EP3827519A1

EP3827519A1 - Electronic circuit and method for operating same

Info

Publication number: EP3827519A1
Application number: EP19734385.8A
Authority: EP
Inventors: Dirk Schuster; Paul Mehringer
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2018-07-23
Filing date: 2019-06-27
Publication date: 2021-06-02
Also published as: DE102018212197A1; WO2020020567A1

Abstract

The invention relates to an electronic circuit having a controllable switch, particularly a semiconductor switch, and a control device for activating the semiconductor switch, wherein the control device is designed to activate the semiconductor switch in a first time span of a predefinable, preferably negative, half-wave of a periodic voltage which can be applied to a load path of the semiconductor switch and to deactivate the semiconductor switch in a second time span following on from the first time span if the voltage being applied to the load path exceeds a predefinable first threshold value, wherein the control device is designed to determine a first variable which characterizes a current flowing through the load path during the predefinable half-wave and/or to determine a second variable which characterizes a frequency of the periodic voltage, and wherein the control device is designed to determine the predefinable first threshold value as a function of the first variable and/or of the second variable.

Description

description

title

Electronic circuitry and operating procedures therefor

State of the art

The disclosure relates to an electronic circuit with a controllable switch, in particular a semiconductor switch, and a control device for controlling the controllable switch.

The disclosure further relates to a method for operating such an electronic circuit.

A circuit of the type mentioned is known from DE 10 2008 042 352 A1. In the known circuit, a switch-on time and / or switch-off time for the controllable switch is calculated using a map or a mathematical function. This requires a comparatively large effort to control the switch and a corresponding electrical energy consumption.

Disclosure of the invention

An object of the present invention is to improve a circuit of the type mentioned at the outset in such a way that it has greater utility and the above-mentioned disadvantages of the prior art are reduced or avoided.

Preferred embodiments relate to an electronic circuit with a controllable switch, in particular a semiconductor switch, and a control device for controlling the semiconductor switch, the

Control device is designed to switch the semiconductor switch in a first To activate the time range of a predefinable, preferably negative, half-wave of a periodic electrical voltage that can be applied to a load path of the semiconductor switch and to deactivate the semiconductor switch in a second time range that follows the first time range if the voltage applied to the load path exceeds a predefinable first threshold value, wherein the control device is designed to determine a first variable that characterizes a current flowing through the load path during the predeterminable half-wave, and / or to determine a second variable that characterizes a frequency of the periodic electrical voltage, and the control device is designed to do this to determine the predefinable first threshold value as a function of the first variable and / or the second variable. This is particularly in the case of fluctuations in the

Load path of the flowing current and / or the frequency of the periodic electrical voltage ensures a reliable deactivation of the semiconductor switch, in particular as shortly as possible before a zero crossing of the periodic electrical voltage following the half-wave under consideration, which improves the efficiency e.g. increases when using the electronic circuit as an active rectifier. In a particularly preferred manner, the determination of the predefinable first threshold value as a function of the first variable and / or the second variable can also modify or adapt an already determined or

existing first threshold.

In further preferred embodiments in which a negative

Half wave is considered, the exceeding of the first predeterminable threshold value by the voltage present on the load path means that the instantaneous value of the voltage present on the load path becomes greater than the predefinable threshold value.

In further preferred embodiments in which a positive

Half wave is considered, the exceeding of the first predefinable threshold value by the voltage applied to the load path means that the instantaneous value of the voltage applied to the load path becomes smaller than the predefinable threshold value.

In further preferred embodiments, it is possible for the predefinable first threshold value to be dependent on the first variable, but not in Dependency of the second variable is determined. In further preferred embodiments, it is possible for the predeterminable first threshold value to be determined as a function of the second variable, but not as a function of the first variable. In further particularly preferred embodiments, it is provided that the predeterminable first threshold value is determined as a function of both the first variable and the second variable.

In further preferred embodiments, it is provided that the first variable characterizes a maximum amount of the current flowing through the load path during the predeterminable half-wave.

In further preferred embodiments it is provided that the

Control device is designed to determine the first variable as a function of the voltage applied to the load path, in particular the control device is designed to determine the first variable as a function of the voltage applied to the load path and at least one parameter of the semiconductor switch, in particular as a function of a switch-on resistance of the semiconductor switch.

In further preferred embodiments it is provided that the

Control device is designed to the in the first time range

To activate semiconductor switches as a function of the voltage applied to the load path, and in particular to only deactivate a deactivation of the semiconductor switch depending on the voltage applied to the load path in a second time range following the first time range. As a result, the semiconductor switch is reliably activated in the first time range (for example, when a predeterminable value is fallen short of)

Voltage value on the load path in the first time range, in the case of a negative half-wave of the voltage under consideration), and at the same time, by releasing a voltage-dependent deactivation, it is only in the second time range following the first time range that an undesired (in particular too early, based on the half-wave under consideration), deactivation of the semiconductor switch takes place, as can occur, for example, due to fluctuations in the voltage on the load path (for example due to the activation of the semiconductor switch). In further preferred embodiments it is provided that the

Control device is designed to determine a third variable, which characterizes a duration of the predeterminable half-wave, and as a function of the third variable, to determine a first point in time, which characterizes a transition from the first time range to the second time range.

In further preferred embodiments it is provided that the

Control device is designed to determine a third variable, which characterizes a duration of the predeterminable half-wave, and to determine the second variable as a function of the third variable.

In further preferred embodiments it is provided that the

Control device determines both the first point in time and the second variable as a function of the third variable.

In further preferred embodiments it is provided that the

Semiconductor switch and the control device are arranged on the same semiconductor substrate, which results in a particularly small configuration.

Further preferred embodiments relate to an active one

Rectifier circuit with at least one circuit according to the embodiments described above.

Further preferred embodiments relate to a method for operating an electronic circuit with a controllable switch, in particular a semiconductor switch, and a control device for controlling the semiconductor switch, the control device being designed to switch the semiconductor switch in a first time range of a predefinable, preferably negative, half-wave to activate a periodic electrical voltage that can be applied to a load path of the semiconductor switch and the

To deactivate semiconductor switches in a second time range following the first time range when the voltage applied to the load path exceeds a predefinable first threshold value, the control device determining a first variable that characterizes a current flowing through the load path during the predefinable half-wave, and / or one second variable determines a frequency of the periodic electrical

Characterizes voltage, and wherein the control device determines the predeterminable first threshold value as a function of the first variable and / or the second variable.

In further preferred embodiments it is provided that the

Control device determines the first variable and the second variable and determines the first threshold value as a function of the first variable and the second variable.

Further preferred embodiments are the subject of the dependent claims.

