FR2624320A1 - MONOLITHIC REGULATOR OF BATTERY CHARGING VOLTAGE BY AN ALTERNATOR PROTECTED AGAINST POTENTIAL VOLTAGES - Google Patents

Abstract

The invention relates to a monolithic alternator battery charging voltage regulator. The regulator comprises a power stage 2 and a low power stage 3 integrated on the semiconductor substrate by means of isolation boxes constituting diodes or diode junctions capable, in the presence of a parasitic voltage, of forming a diode or a parasitic transistor. The semiconductor substrate comprises at the level of the isolation wells a limiting resistor RL intended to limit the current generated by the parasitic voltages liable to make the SO diodes conductive. Application to monolithic battery charge voltage regulators for motor vehicles.

Description

The present invention relates to a monolithic voltage regulator

  battery charge by an alternator protected against

stray voltages.

  The monolithic battery charge voltage regulators by an alternator currently used in motor vehicle electrical circuits allow regulation of this charging voltage depending on the conditions of use of these vehicles. They usually comprise, as shown in FIG. 1a, a power stage (2) comprising a switching MOS transistor (20), a recirculation diode (DR) being connected in inverse series with the MOS transistor (20). The latter is itself normally connected in series with the inductor (21) of the alternator and the recirculation diode (DR) is connected in parallel to the inductor (21). These regulators furthermore comprise a low power stage (3) comprising at least one detection circuit of the alternator phase presence signal comprising an input circuit (30) of the alternator phase signal. The low power stage corresponds to conventional functions such as alternator phase presence detection, lighting or powering a control lamp or

  analogous and, consequently, will not be described in more detail.

  The alternator 1 is normally connected to a rectifier bridge, the rectifier bridge 10, the power stage 2 and the low power stage 3 being connected in parallel between the positive line of battery connection

  and the connection line relative to the reference voltage or ground.

  This type of monolithic regulator, however, remains very sensitive to residual voltage disturbances likely to propagate on the positive lines and battery connection mass, as well as to the inadvertent risk of connection in reverse polarity battery, during interventions of mechanical repair or service on the vehicle, as well

that will be described below.

  With regard to the disturbances inherent in the operation of the vehicle, mention may be made of the appearance of transient switching voltages of the rectifiers of the rectifying bridge, the use of transducers or effectors of the vehicle such as the buzzer or the starter. One solution for attenuating these transient residual voltages may be to use Zener diodes in the rectifying bridge 10, which clip the aforementioned transient voltages at the Zener voltage.

  at about 26 V to 35 V each.

  In addition, in the case where the battery disconnects from the alternator, according to its state of charge, a case referred to as the English term "load-dump", a load jump inherent in this switching appears,

  the alternator providing a voltage jump of approximately 80 to 100 V.

  The corresponding protection inherent in recovery by the

  rectifier bridge or by Zener diodes of this bridge intervenes then.

  In the case where the alternator does not rotate, the engine of the vehicle being stopped, the overvoltages appearing on the lines or electrical distribution network of the vehicle are clipped by the Zener diodes of the bridge rectifier, the clipping intervening to a maximum level of 70 V

  for a much shorter time.

  The aforementioned monolithic regulators are also particularly

  sensitive to untimely inversions during an intervention for repair or service of the vehicle. In this case, in case of false maneuvering of the intervener, the Zener diodes of the rectifier bridge present an inertia

  relatively important thermal, of the order of 2 seconds.

  The current regulators have a much lower thermal inertia, of the order of one-tenth of a second, and the Zener diodes of the rectifier bridge can not therefore make it possible to provide

regulator protection.

  The present invention aims to overcome the aforementioned drawbacks by the implementation of a monolithic regulator battery charge voltage by an alternator protected against any type of

parasitic surge.

  Another object of the present invention is the implementation of a monolithic battery charge voltage regulator by an alternator protected against unintentional battery connection reversals. Another object of the present invention is the implementation of a monolithic regulator of battery charge voltage by an alternator protected against positive or negative transient residual voltages likely to appear on the positive and negative connection lines.

mass of the battery.

