- It has
thousand of volts reverse blocking capacity.
- However it may not requires in
some applications particular in the inverter.
- The flywheel diode is connected
in anti parallel with load in order to conduct inductive load.
- The peak repetitive voltage rating of the SCR is higher than the ASCR.
- The on state voltage drop and turn off time of the SCR is higher than the ASCR.
Asymmetrical SCR
- The
reverse blocking capacity of the ASCR is very low.
- It is in the order of
20 to 30 V.
- The ASCR is useful where very
low reverse blocking capacity requires.
- The forward blocking capacity of the
ASCR is very high typically 400 to 2000 V.
- The forward and reverse blocking
capacity of the ASCR are not equal.
- There is additional N2+
layer added in the ASCR therefore N2 – become narrow.
- The N2+
layer is acts as Electrical field stopper. The P2N2+
junction avalanches at very low voltage therefore the ASCR does any usable peak repetitive voltage rating ( VRRM ).
- The ASCR has faster turn off time and reduction in ON state voltage is
achieved by sacrificing reverse voltage blocking capacity.
- If the gold doping
is same as that of conventional SCR, the on state voltage drop is reduced but
turn off time is unaltered.
- It should be noted that the on state voltage drop
and turn off time of the ASCR is adjusted by suitable doping level of N2
–.
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