Features
•
•
•
•
•
•
•
•
•
•
Full-wave Current Sensing
Mains Supply Variation Compensated
Programmable Load-current Limitation with Over- and High-load Output
Variable Soft Start
Voltage and Current Synchronization
Automatic Retriggering Switchable
Triggering Pulse Typically 125 mA
Internal Supply-voltage Monitoring
Current Requirement
£
3 mA
Temperature-compensated Reference Voltage
Applications
•
Advanced Motor Control
•
Grinder
•
Drilling Machine
Phase-control
IC with Current
Feedback and
Overload
Protection
U2010B
Description
The U2010B is designed as a phase-control circuit in bipolar technology for motor
control applications with load-current feedback and overload protection. It enables
load-current detection and has a soft-start function as well as reference voltage
output.
Figure 1.
Block Diagram
15
Limiting
detector
Voltage
detector
14
Overload
Mains voltage
compensation
High load
Supply
voltage
10
G
N
D
13
12
11
Automatic
retriggering
Phase
control unit
ϕ
= f (V
4
)
Output
-
1
2
+
100%
70%
A
α
max
Current
detector
16
Pulse
output
1
Load
current
detector
2
Full wave
rectifier
B
Programmable Auto-
start
overload
protection
C
I
max
9
Voltage
monitoring
Level
shift
3
4
5
6
Soft
start
7
U2010B
Reference
voltage
8
Rev. 4766A–INDCO–01/04
Mains Supply
General Description
Figure 2.
Block Diagram with External Circuit
2
230 V ~
R
1
R
2
330 kΩ
α
max
V
S
13
12
Supply
voltage
10
GND
11
Overload
Limiting
detector
High load
Voltage
detector
Mains voltage
compensation
C
1
22 µF
Load
15
14
R
8
470 kΩ
LED
18 kΩ/2 W
D
1
D
3
Automatic
retriggering
100%
Output
Current
detector
1
2
Full wave
rectifier
R
3
16
Voltage
monitoring
1
Level
shift
Load
current
detector
180
Ω
70%
A
α
max
9
Mode
U2010B
-
+
Phase
control unit
ϕ
= f(V
4
)
Programmable
overload
protection
B
Auto-
start
C
I
max
A
B
C
S
1
U2010B
R
4
3.3 kΩ
2
3
4
Soft
start
5
C
5
0.1 µF
0.15 µF
6
7
Reference
voltage
8
R
6
R
5
3.3 kΩ
C
3
10 nF
^
V
(R6)
= ±250 mV
R
11
1 MΩ
C
2
4.7 µF
Overload
threshold
C
4
R
14
P
1
R
10
50 kΩ
100 kΩ
Load current
compensation
Set point
C
7
1 µF
R
7
The U2010B contains voltage limiting and can be connected with the mains supply via
D
1
and R
1
. Supply voltage – between pin 10 and pin 11 – is smoothed by C
1
.
In the case of V
6
£
70% of the overload threshold voltage, pins 11 and 12 are connected
internally whereby V
sat
£
1.2 V. When
½
V
6
½ ³ ½
V
T70
½
, the supply current flows across
D
3
.
4766A–INDCO–01/04
U2010B
Pin Configuration
Figure 3.
Pinning DIP16/SO16
ISENSE 1
ISENSE
Cϕ
2
3
16 OUTPUT
15 VSYNC
14
13
12
11
10
9
VRϕ
CONTROL 4
U2010B
COMP
ILOAD
CSOFT
VREF
5
6
7
8
OVERLOAD
HIGH LOAD
VS
GND
MODE
Pin Description
Pin
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Symbol
ISENSE
ISENSE
Cj
CONTROL
COMP
ILOAD
CSOFT
VREF
MODE
GND
VS
HIGH LOAD
OVERLOAD
VRj
VSYNC
OUTPUT
Function
Load current sensing
Load current sensing
Ramp voltage
Control input
Compensation output
Load current limitation
Soft start
Reference voltage
Mode selection
Ground
Supply voltage
High load indication
Overload indication
Ramp current adjust
Voltage synchronization
Trigger output
3
4766A–INDCO–01/04
The series resistance R
1
can be calculated as follows:
V
mains
–
V
Smax
R
1max
= --------------------------------------
2
´
I
tot
where:
V
mains
= Mains supply voltage
V
Smax
= Maximum supply voltage
I
tot
= Total current consumption = I
Smax
+ I
x
I
Smax
= Maximum current consumption of the IC
I
x
= Current consumption of the external components
Voltage Monitoring
When the voltage is built up, uncontrolled output pulses are avoided by internal voltage
monitoring. Apart from that, all 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 automatically ensures the opti-
mum run-up time.
