ATMEL U2008B User Manual

Features

• Full Wave Current Sensing

• Compensated Mains Supply Variations

• Variable Soft Start or Load-current Sensing

• Voltage and Current Synchronization

• Switchable Automatic Retriggering

• Triggering Pulse Typically 125 mA

• Internal Supply-voltage Monitoring

• Current Requirement ≤ 3 mA

Low-cost

Applications

• Low-cost Motor Control

• Domestic Appliance

1. 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.

Figure 1-1. Block Diagram with Typical Circuit: Load Current Sensing

230 V ~

R

6

Load

TIC
226

R

3

8

180 Ω

1

^

V(R6) = ±250 mV

Limiting

detector

Automatic

retriggering

Current

detector

Full wave load

current

detector

Soft start

R

330 kΩ

C

22 kΩ/2 W

R

2

7

Voltage
detector

Phase

control unit

ϕ = f(V

23

3

100 nF3.3 nF

BYT51K

D

1

α

max

R

1

8

1 MΩ

6

Mains voltage
compensation

U2008B

-V

5

)

3

Supply
voltage

limiting

Reference

-

+

R

C

4

Load current

compensation

10

voltage

Voltage

monitoring

100 kΩ

4

Set point

GND

R

7

S

22 µF/

25 V

R

47 kΩ

P

C

1

14

1

Phase-control
IC with
Soft Start

U2008B

Rev. 4712B–AUTO–10/05

Figure 1-2. Block Diagram with Typical Circuit: Soft Start

230 V ~

L

TIC
226

Load

R

180 Ω

BYT51K

D

1

R

α

max

8

470 kΩ

6

Mains voltage

compensation

Limiting

detector

R

680 kΩ

22 kΩ/2W

2

Voltage
detector

R

1

7

Automatic

retriggering

Current

detector

Phase

control unit

ϕ = f(V

)

3

U2008B

-V

5

S

C

1

100 µF/

8

3

1

current detector

Full wave load

-

+

Soft start

Supply
voltage

limiting

Reference

voltage

Voltage

monitoring

25 V

GND

4

23

P

R

68 kΩ

C

5

Soft start

4.7 µF/25 V

C

3

C

4

10

100 nF10 nF

Set point

R

220 kΩ

7

1

50 kΩ

N

2

U2008B

4712B–AUTO–10/05

2. Pin Configuration

Figure 2-1. Pinning

U2008B

ISENSE

CONTROL

GND

Table 2-1. Pin Description

Pin Symbol Function

1 ISENSE Load current sensing
2Cϕ Ramp voltage
3 CONTROL Control input/compensation output
4 GND Ground
5 -VS Supply voltage
6Rϕ Ramp current adjustment
7 VSYNC Voltage synchronization
8 OUTPUT Trigger output

Cϕ

1

2

U2008B

3

4

8

7

6

5

OUTPUT

VSYNC

Rϕ

- VS

2.1 Mains Supply, Pin 5

The integrated circuit U2008B, which also contains voltage limiting, can be connected via D1 and

to the mains supply, see Figure 1-2 on page 2. Supply voltage, between Pin 4 (pos., ⊥) and

R

1

Pin 5, is smoothed by C
The series resistance R1 can be calculated as follows:

R

1max

where:

V

M

V

Smax

I

tot

I

Smax

I

x

Operation with externally stabilized DC voltage is not recommended.

.

1

–

V

MVSmax

------------------------------

0.85

×=

2I

×

tot

= Mains voltage
= Maximum supply voltage
= I

+ Ix = Total current compensation

Smax

= Maximum current consumption of the IC
= Current consumption of the external components

4712B–AUTO–10/05

3

2.2 Voltage Monitoring

When the voltage is built up, uncontrolled output pulses are avoided by internal voltage monitor­ing. Apart from that, all latches of 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.

2.3 Phase Control, Pin 6

The function of the phase control is identical to that of the well-known IC U211B. The phase
angle of the trigger pulse is derived by comparing the ramp voltage V
on the control input, Pin 3. The slope of the ramp is determined by C
ϕ.

at Pin 2 with the set value

2

and its charging current I

3

The charging current can be regulated, changed or altered using R
The maximum phase angle, α

using R

(see Figure 5-1 on page 7).

8

When the potential on Pin 2 reaches the set point level of Pin 3, a trigger pulse is generated
whose pulse width, t
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 V
at its maximum amax, i.e., the current flow angle is minimum. The minimum phase angle amin is
set with V

≥ -1 V.

3

2.4 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 current wave, or for commutator motors, owing
to brush lifters), the automatic retriggering circuit ensures immediate retriggering, if necessary
with a high repetition rate, t

2.5 Current Synchronization, Pin 8

Current synchronization fulfils two functions:

at Pin 6.

