Siemens SLB0587, SLB0587G Datasheet

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SLB 0587

Dimmer IC for Halogen Lamps

SLB 0587

Preliminary Data

Features

●Phase control for resistive and inductive loads

●Sensor operation – no machanically moved switching elements

●Operation possible from several extensions

●Capable of replacing electromechanical wall switches in conventional light installations

●High interference immunity, even against ripple control signals

●Programming input for selection of three different functions (mode A/B/C)

●Soft start

●Safety turn-OFF

Type	Ordering Code	Package

SLB 0587	Q67100-A8310	P-DIP-8

SLB 0587 G	Q67106-A8315	P-DSO-8-1 (SMD)

t New Type

CMOS IC

P-DIP-8

P-DSO-8-1

For applications where the SLB 0586 A has been used, it is possible to replace the SLB 0586 A by the SLB 0587 if the appropriate external wiring in accordance with the data sheet is maintained.

The SLB 0587 is a CMOS IC and the advanced version of the version SLB 0586 A.

The IC permits the design of digital electronic phase controls for operation of incandes-cent lamps, low-voltage halogen lamps with in-series connected transformers, and universal as well as split-pole motors.

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09.94

SLB 0587

SLB 0587 G

Pin Configuration (top view)

Pin Definitions and Functions

Pin	Symbol	Function

1	V DD	Reference point (OV)

2	IPROG	Programming input

3	IPLL	Integrator for PLL

4	ISYNC	Synchronizing input

5	ISEN	Sensor input

6	IEXT	Extension input

7	V SS	Supply voltage

8	QT	Trigger pulse output

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SLB 0587

Figure 1

Block Diagram

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SLB 0587

Functional Description

With the SLB 0587 it is possible to generate one defined current pulse per line half cycle. Together with a triac and a few extra passive components, a line-powered phase-control circuit can be designed. The phase-control angle (turn-ON time of the triac) can be set on the two control inputs, pins 5 and 6, of the IC.

The voltage supply to the IC in a two-wire connection is ensured by limiting the angle of current flow to approx. 152°. This makes it simple to exchange mechanical wall switches in conventional lighting installations. The IC’s internal logic is synchronized with the line by PLL. Thus a phase control range independent of the line frequency is obtained.

Operation with Low-Voltage Halogen Lamps

In normal, resistive operation of a phase control circuit there is alternately part of the positive and negative line-voltage half cycle applied to the load via the triac that has started to conduct because of the trigger pulse. Operation of the circuit with a transformer and low-voltage halogen lamp connected is largely identical to the operation of a normal filament lamp due to the primarily resistive nature of the load. In operation with resistive and inductive portions of load, the zero crossing of the current compared to that of the line voltage line is delayed.

In operation with heavily inductive loads (eg an idling transformer after lamp failure), a highly lossy state (half cycle operation) can occur after a fault, leading to thermal destruction of the transformer. Control mechanisms integrated into the SLB 0587 serve to protect the load from this situation.

If, for instance, a trigger pulse is missing in a half cycle because of a fault, there will be a considerable increase in current in the transformer into the line shortly after the zero crossing of a voltage wave – after the next firing of the triac at large phase-control angles. If the next trigger pulse comes into phase when the triac is still conducting because of the inductive current lag, it has no effect. It is only the subsequent trigger pulse that will fire the triac again.

The case described above, where only one trigger pulse per line cycle leads to firing of the triac, can turn into a steady-state condition in the absence of further measures.

The SLB 0587 provides the following features to prevent Steady-State Half-Cycle Operation:

1)Allowance for the conducting state of the triac when setting the trigger pulses. If a trigger pulse, determined by the set firing angle and status of the internal PLL, coincides with the conducting phase of the triac, the trigger pulse will not be output to the triac until after the zero crossing of the current wave.

2)Detection of high saturation currents at angles of current flow of more than 180° by sampling the synchronizing input levels.

If the frequency of such peak situation current exceeds a value defined in the IC, there will be a safety cut-out.

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SLB 0587

3)Retriggering if the triac does not remain triggered after the trigger pulse.This can occur in particular on highly inductive loads (idling transformer with a small magnetizing current) and insensitive triacs. Approx. 1.5 ms (1.25 ms at 60 Hz) after each trigger pulse from SLB 0587 the conducting state on the triac is sampled via pin 4 of the IC. If the triac still remains turned off, one-shot retriggering will follow. If the frequency of retriggering exceeds an internally defined limit value, there will be a cutout.

Safety Cutout

The purpose of the safety cutout is to prevent thermal destruction of primarily inductive loads (idling transformer) in the event of very lossy instances of operation. Despite the safety precautions that are integrated, you should only use transformers with thermal protection.

Safety cutout occurs when the count of an 4-bit up/down counter reaches 15. The count is determined by the ratio of the up/down counting rates. The up-counting rate is the appearance of high saturation currents and retriggering. A down counting increment is produced when the count is other than zero at every fifteenth line half-wave. The count is zeroed in the off state and when short line outages are detected.

Operation (Figure 3)

The integrated circuit can distinguish the instructions ON/OFF and Change of Phase Control

Angle by the duration of sensor touching.

Turning ON/OFF

Short touching (50 to 400 ms) of the sensor area turns the lamp ON or OFF, depending on its preceding state. The switching process is activated as soon as the sensor is released.

Setting of the Phase Control Angle

If the sensor is touched for a longer period (exceeding 400 ms) the angle of current flow will be varied continuously. It runs accross the control loop in approximately 7.6 s up and down (e.g. bright – dark – bright) until the sensor is released.

Easy operation, even in the lower brightness range of incandescent lamps, is enabled by the following procedure:

The phase control angle is controlled such that the lamp brightness varies physiologically linear with the operating time and pauses for a short period when the minimum brightness is reached.

Using R 2 and C 4 (synchronizing input) in the application circuit (figure 4), the angle of current flow can be controlled for purely resistive loads between 45° and 152° of the half-wave.

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SLB 0587

Control Modes of Operation

Mode

Period of Touching the Sensor/Extension

Short (60 to 400 ms)

Long (more than 400 ms)

Pre-Touch

Post-Touch

Pre-Touch

Post-Touch

Status

A (Pin 2 at V SS)

OFF

Softstart to Max.

OFF

Starts varying at min.

Max.

OFF

Max./Intermediate

Starts varying at

Intermediate

OFF

pre-touch brightness

Repeated dimming

Same dimming

direction

B (Pin 2 open)

OFF

Softstart to

OFF

Softstart to stored

stored brightness

brightness

from last turn-OFF

and varying

Max.

OFF

Max./Intermediate

Starts varying at

Intermediate

OFF

pre-touch brightness

Repeated dimming

Reversed dimming

direction

C (Pin 2 at V DD)

OFF

Softstart to Max.

OFF

Starts varying at min.

Max.

OFF

Max./Intermediate

Starts varying at

Intermediate

OFF

pre-touch brightness

Repeated dimming

Reversed dimming

direction

Figure 3

Control Behaviour of the 3 Operating Modes

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SLB 0587

Figure 2

Internal Wiring of Pins

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