  Another object of the present invention is the implementation of a monolithic battery charge voltage regulator by an alternator comprising a specific protection system against positive or negative transient residual voltages susceptible

  to appear at the input terminals of the low power stage.

  Another object of the present invention is the implementation of a monolithic battery charge voltage regulator by an alternator comprising a protection system specific to the power stage against unintentional inversions of connection polarity.

drums.

  The monolithic battery charge voltage regulator by an alternator object of the invention, wherein the power stages and the low power stage are integrated on the semiconductor substrate, in vertical integration technology, by means of caissons Isolation constituting diodes likely in the presence of a parasitic voltage to form a diode or a parasitic transistor, is remarkable in that the semiconductor substrate comprises at the level of the isolation boxes a limiting resistor for limiting the current generated by said

  parasitic voltages capable of rendering said diodes conductive.

  The invention finds application to the production of monolithic battery charge voltage regulators by an alternator for

  motor vehicles of any type.

  It will be better understood from reading the description and

  observation of the following drawings in which: - Figure I shows the circuit diagram of a regulator according to the invention, - Figures 2a and 2b show in section a particular embodiment of the implementation of a regulator monolithic object of the invention, more particularly in the case of a protection of the low power stage against inadvertent inversion of connection polarity of the battery, - Figures 3a and 3b respectively show a top view and in section, 3, a first and a second nonlimiting advantageous embodiment of the implantation shown in FIGS. 2a and 2b, FIGS. 4a and 4b respectively represent an electrical and sectional equivalent diagram, a schematic layout of a monolithic regulator according to the invention, specially protected at an input of the low power stage thereof, such as the signal input present e * phase, against positive or negative residual voltages, - Figures 5a and 5b respectively represent an equivalent diagram and sectional layout of a particular non-limiting embodiment of the monolithic regulator shown in Figure 4a

and 4b.

  The monolithic battery charge voltage regulator by an alternator object of the invention will first be described in connection with

Figure 1.

  The monolithic battery charging voltage regulator of the invention naturally includes the conventional elements of the regulators used up to now, and in particular, as shown in FIG. 1, a power stage 2 comprising a MOS transistor of switch 20, a recirculation diode DR, connected in inverse series with the switching MOS transistor, this transistor being normally connected in series with the inductor 21 of the alternator I. The low power stage 3 is also of conventional type and comprises at least one detection circuit of the alternator phase presence signal, comprising an input circuit 30 of this signal. As furthermore shown in FIG. 1, the monolithic alternator battery charge voltage regulator, which is the subject of the invention, has, in order to protect the power stage from unwanted inversions of polarity of connection of the battery, a limiting resistor RL, which is connected in series with the diode of

recirculation DR.

  Indeed, the switching MOS transistor 20 comprises a parasitic diode denoted DP between source and drain. Normally reverse biased, this diode becomes conductive, when the connection of the battery is inverted inadvertently, and this diode is short-circuited on the recirculation diode DR. The limiting resistor RL allows

limit this short circuit.

  According to an advantageous characteristic of the embodiment of FIG. 1, the limiting resistor RL is carried out on the cathode side or side

  anode of the recirculating diode DR.

  This resistance RL can advantageously be produced in the epitaxy or epitaxial zone of the semiconductor constituting the diode

DR recirculation.

  Preferably, the limiting resistor RL is a low value resistor, less than one ohm. This limiting resistance RL is

  calculated so that the short-circuit current does not destroy the semiconductor

  neither the links. This maximum short circuit current is of the order of 13 amperes, and for a maximum voltage of 3.2 volts across the regulator, the minimum value of the limiting resistor RL may be

taken equal to 0.15 ohm.

  In normal operation of the regulator, that is to say in the absence of inadvertent battery connection polarity reversal, the limiting resistor RL absorbs maximum power, for an estimated current of 3 amperes with a duty cycle of 50 %, substantially equal to 0.67 Watt. This value is perfectly acceptable, given that the switching MOS transistor 20 goes from a power of 3 Watts in operation in the field of the inductor to

  a power of 0.37 Watt for a control duty cycle of 50%.

  The values indicated above correspond to a regulator delivering a current of 6 amperes when this one operates in full field with a voltage of waste of 0.5 volts between the source and the drain of the

MOS transistor 20.

