U211B-XFPG3Y ATMEL Corporation, U211B-XFPG3Y Datasheet - Page 4

• Manufacturer Part Number: U211B-XFPG3Y
• Description: Phase Control IC with Overload Limitation for Tacho Applications
• Manufacturer: ATMEL Corporation

3. Mains Supply
4. Phase Control
4
U211B
The U211B is equipped with voltage limiting and can therefore be supplied directly from the
mains. The supply voltage between pin 2 (+ pol/_|_) and pin 3 builds up across D
smoothed by C
Further information regarding the design of the mains supply can be found in the section
Hints” on page
supply voltage and is used for regulation.
Operation using an externally stabilized DC voltage is not recommended.
If the supply cannot be taken directly from the mains because the power dissipation in R
be too large, the circuit as shown in
Figure 3-1.
The phase angle of the trigger pulse is derived by comparing the ramp voltage (which is mains
synchronized by the voltage detector) with the set value on the control input pin 12. The slope of
the ramp is determined by C
R
When the potential on pin 7 reaches the nominal value predetermined at pin 12, a trigger pulse
is generated whose width t
pulse width can be evaluated by assuming 8 µs/nF). At the same time, a latch is set, so that as
long as the automatic retriggering has not been activated, no more pulses can be generated in
that half cycle.
The current sensor on pin 1 ensures that, for operations with inductive loads, no pulse will be
generated in a new half cycle as long as a current from the previous half cycle is still flowing in
the opposite direction to the supply voltage at that instant. This makes sure that “gaps” in the
load current are prevented.
The control signal on pin 12 can be in the range of 0 V to -7 V (reference point pin 2).
If V
The phase angle is minimum (
R
2
1
on pin 6. The maximum phase angle
12
=
= -7 V, the phase angle is at maximum (
V
-------------------- -
M
2 I
–
S
V
S
Supply Voltage for High Current Requirements
1
9. The reference voltage source on pin 16 of typically -8.9 V is derived from the
. The value of the series resistance can be approximated using:
24 V~
~
p
2
and its charging current. The charging current can be varied using
is determined by the value of C
min
)
when V
Figure 3-1
R
1
1
max
12
can also be adjusted by using R
= V
should be used.
2
max
2
.
C
),
1
i.e., the current flow angle, is at minimum.
3
4
2
(the value of C
5
2
.
2
4752B–INDCO–09/05
1
and hence the
and R
“Design
1
1
and is
would