Further preferred embodiments relate to a use of the method according to the embodiments for operating an active rectifier circuit, the active rectifier circuit in particular having at least one circuit according to the embodiments.

Further features, possible applications and advantages of the invention result from the following description of exemplary embodiments of the invention, which are shown in the figures of the drawing. All of the features described or illustrated form the subject matter of the invention, independently or in any combination

Summary in the claims or their relationship and regardless of their wording or representation in the description or in the drawing.

The drawing shows:

FIG. 1 schematically shows a simplified block diagram of an electronic circuit according to one embodiment,

FIG. 2A schematically shows a simplified flow diagram of a method according to an embodiment,

FIG. 2B schematically shows a simplified flow diagram of a method according to an embodiment, FIG. 2C shows a simplified flowchart of a method according to an embodiment,

FIG. 3 schematically shows a simplified circuit diagram of an electronic circuit according to a further embodiment,

FIG. 4 shows schematically a time profile of operating variables according to one embodiment,

FIG. 4B shows a detailed view of the time profile from FIG. 4A,

FIG. 5 schematically shows a simplified circuit diagram of an electronic circuit according to a further embodiment,

Figure 6 is a simplified circuit diagram of an electronic circuit

according to a further embodiment,

Figure 7 schematically shows a simplified block diagram of another

embodiment,

Figure 8 schematically shows a time course of operating variables

another embodiment,

FIG. 9 schematically shows a simplified block diagram according to a further embodiment,

10A, 10B each schematically show a simplified flow diagram of a

Method according to a further embodiment,

Figures 11A, 11 B each schematically show operating sizes of other

Embodiments,

FIG. 12 shows schematically operating variables of further embodiments, and

FIG. 13 schematically shows operating variables of further embodiments. FIG. 1 schematically shows a simplified block diagram of an electronic circuit 100 according to an embodiment. The circuit 100 has a controllable switch 110, which in the present case is designed as a semiconductor switch, for example as a MOSFET (metal oxide semiconductor field effect transistor) of the n-type. In other embodiments, the controllable switch 110 can also be designed as a different type of MOSFET (eg p-type) or as a bipolar transistor or IGBT or the like. The semiconductor switch 110 has a source connection (“source electrode”) S, which is connected to a first electrical reference potential BP1, for example the ground potential. Furthermore, the semiconductor switch 110 has a drain connection (“drain electrode”) D, which is connected to a second electrical reference potential BP2. The second reference potential BP2 can, for example, correspond to a periodic voltage, in particular a phase voltage K1 (see FIG. 4A) of a generator 400 (see FIG. 9). The semiconductor switch 110 also has a gate connection (“gate electrode”) G, on which a control device 120 assigned to the semiconductor switch 110 can act in order to operate the

To control semiconductor switch 110. For example, the control device 120 can apply a predeterminable potential to the gate connection G in order to convert the load path 112 of the semiconductor switch 110, which is designed here as a drain-source path, into an electrically conductive state (“low-resistance”) or a blocking state (“high-resistance”). ) or, if necessary, to put them in an intermediate state between the conductive state and the blocking state. In the conductive state, the

Semiconductor switch 110 or its load path 112 a comparatively low electrical resistance ("on resistance", "Ros. _On ") of

For example, 0.1 ohm or less, so that a load current L can flow across the load path 112, and in the blocking state the

Load path 112 has a comparatively large electrical resistance.

In preferred embodiments, the control device 120 is designed to activate the semiconductor switch 110 in a first time range of a predeterminable, preferably negative, half-wave of a periodic electrical voltage UL that can be applied to a load path 112 of the semiconductor switch 110, and the semiconductor switch 110 in a period following the first time range to deactivate the second time range (in the same half-wave of the voltage) when the voltage UL present on the load path 112 is one predeterminable first threshold value, wherein the control device 120 is designed to determine a first variable G1, the current L flowing through the load path 112 during the predeterminable half-wave

characterized, and / or to determine a second variable G2, which characterizes a frequency of the periodic electrical voltage UL, and wherein the control device 120 is designed to determine the predefinable first threshold value as a function of the first variable G1 and / or the second variable G2 , This is particularly in the case of fluctuations in the

Load path 112 flowing current L and / or the frequency of the periodic electrical voltage UL, a reliable deactivation of the semiconductor switch 110, in particular as shortly as possible before a zero crossing of the periodic electrical voltage following the half-wave under consideration, which ensures the efficiency e.g. increases when the electronic circuit 100 is used as an active rectifier.

In further preferred embodiments, it is possible that the predeterminable first threshold value, which can be used for deactivating the semiconductor switch 110, in particular at the end of a considered (presently negative) half-wave of the voltage on the load path 112, depending on the first variable G1, but not in Dependency of the second variable G2 is determined. In further preferred embodiments, it is possible that the predefinable first threshold value as a function of the second variable G2, but not in

Dependency of the first variable G1 is determined. In further particularly preferred embodiments, it is provided that the predefinable first threshold value is determined as a function of both the first variable G1 and the second variable G2.

FIG. 2A schematically shows a simplified flow diagram of a method according to an embodiment. In a first step 200, the

Control device 120 (FIG. 1) the first variable G1 and the second variable G2. In a second step 210 (FIG. 2A), the control device 120 determined the predefinable first threshold value U_Level (see below, FIG. 4B) as a function of the first variable G1 and the second variable G2.

FIG. 4A shows, for example in the form of a first curve K1, a time profile of a periodic phase voltage of a generator, for example Motor vehicle generator, which can be applied to the drain terminal D of the semiconductor switch 110 in the sense of the second reference potential BP2 already described above with reference to FIG. 1, and thus the

Voltage UL on the load path 112 represents. It can be seen from FIG. 4A that positive half-waves HW0 of the phase voltage are exemplary

Accept voltage values between 0 volts (V) and approximately 10 V. Negative half-waves HW cannot form with a comparable magnitude of the amplitude because the semiconductor switch 110 is switched on by the control device 120 in the corresponding time periods HW (that is to say it has a low resistance), as a result of which it can advantageously be used as an active rectifier diode with regard to the phase voltage of the generator. Accordingly, the first curve K1 has voltage values in the range of 0 V and approximately - 400 mV (millivolts) in the periods corresponding to a negative half-wave HW, compare also the second curve K2, which is assigned the same scaling on the time axis t as the first Curve K1, however a different scaling of the vertical axis corresponding to the phase voltage in FIG. 4A.

