DE4238913A1 - Oscillation control in low voltage lighting circuit - initiating oscillation by pulse derived from time base, monitored according to criteria and also stoppable - Google Patents

Abstract

In a procedure for time control of an oscillation in a low voltage discharge lamp circuit supplied with either an AC or DC supply, the oscillation is initiated by a trigger pulse derived from a time base. The oscillation is monitored according to certain criteria and can be stopped after an arbitrary time lapse or in the case of malfunction, with the characteristic of not reacting integrally towards known malfunctions like short circuit and overload. The overload regime corresponding to the load and cold current behaviour of the lamp is designed so as to ignore stochastic overload signals and those during starting by using multiple interrogation with time delay. It also ignores periodically repeating overload signals of short time duration. ADVANTAGE - High accuracy and reproducibility of functions.

Description

The present invention relates to a method and a scarf arrangement for timing a vibration in Switching power supplies for lighting technology, especially for halogen low-voltage lamps with a primary supply with alternating voltage voltage of different frequencies or with DC voltage.

It is known that electronic transformers for halogen never dervoltage lamps usually as a self-oscillating switching power supplies are manufactured. (e.g. company magazine Motorola Compass No. 26/1/92).

This is described in more detail with the aid of the circuit shown in FIG. 1. Trigger pulses for triggering the oscillating circuit are generated by charging the RC combination 1 , 2 and igniting the Diacs 3 .

After the switching power supply has started to charge, this RC combination is blocked via a diode 4 from the vibration output, so that no further ignition pulses can act on the vibration.

In order to terminate the oscillation in the event of a fault, a switching element 5 is necessary which prevents the oscillation from being activated.

About a time integral 6 are used as usual error signals 7 and 8 secondary short circuit or overload and overtemperature.

The disadvantage of these known electronic transformers for Different performance classes are included in the implementation of protective functions necessary high expenditure of discrete Components.

Furthermore, with primary supply with DC voltage and AC voltage no optimal overload protection given, as a Switching over of the evaluation factor did not take place.

Functions that increase utility value such as direct dimming, with the more favorable method of network feedback Phase section dimming, combined with possible alternating voltage power supply or DC voltage supply and one  defined blanking of the vibration in the case of mains overvoltage spit zen, as well as one that can be selected without additional components Switch-off temperature to protect against excessive temperature of the scarf arrangement, are not realized in any known solution.

The invention has for its object a method for timing of a vibration in switching power supplies for lighting technology, especially for halogen low-pressure lamps and to further develop a circuit arrangement for it so that the currently discreetly reali with considerable expenditure on components protective functions and usage values through a integrated solution.

According to the invention, this object is achieved by the in claim 1 listed features solved.

In claim 2 is a circuit arrangement for temporal Control specified.

The advantages achieved with the invention are in particular in that high accuracy and reproducibility reached, and for other functions such as dimming via phases cut and a time-defined blanking of the vibration in the case of mains surge peaks, all of which are specified functions with AC voltage supply and DC voltage power supply.

The details of the embodiment result from the fol ing description and from the drawing to which reference genom men will.

The drawings show:

Fig. 1 Known circuit for self-oscillating switching power supplies,

2 method according to the invention,

Fig. 3 circuit arrangement according to the invention for 8 connections.

The invention will be described in more detail using an exemplary embodiment corresponding to FIG. 2.

A clock generator 1 generates a system clock which is selected so that all necessary times for influencing the oscillation circuit device 10 are provided via corresponding frequency divider stages in the logic part 2 and at the same time a network synchronization D of the logic part 2 takes place.

The system clock pulse is also the reference variable for the trigger pulse for exciting the oscillation circuit 10 , which is generated in the pulse generator 3 .

The oscillation circuit 10 is a self-oscillating system which is monitored by the oscillation detection 4 . If the oscillation goes out at a point in time at which it is not blocked by the logic part 2 , then the pulse generator 3 retriggered the basic clock. The logic part 2 can activate the switch-off function 5 and end the oscillation in the oscillation circuit 10 , the pulse generator 3 being deactivated at the same time.

This type of control is used to implement a phase cut dimming according to the control variable at the dimming input S1 via the dimming circuit 11 .

In direct voltage operation, a replica of the zero crossing of the mains for dimming the direct voltage takes place in logic part 2 . Is an error signal F1, z. B. a mains surge, to the protective function 8 , a time-defined Austa stung the oscillating circuit 10 via the logic part 2 and the switching function 5 , and via the pulse generator 3 is reached. An error signal F2, e.g. B. an overload, switches over the logic partially defined time delay the fault memory 6 , whereby a stationary shutdown of the shutdown function 5 and the pulse generator 3 takes place and the oscillating circuit 10 is constantly switched off.

The time delay is necessary to accommodate a changing load behave in the oscillation circuit, caused by the changing cold currents of the light bulb load, rich at switch-on torque to evaluate.

Through a system of defined time suppression for one-time and periodically occurring overload signals, such as z. B. may occur during dimming and by multiple queries, it is geekge that only device 10 is reacted to a real overload of the oscillating circuit.

An AC / DC voltage detection 7 derived from the supply voltage controls the evaluation thresholds for the overload.

The error signal F3 on the protective function 9 controls the error memory 6 directly. F3 can be an overtemperature signal applied externally or generated by the chip itself.

In Fig. 3, an example for an inventive circuit is shown.

The connection 1 is the supply voltage connection for the power supply unit A, from which a reference voltage source B is supplied, which provides a reference potential with respect to the reference potential GND for further circuit parts.

The connection 2 carries an AC or DC voltage signal to the circuit part overvoltage detection D.

The AC / DC voltage signal is sent to the AC voltage voltage / DC voltage detection C passed on. In the AC / DC voltage detection C continues to be a network generated synchronous signal that for the phase cut dimming G is needed.

The connection from the AC / DC voltage detection C to overload detection + logic and overload delay E controls accordingly a comparator threshold for the applied AC voltage or DC voltage for the applied at terminal 3 overload signal.

In the clock generator H, the system clock is generated when a capacitor 6 is connected to the reference potential at the circuit. This system cycle is the time base for the overload delay in the overload detection + logic + overload delay E as well as for the trigger conditioning in the logic section for trigger and switch-off regime K.

Furthermore, the system clock in the logic of the circuit partly G with DC voltage supply, a mains frequency replica reached.

When a controllable RC combination is connected to connection 5 , circuit G controls the trigger and switch-off regime K. At connection 4 , the switch-off temperature of overtemperature sensor F can be set.

A corresponding overtemperature signal in the overtemperature sensor F or overload signal after a corresponding delay time in overload detection + logic + overload delay E sets the shutdown memory in shutdown regime K.

An overvoltage at terminal 2 controls over the overvoltage detection D a defined time suppression in the switch-off regime K. The circuit part J contains the trigger output, the vibration damping and the vibration detector, whereby the output 7 serves as an interface for controlling and monitoring the switching power supply. The circuit part J is controlled by the switch-off regime K, a detected oscillation at the output 7 giving a corresponding reaction to the regime.

Claims (2)

1. A method for timing a vibration in switching power supplies for lighting technology, especially for halogen low-voltage lamps with a primary supply with AC voltage of different frequencies or with DC voltage, characterized in that the vibration is started with a defined trigger pulse derived from a time base , the vibration after defined criteria is monitored and can be terminated according to arbitrary time sequences and stopped in the event of a fault, with the peculiarity of not responding integrally to the known faults such as short-circuit and overload, so that the overload regime in accordance with the load and cold current behavior of the lamps in the It is designed to negate stochastic or start-up-related overload signals by multiple polling with time delays and to specifically negate periodically repeating short-term overload signals in order to dispense with an additional integration element and at the same time by dimming the oscillation to enable dimming or regulating the output voltage via the phase section and protecting the oscillation circuit from mains spikes by temporally defined oscillation of the oscillation, and to switch off the oscillation without delay in the event of overtemperature. 2. Circuit arrangement for the temporal control of an oscillation in switching power supplies for lighting technology, in particular for halogen low-voltage lamps with a primary supply with AC voltage of different frequency or DC voltage, characterized in that it consists of a power supply (A) connected to the supply connection ( 1 ) and connected to it Reference voltage generation (B), an over voltage detection (D), which is connected to a connector ( 2 ) and continues to be connected to the AC / DC voltage detection (C) and to the logic for trigger and shutdown regimes with shutdown memory (K) , an overload detection + logic + overload delay (E), which is connected to the connection ( 3 ) and further with the DC / AC voltage detection (C), the shutdown memory (K) and the clock regime with clock generator (H), which in turn with the connection ( 6 ), a phase cut dimming + logic (G) and the A Switching regime (K) is connected, an overtemperature sensor (F), which is connected on the one hand to the connection ( 4 ) and on the other hand to the switch-off regime (K), the circuit part for phase section dimming + logic (G), which is connected to the connection ( 5 ), the clock generator (H), the AC / DC voltage detection (C) and the logic for the trigger and switch-off regime (K) is connected, a switching device part trigger output / vibration damping / vibration detector (J), which with the connection ( 7 ) and the circuit part logic for trigger and switch-off regimes (K) is connected and a connection (GND) which is connected to the common reference potential of the circuit.