  In the event of a short-circuit by inadvertent reversal of the polarity of connection of the battery, the power consumed in the regulator is important and of the order of 42 Watts. However, the rectifier bridge 10 is subjected to a power of the order of 2000 Watts during the same period.

  time. Under these conditions, the rectifier bridge is destroyed first.

  As previously indicated, the limiting resistor RL is connected in series with the recirculating diode DR, anode side or cathode side thereof. Thus, the limiting resistor RL does not intervene when the switching MOS transistor 20 is conducting, this having the effect of not increasing the drop voltage of the switching transistor and of not reducing the magnetizing field applied to

the inductor 21 of the alternator 1.

  Preferably, the value of the limiting resistor RL is determined so that the total power absorbed by the regulator object of the invention is always less than or equal to the power absorbed by this regulator, when operating in full field power supply of the inductor 21, that is to say when the recirculation diode DR and the resistance

  RL are not solicited and do not absorb power.

  The current flowing through the regulator object of the invention when the connection of the battery is reversed inadvertently is a function of the voltage across the bridge rectifier 10. For a current of 600 amps from the battery, each branch of the bridge is crossed by a current of 200 amps, which corresponds to a maximum value of 1.6 volts in each diode. These values are indicated for an embodiment corresponding to MOTOROLA 25A diodes sold under the MR2500 type. Two diodes in series are therefore subject to

  voltage of 3.2 volts, value used for the calculation of resistance RL.

  The power of 42 Watts absorbed by the regulator can not be

  accepted by the regulator only for a time of the order of I second.

  The regulator object of the invention is thus protected during the time of a short-circuit or flash between the rectifier bridge and the battery. If the polarity inversion of the battery connection is prolonged, the object regulator

  of the invention may be destroyed before the rectifier bridge 10.

  Of course, in order for the rectifier bridge 10 to be destroyed before the regulator, it is possible to increase the limiting resistance RL by various means such as decreasing the surface area of the recirculating diode DR, increasing the resistance of the epitaxial phase. this diode by

example.

  In the latter case, the magnetizing pulse is not reduced in the inductor 21, since these modifications have no influence on the dynamic resistance of the power MOS transistor 20. By cons, the total power absorbed by the regulator in operation normal

significantly increases.

  For example, if the maximum value of the limiting resistor RL is taken equal to 0.3 ohm at 25 C, the inverse current IiNV becomes equal to 7.5 amps and the power absorbed by the regulator in

  Reverse polarity case of battery connection is 24 Watts.

  In this case, the rectifier bridge is destroyed first and the resulting increase in power consumption is only 0.5 Watt. The power absorbed by the regulator has a peak at 3.5 watts for an excitation current of 5 amperes. When the alternator and the inductor 21 are powered in the field, the power consumed drops to -3 Watts. Another particularly advantageous embodiment of the monolithic battery charge voltage regulator by an alternator which is the subject of the invention will be given in conjunction with FIGS. 2a and 2b in the case where the regulator of the invention is protected at the level of FIG. low power stage of it against the untimely inversions of

  polarity of battery connection.

  As shown in FIGS. 2a and 2b, the limiting resistor RL is connected so as to connect the isolation box S0 to the potential

reference of the regulator.

  As has been represented in FIGS. 2a and 2b, the substrate denoted SU is made by a substrate of semiconductor material, for example of the N type. The limiting resistor RL is integrated in the semiconductor and in the SU substrate and constituted by a Pbase-type diffusion located in an N-type epitaxial EP layer, as shown in Figure 2a and Figure 2b. The EP epitaxial layer or layers mentioned above constitute the low power circuits of the regulator that is the subject of the invention and are placed in P-type isolation chambers constituting SO diodes, as represented in FIGS. 2a and 2b. The P-type isolation boxes are formed by diffusion in the substrate SU and are normally connected to the ground of the device, whereas the positive terminal of the battery is connected to the N-type semiconductor material, silicon for example, constituted by the SU substrate when it is a monolithic regulator constituted

  according to a vertical integration technology.