FIG. 4B schematically shows, in the form of curve K3, a detailed view of the time profile from FIG. 4A, the time range ZB shown in FIG. 4B essentially corresponding to a negative half-wave HW of the phase voltage of the generator. At time t1, the phase voltage falls below the value of 0 V. In further preferred embodiments, the control device 120 activates the semiconductor switch 110 when the phase voltage K3 falls below an activation threshold value U_SW_ON of, for example, approximately −200 mV. This is the case here at time t1 '. The activation of the semiconductor switch 110 accordingly begins at this point in time. The activation of the semiconductor switch 110 (generally comprising recharging the gate electrode G to the electrical potential required for the activation) is completed at the further point in time t1 ". As a result of the activation of the semiconductor switch 110, the differential voltage K3 collapses, compare the course of the curve K3 between the times t1 ', t1 ". The further time profile of curve K3 from time t1 “results from the profile of a current L (FIG. 1) or phase current corresponding to the differential voltage through the load path 112 of the semiconductor switch 110 in relation to its on-resistance (Ros. _On ). As soon as the differential voltage K3 at the time t2 'also as

The first threshold value U_Level, which can be specified as a function of the variables G1 and / or G2 (see step 210 from FIG. 2A) and which can be specified, is deactivated completely, or optionally also partially, according to the embodiments according to the embodiments.

In the present case, a partial deactivation of the semiconductor switch 110 takes place at the point in time t 2 ′ by appropriate activation of its gate electrode G by means of the control device 120. The partial deactivation increases the resistance of the load path 112 of the semiconductor switch 110, and the

Phase voltage K3 drops again accordingly at time t2 ', in order then to continue to increase in accordance with its periodic behavior until the predefinable first threshold value U_Level is reached again at time t3', at which point the semiconductor switch 110 is now completely deactivated, its load path 112 is switched to high resistance. At the time t3, the phase voltage K3 crosses towards positive voltage values, so the next positive half-wave HW0 begins. As an alternative to the above-described process of initially partially deactivating the semiconductor switch 110, a complete deactivation of the semiconductor switch 110 can also take place directly at the time t 2 ′.

After the time t3 there follows a positive half-wave HW0 (FIG. 4A), and after that the sequence described above can be repeated from the time t4 to the time t6 analogously to the time range t1 to t3 (FIG. 4B), the times t2 , t5 a transition from a respective first

Time range T 1 of the negative half-wave HW under consideration for a respective second time range T2 of the negative half-wave HW under consideration

characterize.

In further preferred embodiments, the control device 120 (FIG. 1) is designed to operate in the first time period T1 (FIG. 4B) of the (in the present case negative) half-wave HW that is applied to the load path 112 of the

The periodic electrical voltage K3 (FIG. 4B) that can be applied to the semiconductor switch 110 (FIG. 1) can activate the semiconductor switch 110 as a function of the voltage K3, U _L ZU applied to the load path 112 (for example, as above already described when the activation threshold falls below

U_SW_ON). In other embodiments, other methods of activating the semiconductor switch 110 at the beginning of the negative half-wave HW under consideration can also be provided.

In further preferred embodiments, the control device 120 (FIG. 1) is designed to deactivate the semiconductor switch 110 (for example, in the case of the voltage K3, U _L applied to the load path 112)

Exceeding the predefinable first threshold value U_Level) only in a second time period T2 following the first time period T1.

This results in a reliable activation of the semiconductor switch 110 (in this case at the time t1 ′), and at the same time, by releasing the voltage-dependent deactivation, it is only avoided in the second time range T2 following the first time range T 1 that already in the first

Time range T1 an undesired (in particular too early, based on the half-wave HW considered) deactivation of the semiconductor switch 110 takes place, as occurs, for example, due to fluctuations in the voltage UL (for example due to the activation of the semiconductor switch 110 and / or variations in the current L and / or the frequency of the periodic voltage UL) can occur on the load path 112. As can be seen from FIG. 4B, the phase voltage K3 already exceeds the predefinable first threshold value U_Level between the time t1 'and the time t1', which would lead to an undesired premature deactivation of the semiconductor switch 110. Therefore, in other preferred embodiments

voltage-dependent deactivation of the semiconductor switch 110, compare the predefinable first threshold value U_Level, advantageously only released, ie allowed, in the second time range T2.

This enables, in further particularly preferred embodiments, a voltage-controlled activation of the semiconductor switch 110 at the point in time t 1 ′, which at the same time characterizes the start of the first time range T1 (alternatively, the zero crossing characterizes the

Phase voltage K3 to negative voltage values towards the time t1 the beginning of the first time range T 1). Then there is a time-controlled operation for the rest of the first time period T1, up to the time t2, which characterizes a transition to the second time period T2. In the first Time range T 1 is namely, with the exception of the activation to that

Time t1 '(FIG. 4B), no (further) voltage-dependent control of the semiconductor switch 110 is permitted or released. A release for a voltage-dependent control, in particular deactivation of the

Rather, semiconductor switch 110 occurs only when second time range T2 is reached, that is to say after or after time t2, so that the voltage-dependent complete or initially partial deactivation described above can take place from time t2 '.

FIG. 2B shows a simplified flow diagram of a further embodiment. In step 250, the control device 120 (FIG. 1) activates the semiconductor switch 110 in the first time range T1 (FIG. 4B), preferably voltage-controlled (for example if the value falls below the value U_SW_ON) and then in particular carries out a time control up to the end t2 of the first Time range T1. Then, in step 260, a voltage-dependent deactivation of the

Semiconductor switch 110 is only released in the second time period T2 following the first time period T 1, that is to say from time t 2. It is therefore only from time t2 that the predeterminable first is exceeded

Threshold value U_Level possible by the voltage U _L , K3

Then deactivate semiconductor switch 110 (or initially to partially deactivate).

Investigations by the applicant have shown that changes in the current L through the load path 112 can influence the activation of the semiconductor switch 110 described above.

FIG. 11A shows - comparable to curve K3 from FIG. 4B - a time profile K3 'of the voltage on the load path 112 of the semiconductor switch 110 in an application with a comparatively large load current L' of a maximum of about 100A, and FIG. 11B shows one Comparable time course K3 "of the voltage on the load path 112 at one

Application with a comparatively small load current L "from

In terms of amount, a maximum of about 10A (in the middle of the negative half-wave in question at time t20, which corresponds to time t2 from FIG. 4B). The time ranges T1 ′, T1 “again correspond to a respective first time range of the half-wave under consideration (see time range T1 from FIG. 4B) with preferably in the time-controlled operation of the semiconductor switch 110 (for example no release of a voltage-controlled deactivation before the time t2 or t20)), and the time ranges T2 ′, T2 “again correspond to a respective second time range of the half-wave under consideration (see time range T2 from FIG. 4B, preferably with voltage-controlled operation of the semiconductor switch 110 (release of the voltage-controlled deactivation is permitted from time t2 or t20)).

