The Stack Overflow podcast is back! Listen to an interview with our new CEO.

Questions tagged [tl431]

The tag has no usage guidance.

Filter by
Sorted by
Tagged with
1
vote
2answers
131 views

TL431 / TLV431 supercapacitor voltage clamping circuit

I have a question regarding a circuit I've been working on for some time. The circuit is based around existing supercapacitor protection modules and uses a TL431 (actually a TLV431 lower power ...
8
votes
3answers
2k views

Crowbar circuit causes unexpected behavior for op amp circuit

I am using an op amp to amplify an input signal from a microcontroller, which in general is working fine. For over voltage protection, I added the crowbar circuit taken directly from figure 32, page ...
4
votes
1answer
106 views

I'm trying to build a lipo discharger

The way I want it to work is to slowly discharge the lipo down to storage voltage and then stop. I think the best way to do this is to use a TL431 to control the voltage shutoff and use a power ...
2
votes
0answers
39 views

Ripple in output voltage

I am working on an Active Clamp Forward converter. Schematic is given here: Specs: Output voltage-5V Input voltage 26..42V frequency=500KHz Output power=10W It is working fine in open loop, but in ...
1
vote
2answers
125 views

How can I estimate TL431 output voltage swings based on datasheet alone?

I am trying to design a series-pass regulator that brings 12V down to 3.3V. If I see a 20 mA step change in current, I would like to stay within a certain output voltage range (±2%). What parameters ...
0
votes
1answer
624 views

TL431 as negative voltage reference

Im building a LM317 based power supply and the output range must be 0.3V-21V. I've used a 2 diodes in series and a resistor supplied by a negative voltage and take the node between resistor and diode ...
0
votes
3answers
318 views

TL431 Constant Sinking current

A user already asked a question about it at TL431 Constant current source. My SPECIFIC question is about the figure 29. Sure it is not a complete circuit, so I completed it, in order to understand it, ...
-2
votes
1answer
624 views

Adjustable current limiting in flyback converter using TL431

I'm building a SMPS and I would like to have a current limiting feature on the output. I'm trying to make a feedback loop using TL431, shunt resistor, optocoupler and a potentiometer, but no luck this ...
0
votes
2answers
756 views

Voltage Feedback Using TL431

Hello All , In the Above circuit , TL431 is used to regulate the output voltage which is set by resistors RH1 and RL1. resistor RB is bias resistor to provide the current to regulate the output ...
0
votes
3answers
697 views

Multiplexing PT100 with CD4051

I am interested in developing a generic 8-channel 4-wire PT100 interface for RaspberryPi. Needed accuracy must be better than 1degC and range from 0-200 degC. Additionally i need lead wire ...
0
votes
3answers
445 views

How to use a TL431 for PMOS based reverse polarity protection?

Consider the following illustration: I wonder if it possible to replace the zener with a TL431. The usual application of TL431 supplies specific voltage to next stage but the zener here supplies ...
0
votes
1answer
430 views

TL431 LDO series pass transister heating up

I designed a low drop out 5v voltage regulator from 24v input. Works fine. But the series pass transistor heating up more than 100 degree Celsius (with heat sink). Is it normal? Or how to reduce heat? ...
3
votes
1answer
1k views

Strange oscillations with TL431 voltage reference

I have a problem with TL431 voltage reference circuit: There is no load connected to VREF25. When I remove C8, voltage VREF25 is perfectly stable 2.5V. But when I put C8 back into the circuit, ...
0
votes
0answers
60 views

TL431 not tripping at high loads

In the datasheet for TL431, page 26, figure 32, is an example schematic of a crowbar circuit. I've been toying around with this one, since this is the first time I use a TL431. Instead of a TRIAC I ...
1
vote
3answers
2k views

Configuring a TL341 current limitation

I am trying to get this well known circuit [ work inserted in a series of 69 LEDs to protect them according to this specification. Transistor is 2N2222, hfe=18 according to multimeter. The free-...
0
votes
2answers
2k views

Crowbar circuit with TL431 help

So I'm trying to create a OVP using TL431 an a triac, i have checked the datasheet but since i suck at math i don't really get how to set the ref voltage.. datasheet: http://www.ti.com/lit/ds/symlink/...
3
votes
2answers
11k views

TL431 Low battery cut-off

Good morning Could somebody please explain the operation of the attached diagram to me? The circuit was proposed here and here as a low voltage cut-off circuit, which switches off the MOSFET when ...
3
votes
1answer
3k views

Where should I place the capacitor in this TL431 + TRIAC crowbar circuit?

I'm building a replacement power supply for my C64 and want to add some protection against overvoltage. For that purpose, I tried to find a suitable crowbar circuit that would short-circuit the supply ...
2
votes
2answers
648 views

Coil-less AC-DC line regulator

I'm trying to fix an AC-DC line regulator that I have build and doesn't work as expected. I'm trying to convert AC 220V mains to DC 5V 10mA without a transformer. To do this I'm using an 1uF 250VAC ...
5
votes
5answers
10k views

TL431 Constant current source

I have few doubts regarding TL431. Please correct if i am wrong.. TL431 can be used to generate voltages from Vref to 36V. Output voltage is taken across diode in reverse biassed condition. reverse ...
1
vote
0answers
897 views

Split-phase 230VAC transformerless capacitive power supply for 5V@30mA regulated output — series cap?

I'm a hobbyist developing a hybrid power switch (electromagnetic + solid state) for a resistive electric stove (8kW max) top. I have a profoundly autistic, disabled adult in the house and I need a ...
6
votes
1answer
11k views

TL431 as a comparator?

One of the things I've noticed in a few power supplies is the use of a TL431, a voltage reference, as a comparator of sorts. It seems to be set up in a configuration where when the voltage across it ...
4
votes
2answers
847 views

TL431, take two

I'm using a TL431B (±0.5%) shunt regulator to get 3V ±1% (max.) from a 3.3V ±5% supply, so from 3.135V to 3.465V. The 3.3V supply is a switcher, so has a decent amount of high frequency (~3 MHz) noise ...
2
votes
1answer
1k views

Difference between TL431 and TL432

What is the difference between these parts? The datasheet shows completely different pinnings, but both are specified over the same range and both have the A, B and ungraded specifications for ...
10
votes
2answers
3k views

Does the TL431 have a “dropout voltage” per se?

I want to get a stable 3V reference from a +3.3V ±5% supply (so it can go as low as 3.135V and as high as 3.465V.) I know the TL431 is a shunt/zener regulator, so doesn't really have a dropout ...