes is the resistor R6 to provide other current load values....
0
votes
0
answers
719
views
Latched comparator output higher than supply
I am trying to simulate the following latched comparator (the detail analysis of that circuit can be found here).
At low clock frequency (200MHz), the circuit works perfectly well . However, when I ...
- 1,537