It can be seen that the actual point in time t7 '(FIG. 11A), t7 "(FIG. 11B) of the active, voltage-controlled deactivation or switch-off when the predefinable first threshold value U_Level (in the present example chosen to be approximately -40 mV) ) changes significantly with the variation of the current L, cf. also the duration of the second time periods T2 '> T2'. A switch-off duration T_OFF which is desired from efficiency points of view in further preferred embodiments and which does not occur until shortly before the end, cf. Time t8, which is the considered negative half-wave HW ', cannot be observed.

While at high current (Fig. 11A) the actual time t7 '

Switched off very late (because the one falling on the load route 112

Voltage UL is comparatively large due to the high current, according to L '* R _ü s. _on where R _ü s. _describes the switch-on resistance of the semiconductor switch 1 10 in the activated state), the actual time t7 "occurs

Shutdown at low current (FIG. 11B) very early, because in this case the voltage UL falling across the load path 112 is comparatively low due to the low current.

It would be desirable to maintain a switch-off duration or passive time T_OFF that is as constant as possible, in particular shortly before the end of the half-wave HW, cf. Time t8 in order to reserve switching times and time fluctuations. A large passive portion (long period of time, see time range t7 "to t8 from Fig.

11 B) significantly increases the power loss of the rectification. A very short passive component, cf. 11A increases the risk of actuation beyond the zero point (semiconductor switch 110 is not completely blocked at the beginning of the positive half-wave following the negative half-wave HW).

Accordingly, in particularly preferred embodiments, as already mentioned above with reference to the flow chart according to FIG. 2A described, proposed the predeterminable first threshold value U_Level for the voltage-controlled deactivation of the semiconductor switch 110 in

Determine dependence of the first variable G1 (Fig. 1). This is

in particular also in the event of fluctuations in the current L flowing through the load path 1 12 (FIG. 1), cf. 11 A, 11 B, a safe

Deactivating the semiconductor switch, in particular, as shortly as possible before a zero crossing of the periodic electrical voltage following the half wave HW 'in question, which improves the efficiency e.g. increases when using the electronic circuit as an active rectifier.

In further preferred embodiments it is provided that the first variable G1 characterizes a maximum amount of the current flowing through the load path during the predeterminable half-wave, cf. e.g. the value of the amount of current IL 'from FIG. 11A at time t20 of approximately 100A (ampere) (or 10A in the case of FIG. 11B).

In further preferred embodiments it is provided that the

Control device 120 (FIG. 1) is designed to determine the first variable G1 as a function of the voltage UL ZU applied to the load path 112, the control device 120 in particular being designed to determine the first variable G1 as a function of the voltage applied to the load path 112 Voltage UL and at least one parameter of the semiconductor switch 110, in particular depending on the on-resistance R _ü s. _{on of} the semiconductor switch 110 to determine. This enables particularly efficient determination of the first magnitude, because the on-resistance R _u s. _on the semiconductor switch 110 can usually be determined in advance from a data sheet or can be determined once using measurements. Accordingly, in particularly preferred embodiments, the first variable G1 can be determined as a function of the following equation: U_DS = I_DS * R_DS, on, the drain-source voltage U_DS of the

Semiconductor switch 1 10 corresponds to the voltage UL applied to the load path 112, the drain-source current I_DS corresponding to the current L flowing through the load path 112, and wherein R_DS, on said

Starting resistance Ros. _{on of} the semiconductor switch corresponds.

The control device 120 can thus use U_DS or UL to measure a measure of the DS current present, and thus, for example, the first variable G1 in Determine the dependence of the maximum amount of the current L of a half wave HW 'under consideration. It can be seen from the example according to FIG. 11B that the first threshold value U_Level chosen as an example of -40 mV should be higher in order to enlarge the active control window (corresponding to a length or duration of the second time range T2 “) of the semiconductor switch 110 , This can advantageously be achieved by determining the first threshold value U_Level as a function of the first variable G1.

FIG. 10A schematically shows a simplified flow diagram of a method according to a further embodiment. In the optional step 600, the semiconductor switch 110 is activated in the sense of a time control, cf. the time range T 1 according to FIG. 4B. The optional step 600 can also be omitted in the case of further embodiments or a different control of the

Provide the semiconductor switch as the time control mentioned. In step 610, the voltage UL applied to the load path 112 is determined, for example the control device 120 carries out a corresponding measurement for this.

A value of the voltage UL CLOSE applied to the load path 112 at time t2 is preferably determined, which characterizes an amount of a maximum current L through the load path 112 during the half wave HW under consideration. This corresponds to the determination of the first variable G1 (FIG. 1). Then, in step 620 of FIG. 10A, the predeterminable first threshold value U_Level is determined as a function of the first variable G1. Alternatively, a standard value for the predefinable first threshold value U_Level can also already be predetermined (e.g. from previous operating cycles and / or half-waves and / or by means of parameterization or configuration), which is then modified in step 620 depending on the variable G1. In other words, the determination (cf. step 210 from FIG. 2A) of the predefinable first threshold value U_Level as a function of the first variable G1 can also include modifying an existing first threshold value U_Level. A step 630 then takes place in accordance with FIG. 10A

Activation of the semiconductor switch 110 in the sense of a voltage control, in particular a voltage-dependent deactivation (or initially

Partial deactivation) of the semiconductor switch 110, in particular in the second time period T2 (FIG. 4B), as soon as the one applied to the load path 112

Voltage UL exceeds the predefinable first threshold value U_Level, which may have been modified or adapted in step 620. For example, step 620 can change the predefinable first threshold value U_Level by one include predeterminable value or proportion or changing the predeterminable first threshold value U_Level to a predeterminable proportion. For example, on the basis of the situation shown in FIG. 11B, with a predefinable first threshold value U_Level that is initially selected as an example to - 40 mV, the predefinable first threshold value U_Level can be changed to approximately 20% of this value in step 620, that is to say approximately - 8 mV whereby an adaptation to the comparatively low existing load current L and thus an extension of the active control period T2 “before the voltage-dependent deactivation is achieved.

According to investigations by the applicant, changes in particular in the frequency of e.g. (Phase) voltage UL, K3 supplied by a generator influence the activation of the semiconductor switch 110 described above.