  As shown in FIG. 2a, when the battery is connected normally, the P-N junction formed by the zone of material

  P-type semiconductor of the box and the zone of semiconductor material

  The N-type of the substrate SU is reverse biased and the diode S0 thus formed is polarized in the off direction, the current from the positive terminal of the battery being thus unable to pass through the boxes.

isolation.

  On the other hand, when the battery is connected in reverse, on inadvertent polarity reversal of the connection of the battery, as represented in FIG. 2b, the aforementioned PN junction constituting the diode S0 is forward-biased, which leads in the regulators to classical type, the destruction by short circuit of the semiconductor in the absence

protection.

  The limiting resistor RL shown in FIGS. 2a and 2b makes it possible to support the reverse battery voltage and thus prevents the destruction of the semiconductor. However, as shown in FIG. 2b, there is formation at the zone where the distance between the wall of the junction between the diffused P-type material and the N-type material of the substrate and the junction between the diffused-type material P and the material and the N-type material of the epitaxial zone EP of a parasitic transistor denoted tp, NPN-type parasitic transistor. This parasitic transistor tp injects a current into the epitaxial zone EP, which adds to the current

  circulating in the limiting resistor RL.

  Two particularly advantageous embodiments of the limiting resistor RL making it possible to reduce or eliminate the effect of the above-mentioned parasitic transistor tp will now be described respectively in FIG.

  connection with Figure 3a and Figure 3b.

  In FIG. 3a, there is shown in plan view the zone of

  diffusion on the surface of the substrate SU of the limiting resistor RL.

  According to the above-mentioned figure, the effect of the parasitic transistor tp consisting of the semiconductor material N of the substrate SU, the semiconductor material P of the isolation chamber SO, the semiconductor material N of the epitaxy EP during the battery polarity reversal can be substantially reduced by providing an isolation box S0 such that it has an elongated shape, the limiting resistor RL being straight and extending substantially along the length L of the housing SO isolation considered. This configuration makes it possible to increase the resistance of the epitaxy EP and the resistance of the base of the parasitic transistor tp. It will be understood in these conditions that the effect of the parasitic transistor tp

is thus significantly reduced.

  In order to eliminate the most active part of the parasitic transistor tp, and transform it into a diode, as shown in FIG. 3b, this figure corresponding to a view of a modification of FIG. a cut plane AA, the epitaxial zone EP comprises a deep diffusion zone, denoted ZDP, strongly doped and whose constituent semiconductor material is of the same nature as the epitaxial zone EP. Thus, since the EP epitaxial zone is made of N-type semi-conductor material, the ZDP deep diffusion zone known as

  Anglo-Saxon word "SINKER" is made of a semi-

  N + type conductor. The ZDP deep diffusion zone is located between the limiting resistor RL and the isolation chamber SO. The diffusion zone Pbase constituting the limiting resistor RL and the same limiting resistor RL is superficially connected to the semiconductor zone P constituting the isolation chamber SO via a metallization ME. This embodiment is particularly advantageous because it makes it possible to short-circuit the junction

  base-collector of the parasitic transistor tp.

  A more particularly advantageous embodiment of a monolithic battery charge voltage regulator by an alternator, according to the subject of the present invention, in the case where it is protected at the level of the bass stage. power 3 and in particular an input thereof, such as in particular the input 30 of the phase presence detection signal against residual overvoltages,

  will now be described in connection with Figures 4a and 4b.

  As shown in FIGS. 4a and 4b, each low power stage comprises, at each input of the phase presence detection signal, for example, a residual voltage clipping circuit consisting of a Zener diode ZI, Z2, connected in series with a diode D1, D2, respectively. As can be understood from the examination of FIG. 4a, the assembly formed by the Zener diode Z1 and the diode DI makes it possible to ensure the clipping of the residual positive surge, whereas the assembly constituted by the Zener diode Z2 and the diode D2, allows

  to ensure the clipping of negative residual surge.

  The set of Zener diodes Z1, Z2 and diodes DI, D2, allows the signal to be clipped to a value close to 8 volts above the voltage

  positive of the battery, and 8 volts below the potential of mass.