8

, (minimum current flow angle ϕ

max

, is determined from the value of C3 (tp = 9 µs/nF, Figure 5-3 on page 8). At

p

, until the triac remains reliably triggered.

pp/tp

) can also be adjusted by

min

= -9 V the phase angle is

3

• 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 the separate current synchronization input with specified series resistance.

4

U2008B

4712B–AUTO–10/05

2.6 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 automatic retriggering and at the same time is available at Pin 3 (Figure 5-5 on

page 9). By suitable dimensioning, it is possible to attain the specified compensation effect.

Automatic retriggering and mains voltage compensation are not activated until ⏐ V
increases to 8 V. The resistance R
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

- V4⏐ ≤ 7 V (see Figure 2-2).

7

Figure 2-2. Suppression of Automatic Retriggering and Mains Voltage Compensation

defines the width of the zero voltage cross-over pulse,

sync.

Mains

R

2

7

U2008B

- V4⏐

7

A further feature of the IC is the selection between soft start and load-current compensation.
Soft start is possible by connecting a capacitor between Pin 1 and Pin 4 (Figure 5-4 on page 8).
In the case of load-current compensation, Pin 1 is directly connected with resistance R
used for sensing load current.

2.7 Load Current Detection, Pin 1

The circuit continuously measures the load current as a voltage drop at resistor R6. The evalua­tion and use of both half waves results in a quick reaction to load-current change. Due to voltage
at resistor R
internal current source, whose positive current values are available at Pin 3 (see Figure 5-7 on

page 9). The output current generated at Pin 3 contains the difference from the load-current

detection and the mains-voltage compensation (see Figure 5-5 on page 9).

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

, there is an increase of input current at Pin 1. This current increase controls the

6

2x

BZX55

C6V2

U2008B

4

, which is

6

4712B–AUTO–10/05

5

3. Absolute Maximum Ratings

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

Parameters Symbol Value Unit

30 mA

100 mA

5

20

VS to 0 V

500 mA

0.5 mA

1mA

-VS to +2 V

2

V

S

-40 to +125 °C

-10 to +125 °C

±I
±i

-I

-i

syncV
syncV

Current limitation Pin 5
t ≤ 10 µs

Synchronous currents Pin 7
t ≤ 10 µs

Phase Control Pin 3

Control voltage -V
Input current ±I
Charge current Pin 6 -I

ϕmax

Load Current Monitoring/Soft Start, Pin 1

Input current I
Input voltage V
Pulse output

Input voltage Pin 8

+V

-V
Storage temperature range T
Junction temperature range T

S

S

I

I

I

I

I

I

stg

j

mA
mA

V
V

4. Thermal Resistance

Parameters Symbol Value Unit

Junction ambient

DIP8 R
SO8 on p.c. R
So8 on ceramic R

thJA

thJA

thJA

110 K/W
220 K/W
140 K/W

5. Electrical Characteristics

Parameters Test Conditions Symbol Min. Typ. Max. Unit
Supply (Pin 5)

-I

= 3.5 mA

Supply-voltage limitation

S

= 30 mA

-I

S

Current requirement Pins 1, 4 and 7 open -I

Voltage Monitoring (Pin 5)

Turn-on threshold -V

Phase Control

Input current

Voltage limitation ±I

Voltage sync. Pin 7
Current sync. Pin 8

= 2 mA Pin 7 ±V

L

Reference Ramp (see Figure 5-1 on page 7)

Charge current Pin 7 I
Start voltage Pin 2 -V

±I

±I

-V

-V

TON

syncV

syncI

syncV

ϕ

max

S
S

S

14.5

14.6

16.5

16.8

3.0 mA

11.3 12.3 V

0.15 2

3

30

8.0 8.5 9.0 V

1 100 µA

1.85 1.95 2.05 V

V
V

mA

µA

6

U2008B

4712B–AUTO–10/05

U2008B

5. Electrical Characteristics (Continued)

Parameters Test Conditions Symbol Min. Typ. Max. Unit

Temperature coefficient of start
voltage

Pin 2 -TC

Rϕ - reference voltage Iϕ = 10 µA, Pins 6 to 5 V

Temperature coefficient

= 10 µA, Pin 6

I

ϕ

Iϕ = 1 µA

TC
TC

Pulse Output (see Figure 5-2 on page 8) (Pin 8)

Output-pulse current V
Output-pulse width C

= -1.2, RGT = 0 Ω I

8

= 3.3 nF, VS = V

3

limit

Automatic Retriggering (Pin 8)

Turn-on threshold voltage ±V
Repetition rate I

≥ 150 µA t

7

Soft Start (see Figure 5-4 on page 8) (Pin 1)

Starting current V
Final current V

= 8 V I

1–4

= -2 V I

1–4

Discharge current -I
Output current Pin 3 -I

Mains Voltage Compensation (see Figure 5-5 on page 9)

Current transfer gain I

7/I3

Reverse current V

Load-current Detection, V

= 0 (see Figure 5-7 on page 9)

7

Transfer gain I
Offset current V

Pins 7, Pin 3
Pins 1 and 2 open

= V3 = V7 = 0, Pin 3 ±I

(R6)

3/V1

= 0, V3 = -8 V, Pin 3 I

1

G

Input voltage Pin 1 -V
Input offset voltage Pin 1 ±V

R

0.96 1.02 1.10 V

100 125 150 mA

20 60 mV

357.5t

51015µA

15 25 40 µA

0.5 mA

0.2 2 mA

14 17 20

t

Rϕ

VRϕ
VRϕ

0

p

ION

pp

0

0

0

0

i

R

G 0.28 0.32 0.37 µA/mV

0

I

0

036µA

300 400 mV

-0.003 %/K

0.03

0.06

30 µs

2µA

6mV

%/K
%/K

p

4712B–AUTO–10/05

Figure 5-1. Ramp Control

250

200

33 nF 10 nF

150

100

Phase Angle α (°)

50

0

0 200 400 600 800 1000

6.8 nF 4.7 nF 3.3 nF

Rϕ(R8) (kΩ)

2.2 nF

Cϕ/t = 1.5 nF

7

Figure 5-2. Pulse Output

120

100

80

)
A

m

(

60

T
G

I

40

20

VGT = -1.2 V

0

0 200 400 600 800

Figure 5-3. Output Pulse Width

400

∆tp/∆Cϕ = 9 µs/nF

300

200

(µs)

p

t

100

0

0102030

Figure 5-4. Option Soft Start

1

1000

RGT (Ω)

Cϕ (nF)

0

-1

)
V

(

4

-

-2

1

V

-3

-4

-5
01 2 3 4

8

U2008B

C5 = 1 µF

4.7 µF

Supply

= 22 kΩ/2 W

R

1

= 100 µF/25 V

C

1

t ( s )

10 µF

5

4712B–AUTO–10/05

Figure 5-5. Mains Voltage Compensation

0

-40

-80

(µA)

3

I

-120

U2008B

-160
Pins 1

= -13 V

V

-200

S

-2 -1 0 1 2

Figure 5-6. Maximum Resistance of R

100

80

)

Ω

k

(

x

60

a
m

1

R

40

20

0

02 4 6 8

Figure 5-7. Load-current Detection

Reference Point
Pin 10

I7 (mA)

1

Max. Series Resistance

= 230 V

V

M

IS (mA)

1
0

4712B–AUTO–10/05

200

V6 = Ref = V
VS = -13 V
V

160

120

(µA)

5

I

80

40

0

-400 -200 0 200 400

= V10 = 0 V

15

8

V

(R6)

Reference Point
Pin 8

(mV)

9

Figure 5-8. Power Dissipation of R

10

Power Dissipation at Series Resistance R

8

)

6

W

(

V

P

4

2

1

1

0

010203040

R1 (kΩ)

50

Figure 5-9. Power Dissipation of R1 According to Current Consumption

10

Power Dissipation at Series Resistance

8

6

(W)

V

P

4

2

0

0 3 6 9 12 15

IS (mA)

10

U2008B

4712B–AUTO–10/05

6. Ordering Information

Extended Type Number Package Remarks

U2008B-xY DIP8 Tube, Pb-free
U2008B-xFPY SO8 Tube, Pb-free
U2008B-xFPG3Y SO8 Taped and reeled, Pb-free

7. Package Information

Package DIP8

Dimensions in mm

0.58

0.48

1.64

1.44

7.62

9.8

9.5

2.54

0.5 min

4.8 max

3.3

7.77

7.47

6.4 max

0.36 max

9.8

8.2

U2008B

Package SO8

Dimensions in mm

0.4

85

technical drawings
according to DIN
sp e c ific atio ns

14

5.00

4.85

1.4

0.25

1.27

3.81

85

0.10

5.2

4.8

3.7

0.2

3.8

6.15

5.85

4712B–AUTO–10/05

14

technical drawings
according to DIN
specifications

11

8. Revision History

Please note that the following page numbers referred to in this section refer to the specific revision
mentioned, not to this document.

Revision No. History

4712B-AUTO-08/05

• Put datasheet in a new template

• First page: Pb-free logo added

• Page 11: Ordering Information changed

12

U2008B

4712B–AUTO–10/05

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4712B–AUTO–10/05