FIG. 12 shows - again comparable to curve K3 from FIG. 4B - temporal profiles K3 '", K3" "of the voltage UL on the load path 112 (FIG. 1) of the semiconductor switch 110, the profile K3" "exemplifying a frequency of the periodic voltage of about 2 kHz (kilohertz), and the curve K3 "" corresponds to a frequency of about 500 Hz (Hertz). A

The peak amplitude of both curves K "', K" "in the present case is approximately - 200 mV. It can be seen immediately that the turn-off period or passive time T_OFF_1, T_OFF_2 (time period between voltage-dependent deactivation of the semiconductor switch 110 when the predefinable first one is exceeded

Threshold value U_Level up to the subsequent zero crossing of the voltage UL, that is to say the end of the current half-wave HW (FIG. 4B)) is dependent on the frequency. In the case of a value of the predefinable first threshold value U_Level of -40 mV, which is assumed to be constant, as shown here by way of example, in the case of the curve K "'(frequency 2 kHz), the voltage-dependent deactivation takes place at time t91 and the end of the half-wave at time t92, with T_OFF_1 = t92 - 191, whereas in the case of curve K ““ (frequency 500 Hz) the

voltage-dependent deactivation at time t93> t91 and the end of the half-wave at time t94, with T_OFF_2 = t94-193.

In further preferred embodiments, the passive time is T_OFF = 1 / w * arcsin (U_Level / U_DS, peak), where w is one with the above said frequency f corresponds to the angular frequency (w = 2 * Pi * f, where Pi is the number of circles), where arcsin () is the arc sine function, and where U_DS, Peak is the peak amplitude of the voltage UL or K “', K“ “of 12 is exemplary - 200 mV.

To take this effect into account, others are preferred

Embodiments proposed, alternatively or - advantageously in addition to - a determination or modification or adaptation of the predeterminable first threshold value U_Level depending on the first variable G1 (and thus e.g. of U_DS, Peak) the determination or modification or adaptation of the

predeterminable first threshold value U_Level as a function of the second variable G2, which, in addition to taking into account the possible different currents L, taking into account the possible ones

corresponds to different frequencies of the voltage UL, so that the predeterminable first threshold value U_Level, based on the principle of particularly preferred embodiments, is determined as a function of both effects or

can be modified or adapted.

In further preferred embodiments it is provided that the

Control device 120 (FIG. 1) is designed to determine a third variable G3, which characterizes a duration ZB of the predeterminable half-wave HW (FIG. 4B). Depending on the third variable G3, e.g. the first time t2 can be determined, which is a transition from the first

Time range T1 to the second time range T2 (and thus a change to the voltage control, in particular release of the voltage-dependent deactivation when the predefinable first threshold value U_Level) is characterized.

In further preferred embodiments it is provided that the

Control device 120 is designed to determine the third variable G3, which characterizes the duration ZB of the predeterminable half-wave, and as a function of the third variable G3, to determine the second variable G2, which characterizes the frequency of the voltage UL. In further preferred embodiments it is provided that the

Control device 120 determines both the first point in time t2 and the second variable G2 as a function of the third variable G3.

FIG. 2C schematically shows a simplified flow diagram of a method according to a further embodiment. In step 280, the

Controller 120 the third size G3, e.g. by investigation or

Time measurement of duration ZB (Fig. 4B). In step 290, the

Control device 120 from the third variable G3 the first time t2 and the second variable G2. The predeterminable first threshold value U_Level can then be determined (not shown) as a function of the first variable (G1) (possibly already determined beforehand) and the second variable G2 by means of the control device 120, or modified or adapted.

In further preferred embodiments, knowing the third size G3, e.g. the duration ZB (FIG. 4B), and in particular on the assumption that the time profile K3 of the voltage UL in the considered (in the present example negative) half-wave HW corresponds to a sine half-wave, the predeterminable first threshold value U_Level is determined as a function of the following equation: U_Level = U_DS, Peak * sin (2 * w * T_OFF / (2 * T_ON)),

[Equation 1], where U_DS, peak specifies the peak amplitude of the voltage UL, sin () specifies the sine function, T_OFF specifies a predefinable passive time, and T_ON specifies a previous activation time (duty cycle of the

Semiconductor switch) indicates.

FIG. 10B schematically shows a simplified flow diagram of a method according to a further embodiment. In step 650, the

Control device 120 the second variable G2, which characterizes the frequency of the periodic voltage UL. In step 652 the

Semiconductor switch 110 in the sense of a time control, i.e. e.g. corresponding to the first time range T1 from FIG. 4B, in particular with voltage-controlled activation, cf. Time t1 ', and subsequent time-controlled further activation (leaving it in the activated state) for the duration of the first time range T 1, that is to say up to time t2. In step 654, the

Control device 120 the first variable G1, for example depending on the voltage UL, in particular the peak amplitude U_DS, peak of the voltage UL. In step 656, control device 120 determines the predeterminable first threshold value U_Level as a function of the first variable G1 and the second variable G2, for example as a function of the abovementioned [equation 1]. Then, in step 658, the control device 120 controls the semiconductor switch 110 with the predeterminable one determined in step 656 first threshold value U_Level,

especially in the sense of voltage-dependent control, cf. Time domain T2 (Fig. 4B). This means that the predeterminable first threshold value U_Level, which has just been determined, is preferably used for the evaluation of the

Voltage UL is used (e.g. by the aforementioned check whether the voltage exceeds the threshold U_Level just determined). This results in a particularly efficient threshold value adaptation of the predeterminable first threshold value U_Level, in particular also when the current L and / or the frequency of the voltage UL vary.

FIG. 3 schematically shows a simplified circuit diagram of an electronic circuit 100a according to a further embodiment. A control logic 122, which is part of a control device 120a for the semiconductor switch 110, for example, provides control signals S0T, S02 'which act on the switches S01, S02, by means of which the gate electrode G of the semiconductor switch 110 can be charged to corresponding reference potentials, as a result of which the semiconductor switch 110 can be activated or deactivated or partially deactivated. The

The functionality of the control device 120a can, for example, be comparable to the functionality of the control device 120 described above with reference to FIG. 1.

The control device 120a is advantageously designed to carry out the method according to the above-described embodiments, in particular also to determine the variables G1 and / or G2 and / or G3 and to determine the predeterminable first threshold value U_Level as a function of the first variable G1 and / or the second Size G2, for example using control logic 122.

Optionally, control device 120a can be used in other preferred ones

Embodiments have a diode D01 and a capacitor C01, which are connected in series with respect to the drain terminal D and the first reference potential BP1, as can be seen in FIG. As a result, the capacitor C01 can be charged if a positive one is present at the drain terminal D. Potential compared to the first reference potential BP1 is present (for example during a positive half-wave HWO (FIG. 4A) a phase voltage K1, K2, K3 applied to the drain terminal D. In other words, the capacitor C01 can be charged during a positive half-wave HWO of the phase voltage The operable electrical charge stored in the capacitor C01 can then advantageously be used during a negative half-wave HW following the positive half-wave HWO of the phase voltage applied to the drain terminal D, with appropriate control of the

Switch S01 can be reloaded into the gate electrode G of the semiconductor switch 110 in order to activate it (for example voltage-controlled, compare time t1 'according to FIG. 4B). This allows an external electrical

Energy supply for driving the gate electrode G is advantageously eliminated.

