U211B ATMEL Corporation, U211B Datasheet - Page 8

• Manufacturer Part Number: U211B
• Description: as U209B + Foldback
• Manufacturer: ATMEL Corporation

Design Calculations for Mains Supply
The following equations can be used for the evaluation of the series resistor R
R
P
where:
V
V
I
I
I
I
R
U211B
8 (21)
tot
Smax
p
x
(R1max)
S
1
1max
M
Mains
Supply
Trigger
Pulse
Load
Voltage
Load
Current
can be easily evaluated from the figures 22 to 24.
Figure 8. Explanation of terms in phase relationship
+ 0.85
V
= Mains voltage
= Supply voltage on Pin 3
= Total DC current requirement of the circuit
= I
= Current requirement of the IC in mA
= Average current requirement of the triggering pulse
= Current requirement of other peripheral components
V
+
GT
I
V
L
L
S
(V
+ I
Mmax
V
p
Mmin
+ I
2 R
– V
t
p
2 I
p/2
x
1
– V
tot
Smin
Smax
)
2
F
p
t
pp
ö
= 4.5 t
R
p
1min
3/2p
+
V
M
2 I
– V
2p
Smax
Smin
1
for worst case conditions:
Rev. A4, 03-Aug-01