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Why MOSFET has a diode?
MOSFETs have an extremely useful property; that is, when VGS=0, they still conduct in reverse. They do this because they have a parasitic diode between source and drain called an intrinsic body diode.
What is a MOSFET body diode?
The body diode of the MOSFET forms between the n- layer of the MOSFET’s drain and the p+ well of the device’s source. This is the diode depicted in virtually all MOSFET datasheets. In switching applications that use the body diode, the reverse recovery of this PN junction needs to be understood.
What is an ideal diode used for?
The key function of an ideal diode is to control the direction of current-flow. Current passing through a diode can only go in one direction, called the forward direction. Current trying to flow the reverse direction is blocked. They’re like the one-way valve of electronics.
What is the body diode of the power MOSFET?
Unlike virtually every other active device, the power MOSFET is unusual in that its schematic symbol includes a parasitic device – the body diode. The body diode is intrinsic to the device’s structure.
Can a p-FET be used as a resistor?
This design also uses a clamping diode to keep the gate voltage within a safe range. But there are P-FETs out there that wouldn’t need that diode or resistor. This method wastes ten times less power than a simple diode would have. We’ve embedded the video after the break where [Afroman] shares the math and reasoning behind his component choices.
Why do I need a diode in my p-FET?
You want to make sure that a battery plugged in the wrong way, or a polarity mistake with your bench PSU doesn’t damage that hardware. It’s easy enough to plop in a diode for protection, but as [Afroman] points out, that wastes power in the form of heat when the circuit is working correctly.
How is a p-channel MOSFET different from other MOSFETs?
A P-Channel MOSFET is a type of MOSFET in which the channel of the MOSFET is composed of a majority of holes as current carriers. When the MOSFET is activated and is on, the majority of the current flowing are holes moving through the channels. This is in contrast to the other type of MOSFET, which are N-Channel MOSFETs,