  As has been represented in FIGS. 4a and 4b, each set consisting of a Zener diode Z1, Z2 and a diode D1, D2 is placed in an elementary isolation box C1, C2. The elementary isolation caissons C1, C2 are separated from the isolation caissons containing the low-power circuits of the regulator, the assembly consisting of the low-power circuits of the regulator, circuits of conventional type and the clipping circuits constituted by by Zener diodes Z1, Z2 and diodes D1 and D2 being placed in an isolation chamber SO constituting an island isolation box. Thus, as has been shown in a non-limiting manner in FIG. 4b, in vertical integration technology, the substrate SU consisting of an N-type semiconductor material comprises an island isolation box constituted by a semi-conducting material. P-type driver, constituting a diode junction denoted S0, zones of N-type semiconductor material being diffused or reported by epitaxy to constitute the elementary isolation caissons C1 and C2. In the zones of N-type semiconductor material constituting isolation caissons CI and C2, the diodes D1 and D2, and Zener diodes Z1 and Z2, are then diffused respectively. The diodes D1 and D2 are constituted by the diffusion of zones of P-type material, whereas Zener diodes Z1 and Z2 are conventionally constituted by the diffusion of three zones of N-type semiconductor material. , constituting the association of a Zener diode and a transistor equivalent to a Zener diode. The embodiment of these zener diodes ZI, Z2 will not be described in more detail because it corresponds to a perfectly conventional embodiment in integrated circuit technology. This embodiment has the advantage, given the presence of the transistor associated with each Zener diode, to reduce the influence of the series resistance of the aforementioned Zener diode. The set constituted by the Zener diode with which is associated a

  remaining transistor equivalent to a Zener diode.

  The phase detection signal applied to one of the inputs 30 of a monolithic regulator according to the invention has an amplitude which exceeds the battery voltage applied across the subregulator. This overshoot originates from the threshold voltages of the rectifying diode rectifier diodes 10. As a first approximation, the phase detection signal exceeds the positive battery voltage by a value close to 1 volt and the mass potential of a value close to - I volt. In fact, low energy voltage peaks may be present at the input of the phase detection signal 30, since the diodes of the rectifier bridge 10 have a non-negligible response time and they are not placed directly on the detector. chip of semiconductor material of the regulator. These voltage peaks can tire or destroy the regulator if they exceed

  the voltage values admitted by semiconductor technology.

  The clipping circuit as shown in FIG. 4a and in FIG. 4b allows clipping of the phase detection signal at a voltage close to 8 volts above the positive battery voltage, and 8 volts below the potential. massive. This clipping is done at the level of the

  silicon chip of the monolithic regulator object of the invention.

  Thus, the Zener diode Zi and the diode Dl perform clipping at + 8 volts with respect to the positive potential of the battery applied to one of the terminals of the regulator. Zener diode Z2 and diode D2 perform clipping at -8 volts with respect to the ground potential applied to the other terminal of the controller. The clipping circuit as shown in FIG. 4b is formed in a bipolar part of the integrated circuit, the diodes C1 and C2 representing the elementary isolation boxes of this protection circuit. These isolation caissons do not disturb the circuits of

  the low power stage of the integrated circuit, since, as described above,

  they are separated from the isolation boxes containing the aforementioned circuits. As has also been shown in FIG. 4b, the IC and C2 isolation boxes include a limiting resistor RL in order to protect against any inadvertent risk of a change in the polarity of the battery connection. Of course, in FIG. 4b, the limiting resistor RL is represented in the form of a discrete element, but this is done according to the described embodiment.

  previously in the description by diffusion of a Pbase zone in the

  N-type semiconductor material, according to Figures 3a and 3b. The clipping circuit as shown in FIGS. 4a and 4b can non-limitatively be provided to ensure protection of an input of the low power stage of a regulator according to the subject of the invention, other than the input 30 of the alternator phase detection signal, and for example a

  input such as the input connected to the control lamp.

  Another embodiment of a monolithic battery charge voltage regulator by an alternator according to the object of the invention protected at its low power stage against residual and low energy overvoltages occurring on the positive terminals of the battery and the ground as well as on the input terminal 30 of the alternator phase presence signal, a further embodiment

  advantageous, will be given in conjunction with Figures 5a and 5b.

