Datasheet U2008B-xFP, U2008B-x, U2008B-xFPG3 Datasheet (ATMEL)

U2008B

Rev. A4, 12-Jan-01 1 (10)

Low-Cost Phase-Control IC with Soft Start

Description

The U2008B is designed as a phase-control circuit in
bipolar technology. It enables load-current detection as
well as mains-compensated phase control. Motor control

with load-current feedback and overload protection are
preferred applications.

Features

 Full wave current sensing
 Mains supply variation compensated
 Variable soft-start or load-current sensing
 Voltage and current synchronization
 Automatic retriggering switchable
 Triggering pulse typ. 125 mA

 Internal supply-voltage monitoring
 Current requirement  3 mA

Applications

 Low-cost motor control
 Domestic appliance

Block Diagram

Automatic

retriggering

Limiting

detector

Current

detector

Full wave load

current detector

Soft start

Voltage
detector

7

Phase

control unit

 = f (V

3

)

6

Mains voltage

compensation

Supply
voltage

limiting

Reference

voltage

Voltage

monitoring

23

5

4

1

8

R

2

330 k

22 k/2W

BYT51K

R

1

D

1

R

8

1 M

180

R

3

TIC
226

Load

100 k

R

10

Load current

compensation

C

4

Set point

100 nF

C

3

3.3 nF

R

6

230 V ~

R

14

47 k

P

1

R

7

GND

–V

S

C

1

25 V

+

–

^

V

(R6)

= ±250 mV

U2008B



max

22 F/

Figure 1. Block diagram with typical circuit: Load current sensing

U2008B

Rev. A4, 12-Jan-012 (10)

Ordering Information

Extended Type Number Package Remarks

U2008B-x DIP8 Tube

U2008B-xFP SO8 Tube

U2008B-xFPG3 SO8 Taped and reeled

Automatic

retriggering

Limiting

detector

Current

detector

Full wave load

current detector

Soft start

Voltage
detector

7

Phase

control unit

 = f (V

3

)

6

Mains voltage

compensation

Supply

voltage

limiting

Reference

voltage

Voltage

monitoring

23

5

4

1

8

R

2

680 k

22 k/2W

BYT51K

R1D

1



max

R

8

470 k

180

R

3

TIC
226

Load

68 k

R

10

C

4

Set point

100 nF

C

3

10 nF

230 V ~

P

1

50 k

R

7

220 k

GND

–V

S

C

1

100 F/

25 V

+

–

L

C

5

Soft start

4.7F/ 25 V

N

U2008B

Figure 2. Block diagram with typical circuit: Soft start

U2008B

Rev. A4, 12-Jan-01 3 (10)

Pin Description

1

2

3

4

8

7

6

5

I

sense

Cϕ

Control

GND

Output

V

sync.

Rϕ

V

S

U2008B

Figure 3. Pinning

Pin Symbol Function

1 I

sense

Load current sensing

2 Cϕ Ramp voltage
3 Control Control input / compensation

output
4 GND Ground
5 –V

S

Supply voltage
6 Rϕ Ramp current adjustment
7 V

sync.

Voltage synchronization
8 Output Trigger output

Mains Supply, Pin 5, Figure 2

The integrated circuit U2008B, which also contains
voltage limiting, can be connected via D1 and R1 via the
mains supply. Supply voltage  between Pin 4 (pos.

,

)

and Pin 5  is smoothed by C1.
Series resistance R1 can be calculated as follows:

R

1max

 0.85 x

VM–V

Smax

2 xI

tot

where:

V

M

 Mains voltage

V

Smax

 Maximum supply voltage

I

tot

 I

Smax

I

x

= Total current compensation

I

Smax

= Maximum current consumption of the IC

I

x

= Current consumption of the external

components

An operation with external stabilized DC voltage is not
recommended.

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 optimum run-up time.

Phase Control, Pin 6

The function of the phase control is largely identical to
that of the well-known IC U211B. The phase angle of the
trigger pulse is derived by comparing the ramp voltage V

2

at Pin 2 with the set value on the control input, Pin 3. The
slope of the ramp is determined by C



and its charging

current I .
The charging current can be regulated, changed, altered

using R at Pin 6. The maximum phase angle, α

max,

(minimum current flow angle 

min

) can also be adjusted

by using R



(see figure 5).

