U2102B-XFPG3Y ATMEL Corporation, U2102B-XFPG3Y Datasheet - Page 5

• Manufacturer Part Number: U2102B-XFPG3Y
• Description: Multifunction Timer IC
• Manufacturer: ATMEL Corporation

3. Power Supply, Synchronization Pins 15 and 16
4767B–INDCO–10/05
The U2102B’s voltage limitation circuit enables the power supply via the dropping resistor R
the case of DC loads, the entire supply current flows into pin 16 and is supplied via an internal
diode to pin 15, where the resultant supply voltage is limited and smoothed by C
resistor at pin 16 is necessary in order to guarantee reliable synchronization. As a result, the rec-
tified and divided line voltage appears at pin 16, where the amplitude is limited. The power
supply for the circuit can be realized in all modes for DC loads as shown in
The voltage at pin 16 is used to synchronize the circuit with the mains and generate the system
clock required for the buffers. The circuit detects a “zero crossing” when the voltage at pin 16
falls below an internal threshold of approximately 8 V.
Figure 3-1.
R
where:
V
V
I
I
I
R
tot
Smax
x
Nmin
S
1
1max
is calculated as follows:
= V
= Supply voltage
= I
= Maximum current consumption of the IC
= Current consumption of the external components
=
Smax
0.85
mains
+ I
– 15%
Power Supply for DC Loads (R
V
--------------------------- -
x
Nmin
Voltage
limitation
I
Sync.
tot
–
V
S
Temp.
monit.
Push
pull
GND
+V
16
15
14
13
S
1
is Identical with R
C
R
1
G
R
1
= R
sync
IGBT
R
sh
Load
sync
)
Figure 2-2 on page
V
mains
1
. The pull-down
U2102B
1
. In
4.
5