  This embodiment makes it possible to protect the junctions constituted by vertical integration technology, by the bottom of the isolation boxes and the SU substrate connected to the positive pole of the battery. These junctions are denoted S1 and S2 in FIG. 5b and of course in FIG. A and constitute isolation caissons of islands of elementary isolation caissons. As will be seen in FIG. 5a in particular, in the case where the input terminal is non-limitingly constituted by the input terminal 30 of the phase presence signal, the Zener diode Z2 and the diode D2 are represented. in a manner comparable to the embodiment of FIG. 4a, whereas the Zener diode ZI and the diode D1 of the same

  Fig. 4a have been modified to obtain improved operation.

  As can be seen in FIG. 5a, the Zener diode Z1 is constituted by a plurality of equivalent Zener diodes, denoted Z11, Z12, Z13, Z14, Z15, which are connected in series and intended to form a circuit for clipping ZI, D1, positive residual parasitic voltage, similar to the operation of the embodiment of Figure 4a. Each Zener diode Z11, Z12, Z13, Z14, Z15 is formed in a corresponding elementary isolation well, denoted Cl1,

C12, C13, C14, C15.

  Thus, each junction constituting isolation caisson SI island,

  S2 is provided with a corresponding limiting resistor RL1, RL2.

  FIG. 5b shows the layout diagram of the different zener diodes Z11, Z12, Z15, their respective isolation chamber C1, C12, C15 consisting of a zone of semiconductor material of the N type diffused or epitaxially grown in the P-type semiconductor material constituting in the substrate SU in N-type semiconductor material the

  constituent junction of the isolation chamber S1, respectively S2.

  As will also be noted in FIG. 5b, the limiting resistor RLI, RL2 is constituted by a superficial Pbase diffusion connected to the reference voltage and formed in an epitaxial N zone constituting an elementary isolation box of the corresponding limiting resistor. each elementary casing being denoted C16, C17. The clipping circuit as shown in Figure 5a and Figure 5b is designed to be integrated on the substrate of the semiconductor material of the monolithic regulator object of the invention. However, it can not absorb the high energy surges caused by the phenomenon of battery disconnection or "lload-dump" and capacitive discharges if the elements that compose it are not highly dimensioned as in the case of an integrated circuit. The operation of the clipping circuit represented in FIG. 4a and in FIG. 4b is therefore linked to the use of a bridge

  rectifier 10 equipped with clipping diodes such as Zener diodes.

  Low energy voltage peaks can be applied to terminals of the regulator, according to the invention, even if the rectifier bridge is equipped with clipping diodes which go into avalanche mode for a low reverse voltage of 20 to 30 volts. These peaks are due to the fact that the clipping diodes can have a non-negligible response time and they are not directly placed on the semiconductor material chip of the regulator. These voltage peaks can cause fatigue or destruction of the regulator if it exceeds the voltage values permitted by semiconductor technology. The so-called vertical integration technology makes it possible to create the separate isolation chambers, Cl1, C12, C15, C16 which can contain the bipolar elements necessary for the realization of the clipping circuit such as

  as shown in FIGS. 5a and 5b.

  The negative residual voltage peaks between the positive terminal of the battery and the ground can be eliminated by diodes already present in the power stage, such as the recirculation diode RD in series with the parasitic diode DP of the switching MOS transistor.

supplying the inductor 21.

  However, the negative residual voltage peaks can reach several volts and it is necessary to protect the junctions connected between the positive terminal of the battery and the ground, these junctions

  normally being blocked when the battery voltage is not reversed.

  This protection is of course carried out, as described above,

  through the limiting resistors RL1 and RL2.

  The constituent diode junctions of the elementary isolation caissons C1, C12, C13, C14, C15 represent the internal parts of a group of caissons having common insulating walls. These caisson groups constitute an island, which is protected by the island isolating box SI or S2, the diode junction C2 represents the internal part of an elementary isolation box completely separated from the preceding group and constituting a different island. and protected by an island isolation box

S2 different.