When the potential on Pin 2 reaches the set point level of
Pin 3, a trigger pulse is generated whose pulse width, tp,
is determined from the value of C (tp = 9 s/nF, see
figure 7). 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 3 (with respect to Pin 4)
has an active range from –9 V to –2 V. When V3 = –9 V,
then the phase angle is at its maximum α

max,

i.e., the

current flow angle is minimum. The minimum phase
angle α

min

is set with V3  –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 threshold 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 commu­tator motors, owing to brush lifters), the automatic
retriggering circuit ensures immediate retriggering, if
necessary with a high repetition rate, tpp/tp, until the triac
remains reliably triggered.

U2008B

Rev. A4, 12-Jan-014 (10)

Current Synchronization, Pin 8

Current synchronization fulfils two functions:
 Monitoring the current flow after triggering.

In case the triac extinguishes again or it does not switch
on, automatic triggering is activated as long as
triggering is successful.

 Avoiding triggering due to inductive load.

In the case of inductive load operation, the current
synchronization ensures that in the new half wave no
pulse is 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.

A special feature of the IC is the realization of current
synchronization. The device evaluates the voltage at the
pulse output between the gate and reference electrode of
the triac. This results in saving separate current
synchronization input with specified series resistance.

Voltage Synchronization with Mains Voltage
Compensation, Pin 7

The voltage detector synchronizes the reference ramp
with the mains supply voltage. At the same time, the
mains-dependent input current at Pin 7 is shaped and rec­tified internally. This current activates the automatic
retriggering and at the same time is available at Pin 3 (see
figure 9). By suitable dimensioning, it is possible to attain
the specified compensation effect. Automatic
retriggering and mains voltage compensation are not
activated until |V7 – 4| 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 compensation current. If the mains voltage
compensation and the automatic retriggering are not
required, both functions can be suppressed by limiting
|V

7 – 4

|  7 V (see figure 4).

R

2

2x

BZX55

C6V2

U2008B

7

4

Mains

Figure 4. Suppression of automatic retriggering and mains

voltage compensation

A further feature of the IC is the selection between soft­start or load-current compensation. Soft start is possible
by connecting a capacitor between Pin 1 and Pin 4, see
figure 8. In the case of load-current compensation, Pin 1
is directly connected with resistance R6, which is used for
sensing load current.

Load Current Detection, Pin 1

The circuit continuously measures the load current as a
voltage drop at resistance R6. The evaluation and use of
both half waves results in a quick reaction to load-current
change. Due to voltage at resistance R6, there is an
increase of input current at Pin 1. This current increase
controls the internal current source, whose positive
current values is available at Pin 3 (see figure 11). The
output current generated at Pin 3 contains the difference
from the load-current detection and from the
mains-voltage compensation (see figure 9).

The effective control voltage is the final current at Pin 3
together with the desired value network. An increase of
mains voltage causes the increase of control angle α. An
increase of load current results in a decrease in the control
angle. This avoids a decrease in revolution by increasing
the load as well as the increase of revolution by the
increment of mains supply voltage.

U2008B

Rev. A4, 12-Jan-01 5 (10)

Absolute Maximum Ratings

VS = 14 V, reference point Pin 4, unless otherwise specified

Parameters Symbol Value Unit

Current limitation Pin 5 –I

S

30 mA

t  s –i

S

100 mA

Sync. currents Pin 7

t  s

I

syncV

i

syncV

5

20

mA
mA

Phase control Pin 3
Control voltage –V

I

VS to 0 V

Input current  I

I

500 A

Charge current Pin 6 – I

ϕ

max

0.5 mA

Load current monitoring / Soft start, Pin 1
Input current I

I

1 mA

Input voltage V

I

–40 to + 125 V

Pulse output

Input voltage Pin 8 +V

I

–V

I

2

V

S

V
V

Storage temperature range T

stg

40 to 125



C

Junction temperature range T

j

10 to 125



C

Thermal Resistance

Parameters Symbol Value Unit

Junction ambient DIP8

SO8 on p.c.
SO8 on ceramic

R

thJA

R

thJA

R

thJA

110
220
140

K/W
K/W
K/W

U2008B

Rev. A4, 12-Jan-016 (10)