Further optionally, the controller 120a may, in other preferred embodiments, include a voltage stabilization circuit 124 (e.g.

Zener diode) which stabilizes the charging voltage of the capacitor C01.

FIG. 5 schematically shows a simplified circuit diagram of an electronic circuit according to a further embodiment. The circuit shown in FIG. 5 comprises a first timer circuit (timer) 1200a, a second timer circuit 1200b and a logic circuit 1200c, which control signals S0T, S02 'for the in a particularly energy-efficient manner

Control of the semiconductor switch 110 according to Figure 3 provides. The components 1200a, 1200b, 12000c described above with reference to FIG. 5 or their functionality can be preferred in the case of further ones

Embodiments can advantageously be provided in the control logic 122 according to FIG. 3. The electrical supply of the control logic 122 can advantageously also come from the capacitor C01, so that a separate electrical energy supply device is unnecessary for the operation of the control logic. In other embodiments, this also applies to those below

Circuit components described with reference to FIG. 6.

The first timer circuit 1200a according to FIG. 5 has a first current source 11, via which the capacitor C1 can be charged under control by means of the switch S1, and a second current source I2, via which the capacitor C1 can be discharged under the control of by means of the second switch S2. Are preferred Both current sources 11, I2 are each designed as constant current sources, the amount of the current provided by the second current source I2 being twice as large as the amount of the current provided by the first current source E1 (the current direction is opposite to one another in order to charge or Allow capacitor C1 to discharge).

For the voltage across the capacitor C1, there is an example of the time profile indicated in FIG. 8 by means of the curve K4. As can be seen, one end of the discharge process of the capacitor C1 corresponds to the predefinable time t2, which characterizes a transition from the first time period T1 (FIG. 4B) to the second time period T2, while a charging process extends over the entire duration ZB of a negative half-wave HW, cf. , the period t4 to t6 in FIG. 8. In preferred embodiments, the charging of the capacitor C1 (FIG. 5) corresponds to a determination or “learning” of the duration ZB, cf. the period t4 to t6 in FIG. 8, which can fluctuate accordingly due to a variable speed of a generator that provides the phase voltage, and thus a determination of the third variable G3. Discharging the capacitor C1 with respect to charging twice the speed (due to the charging current being twice as large, see current source I2) thus causes the predeterminable point in time t2 or t5 (FIG. 8) to be determined in the middle of the duration ZB of the half-wave HW (Fig. 4B). Furthermore, the variable G3 determined in this way can be used to determine the second variable G2 and / or the predeterminable first threshold value UJevel.

Using a Schmitt trigger A6 (FIG. 5) and a downstream AND gate A8, a logic signal A8 'is generated as a function of the voltage at the capacitor C1 and the signal A_discharge, which can be supplied to the logic logic 1200c. In the present case, the switches S1, S2 of the first timer circuit 1200a are controlled, for example, as a function of the signals AJaden, A_ischaden, which, as described below, can be determined, for example, and again in a very energy-efficient manner, using the circuit in accordance with FIG. 6.

FIG. 6 shows a Schmitt trigger A1, the one on the input side

Phase voltage (compare, for example, reference symbol K3 from FIG. 4B) is supplied with the signal phase, and from this generates a binary signal Ph_neg, which indicates when a negative half-wave HW (FIG. 4B) is present. In other words, the signal Ph_neg then has a value, for example from logic one to when there is a negative half-wave HW of the phase voltage. The signal phase can be derived, for example, from the drain connection D (FIG. 3) of the semiconductor switch 110 and thus also corresponds to the voltage UL which is present at the load path 112.

FIG. 6 also shows a counter module A2, in particular an alternating counter, which can be implemented, for example, by means of a flip-flop. The signal Ph_neg is supplied as the clock signal CLK to the alternating counter A2, which, depending on this, forms two output signals count_2, count_2 '.

Depending on the signals Ph_neg, count_2, count_2 ', the signals AJaden, A_ladaden, BJaden, B_entladen are formed by means of two AND gates A3, A4, the two signals AJaden, A_ischaden being used for the operation of the first timer circuit 1200a as described above.

The second timer circuit 1200b has one to the first

The timer circuit 1200a has a comparable structure and is used to generate the logic signal A9 ″ which, together with the further signals A8 ″, Ph_neg by means of the logic elements A10, A5 into the complementary ones

Control signals S0T, S02 'is transformed to control the

Gate electrode G of the semiconductor switch 110.

In preferred embodiments, charging corresponds to the

Capacitor C2 of the second timer circuit 1200b (FIG. 5) with a determination or “learning” of the duration ZB (or the third variable G3) in the

Period t1 to t3 in FIG. 8, and the discharging of the capacitor C2 at twice the speed in relation to the charging (current source I3) (due to the charging current being twice as great, cf. the current source I4)

Definition of the predeterminable time t5 or t2 (FIG. 8) in the middle of the duration ZB of the half-wave HW (FIG. 4B).

The timer circuits 1200a, 1200b described above can also be referred to as period duration timers or PD timers, because a first PD timer learns the duration ZB of the half wave HW during a first (negative) half-wave HW of the phase voltage K3 under consideration, while the second PD timer is used to drive the semiconductor switch 110 during the same half wave HW under consideration, and vice versa. With others

preferred embodiments, the learning time (e.g. time t1 to t3 or t4 to t6) and the activation time (e.g. time t1 to t2 or t4 to t5) are not the same, but the activation time is generally shorter than the learning time. This is advantageous because, from period to period of the phase voltage, the period time (and thus also the duration ZB of a negative half-wave HW considered as an example) can decrease (for example by a

Speed change of the generator), can be maintained via a passive rectification window. In further preferred embodiments, the time ratio between the learning time and the activation time is typically between approximately 50% to approximately 99%. This also applies to all the other embodiments described above which relate to the time ranges T1, T2 and not (only) for the embodiment described with reference to FIG. 5.

In further preferred embodiments, the learning time is determined by the time difference between the times t3, t1 according to FIG. 4B, while the activation time is determined by means of the time difference between the times t2, t1. In other words, in preferred embodiments, the learning time corresponds to the sum of the first time range T 1 and the second time range T2, whereas the activation time corresponds to the first time range T1 and can be used in particular to determine the time t2.