  In the case where the diode junction C2 becomes conducting, the parasitic transistor formed by the diode junction S2 and the diode junction C2, parasitic transistor noted Tp in FIG. 5b, injects a current into the substrate SU and not into the boxes Cl1. at C15 or C16. Conversely, if i: 624320 one of the junctions CII to C15 becomes busy, the parasitic transistors that it forms with the junction of the island isolation box S1 injects

  currents in the substrate SU and not in the box C2.

  This possibility of producing groups of separate island boxes allows the application of negative potential in a group of isolation boxes, without disturbing the circuits located in another group of caisson or island of the same monolithic circuit. In this context, a group of isolation caissons forming an island can be defined by the internal parts of the caissons, the bottom of the group of caissons constituting the diode junction of the island isolation chamber SI or 52 and a connection with the earth.

  of the device via a limiting resistor RL1 or RL2.

  This property is used to clip the negative peaks appearing on the input terminal of the phase presence signal 30. The clipping device Z2, D2, closes the negative peaks present on the input terminal of the phase presence signal at a value of - 8 volts. The potential of the cathode of the diode D2 is close to -0.8 volts. The diode of the elementary isolation box C2 is therefore polarized in the direct direction and the parasitic transitor formed by the diode junction of the elementary isolation box C2 and the diode junction of the island isolation box S2 injects a current into the substrate SU and not in neighboring boxes

  since the diodes C2 and S2 form a box separated from the others.

  Positive residual peaks or voltages are clipped by the series clipping circuit ZII, ZI2, Z13 to Z15 and the clipping voltage is

about 37 volts.

  Finally, as will be seen in FIG. 5a, the corresponding input terminal, the input terminal 30 of the phase detection signal for example, or the positive terminal of the battery is connected to the clipping circuit ZII to Z15. positive parasitic residual voltages, by means of switching diodes denoted DII and D12. These diodes are not

  shown in the layout diagram of Figure 5b.

  A monolithic battery charge voltage regulator has thus been described by an alternator protected against particularly high parasitic voltages. Indeed, the monolithic battery charge voltage regulator by an alternator object of the invention in view of these embodiments allows to protect both against or inadvertent reversals of battery connection polarity, or against positive residual or negative overvoltages present in operation of the alternator and the engine of the vehicle or, on the contrary, when the latter are at a standstill. Of course, the realization of all the aforementioned protections makes it possible to obtain a monolithic battery charge voltage regulator by an alternator, highly efficient insofar as it appears protected against

any type of parasitic surge.

Claims (15)