Electrical Characteristics

VS  –13 V, T

amb

= 25°C, reference point Pin 4, unless otherwise specified

Parameters Test Conditions / Pins Symbol Min. Typ. Max. Unit

Supply Pin 5

Supply-voltage limitation –I

S

= 3.5 mA

–I

S

= 30 mA

–V

S

–V

S

14.5

14.6

16.5

16.8

V
V

Current requirement Pins 1, 4 and 7 open –I

S

3.0 mA

Voltage monitoring Pin 5
Turn-on threshold –V

TON

11.3 12.3 V

Phase control

Input current Voltage sync. Pin 7

Current sync. Pin 8

I

syncV

I

syncI

3

0.15 2
30

mA

A

Voltage limitation  I

L

= 2 mA Pin 7 V

syncV

8.0 8.5 9.0 V

Reference ramp, see figure 5
Charge current Pin 7 I

ϕ

1 100 A

Start voltage Pin 2 –V

max

1.85 1.95 2.05 V

Temperature coefficient of
start voltage Pin 2 –TC

R

–0.003 %/K

Rϕ − reference voltage I

ϕ

=  Α Pins 6 – 5 V

R

ϕ

0.96 1.02 1.10 V

Temperature coefficient I

ϕ

=  Α Pin 6

I

ϕ

=  Α

TC

VR

ϕ

TC

VR

ϕ

0.03

0.06

%/K
%/K

Pulse output, see figure 6 Pin 8
Output-pulse current V

8

= – 1.2 , R

GT

= 0  I

0

100 125 150 mA

Output-pulse width C3 = 3.3 nF, V

S

= V

limit

t

p

30 s

Automatic retriggering Pin 8
Turn-on threshold voltage V

ION

20 60 mV

Repetition rate I7  150 A t

pp

3 5 7.5 t

p

Soft start, see figure 8 Pin 1
Starting current V

1-4

= 8 V I

0

5 10 15  A

Final current V

1-4

= –2 V I

0

15 25 40 A

Discharge current –I

0

0.5 mA

Output current Pin 3 –I

0

0.2 2 mA

Mains voltage compensation, see figure 9
Current transfer gain I7/I

3

Pins 7, Pin 3

Pins 1 and 2 open G

i

14 17 20

Reverse current V

(R6)

= V

3

= V7 = 0, Pin 3 I

R

2  A

Load-current detection, V

7

= 0, see figure 11

Transfer gain I3/V

1

G 0.280 0.320 0.370 A/mV

Offset current V

1

= 0,V

3

= –8 V, Pin 3 I

0

0 3 6 A

Input voltage Pin 1 –V

I

300 400 mV

Input offset voltage Pin 1 V

0

6 mV

U2008B

Rev. A4, 12-Jan-01 7 (10)

6.8 nF

33 nF

0

50

100

150

200

250

0 200 400 600 800 1000

Phase angle ( )

R (R8) ( k )



°

10 nF

4.7 nF 3.3 nF 2.2 nF

C

/ t

= 1.5 nF

Figure 5. Ramp control

0 200 400 600 800

0

20

40

60

80

120

I ( mA )

GT

RGT (  )

1000

100

VGT=–1.2V

Figure 6. Pulse output

01020

0

100

200

300

400

t ( s )

p

C = ( nF )

30



tp/C=9s/nF

Figure 7. Output-pulse width

01234

–5

–4

–3

–2

–1

1

V ( V )

1–4

t ( s )

5

0

C5=1F

4.7F

10F

Supply
R1=22k/2W
C1=100F/25V

Figure 8. Option soft start

–2 –1 0 1

200

160

120

80

40

0

I ( A )

3

I7 ( mA )

2



Reference Point
Pin 10

Pins 1
Vs=–13V

Figure 9. Mains voltage compensation

02468

0

20

40

60

80

100

R (k )

1max

IS ( mA )

10



Max. Series Resistance
VM=230V

Figure 10. Maximum resistance of R

1

U2008B

Rev. A4, 12-Jan-018 (10)

–400 –200 0 200

0

40

80

120

160

200

I ( A )

5

V

(R6)

( mV )

400



Reference Point
Pin 8

V6=V

Ref=V8

VS=–13V
V15=V10=0V

Figure 11. Load-current detection

010203040

0

2

4

6

8

10

P ( W )

V

R1 ( k )

50

Power Dissipation at Series Resistance R

1

Figure 12. Power dissipation of R

1

036912

0

2

4

6

8

10

P ( W )

V

IS ( mA )

15

Power Dissipation at Series Resistance

Figure 13. Power dissipation of R

1

according to current consumption

U2008B

Rev. A4, 12-Jan-01 9 (10)

Package Information

9.8

9.5

Package DIP8

Dimensions in mm

1.64

1.44

4.8 max

0.5 min

3.3

0.58

0.48

7.62

2.54

6.4 max

0.36 max

9.8

8.2

7.77

7.47

85

14

technical drawings
according to DIN
specifications

technical drawings
according to DIN
specifications

Package SO8

Dimensions in mm

5.00

4.85

0.4

1.27

3.81

1.4

0.25

0.10

5.2

4.8

3.7

3.8

6.15

5.85

0.2

85

14

U2008B

Rev. A4, 12-Jan-0110 (10)

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