TEA1007

TELEFUNKEN Semiconductors
Rev. A1, 28-May-96

1 (8)

Simple Phase Control Circuit

Description

Integrated circuit, TEA1007, is designed as a general
phase control circuit in bipolar technology. It has an
internal supply voltage limitation. With typical 150 mA
ignition pulse, it is possible to determine the phase-shift

of the ignition point by comparing the mains sync. ramp
voltage with a preset required value. It generates a single
ignition pulse per half wave; therefore, it is suitable for
capacitive and inductive loads in low cost applications.

Features

D Current consumption v 2.5 mA

D Ignition pulse typ. 150 mA

D Voltage and current synchronization

D Internal supply voltage control

Package: DIP8

Block Diagram

R = series resistance

Figure 1. Block diagram with typical circuitry

TEA1007

TELEFUNKEN Semiconductors

Rev. A1, 28-May-96

2 (8)

General Description

The phase-shift of the ignition point is determined in the
usual manner by comparison between a mains
synchronized ramp voltage and a predetermined required
value. The capacitor C

ö/t

between Pin 7 and the common

reference point Pin 8 is discharged at the zero transition
of the mains voltage via the V

detector, gate G

and

switch S

. After the end of the zero transition pulse, C

ö/t

is charged from the constant current source I

, whose

value is adjusted externally with R

at Pin 3 due to the

unavoidable tolerance of C

ö/t

(Phase 1).

When the potential at Pin 7 reaches the nominal value
predetermined at Pin 6, the thyristor Th

, which also

functions as a comparator, ignites and sets the following
clock flip-flop. The output of the clock flip-flop releases
the output amplifier, connects a second constant current
source to the capacitor C

ö/t

, and switches the reference

voltage switch S

to an internally generated threshold

voltage V

Ref1

via an RS flip-flop and the OR gate G

The capacitor C

ö/t

is charged in this second phase by

+ I

until it reaches the internal reference voltage

Ref

. The length of this Phase 2 corresponds to the width

of the output pulse t

. When the capacitor voltage reaches

the value V

Ref

, thyristor Th

ignites again and resets the

clock flip-flop to its initial state. The output pulse is thus
terminated and the constant source I

is switched off.

However, the RS flip-flop holds the switch S

so that the

internal reference voltage remains connected to Th

. As

Ref

is greater than the maximum permissible control

voltage at Pin 6, this prevents more than one ignition
pulse from being generated in each half-cycle of the
mains voltage. This is particularly important because the
energy contents of the output pulse is of the same order
as the internal requirements of the circuit for each
half-wave.

In the following zero transition of the mains voltage, the
zero transition detector (Input Pin 5) resets the RS
flip-flop, discharges C

ö/t

again via S

, and also insures

that the clock flip-flop is in the reset condition. A further
part of the basic function is the current detector with its
input at Pin 4. When controlling inductive loads, the load
current lags behind the mains voltage which means that
the circuit could generate an ignition pulse during the
period in which current is still flowing with a polarity
opposite to that of the mains voltage if the current were
not taken into account (see figure 2).

This, in turn, would lead, to so-called "gaps" in the load
current as the next ignition pulse is generated in the subse-
quent half-cycle.

95 11358

Figure 2. Functional diagram for inductive load of

max

95 11360

Figure 3. Triac voltages + currents at resistive load

= Zero cross voltage

= Zero cross current

= Mains voltage

= Load current

= Gate current

= Triac voltage at anode HI

TEA1007

TELEFUNKEN Semiconductors
Rev. A1, 28-May-96

3 (8)

In indication as to whether load current is flowing or not
is provided by the triac itself. When the triac is ignited,
the voltage at electrode H

drops from the instantaneous

value of the mains voltage to approximately 1.5 V, the
value of the forward voltage of the triac. When the load
current drops below the hold current of the triac towards
the end of the half-cycle, V

again returns to the instan-

taneous value of the mains voltage. The current detector
with its input at Pin 4 now controls this triac voltage and
blocks the pulse generator via G

and S

by increasing the

reference voltage as long as the triac is conducting. As, in
the case of a resistive load, the triac may be extinguished
shortly before the zero transition of the mains voltage
when the load current drops below the hold current the
RS flip-flop must prevent any possible second ignition
pulse from being generated.

95 11359

Figure 4. Functional diagram for resistive load and

min

Additional Function

An internal supply voltage control circuit insures that
output pulses can be generated only when the supply
voltage required for operation of all logic functions is
available.

Series resistance R

can be calculated approx. as follows:

1 max

+ 0.85

M min

S max

tot

= I

+ I

whereas

tot

= Total current consumption

= Current requirement of the lC

= Average current requirement of the triggering pulses

= Current requirement of other peripheral components

Determination of Gate Series
Resistance, Firing Current and Pulse
Width

Firing current requirement depends upon the triac used
which can be regulated with series resistance as given
below:

G max

[

12.5 V V

G max

110

[

whereas:

=Triac's gate voltage

=Triac's gate current

=Gate current requirement average

=Period duration of mains frequency

=(firing) pulse width

=Ramp capacitor

TEA1007

TELEFUNKEN Semiconductors

Rev. A1, 28-May-96

4 (8)

Absolute Maximum Ratings

Reference point Pin 8

Parameters

Symbol

Value

Unit

Current consumption

Pin 1

t<10

Sync. currents:

Pin 4
Pin 5

t<10 ms

Pin 4
Pin 5

syncI

syncV

sync.I

sync.V

10
10
60
60

Input current

Pin 3

Input voltages:

Pin 6
Pin 2

Power dissipation

amb

= 45

°C

amb

= 85

°C

tot

400
225

Junction temperature

125

°C

Ambient temperature range

amb

0 to 80

°C

Storage temperature range

stg

40 to +125

°C

Thermal Resistance

Parameters

Symbol

Value

Unit

Junction ambient

DIP8
SO8 (P.C.)
SO8 (ceramic)

thJA

200
220
140

K/W

Electrical Characteristics

Reference point Pin 8, unless otherwise specified

Parameters

Test Conditions / Pin

Symbol

Min

Type

Max

Unit

Mains supply

Pin 1

13.5

Current consumption

2.5

Sync. currents

Pin 4
Pin 5

syncI.

syncV

0.35
0.65

Output pulse current

= 13.5 V,

= 0, V

= 1.2 V Pin 2

180

Output pulse width

ö/t

= 3.3 nF

Pin 2

ö/t

= 6.8 nF

30
64

Charge current

Phase 1"

Pin 7

ö/t

= 3.3 nF

ö/t

= 6.8 nF

4.3

Phase 2"

Pin 7

1.3

Drive current

Pin 6

0.5

Balance between two half
cycles

constant

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