The principle according to the present embodiments advantageously enables the use of a when the first point in time t2 (FIG. 4B) is reached

voltage-controlled method for deactivating the semiconductor switch 110. In particular, in preferred embodiments the

Semiconductor switches 110 can still be activated or remain activated as long as the applied phase voltage is below the predeterminable first threshold value U_Level. The predeterminable first can also be advantageous

Threshold value U_Level as a function of the variables G1 and / or G2 are determined or modified or adapted, so that in particular also

Fluctuations in the current L flowing through the load path 112 and / or the frequency of the periodic electrical voltage UL ensure that the semiconductor switch 110 is deactivated safely, in particular as shortly before as possible considered half-wave HW (Fig. 4B) following zero crossing of the periodic electrical voltage is guaranteed.

FIG. 7 schematically shows a simplified block diagram according to a further embodiment. Reference numeral 300 denotes a semiconductor substrate on which both the semiconductor switch 110 and the control device 120 of the circuit 100 are arranged. This results in a particularly small configuration. For example, the semiconductor substrate 300 with the components 110, 120 can have such a small construction volume that

conventional, passive rectifier diodes in a corresponding target system (e.g. active rectifier) through the semiconductor substrate 300 with the

Electronic circuit 100 can be replaced according to the embodiments. This advantageously provides the possibility of active rectification, which, due to the low forward resistance of the load path 112 of the semiconductor switch 110 in its activated, that is to say switched on, state, results in much lower ohmic losses than the operation of conventional rectifier diodes. Furthermore, the circuit 100 arranged on the semiconductor substrate 300 enables simple construction, simple assembly, the small size mentioned, high mechanical robustness, and

comparatively low manufacturing costs.

The circuit 100, 100a according to the embodiments can advantageously be provided in the form of an electrical dipole, the first connection of which is, for example, the drain electrode D (FIG. 1) and the second connection of which is, for example, a ground connection (source electrode S) for connection to the first reference potential BP1 is. With the optional provision of the capacitor C01 according to FIG. 3, a safe autonomous operation of the circuit 100a is ensured even during negative half-waves HW of the phase voltage of the semiconductor switch 110 applied to the load path 112. In further embodiments, the capacitance of the capacitor C01 can particularly preferably be chosen to be comparatively low, for example in the region of a capacitance of the gate electrode G of the semiconductor switch 110 or

for example in the range from about 40% to about 150% of the capacity of the gate electrode G of the semiconductor switch 110. According to studies by the applicant, this capacity is sufficient for a safe and complete

Activation of the semiconductor switch 110 during a (eg negative) Half-wave HW of the phase voltage (including, for example, the operation of the circuit components according to FIGS. 5, 6). For a new activation in the context of a subsequent further (eg negative) half-wave of

Phase voltage, capacitor C01 can be charged by a corresponding positive half-wave HWO (FIG. 4A) following the first half-wave HW, and so on.

In further advantageous embodiments, several are also conceivable

Integrate semiconductor switch 110 and their assigned control devices 120 on the same semiconductor substrate 300, see FIG. 7.

For example, two may be the same or different

Semiconductor switches 110, each with an associated control device 120, can be integrated on a (same) semiconductor substrate 300, the first integrated semiconductor switch 110 being able to form a so-called high-side switch, and the second integrated semiconductor switch 110 being able to form a so-called low-side switch.

Further preferred embodiments relate to an active one

Rectifier circuit 500 with at least one circuit 100, 100a according to the embodiments. FIG. 9 schematically shows a simplified block diagram for this.

A generator 400 is shown, for example a generator for a motor vehicle, with three phase-forming winding phases 402, 404, 406, which are connected in a triangular topology. The entirety of all winding phases 402, 404, 406 forms, for example, a stator winding of the generator 400. An excitation winding 408, which can be acted upon with an excitation current I _{EGG in} a manner known _per se, is assigned to the rotor (not shown) of the generator 400. When the rotor and thus the excitation winding 408 rotate relative to the stator winding of the generator 400, a corresponding phase voltage is induced in the phase-forming winding phases 402, 404, 406, which can be supplied to the active rectifier circuit 500 via the circuit nodes 410, 411, 412, cf. also reference number 413.

The active rectifier circuit 500 has a first series circuit 421 composed of two electronic circuits 100b_1, 100b_2, each of which, for example 1 to 8, and each operate as an active rectifier as described above with reference to FIGS. 1 to 8. The first series circuit 421 is assigned to a first phase of the generator 400, cf. also the circuit node 410. A second series circuit 422 consisting of comparable two-terminal poles 100b_3, 100b_4 (each similar or identical to the configuration 100 or 100a) is assigned in a comparable manner to the second phase of the generator 400, cf. also the circuit node 411. A third series circuit 423 composed of comparable two-terminal poles 100b_5, 100b_6 (each similar or identical to the configuration 100 or 100a) is assigned in a comparable manner to the third phase of the generator 400. Accordingly, there is an actively rectified by the rectifier circuit 500 at the terminals 502, 504

Output voltage UA on.

In further particularly preferred embodiments, the circuit 100, 100a, 100b_1, .., 100b_6 according to the embodiments can advantageously be used instead of conventional passive diodes, for example press-in diodes

Provision of an active rectifier circuit 500 can be used.

Due to the embodiments described above with reference to FIGS. 1 to 8, no separate control logic is particularly advantageous because each circuit 100, 100a according to the embodiments is assigned its own control device 120, which is particularly advantageous on the same substrate as the associated semiconductor switch 110 of the circuit 100, 100a can be arranged.

Further preferred embodiments relate to a use of the method according to the embodiments for operating an active one

Rectifier circuit 500, the active rectifier circuit 500 in particular having at least one circuit 100, 100a, 100b_1, .., 100b_6 according to the embodiments.

The principle according to the embodiments can be used particularly advantageously to provide active rectifier circuits in the form of a two-pole 100, 100a or multi-phase rectifier circuits 500. Active rectifier circuits for

Generators, in particular three-phase generators (single or multi-phase), be provided by motor vehicles, for example. The principle according to the embodiments can also be used to rectify electrical voltages of any AC sources such as

Transformers and the like can be used. Here too there are comparable advantages. The principle according to the embodiments enables a very efficient operation of the semiconductor switch by, among other things, a switch-off duration T_OFF that is as constant as possible, in particular regardless of fluctuations in the current L and / or the frequency of the voltage UL, is ensured.

The principle according to the embodiments can also advantageously be used as an active two-pole 100, 100a for all circuits, in particular power electronics circuits, which require a free-wheeling diode, for example for pulse inverters, which are equipped, for example, with IGBTs (bipolar transistors with insulated gate electrodes). In this case, the electronic circuit 100, 100a can accordingly be used as an active diode in the sense of a freewheeling diode for the IGBT (s).