The function of the phase control is mainly identical to the well-known IC U211B. The
phase angle of the trigger pulse is derived by comparing the ramp voltage V
3
, 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
j
and its charging current I
j
. The charging
current can be varied using R
j
at pin 14. The maximum phase angle,
a
max
, can also be
adjusted by using R
j
(minimum current flow angle
j
min), see Figure 5 on page 10.
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
j
(t
p
= 9 µs/nF). At the same time, a latch is set with
the output pulse as long as the automatic retriggering has not been activated. When this
happens, no more pulses can be generated in that half cycle. The control input at pin 4
(with respect to pin 10) has an active range from V
8
to -1 V. When V
4
= V
8
, then the
phase angle is at its maximum,
a
max
, i.e., the current flow angle is minimum. The mini-
mum phase angle,
a
min
, is set with V
4
³
-1 V.
Phase Control
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 threshold level of typically 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 the current wave, or for commu-
tator motors, owing to brush lifters), the automatic retriggering circuit ensures immediate
retriggering, if necessary with a high repetition rate, t
pp
/t
p
, until the triac remains reliably
triggered.
4
U2010B
4766A–INDCO–01/04
U2010B
Current Synchronization
Current synchronization fulfils two functions:
–
Monitoring the current flow after triggering.
In case the triac extinguishes again or does not switch on, automatic
triggering is activated until the triggering is successful.
Avoiding triggering due to an inductive load.
In the case of inductive load operation, the current synchronization ensures
that in the new half wave, no pulse will be enabled as long as there is a
current available from the previous half wave, which flows from the opposite
polarity to the actual supply voltage.
–
Th current synchronization as described above is a special feature of the U2010B. The
device evaluates the voltage at the pulse output between gate and reference electrode
of the triac. As a result, no separate current synchronization input with specified series
resistance is necessary.
Voltage Synchronization
with Mains Voltage
Compensation
The voltage detector synchronizes the reference ramp with the mains supply voltage. At
the same time, the mains-dependent input current at pin 15 is shaped and rectified inter-
nally. This current activates the automatic retriggering and at the same time is available
at pin 5. By suitable dimensioning, it is possible to obtain the specified compensation
effect. Automatic retriggering and mains voltage compensation are not activated until
½
V
15 - 10
½
increases to 8 V. The resistance R
sync.
defines the width of the zero voltage
cross over pulse, synchronization current, and hence the mains supply voltage compen-
sation current.
Figure 4.
Suppression of Mains Voltage Compensation and Retrigger Automatic
Mains
R
2
15
2x
C6V2
10
U2010B
If the mains voltage compensation and the automatic retriggering are not required, both
functions can be suppressed by limiting
½
V
15 - 10
½ £
7 V, see Figure 4.
Load-current
Compensation
The circuit continuously measures the load current as a voltage drop at resistance R
6
.
The evaluation and use of both half waves results in a quick reaction to load-current
change. Due to the voltage at resistance R
6
, there is a difference between both input
currents at pins 1 and 2. This difference controls the internal current source, whose pos-
itive current values are available at pins 5 and 6. The output current generated at pin 5
contains the difference from the load-current detection and from the mains voltage com-
pensation, see Figure 2 on page 2.
5
4766A–INDCO–01/04
