18 THE SWITCHING POINT WHERE BOTH TRANSISTORS ARE SATURATED (REGION...

2.18 The switching point where both transistors are saturated (region C) is found by

solving for equal currents:

β β

( ) ( )

2 2

− = − −

n p

V V V V V

in intn DD tp

2 2

( ) ( ( ) ) ( ( ) )

2 2 2

− + − + + + − + =

β β β β β β

V V V V V V V V

2 2 0

n p n tn p DD tp n tn p DD tp

− + + + −

β β β β

V V V V V V

n tn p DD tp DD tp tn n p

= −

V

in

β

+ +

DD tp n tn

V V V

p

=

+

n

1

The output voltage in region B is found by solving

β − = β   − − − −   −

V V

( ) ( ) ( ) ( )

2 outn DD

V V V V V V V

tn p DD tp DDin in out

 

( ) ( ) ^{( )} ( )

= − + − − − + − +

V V V V V

^β_β

V V V V V V

n

tp tp tn DD DD tpout in in in in

p

and the output voltage in region D is

β − − = β    − −   

( ) ^{( )}

( ) ( ) ( )

= − − − − − +

V V V V V

^β_β

V V V

tn tn DD tpout in in in