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0
votes
1answer
48 views

Turn on power when voltage higher than set value

We are trying do design a circuit which works by harvesting energy from a split core current transformer. Most of the electronic works correctly, we use a 1.5F 5.5V SuperCap to provide enough power ...
1
vote
1answer
125 views

Mosfet Gate-Source Zener [closed]

I want to confirm this circuit is going to work and ask how to calculate the zener voltage. The load is going to be driven by 30 volts, and the gate voltage is the same 30v, through an optocoupler.
1
vote
3answers
82 views

MOSFET for revrerse voltage protection

I have used the following circuit to for the purpose of reverse voltage protection. But, I am a little bit confuse about the working of the zener diode in combination of the 100k resistor in this ...
4
votes
1answer
224 views

help understanding this reverse polarity protection circuit

Going through LT4363 evaluation kit DC2062A-B (schematic here), I came across a reverse protection circuitry that protects downstream components from reverse transients and reverse DC voltage: In ...
1
vote
1answer
42 views

Powering a low current device from a mosfet N

I have a question regarding a circuit providing low current capacity voltage for device powering, that goes down from a lot higher voltage: How does it exactly work? I understand that the Q1 gate is ...
0
votes
1answer
57 views

High side driver internal design

I have a question about the high side driver VN7016AJ for automotive applications, during ISO pulse1 -150 V will be applied at its VCC pin, I found from the User manual (UM1922) that when -150 V is ...
0
votes
2answers
162 views

Confusions with placing and sizing the flyback diode, TVS and Zener

I have couple of questions regarding the location of flyback diode and sizing and locating the Zener and TVS diodes. For example below at the far end there is a magnetic relay which is controlled by a ...
2
votes
1answer
98 views

Schematic for input protection with NMOS? Does this really work?

I was reading an old schematic and found this and sketched it up; (see box in image "Some kind of protection") The closest thing to this schematic that I've been able to find, that could have briefly ...
4
votes
2answers
251 views

Is this resistor necessary for protection?

I would like to incorporate this circuit in my design so that I could use a low current capacity slide switch to control the 2A current of a Li-poly. Now, I understand the purpose of having two PMOS ...
4
votes
1answer
889 views

Flyback diode is acting weird

I have the following schematic: Vcc can vary from 12 to 15 volts, so the design was intended to switch on the relay through a MOSFET when the input voltage is over 13.4 volts. The actual Zener I've ...
0
votes
1answer
192 views

Driving a 35V PMOS circuit from a Grounded/Floating input

I have an application where I need to switch a contactor on and off using a spare output of an off the shelf Battery Management System (BMS) The input is the signal coming from the BMS, while the ...
2
votes
2answers
5k views

MOSFET protection using zener diode

I have a question about this circuit, using Zener diode as a protection for mosfet. I've found some related topics but didn't found any circuit which uses the same configuration. Can anyone suggest ...
1
vote
2answers
685 views

Half-Bridge MOSFET Driver for 48V

So I designed this Half-Bridge Mosfet Driver for 48V. Since I'm pretty new to this type of circuit I would like to ask if there are going to be any problems with this circuit. (eg. speed, power loss, ...
2
votes
1answer
2k views

MOSFET Gate protection

I am using SSM3J334R P channel MOSFET for switching high voltage which has following specs Drain-Source voltage (VDSS) -30 V Gate-Source voltage (VGSS) ±20 V ...
0
votes
3answers
270 views

Question about Non-isolated Buck Converter [closed]

I have a tutorial problem about buck converter with MOSFET, anyone can help? During the test of the non-isolated buck converter (see the circuit below), when we measure the gate signal, there is an ...
1
vote
1answer
469 views

Mosfet Vgs protection

If I have a P-channel mosfet and I want it to operate with Vgs much more than absolute maximum ratings what's the best solution which can I do? I thought that a zener between gate and source might be ...
0
votes
1answer
534 views

24V H Bridge Gate driver - FOD3184 & FQP47N06

I am trying to design a H-bridge to drive 24V motors. No issue on the low side but I would like to use the FOD3184 Opto/Gate driver on the high side of the H-bridge to drive a P MOSFET and I am ...
4
votes
1answer
598 views

Characteristics of built-in Zener protection on FET gates

A lot of SOT-23 FET gates have built-in back-to-back Zener diodes to source, presumably to protect against over-voltage. However, the datasheets typically say nothing about the characteristics of ...
0
votes
1answer
174 views

Is this something a P.L.C. would be able to do?

I wish to replace the zener diodes with a programmable chip, so that I can program the chip to do exactly what the zener diodes do in this circuit. This will then make the circuit universal to all my ...
0
votes
1answer
612 views

How to PWM-drive a N-channel non-logic level power MOSFET with a 3.3V signal?

Follow-up of Using IR21531 as a simple 1 channel gate driver After doing the above question (I'm very sorry, beacuse my question seems a XY one), I'll try to explain better what I believe that I want ...
4
votes
1answer
455 views

Check for if I've picked the correct flyback and zener diodes for a solenoid valve driver

I want to use an arduino power driver shield which contains the RFP30N06LE MOSFET to drive the 12V version of a solenoid valve which has a power consumption of 2.0 Watts (so 167 mA current draw I ...
0
votes
1answer
756 views

MOSFET gate protection zener diode math .please help

My circuit's voltage input can range from 6V to 12.6V. I want to use a p-ch mosfet for reverse bias protection. However, the FET I want to use has a maximum VGS of +/- 8V, so I have to protect it in ...
3
votes
1answer
9k views

Using NPN BJT with a P Channel MOSFET to switch 3.3V to 24V

simulate this circuit – Schematic created using CircuitLab I have some 3.3V I/O on a PC Board. When an output is switched on, I need to switch the 3.3V output voltage with a +24VDC and provide ...
1
vote
1answer
1k views

Where do you put the gate-protection zener diode in an NMOS H-Bridge?

Do you even include it for an NMOS H-bridge? Because typically I've only ever seen them in NMOS/PMOS bridges, not full NMOS bridges. (Inductive load) The protection zeners would go here right?
1
vote
3answers
778 views

3v3 Microcontroller controlling a MOSFET that needs 5V

I'm designing a heater controller that has a primary input voltage between 12 and 24V. Everything except the heater runs on 3V3, including microcontroller, LED's, potentiometers and the MOSFET. The ...
0
votes
3answers
7k views

Make a zener diode out of a MOSFET

Does anyone know if its possible to wire up a MOSFET transistor as a zener diode? I have been happily making normal diodes from my MOSFETs by shorting the gate and the source simulate this circuit &...
2
votes
5answers
22k views

Zener + MOSFET overvoltage protection

I need a simple circuit to protect my device from overvoltage (more than 13V). Typical working DC input voltage is 7-12V. Can I use this circuit: Will it work? UPD. OK, it will not. I was too stupid....
2
votes
2answers
4k views

Intrinsic Zener diode in MOSFET

I understand why some transistors have a built-in (normal) diode from drain to source, so that when the transistor turns off, back-emf can flow back up, specially important in inductive charges, but ...
5
votes
2answers
3k views

MOSFET controlled by optocoupler using Arduino

I have a question about using an Arduino to control a MOSFET with optocoupler. The question is, the supply voltage may vary from 5 to 36 Volts. For example, sometimes I will use a 5V switching ...
3
votes
1answer
4k views

Floating Voltage to Bias a P-Channel Mosfet without Exceeding Source-Gate Max Voltage

I'm not sure if this is what you'd call "floating voltage" or not. I'm lacking on some terminology so bear with me. Here's the circuit with explanation below: The premise of the circuit is this: I ...