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What is the effect of reverse recovery time in diode circuits?
A diode exhibits considerable loss during reverse recovery, i.e., while it switches from the forward-biased state to the reverse-biased state. In the forward-biased (i.e., current-conducting) state, a large amount of electron and hole carriers is injected into the drift layer.
What is reverse recovery charge of diode?
Qrr or reverse recovery charge is the charge that accumulates in the PN junction of a MOSFET’s body diode when the diode is forward biased. In most applications, current flows through the body diode twice for each switching cycle, causing charge to build up.
What happens during the reverse recovery time of a diode?
During this reverse recovery time of the diode, one can see that there will be fairly large amount of current flowing through the diode, but in the opposite direction (I rr in Figure 1). However its magnitude reduces and gets saturated to a value of reverse saturation current, once the time-line crosses reverse recovery time (t rr) of the diode.
How does a diode block a reverse voltage?
All stored charge must be removed so that the depletion region can become big enough to block the reverse voltage. In order to block a high reverse voltage (600 V), those diodes require a wide drift region. The wider the drift region, the more minority charge carriers it can contain during forward conduction.
When does the diode stop conducting the current?
That is, the diode which is conducting current in its forward direction is expected to stop conducting instantly. However, practically, this cannot be experienced as the flow of majority charge carriers through the diode does not cease right at the moment of reversing the bias.
How is the Qrr of a power diode determined?
Those four parameters are determined by the manufacturing processes used to produce a particular device family. The QRR of a power diode is a direct measure of its stored charge; either from the barrier junction capacitance of Schottky devices or the minority carriers that flow within the cathode and drift region of PN-junction-based devices.