1
.1. 1.
/ .
:
.
:
(1)
I.
; ( , . . - . - , , R , . , , :
:
(2)
I - , I .
I I :
(3)
, 2 U=U, I >I
2
Udropout [B] | U [B] | I [A] | |||
U MIN [B] | U MAX [B] | ||||
78L05 | 7.2 | 24 | 0.1 | ||
78L06 | 8.2 | 24 | 0.1 | ||
78L08 | 10.2 | 24 | 0.1 | ||
78L09 | 11.2 | 24 | 0.1 | ||
78L12 | 14.2 | 24 | 0.1 | ||
78L15 | 17.2 | 24 | 0.1 | ||
78L18 | 20.2 | 24 | 0.1 | ||
78L24 | 26.2 | 24 | 0.1 | ||
78L05 | 7.5 | 24 | 0.5 | ||
7806 | 8,5 | 24 | 0.5 | ||
7808 | 10,5 | 24 | 0.5 | ||
7812 | 14,5 | 24 | 0.5 | ||
7815 | 17,5 | 24 | 0.5 | ||
7820 | 22,5 | 24 | 0.5 | ||
7824 | 26,5 | 24 | 0.5 | ||
7805 | 24 | ||||
7805 | 24 | ||||
7812 | 24 | ||||
7815 | 24 | ||||
LM323K | 24 | ||||
78P05 | 24 |
2
, 7805, Udropout - . , .
|
|
U_ :
(4)
C2
. 2. U . , .
.
C > I/(2*f*dU) (5)
I- [A]; f - []; - []; dU - [].
dU = Umax - Umin
Umin = U
Umax . , , . , .
Umax :
Umax= (1.151.25) U (6)
(6) . , , .. 2U .
VD1
2 VD2, :
U* = U + U (7)
U* - , U.
U = 0. 7 - , . , .
3
U [B] () | P [] | U [B] | U [B] | I [] | I [] | I[] | |
815 | 5.6 | 5.66 | 6.76 | ||||
615 | 6.8 | 6.12 | 7.48 | ||||
2175 | 7.5 | 7.0 | 8.5 | ||||
241 | 8.0 | 6.28 | 8.21 | ||||
2482 | 8.2 | 7.0 | 8.5 | ||||
815 | 10.0 | 9.0 | 11.0 | ||||
815 | 12.0 | 10.8 | 13.3 | ||||
814 | 13.0 | 11.5 | 14.0 | ||||
815 | 15.0 | 13.3 | 16.4 | ||||
815 | 18.0 | 16.2 | 18.8 | ||||
2524 | 24.0 | 22.8 | 25.2 | ||||
816 | 22.0 | 19.8 | 24.2 | ||||
816 | 27.0 | 24.2 | 29.5 |
3 :
I > I + I (8)
U* = U (9)
U - , 3.
|
|
I> IA (10)
I 3
=(0.637 * IA)*(U* + U) > (11)
, 3.
VD2
4 I U .
I > 2I; U > 2U (12)
4
U [B] | I [] | U [B] | |
219 | 1.0 | ||
310 | 0.55 | ||
410 | |||
424 | 1.1 | ||
2504 | 1.2 | ||
2509 | 1.1 | ||
2510 | 1.1 | ||
202 | 3.5 | 0.9 |
R2
R2 , 1 .
R2 > 1,41UAC/ I (13)
= (I)2 * R2 (14)
(0.125, 0.25, 0.5; 1; 2.) .