U217.PDF

U217B/ U217B-FP

Zero Voltage Switch with Adjustable Ramp

Description

The integrated circuit, U217B, is designed as a zero-

voltage switch in bipolar technology. It is used to control

resistive loads at mains by a triac in zero-crossing mode.

A ramp generator allows to realize power control function

by period group control, whereas full wave logic

guarantees that full mains cycles are used for load

switching.

Features

Applications

Direct supply from the mains

Full wave power control

Current consumption

0.5 mA

Temperature regulation

Very few external components

Power blinking switch

Full wave drive – no dc current component in the load

circuit

Negative output current pulse typ. 100 mA –

short circuit protected

Package: DIP8, SO8

Simple power control

Ramp generator

Reference voltage

Block Diagram

95 10872

D 1

BYT86/800

220 k

R 2

R 1

18 k

2 W

Load

1000 W

(250 V~)

(R sync )

C 2

R 4

100 k

C 1

100 F/

16 V

V M =

230 V~

2.2 F/

10 V

Ramp

generator

Synchronization

Supply

TIC

236N

GND

R 5

15 k

MT2

100

MT1

Full wave logic

max

–

Pulse

amplifier

R 3

Comparator

100 k

min

Reference voltage

1.25 V

R 6

58 k

Figure 1. Block diagram with typical circuit, period group control 0 to 100%

TELEFUNKEN Semiconductors

Rev. A1, 24-May-96

1 (11)

U217B/ U217B-FP

General Description

Firing Pulse Width t p , (Figure 4)

This depends on the latching current of the triac and its

load current. The firing pulse width is determined by the

zero crossing identification which can be influenced with

the help of sync. resistance, R sync , (figure 6).

The integrated circuit, U217B, is a triac controller for the

zero crossing mode. It is meant to control power in

switching resistive loads of mains supply.

Information regarding supply sync. is provided at Pin 8

via resistor R Sync .

To avoid dc load on the mains, full wave logic guarantees

that complete mains cycles are used for load switching.

A fire pulse is released when the inverted input of the

comparator is negative (Pin 4) with respect to the non–

inverted input (Pin 3) and internal reference voltage.

A ramp generator with free selectable duration is possible

with capacitor C 2 at Pin 2 which provides not only

symmetrical pulse burst control (figure 3), but also

control with superimposed proportional band (figure 10).

Ramp voltage available at capacitor C 2 is decoupled

across emitter follower at Pin l. To maintain the lamp

flicker specification, ramp duration is adjusted according

to the controlling load. In practice, interference should be

avoided (temperature control). Therefore in such cases a

two point control is preferred to proportional control. One

can use internal reference voltage for simple applications.

In that case Pin 3 is inactive and connected to Pin 7

(GND), figure 9.

t p =

arc. sin

I L V M

P 2

whereas

I L = Latching current of the triac

V M = Mains supply, effective

P = Power load (user’s power)

Total current consumption is influenced by the firing

pulse width, which can be calculated as follows:

R sync

V M 2 sin (

t p

2 )–0.6 V

3.5 10 –5 A

–49 k

10.00

V mains = 230 V~

1.00

95 11306

I L ( mA)

0.10

200

100

0.01

Ramp

control

100

1000

10000

96 11939

P ( W )

Figure 4.

–V S

C 2

2000

Figure 2. Pin 1 internal network

1600

V M =230V AC

T amb =25°C

1200

V 1

1.4 V

Final voltage

800

V min

400

7.3 V

Initial voltage

V max

300

600

900

1200

1500

–V S(Pin5)

95 11307

95 9978

t p ( s )

Figure 3.

Figure 5.

2 (11)

TELEFUNKEN Semiconductors

Rev. A1, 24-May-96

U217B/ U217B-FP

Triac Firing Current (Pulse)

Supply Voltage

The integrated circuit U217B (which also contains

internal voltage limiting) can be connected via the diode

(D 1 ) and the resistor (R 1 ) with the mains supply. An

internal climb circuit limits the voltage between Pin 5 and

7 to a typical value of 9.25 V.

