ATMEL Corporation U2008B-xFP, U2008B-x, U2008B-xFPG3 Datasheet

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U2008B

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

 

Internal supply-voltage monitoring

Mains supply variation compensated

 

Current requirement 3 mA

Variable soft-start or load-current sensing

Applications

Voltage and current synchronization

Automatic retriggering switchable

 

Low-cost motor control

Triggering pulse typ. 125 mA

 

Domestic appliance

Block Diagram

 

 

 

 

 

22 k /2W

 

BYT51K

 

 

 

 

 

230 V ~

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

R2

R1

D1

R8

 

 

 

 

 

 

 

 

 

max

 

 

 

 

 

 

 

 

 

330 k

1 M

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Load

 

 

 

7

 

6

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Limiting

Voltage

 

 

 

Mains voltage

 

 

 

 

 

 

detector

detector

 

 

 

compensation

 

 

 

 

 

 

Automatic

 

 

 

 

 

 

 

 

 

 

 

 

retriggering

 

 

 

 

 

U2008B

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Phase

 

 

 

 

5

±VS

 

 

 

 

Current

control unit

 

 

 

 

 

 

TIC

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

detector

 

ö = f (V3)

 

 

 

 

 

 

C1

 

226

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

22 mF/

 

R3

 

 

 

 

 

 

 

 

 

 

 

8

 

 

 

 

 

 

Supply

 

 

25 V

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

voltage

4

GND

 

 

180

 

 

 

 

 

 

 

limiting

 

 

 

 

Full wave load

 

 

 

+

±

Reference

 

 

 

 

 

 

 

 

 

voltage

 

 

 

 

 

1

 

 

 

 

 

 

 

 

 

current detector

 

 

 

 

 

 

 

 

 

 

 

 

Soft start

 

 

 

 

 

Voltage

 

 

R14

 

 

 

 

 

 

 

 

monitoring

 

 

 

 

 

 

 

 

 

 

 

 

47 k

 

 

 

 

 

2

3

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

R10

 

100 k

Set point

P1

 

 

 

 

 

 

 

 

 

 

R6

^

 

 

 

 

 

 

 

 

 

 

 

 

V(R6) = ±250 mV

 

C3

C4

 

Load current

 

R7

 

 

 

 

 

3.3 nF

100 nF

 

compensation

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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

Rev. A4, 12-Jan-01

1 (10)

ATMEL Corporation U2008B-xFP, U2008B-x, U2008B-xFPG3 Datasheet

U2008B

Ordering Information

Extended Type Number

Package

Remarks

U2008B-x

DIP8

Tube

U2008B-xFP

SO8

Tube

U2008B-xFPG3

SO8

Taped and reeled

230 V ~

 

 

 

22 k /2W

BYT51K

 

 

 

 

 

L

 

 

R2

R1

D1

R8

 

 

 

 

 

 

 

 

 

max

 

 

 

 

 

 

 

 

680 k

 

 

470 k

 

 

 

Load

 

 

 

7

 

6

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Limiting

Voltage

 

 

 

Mains voltage

 

 

 

 

 

detector

detector

 

 

 

compensation

 

 

 

 

 

Automatic

 

 

 

 

 

 

 

 

 

 

 

retriggering

 

 

 

 

 

U2008B

 

 

 

 

 

 

 

Phase

 

 

 

 

5

±VS

 

 

 

 

control unit

 

 

 

 

 

TIC

 

Current

 

 

 

 

 

 

 

 

detector

 

ö = f (V3)

 

 

 

 

 

C1

226

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

R3

 

 

 

 

 

 

 

Supply

 

 

100 mF/

8

 

 

 

 

 

 

 

 

25 V

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

voltage

 

GND

 

180

 

 

 

 

 

 

 

limiting

4

 

 

 

Full wave load

 

 

 

+

±

Reference

 

 

 

 

 

 

 

 

voltage

 

 

 

 

1

 

 

 

 

 

 

 

 

current detector

 

 

 

 

 

 

 

 

 

 

 

Soft start

 

 

 

 

 

Voltage

 

 

 

 

 

 

 

 

 

 

monitoring

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2

3

 

 

 

 

 

 

 

 

 

 

 

 

R10

 

68 k

Set point

P1

C5

Soft start

 

 

 

 

 

50 k

C3

C4

 

 

 

 

 

 

 

4.7mF/

25 V

 

 

 

 

 

R7

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

10 nF

100 nF

 

 

 

 

220 k

 

N

 

 

 

 

 

 

 

 

 

 

 

Figure 2. Block diagram with typical circuit: Soft start

2 (10)

Rev. A4, 12-Jan-01

U2008B

Pin Description

Isense

 

 

 

Output

1

 

8

Cϕ

 

 

 

Vsync.

2

 

7

 

 

U2008B

 

Rϕ

Control

 

 

 

3

 

6

GND

 

 

 

VS

 

 

 

4

 

5

 

 

 

 

 

 

 

 

 

 

Figure 3. Pinning

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:

 

 

VM ± VSmax

 

R1max 0.85 x

 

 

 

2 x Itot

 

 

 

where:

 

 

 

 

VM

Mains voltage

VSmax

Maximum supply voltage

Itot

ISmax Ix = Total current compensation

ISmax

=

Maximum current consumption of the IC

Ix

=

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.

Pin

Symbol

Function

1

Isense

Load current sensing

2

Cϕ

Ramp voltage

3

Control

Control input / compensation

 

 

output

4

GND

Ground

5

±VS

Supply voltage

6

Rϕ

Ramp current adjustment

7

Vsync.

Voltage synchronization

8

Output

Trigger output

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 V2 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 ö.

The charging current can be regulated, changed, altered

using R at Pin 6. The maximum phase angle, αmax, (minimum current flow angle ömin) 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 ms/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 αmax, i.e., the current flow angle is minimum. The minimum phase

angle αmin 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.

Rev. A4, 12-Jan-01

3 (10)

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