U2010B Datasheet, PDF (3/12 Pages) TEMIC Semiconductors – Phase Control Circuit for Current Feedback

U2010B
Pin Description
I_sense
1
I_sense
2
Cö
3
Control ₄
Comp. 5
I_Load
6
C_soft
7
V_Ref
8
16 Output
15 V_Sync.
14 ^VRö
13 ^Overload
12 ^{High load}
11 V_S
10 ^GND
9 ^Mode
95 11406
Pin Symbol
Function
1
I_sense Load current sensing
2
I_sense Load current sensing
3
Cö Ramp voltage
4 Control Control input
5
Comp. Compensation output
6
I_Load Load current limitation
7
C_soft Soft start
8
V_Ref Reference voltage
9
Mode Mode selection
10
GND Ground
11
V_S Supply voltage
12 High load High load indication
13 Overload Overload indication
14
V_Rö Ramp current adjust
15
V_Sync. Voltage synchronization
16 Output Trigger output
Series resistance R₁ can be calculated as follows:
V_mains
V_Smax
I_tot
I_Smax
I_x
+ R_1max
V_mains – V_Smax
2
I_tot
whereas
+ Mains supply voltage
+ Maximum supply voltage
+ ) Total current consumption = I_Smax I_x
+ Maximum current consumption of the IC
+ Current consumption of the
external components
Voltage Monitoring
As the voltage is built up, uncontrolled output pulses are
avoided by internal voltage monitoring. Apart from that
all the latches in the circuit (phase control, load limit
regulation) are reset and the soft-start capacitor is short
circuited. This guarantees a specified start-up behavior
each time the supply voltage is switched on or after short
interruptions of the mains supply. Soft-start is initiated
after the supply voltage has been built up. This behavior
guarantees a gentle start-up for the motor and auto-
matically ensures the optimum run-up time.
Phase Control
The function of the phase control is largely identical to the
well known IC family U211B. The phase angle of the
trigger pulse is derived by comparing the ramp voltage V₃
which is mains synchronized by the voltage detector with
the set value on the control input, Pin 4. The slope of the
ramp is determined by C_ö and its charging current I_ö. The
charging current can be varied using R_ö at Pin 14. The
maximum phase angle, α_max, can also be adjusted by
using R_ö (minimum current flow angle ö_min) see figure 4.
When the potential on Pin 3 reaches the set point level of
Pin 4, a trigger pulse width, t_p, is determined from the
value of C_ö (t_p = 9 ms/nF). At the same time, a latch is set
with the output pulse, as long as the automatic
retriggering has not been activated, then no more pulses
can be generated in that half cycle. Control input at Pin 4
(with respect to Pin 10) has an active range from
V₈ to –1 V. When V₄ = V₈, then the phase angle is at its
w ^{maximum, αmax, i.e., the current flow angle is minimum.}
The minimum phase angle, α_min, is set with V₄ –1 V.
Automatic Retriggering
The current-detector circuit monitors the state of the triac
after triggering by measuring the voltage drop at the triac
gate. A current flow through the triac is recognized, when
the voltage drop exceeds a thres hold level of typ. 40 mV.
If the triac is quenched within the relevant half-wave after
triggering; for example owing to low load currents before
or after the zero crossing of current wave or; for commu-
tator motors, owing to brush lifters. Then the automatic
retriggering circuit ensures immediate retriggering, if
necessary with a high repetition rate, t_pp/t_p, until the triac
remains reliably triggered.
TELEFUNKEN Semiconductors
Rev. A1, 28-May-96
3 (12)