U2008.PDF

U2008B

Low Cost Current Feedback Phase Control Circuit

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

Internal supply-voltage monitoring

Mains supply variation compensated

Current requirement 3 mA

Variable soft-start or load-current sensing

Applications

Voltage and current synchronization

Low cost motor control

Automatic retriggering switchable

Domestic appliance

Package: DIP8, SO8

Triggering pulse typ. 125 mA

Block Diagram

22 k/2W

BYT51K

230 V ~

R 2

330 k

R 1

D 1

R 8

1 M

max

Load

96 11643

Limiting

detector

Voltage

detector

Mains voltage

compensation

Automatic

retriggering

Phase

control unit

= f (V 3 )

–V S

Current

detector

TIC

226

C 1

22 F/

R 3

Supply

voltage

limiting

25 V

180

GND

Full wave load

current detector

–

Reference

voltage

Soft start

Voltage

monitoring

R 14

47 k

R 10

100 k

Set point

P 1

50 k

V (R6) =

R 6

250 mV

C 3

3.3 nF

C 4

Load current

compensation

R 7

12 k

100 nF

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

TELEFUNKEN Semiconductors

Rev. A1, 28-May-96

1 (10)

Full wave current sensing

U2008B

230 V ~

22 k/2W

BYT51K

R 1

D 1

max

R 2

680 k

R 8

470 k

Load

96 11644

Limiting

detector

Voltage

detector

Mains voltage

compensation

Automatic

retriggering

Phase

control unit

= f (V 3 )

–V S

TIC

226

Current

detector

C 1

100 F/

25 V

R 3

Supply

voltage

limiting

180

GND

Full wave load

current detector

–

Reference

voltage

Soft start

Voltage

monitoring

R 10

68 k

Set point

P 1

50 k

Soft start

4.7F/ 25 V

C 5

C 3

C 4

R 7

220 k

10 nF

100 nF

Figure 2. Block diagram with typical circuit: Soft start

2 (10)

TELEFUNKEN Semiconductors

Rev. A1, 28-May-96

U2008B

Pin Description

I sense

Output

Symbol

Function

I sense

Load current sensing

Ramp voltage

V sync.

Control Control input / compensation

output

GND

Ground

Control

–V S

Supply voltage

Ramp current adjustment

GND

V S

V sync.

Voltage synchronization

Output

Trigger output

95 11405

Mains Supply, Pin 5, Figure 2

The integrated circuit U2008B, which also contains

voltage limiting, can be connected via D 1 and R 1 via the

mains supply. Supply voltage between Pin 4 (pos. , )

and Pin 5 is smoothed by C 1 .

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 .

a max,

(minimum current flow angle min ) can also be adjusted

by using R (see figure 4).

Series resistance R 1 can be calculated as follows:

V M –V Smax

2 xI tot

R 1max 0.85 x

When the potential on Pin 2 reaches the set point level of

Pin 3, a trigger pulse is generated whose pulse width, t p ,

is determined from the value of C (t p = 9 s/nF, see

figure 6). 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 –1 V. When V 3 = –9 V,

then the phase angle is at its maximum

whereas

V M Mains voltage

V Smax Maximum supply voltage

I tot I Smax I x = Total current compensation

The appendix provides further information regarding the

design (see figures 10, 11 and 12). An operation with

external stabilized DC voltage is not recommended.

a max i.e., the

current flow angle is minimum. The minimum phase

angle

a min is set with V 3 –1 V.

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

automatically ensures the optimum run-up time.

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 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.

Phase Control, Pin 6

The function of the phase control is largely identical to the

well known IC family TEA1007. The phase angle of the

TELEFUNKEN Semiconductors

Rev. A1, 28-May-96

3 (10)

The charging current can be regulated, changed, altered

using R at Pin 6. The maximum phase angle,

U2008B

Current Synchronization, Pin 8

Mains

96 11645

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.

R 2

BZX55

C6V2

U2008B

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.

Figure 3. Suppression of automatic retriggering and mains

voltage compensation

A further feature of the IC is the selection between soft-

start or load-current compensation. Soft-start is possible

by connecting a capacitor between Pin 1 and Pin 4, see

figure 7. In the case of load current compensation, Pin 1

is directly connected with resistance R 6 , which is used for

sensing load current.

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 rec-

tified internally. This current activates the automatic

retriggering and at the same time is available at Pin 3 (see

figure 8). By suitable dimensioning, it is possible to attain

the specified compensation effect. Automatic

retriggering and mains voltage compensation are not

activated until |V 7 – 4 | increases to 8 V. 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 3).

Load Current Detection, Pin 1

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 voltage at resistance R 6 , 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 9). The

output current generated at Pin 3 contains the difference

from the load-current detection and from the

mains-voltage compensation (see figure 1).

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

4 (10)

TELEFUNKEN Semiconductors

Rev. A1, 28-May-96

. 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

Absolute Maximum Ratings

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

Parameters

Symbol

Value

Unit

Current limitation

Pin 5

–I S

t s

–i S

100

Sync. currents

Pin 7

I syncV

i syncV

t s

Phase control

Pin 3

Control voltage

–V I

V S to 0

Input current

I I

500

Charge current

Pin 6

– I

max

0.5

Load current monitoring / Soft-start

Pin 1

Input current

I I

Input voltage

V I

–40 to + 125

Pulse output

Input voltage

Pin 8

+V I

–V I

V S

Storage temperature range

T stg

40 to 125

Junction temperature range

T j

10 to 125

Thermal Resistance

Parameters

Symbol

Value

Unit

Junction ambient

DIP8

SO8 on p.c.

SO8 on ceramic

R thJA

110

220

140

K/W

Electrical Characteristics

V S –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

14.5

14.6

16.5

16.8

Current requirement

Pins 1, 4 and 7 open

–I S

3.0

Voltage monitoring

Pin 5

Turn-on threshold

–V TON

11.3

12.3

Phase control

Input current

Voltage sync. Pin 7

Current sync.

I syncV

I syncI

0.15

Pin 8

Voltage limitation

I L = 2 mA

Pin 7

V syncV

8.0

8.5

9.0

TELEFUNKEN Semiconductors

Rev. A1, 28-May-96

5 (10)

Plik z chomika:

Inne pliki z tego folderu:

Inne foldery tego chomika: