tca785_ph_ctrl

Semiconductor Group

1

         TCA 785

This phase control IC is intended to control thyristors, triacs, and transistors. The trigger pulses
can be shifted within a phase angle between 0 ˚ and 180 ˚. Typical applications include
converter circuits, AC controllers and three-phase current controllers.

This IC replaces the previous types TCA 780 and TCA 780 D.

(top view)

Pin Configuration

Phase Control IC

 TCA 785

Bipolar IC

Features

●

Reliable recognition of zero passage

●

Large application scope

●

May be used as zero point switch

●

LSL compatible

●

Three-phase operation possible (3 ICs)

●

Output current 250 mA

●

Large ramp current range

●

Wide temperature range

P-DIP-16-1

Type

Ordering Code

Package

TCA 785

Q67000-A2321

P-DIP-16-1

Pin

Symbol

Function

1

GND

Ground

2
3
4

Q2
Q U
Q2

Output 2 inverted
Output U
Output 1 inverted

5

VSYNC

Synchronous voltage

6
7

I
Q Z

Inhibit
Output Z

8

V REF

Stabilized voltage

9
10

R9
C10

Ramp resistance
Ramp capacitance

11

V11

Control voltage

12

C12

Pulse extension

13

L

Long pulse

14
15

Q 1
Q 2

Output 1
Output 2

16

VS

Supply voltage

Pin Definitions and Functions

    09.94

Semiconductor Group

2

         TCA 785

Functional Description

The synchronization signal is obtained via a high-ohmic resistance from the line voltage
(voltage V5). A zero voltage detector evaluates the zero passages and transfers them to the
synchronization register.

This synchronization register controls a ramp generator, the capacitor C10 of which is charged
by a constant current (determined by R9). If the ramp voltage V10 exceeds the control voltage
V11 (triggering angle

ϕ), a signal is processed to the logic. Dependent on the magnitude of the

control voltage V11, the triggering angle

ϕ can be shifted within a phase angle of 0˚  to 180˚.

For every half wave, a positive pulse of approx. 30

 µs duration appears at the outputs Q 1 and

Q 2. The pulse duration can be prolonged up to 180˚  via a capacitor C12. If pin 12 is connected
to ground, pulses with a duration between

ϕ and 180˚ will result.

Outputs

 and

 supply the inverse signals of Q 1 and Q 2.

A signal of

ϕ +180˚ which can be used for controlling an external logic,is available at pin 3.

A signal which corresponds to the NOR link of Q 1 and Q 2 is available at output Q Z (pin 7).

The inhibit input can be used to disable outputs  Q1,  Q2 and

 ,

 .

Pin 13 can be used to extend the outputs

 and

 to full pulse length (180˚ –

ϕ).

Q 1

Q 2

Q 1

Q 2

Q 1

Q 2

Block Diagram

Semiconductor Group

3

         TCA 785

Pulse Diagram

Semiconductor Group

4

         TCA 785

Unit

Parameter

Symbol

min.

max.

Limit Values

Absolute Maximum Ratings

V

Supply voltage

VS

– 0.5

18

mA

Output current at pin 14, 15

IQ

– 10

400

K/W

Thermal resistance
system - air

Rth SA