FIG. 13 shows schematically operating variables of further embodiments in which the desired switch-off duration T_OFF can be achieved alternatively or in addition to the above-described embodiments by changing the implementation of the PD timers 1200a, 1200b (FIG. 5). A time curve KT of a phase voltage is shown, similar to curve K1 according to FIG. 4A, as it can be applied to the load path 112 (FIG. 1) of the semiconductor switch 110 as voltage UL. The curves K4 ', K5' generally correspond to the time profile K4, K5 from FIG. 8, that is to say the profile of the voltages at the capacitors C1, C2 of the PD_Timer 1200a, 1200b (FIG. 5). In order to achieve a desired switch-off time T_OFF, in alternative embodiments or in addition to the above-described embodiments, a discharge rate of the capacitors C1 and / or C2 can vary from the values w (angular frequency, also characterized by the third variable G3) and / or U_D, peak (peak amplitude the voltage UL). This is indicated in FIG. 13 by the variable slope of the “falling edge” F1 in the area B1 of the curve K4 ', see FIG. also the double arrow a1. In preferred embodiments, this can be done, for example, by at least temporarily switching on at least one further constant current source (not shown) in addition to, for example, the constant current source I2 in that of the falling one Edge F1 corresponding to time period T3. As an alternative or in addition, in further embodiments a part of the charge of the capacitor C1, C2 in question can also be discharged, as it were as an "offset", cf. the area B2 of the curve K5 '(for capacitor C2), and the discharge and charge can be carried out with the same ramp or slope, that is to say by means of the same

Constant current source (s) I3, I4 as described above with reference to FIG. 5.

Claims

Expectations

1. Electronic circuit (100; 100a) with a controllable switch (110), in particular a semiconductor switch (110), and a control device (120) for controlling the semiconductor switch (110), the control device (120) being designed to switch the semiconductor switch ( 110) CLOSE in a first time range (T1) of a predeterminable, preferably negative, half-wave (HW) of a periodic electrical voltage (UL; K1, K2, K3) that can be applied to a load path (112) of the semiconductor switch (110)

activate and the semiconductor switch (110) in one at first

Time range (T1) to deactivate the following second time range (T2) when the voltage (UL; K1, K2, K3) applied to the load path (112) exceeds a predefinable first threshold value (U_Level), the control device (120) being designed for this purpose is to determine (200) a first variable (G1) which characterizes a current (L) flowing through the load path (112) during the predeterminable half-wave (HW), and / or to determine (200) a second variable (G2) , which characterizes a frequency of the periodic electrical voltage (UL; K1, K2, K3), and wherein the control device (120) is designed to determine the predefinable first threshold value (U_Level) as a function of the first variable (G1) and / or the second Size (G2) to be determined (210).

2. Circuit (100; 100a) according to claim 1, wherein the first variable (G1) characterizes a maximum amount of the current flowing through the load path (112) during the predeterminable half-wave (HW).

3. Circuit (100; 100a) according to at least one of the preceding claims, wherein the control device (120) is designed to determine the first variable (G1) and the second variable (G2) and the first threshold value

(U_Level) depending on the first variable (G1) and the second variable (G2).

4. Circuit (100; 100a) according to at least one of the preceding claims, wherein the control device (120) is designed to determine the first variable (G1) as a function of the voltage (UL; K1, K2, K3) applied to the load path (112) ), the control device (120) in particular being designed to determine the first variable (G1) as a function of the voltage (UL; K1, K2, K3) applied to the load path (112) and at least one

Determine the characteristic of the semiconductor switch (110), in particular as a function of a switch-on resistance of the semiconductor switch (110).

5. Circuit (100; 100a) according to at least one of the preceding claims, wherein the control device (120) is designed to, in the first time range (T1), the semiconductor switch (110) as a function of the voltage (UL) applied to the load path (112) ; K1, K2, K3) CLOSE (250), and in particular a deactivation of the semiconductor switch (110) dependent on the voltage (UL; K1, K2, K3) present only in the first time range ( T1) to release (260) the following second time range (T2).

6. Circuit (100; 100a) according to at least one of the preceding claims, wherein the control device (120) is designed to determine a third variable (G3) which characterizes a duration (ZB) of the predeterminable half-wave (HW), and in Depending on the third variable (G3) a) to determine a first point in time (t2) which characterizes a transition from the first time range (T1) to the second time range (T2) and / or b) to determine the second variable (G2).

7. Circuit (100; 100a) according to at least one of the preceding claims, wherein the semiconductor switch (110) and the control device (120) are arranged on the same semiconductor substrate (300).

8. Active rectifier circuit (500) with at least one circuit (100;

100a) according to at least one of the preceding claims.

9. A method for operating an electronic circuit (100; 100a) with a controllable switch (110), in particular semiconductor switch (110), and a control device (120) for controlling the semiconductor switch (110), the control device (120) being designed for this purpose , the Semiconductor switch (110) in a first time range (T1) of a predeterminable, preferably negative, half-wave (HW) of a periodic electrical period that can be applied to a load path (112) of the semiconductor switch (110)

Activate voltage (UL; K1, K2, K3) CLOSE and then deactivate the semiconductor switch (110) in a second time period (T2) following the first time period (T1) when the one present on the load path (112)

Voltage (UL; K1, K2, K3) exceeds a predeterminable first threshold value (U_Level), the control device (120) determining (200) a first variable (G1) which prevents the load path (112 ) flowing current (L) characterized, and / or a second variable (G2) determined (200), which characterizes a frequency of the periodic electrical voltage (UL; K1, K2, K3), and wherein the control device (120) the predeterminable first Threshold value (U_Level) determined as a function of the first variable (G1) and / or the second variable (G2) (210).

10. The method according to claim 9, wherein the control device (120) determines the first variable (G1) and the second variable (G2) and determines the first threshold value (U_Level) as a function of the first variable (G1) and the second variable (G2) ,

11. The method according to at least one of claims 9 to 10, wherein the

Control device (120) determines the first variable (G1) as a function of the voltage (UL; K1, K2, K3) applied to the load path (112), wherein in particular the control device (120) determines the first variable (G1) in

Dependency of the voltage (UL; K1, K2, K3) applied to the load path (112) and at least one parameter of the semiconductor switch (110), in particular depending on a switch-on resistance of the

Semiconductor switch (110) determined.

12. The method according to at least one of claims 9 to 11, wherein the

Control device (120) in the first time range (T1) activates the semiconductor switch (110) as a function of the voltage (UL; K1, K2, K3) applied to the load path (112), and in particular one of those applied to the load path (112) Voltage (UL; K1, K2, K3) dependent deactivation of the semiconductor switch (110) only in a second time period (T2) following the first time period (T1).