  A monolithic battery charge voltage regulator by an alternator (1), comprising a power stage (2) comprising a switching MOS transistor (20), a recirculation diode (RD) being connected in inverse series with said transistor MOS switching, said MOS transistor being normally connected in series with the inductor (21) of the alternator and the recirculation diode (DR) being normally connected in parallel with said inductor (21), said regulator further comprising a stage low-power device (3) comprising at least one detection circuit of the alternator phase presence signal, comprising an input circuit (30) of the alternator phase signal, the stages (30) of the alternator phase signal, the power stages (2 ) and low power stage (3) being integrated on the semiconductor substrate (SU) in vertical integration technology by means of isolation chambers constituting diodes (SO) susceptible in the presence of a parasitic voltage forming a diode or a parasitic transistor (Tp), characterized in that said semiconductor substrate (SU) comprises at said isolation boxes a limiting resistor (RL) for limiting the current generated by said parasitic voltages likely to render the said conducting diodes (SO).   A monolithic battery charge voltage regulator by an alternator according to claim 1, characterized in that for the purpose of protecting said power stage (2) against unintentional inversions of battery connection polarity, said switching MOS transistor (20) having a parasitic diode (DP) between source and drain, normally reverse biased, said limiting resistor (RL) is connected in series   with the recirculation diode (DR).   A monolithic alternator battery charge voltage regulator according to claim 2, characterized in that said limiting resistor (RL) is formed on the cathode or anode side of the recirculation diode (DR).   A monolithic battery charge voltage regulator by an alternator according to claim 3, characterized in that said limiting resistor (RL) is a low value resistor, less than 1 ohm. 5. Monolithic battery charge voltage regulator by   an alternator according to one of claims I to 4, characterized in that   said limiting resistor (RL) is produced by diffusion in epitaxy   (EP) of the semiconductor constituting the recirculation diode (DR).   A monolithic battery charge voltage regulator with an alternator according to claim 1, characterized in that for the purpose of protecting said low power stage against unintentional reversals of branching polarity of said limiting resistor (RL) is connected in such a way connect the isolation box (SO) to the potential of regulator reference.   7. Monolithic battery charge voltage regulator by   an alternator according to one of claims 1 to 6, characterized in that   said limiting resistor (RL) is integrated in the semiconductor and   constituted by a base diffusion P lying in an epitaxial layer (EP).   Monolithic battery charge voltage regulator by an alternator according to claim 7, characterized in that, in order to reduce the effect of the parasitic transistor (tp) constituted by the semiconductor material (N) of the substrate (SU ), the semiconductor material (P) of the isolation box (SO), the semiconductor material (N) of the epitaxy (EP), during the inversion of the connection polarity of the battery, said box ( SO) has an elongated shape and the limiting resistor (RL) is straight and extends substantially along the length (L) of the isolation chamber considered in order to increase the resistance of the epitaxy (EP) and the resistance   from the base of the parasitic transistor (tp).   9. Monolithic battery charge voltage regulator by an alternator according to claim 7, characterized in that, in order to suppress the most active part of the parasitic transistor (tp) and transform it into a diode, said epitaxy (EP) has a strongly doped deep diffusion zone (ZDP) of conduction type (N +) of the same nature as the epitaxial zone (N), said deep diffusion being situated between said limiting resistor (RL) and the isolating (SO) said base diffusion area P constituting said limiting resistor (RL) being superficially connected to the P-type semiconductor zone constituting said isolation box (SO) via a metallization (ME), the junction base collector of the parasitic transistor (tp) thus being short-circuited.   A monolithic alternator battery charge voltage regulator according to claim 1, characterized in that for the purpose of protecting an input of the low power stage (3), such as in particular the input (30) of the phase presence detection signal against residual overvoltages, each low power stage comprises at each input of the phase presence detection signal a capping circuit consisting of a Zener diode (ZI, Z2) connected in series with a diode (DI, D2) respectively, each set consisting of a Zener diode (ZI, Z2) and a diode (D1, D2) being placed in an isolation box (CI, C2), said isolation boxes (C1, C2 ) being separated from the isolation boxes containing the low power regulator circuits. 11. Monolithic battery charge voltage regulator by   an alternator according to claims 1 and 10, characterized in that   said isolation boxes (C1, C2) have a limiting resistor (RL) to provide protection against any inadvertent risk of   change of polarity of connection of the battery.   Monolithic battery charge voltage regulator by an alternator according to claim 10 or 11, characterized in that to protect the junctions, constituted by vertical integration technology by the bottom of the isolation boxes and the connected substrate. at the positive pole of the battery and constituting diodes (S1, S2), said junctions constituting cubic isolation caissons of elementary isolation caissons (CI 1, C12, C13, C14, C15) of Zener diodes (Zll, Z12, Z13, Z14, ZIS) connected in series and intended to constitute a circuit for clipping (Z1, DI) positive residual parasitic voltages, each junction constituting (S1, 52) island isolation box is provided with a limiting resistance (RL1, RL2). 13. Monolithic battery charge voltage regulator by an alternator according to claim 12, characterized in that said limiting resistor (RLI) (RL2) is constituted by a superficial base diffusion P connected to the reference voltage in an N epitaxial zone.   elementary isolation caisson (C16, C17).   14. Monolithic battery charge voltage regulator by   an alternator according to one of claims 11 to 13, characterized in that   the residual negative parasitic voltage clipping circuit is constituted by a Zener diode (Z2) connected in series with a diode (D2), said   diodes being arranged in their island isolation box (S2).   15. Monolithic battery charge voltage regulator by   an alternator according to one of claims 12 to 14, characterized in that   the input terminal of the phase detection signal or the positive terminal of the battery is connected to the said clipping circuit (Zll to Z15) positive residual stray voltages via switching diodes DII and D12.