The diode between drain and source in MOSFETs, formed by the PN junction between source and drain. This intrinsic diode is the reason MOSFETs can block current in only one direction.
Questions tagged [body-diode]
28 questions
18
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3 answers
How should I understand the intrinsic body diode inside a MOSFET?
I know there is an intrinsic body diode inside all the MOSFETs, but I'm confused about the reason why it's there. I've searched the articles but can't find a good explanation for it. Can anyone use the "normal" NMOS structure (when I say normal, I…
Nobody
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MOSFET with *actual pin* for body
I have always thought that MOSFETs have four pins [see wikipedia], one of them connected to the body (i.e. substrate).
However, when trying to order some, I have been completely unable to find any with a separate connection for the body; all the…
user82975
6
votes
2 answers
Can a MOSFET be used to switch between two supply voltages?
My goal is to programmatically switch between supply voltages (3.3V and ~2.6V) for a load. The 2.6V level doesn't need to be exact, +/- 0.2V is OK.
I created the following circuit, which uses my MCU's GPIO to control an NPN BJT / P-channel MOSFET…
kirtan-shah
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5
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1 answer
Role of the body diode in a solid state relay
The solid state relay with MOSFETs connected back-to-back (source-to-source) is claimed to work by the mutual action of the body diode according to this website, and this TI paper.
However, I had been thinking that in the on-state, the body-diode is…
oliver
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5
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What is a "Body dragger" in this load switch IC?
I am studying a white paper from Intersil/Renesas for a load switch IC ISL7x061SEH PMOS and SL7x062SEH NMOS. In the chips block diagram I see a block called "body dragger" that I don't understand, and it is not mentioned again in the paper or…
ztan
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4
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Can you use a diode to cancel the body diode of a MOSFET?
From what I understand, MOSFETs inherently have a diode between the source and drain known as a body diode. If I were to use an nMOSFET as a low side switch, would it be bad to have a diode between the load and the drain of the MOSFET? What effect…
superN8
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4
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2 answers
I need some help understanding overshoot and ringing in MOSFET half bridges
From FDA75N28 datasheet:
What I am having difficulty understanding are the reasons behind overshoot and ringing in V_DS.
Now, to what I already know:
The current that passes in an inductor cannot change abruptly, but has to change…
rmarques
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3 answers
Does body diode reduce MOSFET switching loss in a power converter?
In power converters, it is common that MOSFETs are fed a PWM signal to have cyclic switching. Part of the power is lost in the process. Does the body diode reduce this loss? It seems most power MOSFETs have the diode included.
HYQ
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3
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Use of MOSFETs body diode
I have an N-MOSFET array IC and I don't need to use all of them, but I do need to use a diode. Is it OK to use the body diode of one of the MOSFETs as a regular diode to decrease component count and footprint? Can I just tie source to gate and use…
Cano64
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3
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5 answers
Replacing a Switch and Avoiding body diode conduction
I am trying to design a replacement for a 2:1 switch using FETs, which would be really easy if I didn't have to concern myself with the body diodes that are present on PMOS transistors.
My scenario is that I have two batteries in parallel to power…
MrPhooky
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2
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ORing mosfet controller with ability to switch off the load
My system is powered from a wall adapter and backup SLA battery.
simulate this circuit – Schematic created using CircuitLab
Since the voltage of the wall adapter is higher than the SLA, I have ORed the two so that the battery will be used only when…
Fiebbo
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2
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1 answer
Turning an NMOS with substrate terminal into a PMOS
Some NMOS's come with a substrate/bulk/body terminal so the "Source Voltage" referred to in literature then Substrate Voltage. Say then we short the gate to the drain and have the substrate take the input. We would then use this in the same NMOS…
Majin_Boo
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2
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3 answers
Where does the MOSFET body diode come from?
Where does the body diode in a MOSFET come from? I understand that its built in and an intrinsic part of the MOSFET. All illustrations of a MOSFET that I've seen depict the structure as two diodes back to back but non hint at where the diode comes…
vini_i
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2
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Extra Shottky Flyback Diodes on FET-based BLDC Motor Driver?
TL;DR: I have a FET-based BLDC motor driver design, and I need to decide whether to add discrete Shottky diodes in parallel with each FET for reliable and long-lived operation in an automotive-like application. Yes? No? What do I need to…
PKL
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1 answer
Why do some analog circuits use a FET with shorted drain and source?
Why do some analog circuits use a FET with shorted drain and source? Depending of the type of FET, it may either act as a capacitor or a diode? It each case, why not just use a cap or a diode?
Below is one example.
Slimane
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