Series resistance R 1 can be calculated (figures 7 and 8) as

follows:

This depends on the triac requirement. It can be limited

with gate series resistance which is calculated as follows:

R Gmax

7.5 V – V Gmax

I Gmax

– 36

(V M – V S ) 2

2 R 1

V min – V Smax

2 I tot

R 1max = 0.85

;

P (R1) =

I Gmax

I P =

t p

I tot = I S + I P + I x

whereas

V M = Mains voltage

V S = Limiting voltage of the IC

I tot = Total current consumption

I S = Current requirement of the IC (without load)

I x = Current requirement of other peripheral

components

P (R1) = Power dissipation at R 1

whereas:

V G = Gate voltage

I Gmax = Max. gate current

I p

= Average gate current

t p

= Firing pulse width

= Mains period duration

V Mains =230V

95 10114

I tot ( mA )

95 10116

I tot ( mA )

Figure 6.

Figure 7.

TELEFUNKEN Semiconductors

Rev. A1, 24-May-96

3 (11)

U217B/ U217B-FP

Absolute Maximum Ratings

Reference point Pin 7

Parameters

Symbol

Value

Unit

Supply current

Pin 5

–I S

Sync. current

Pin 8

I Sync.

Output current ramp generator

Pin 1

I O

Input voltages

Pin 1, 3, 4, 6

Pin 2

Pin 8

–V I

V S

2 to V S

V I

7.3

Power dissipation

T amb = 45

400

T amb = 100

P tot

400

125

Junction temperature

T j

125

Operating-ambient temperature range

T amb

0 to 100

Storage temperature range

T stg

–40 to + 125

Thermal Resistance

Parameters

Symbol

Maximum

Unit

Junction ambient

R thJA

200

K/W

Electrical Characteristics

–V S = 8.5 V, T amb = 25

C, reference point Pin 7, unless otherwise specified

Parameters

Test Conditions / Pin

Symbol

Min

Typ

Max

Unit

Supply voltage limitation

–I S = 5 mA

Pin 5

–V S

8.6

9.25

9.9

Supply current

Pin 5

–I S

500

Voltage limitation

I 8 =

1 mA

Pin 8

V I

7.5

8.7

Synchronous current

Pin 8

I sync

0.12

Zero detector

I sync

Output pulse width

V M = 230 V,

R sync = 220 k

R sync = 470 k

t P

260

460

Output pulse current

V 6 = 0 V

Pin 6

–I O

100

Comparator

Input offset voltage

Pin 3,4

V I0

Input bias current

Pin 4

I IB

Common mode input

voltage

Pin 3,4

–V IC

(V S –1)

Threshold internal

reference

V 3 = 0 V

Pin 4

–V T

1.25

Ramp generator , Pin 1, figu re 1

Period

–I S = 1 mA, I sync =1 mA,

C 1 = 100 F, C 2 = 1 F,

R 4 = 100 k

1.5

Final voltage

V 1

0.9

1.40

1.80

Initial voltage

6.8

7.3

7.8

Charge current

V 2 = 0 V, I 8 = –1 mA Pin 2

–I 2

4 (11)

TELEFUNKEN Semiconductors

Rev. A1, 24-May-96

T b =45

U217B/ U217B-FP

Applications

R L

270 k

Load

BYT86/800

V M = 230 V ~

18 k

1.5 W

VDR

+5 V

CNY21

U217B

5 6 k

47 F/

10 V

39 k

I I 1.5 mA

V I

95 11308

Figure 8. Power switch

95 11309

D 1

BYT86/800

2.2 F/

10 V

C 2

R 2

220 k

18 k/

2 W

Load

1000 W

R 1

(250 V~)

(R sync )

R 8

470 k

R 4

100 k

C 1

BC237

V M =

230 V~

Ramp

generator

Synchronization

Supply

NTC/M87

B value =

3988

R (25)

100 k

R 6

100 k

R 5

100

–

Full wave logic

R 9

150

Pulse

amplifier

R 3

Comparator

R p

R 7

130 k

Reference voltage

1.25 V

220 k

Figure 9. Temperature control 15 to 35°C with sensor monitoring

NTC–Sensor M 87 Fabr. Siemens

R( 25 ) =100 k/B =3988

R (15) = 159 k

R( 35 ) = 64.5 k

R 5 1) determines the proportional range

TELEFUNKEN Semiconductors

Rev. A1, 24-May-96

5 (11)

Plik z chomika:

Inne pliki z tego folderu:

Inne foldery tego chomika: