FR2629663A2 - BRIGHTNESS CONTROL CIRCUIT FOR INCANDESCENT LAMPS AND NETWORK CONNECTION BLOCKS HAVING A PROTECTION AND LIMITATION CIRCUIT BREAKER FOR ELECTRONIC SAFETY - Google Patents

Abstract

Brightness control circuit, for incandescent lamps and mains connection blocks, comprising a protection and limitation circuit breaker intended for obtaining electronic security. The circuit comprises, in addition to that of the main patent, an electronic circuit breaker M, C2 which avoids having to replace a blown fuse, as would be necessary in the case of common light intensity dimmers. Application: damping surge peaks in a domestic circuit.

Description

The main patent application relates to a circuit

  brightness control device for incandescent lamps-

  and parts of a switching network.

  network connection blocks, this circuit does not include the anti-parasitic components required in triac-type dimmers. This

  control circuit allows to give up the means of anti-

  interference in common control devices

  phase interruptions, which are connected with triacs, and yet maintain a sufficiently low level of parasitic voltages with in mfe

  time elimination of noise in the control circuit.

  It can apply to a domestic installation.

  The peculiarity of the main patent application lies in the fact that a self-locking field effect transistor, placed in the diagonal of a bridge-type rectifier, is controlled by a control circuit of a

  such that the field effect transistor is conductive

  zero-crossing of the AC voltage and remains in the conductive state, for an adjustable time, in the

  control circuit for a desired part of the half

  network wave, and then cut with a suitably set cutoff edge, before it happens

the new passage to zero.

  The invention contained in this application for

  certificate of addition (hereinafter referred to as "the invention") has

  the purpose of developing the proposal of the application

  patent application in such a way that the

  brightness is complemented by a type of security

  electronic circuit breaker. As a result, the replacement is avoided.

  fusing of the fused fuse, necessary in current dimmers, for example in the event of a short circuit caused by the burning of the filament of an incandescent lamp. Since the adaptation of the disturbance limiting devices and tips, as well as a protective device are necessary, additional measurements concerning the circuit are essential, compared to the circuit embodiment according to the present invention.

main patent application.

  For the solution of this problem, it is provided according to the present application that with the aid of an additional Miller capacitor and the corresponding pre-resistance, as well as another capacitor, which lies between a part of this pre-resistance and ground, the break-off voltage adopts an S-shaped pattern with a predetermined slope between the two curved parts of the S, and between the source of the metal-oxide field-effect transistor and the mass, are arranged in series two resistors in which the resistor, which is located in parallel with the base emitter zone of the transistor and which directly determines the maximum current passing through

  the transistor by controlling the gate voltage of the transistor

  metal oxide field effect, has a resistance value

  this weaker than the resistance on which rests the base emitter zone of the transistor, which makes cut the monoflop ("monoflop") and which interrupts thereby the passage of the current in the metal-oxide transistor to

  field effect, and that the Miller capacitor serves as

  dubbing function to turn on the

  metal-oxide field-effect transistor in case of over-

caused by spikes.

  The circuit arrangement according to the invention offers the advantage of a current limitation in the field effect metal-oxide transistor connected in the circuit, in the event of a short circuit of the charge or discharge as a result of surge that is coupled in the circuit

(Spikes).

  The additional Miller capacitor can also

  be formed by other components, such as resistance

  those with automatic variation, transil diodes or

similar organs.

  The pre-resistance corresponding to the Miller capacitor, or the other capacitor mentioned above, can be switched mechanically or automatically, between operation with incandescent lamps and operation with a mains connection block, such that, in the case of operation with incandescent lamps, the other capacitor or pre-resistor corresponding to the Miller capacitor has a lower value and thus a lower cutoff time constant. In what follows, it is described, with reference to the appended drawing, and by way of illustration and in no way limiting,

  an example of the execution of the protective and limiting circuit

  according to the invention. We show:

  in Figure 1, the known connection diagram,

  born to the luminosity control circuit of incandescent lamps

  descence and connection blocks to the network,

  in Figure 2, the protective and limiting circuit

  tationdansd in the embodiment of the invention, in Figure 3, a graphical representation of the manner in which the breaking of the voltage occurs; and in FIG. 4, an automatic commutation, intended to reduce the loss of power with maintenance of the voltage

parasitic at a low level.

  The block connection scheme according to Figure 1 shows in detail an overview of the brightness control circuit, as described in the main patent application. According to the latter, the block 1 contains the rectifier GL, the variable resistance (or varistor) V for limiting the peaks and the

  pre-self L with a lower inductance than the pre-

  resistance in the case of fast points for the resistance

  this automatically varies Vs. Block 2 includes the

  sistor T 1 metal-oxide field effect and the protective circuit and limitation, not shown, as well as: the

  circuit intended for the formation of the. cutoff side.

  Block 3 includes power supply already

  known from the monostable latch M, the detection of half

  wave of the network and, from it, the excitation of the monostable latch during the zero crossing of the half-wave of the network, and the rocker.monostable itself, whose operating time can be set by means of a potentiometer. In addition, N denotes the neutral, L the line of

  network, Z a Zener diode, ZC a charge diode.

  An exemplary embodiment of the circuit device according to the invention is explained in the following with reference to Figure 2, the elements for the determination of the sidewall slope and the necessary anti-interference are shown in detail. This is obtained in particular thanks to the elements R1 (pre-resistance), C1 (other capacitor),

  R2 (pre-resistance) and C2 (Miller capacitor addition-

  nel), as well as by Miller's ability of the metal-oxide field-effect transistor Tl and to a small extent

by a resistance R3.

  If the monostable rocker is triggered during

  zero crossing, this does not create parasitic voltage.

  If there was a cut inside the half-wave-output A, voltage jump, from H to L-, it would occur, in case

  absence of the elements mentioned above, a strong tendency

parasitic interference.

  In the case of incandescent lamps, the rise of

  the drain voltage follows proportionally

  current conversion of the metal-oxide field effect transistor T1, after discharge of the high-capacitance capacitor Miller capacitor, and the steepest slope of this rise

  tension is reached shortly before reaching the

  maximum. The capacitance of the capacitor C2 put in circuit delays the decrease of the gate voltage by a reaction coupling caused by the variation of the / dt of the

drain voltage.

  It is therefore a Miller circuit with, as a pre-resistor, the resistor R1 in series with respect to the resistor R and with the capacitor C2 as a Miller capacitor. Since, for reasons of energy loss in the transistor T1 metal-oxide effect of

  field, we can not flatten the flank of

  re, a complementary circuit arrangement is necessary

  re. The capacity of the Miller capacitor, located in the

  the metal-oxide field-effect transistor T, deter-

  mine the flank at the beginning of the growth of the drain voltage, while the capacitance of the Miller capacitor C2 determines with the resistors R1 and R2 the bulk of the flank. In this case, C2 is dimensioned so as not to exceed the maximum permissible energy loss for T1. The capacitor C1 exerts an influence, with the resistor R1, and with its discharge time constant of t -3 T,

  on the control voltage in the low values, that is

  that is, shortly before the metal-oxide transistor with

  field does not cut entirely. If we measure the tension

  this-mass (or source-drain), one obtains, according to the way in which the circuit is realized, a plot of tension of

  cut corresponding to the graphical representation

shown in Figure 3.

  Figure 3 shows in detail the different layouts

  of cut-off voltage appearing in different

  tions (ordinates U: voltage, abscissa t: time). The curve "a" shows the shape of the cutoff voltage if there is no intervention on the circuit, the curve "b" shows this pace in the case of the activation of the elements C2, R1 and R2; while, in curve "c", we

  takes into account elements C1, C2 as well as R1 and R2.

  Thanks to the S curve, which is formed during the variation represented in "c", the harmonic waves are reduced to a large extent, which makes it possible to obtain a

49 dB improvement.

  In the case of incandescent lamps, the voltage

  load decreases immediately with the decrease in

  during the break, which equates to an increase in the source-to-mass voltage. It occurs thus, on the

  Miller capacitor C2, a feedback that is from

  so much greater than the increase in source-voltage

  mass is great. The report, which is established between the

  tion of the source-mass voltage and the drop in the source-carrier voltage, results in a certain drain current, which decreases with time. In the case of a block

  connection to the network, there are

  trage, which determine the tension. When switching off the door voltage, the source-mass voltage varies only slowly and is far from reaching its maximum value, whereas the drain current is already

completely cut.

  The small variation of the source-mass voltage is exerted as if there were no Miller capacitor

  in the circuit. The fall of the current is

  faster than in the case of a charge constituted by

  an incandescent lamp. If, in the case of a functioning

  network connection block, the flank is de-

  terminated according to parasitic voltages conditions, it becomes flatter with a charge constituted by an incandescent lamp. Thus, the parasitic voltage decreases, but the loss increases in the transistor T1 metal-oxide to

field effect.

  To avoid this, it is possible to manually reduce R1 or C1 in the case of operation on incandescent lamp, so that the parasitic voltage is kept within limits still allowed, and the loss of power corresponds to that of the operation.

  with network connection blocks. Figure 4 shows

  be an automatic switching to reduce the loss while maintaining the parasitic voltage between permissible limits. When, in the case of operation with mains connection block, the drain current has become zero, the source-to-ground-mass voltage at the highest point of the half-wave of the network is in the event of a break-up of 5 150 V. If therefore, the transistor T4 is connected to 2 150 V by means of its basic control by the resistors R11 and R12 in the collector-emitter path, the time constant Ril.C1 is reduced to R1 x R13 xC1

R1 + R13

  that is to say, in the case of the cut-off in the field of incandescent lamps, the variation of the voltage of the current accelerates when the source-mass voltage starts to exceed 150 V. This reduces the loss of power. In the case of a cut made in the mains connection block, nothing changes in the breaking behavior as long as current flows through the transistor T

metal-oxide field effect.

  The voltage flank, during the current flow, and the current characteristic are exactly the same as what happens without an automatic device

of commutation.

  In the circuit arrangement according to FIG.

  known arrangement R6C3 serves to dampen the peaks of

  which occur, for example in the case of a

  inductive age. The elements or components R4, R5, T2, T3, R7, and, in addition, the reactions of the monostable flip-flop serve to limit the current when the transistor T1 metal-oxide field effect is conducting (connected), in the case a short circuit of the load or discharge

as a result of peak.

  In known manner, a source resistor (R4 + R5) is introduced into the portion traversed by the transistor current, in order to be able to exploit, as a criterion for a setting operation, the voltage caused on said resistor by the current. According to the invention, this resistance is represented by R4 and R5, the value of the resistor R4 being greater than that of the resistor R5. Since each resistor delivers the control voltage for the base emitter zone of a transistor T2 and T3, it follows that, during the growth in time of the current, firstly the monostable flip-flop circuit

  "monoflop" is kept out of circuit at point "A" in step

  from "H" to "L" through T3 and this is

  that it ensures the limitation of the direct current

  on the metal-oxide field effect T1 transistor, for example

  reducing the door voltage via T2.

  The current regulated by the gate U is higher than the normal operating current, and furthermore, this current results directly from the height of the gate control voltage U, the value of the resistance

  RDSoN * of the metal-oxide field effect transistor is rapidly

  increase and, despite the fact that the current is kept constant, the loss of power on T1 will increase. Thanks to the resistance R4, and its value higher than that of R5, it is ensured that, in each case,

  after a short time, the door U of the monosta-

  ble will be switched to zero and, thus, an increase

loss will be prohibited.

  In addition to this, a voltage limitation is

  dispensable when the transistor T1 metal-oxide field effect is blocked. The varistor Vs of block 1 of FIG.

  and the member RC formed by R6 and C3, according to FIG.

  wind to this in a known way. But, in the case of pulses

  fast are due to poies with considerable energy

  these measures are not enough. The capacitor C2 is thus used here to put T1 in circuit. The Zener diode D1 has the function of prohibiting the door voltage U

to exceed the Zener voltage.

  The measurement known per se, of eliminating the overvoltage using the switch of T1 is executed,

  in the case of the circuit of the invention, by means of the conden-

  C2 which, as mentioned above, is also indispensable also for determining the slope of the sidewall.

  * It may be noted that RDSON refers to the internal resistance

  the source-drain path of the

  field-effect oxide, when this transistor is conductive

  whereas, in Figure 1, CO designates in the

block III the control circuit.

Claims (3)

  1. Brightness control circuit for incandescent lamps and mains network switching network component parts, which circuit does not have the necessary suppressors in the triac-type luminous intensity dimmers, but having a field effect transistor and self-locking which, located in the diagonal of a rectifier (GL) bridge, is controlled by a control circuit (CO) so that the transistor (T1) field effect is conductive to the zero crossing of the AC voltage and remains in the conductive state in the control circuit for a settable time on the desired half-wave portion of the grating and then cuts the circuit with a slope of the set cut-off curve suitably before the new zero crossing according to claim 1 of the main patent occurs, circuit characterized in that with the aid of a capacitor of Miller additio nnel (C2) and the corresponding pre-resistance (R1 + R2), as well as another capacitor (C1), which lies between a part of this pre-resistance and the ground, the voltage   of source-mass cutoff adopts a S-shaped pattern pre-   feeling a predetermined slope between the two   curved parts of the S, and in that between the source of the   sistor (T1) metal-oxide field effect and mass, are   arranged in series two resistors (R4 and R5), the resistor   (R5), which is located in parallel with the zone emitting   base transistor (T2) and which determines directly   the maximum current flowing in the transistor (T1) by controlling the gate voltage of the transistor - (T1) metal-oxide effect   field strength, having a lower resistance value than that of the   (R4), on which the basic transmission area of the tran-   sistor (T3), which causes the monostable flip-flop (M) to be cut off and thereby interrupts the current flow in the metal-oxide field effect transistor (T1), and in that the capacitor   Miller serves as a dubbing feature for   the transistor (T1) metal-oxide effect of   field in case of surges caused by spikes.   2. Brightness control circuit according to the   1, characterized in that the capacity of the condensate   (C2) can also be formed by other components   such as resistors with automatic variation   ("varistor"), transil diodes or similar organs.   3. Brightness control circuit according to one of   Claims 1 and 2, characterized in that the pre-resistor   (R1) or the capacitor (C1) can be switched mechanically or automatically, between operation with incandescent lamps and operation with a mains connection block, so that in the case of operation with incandescent lamps, the capacitor (C1), or the pre-resistance (R1), has a lower value and thus a constant shorter break time.