Adaptive universal LED bypass

Abstract

The invention relates to an adaptive universal LED bypass. An electronic circuit is presented. The electronic circuit is configured to be connected to at least one light emitting diode (LED) and at least one driver circuit. The driver circuit is configured to provide a driver current ID. The electronic circuit includes: a bypass circuit configured to cause at least a portion of the driver current ID to bypass the LED; and a detection circuit defining a threshold voltage Vth, where the detection circuit is configured to activate the bypass circuit when an output voltage Vout at the driver circuit falls below the threshold voltage Vth, where the threshold voltage Vth matches a minimum output voltage Vout, min of the driver circuit. The invention further relates to a driver system, to a lighting system and to a method for bypassing at least one LED.

Description

Technical Field

[0001] The present disclosure relates to circuits and methods for bypassing at least one light emitting diode (LED). Background Art

[0002] LEDs are used in various applications, for example for displaying information or for illuminating objects or areas. A particular example is a headlight, such as a taillight, in automotive applications. A plurality of LEDs can, for example, be connected in series to form an LED string, and further a plurality of LED strings can be arranged in parallel to form an LED matrix. However, in principle, other applications and arrangements for LEDs are also possible.

[0003] In principle, an LED is a semiconductor device that emits light when an electric current passes through it. Therefore, the LED is usually powered by a driver circuit that provides such an electric current. In addition, a supply voltage is required. Especially in automotive applications, the supply voltage is usually provided by a battery. However, other options are generally also possible.

[0004] As an example, in automotive applications, the battery voltage may typically be 12.5V, but it may be as low as 6V in the normal functional range. Therefore, when designing a driver system for a taillight, it is usually impossible to use more than two red LEDs connected in series with a forward voltage of 2.4V while ensuring that the LED string is always on and does not flicker. In this case, one option may be to use an external circuit to monitor the battery voltage and bypass one or more LEDs in the LED string when the battery voltage drops below a predetermined threshold voltage. However, this may result in inaccurate bypassing of the LEDs, especially in the case of longer LED strings. LEDs are a load whose forward voltage typically varies dramatically depending on temperature, driver current, aging effects and / or binning. Binning generally refers to the variation in the forward voltage of an LED due to manufacturing errors. For example, due to binning, the voltage drop across an LED may vary by 0.15V. For example, variations due to temperature may be in a similar range. Therefore, ignoring aging effects, the total variation may be, for example, about 1.5V or even more. Therefore, it is difficult to predetermine a suitable threshold voltage for the battery voltage used to bypass the LEDs. The above mentioned variations must be taken into account, which may limit the application of the system.

[0005] Rohm Co., Ltd. provides two corresponding systems in BD18326NUF-M and BD18336NUF-M. Summary of the invention

[0006] In a first aspect of the present disclosure, an electronic circuit is disclosed. The electronic circuit is configured to be connected to at least one light emitting diode (LED) and at least one driver circuit. The driver circuit is configured to provide a driver current I DThe electronic circuit includes a circuit configured to cause the driver current I D The electronic circuit further comprises a detection circuit. The detection circuit defines a threshold voltage V th The detection circuit is configured to detect when the output voltage V out drops to the threshold voltage V th The bypass circuit is activated when V th The minimum output voltage of the driver circuit V out,min Match.

[0007] In another aspect of the present disclosure, a driver system is disclosed. The driver system comprises at least one electronic circuit according to any of the embodiments of the electronic circuits disclosed in detail above or below. The driver system also comprises a circuit configured to provide a driver current I D at least one driver circuit.

[0008] In another aspect of the present disclosure, a lighting system is disclosed. The lighting system comprises at least one driver system according to any of the embodiments involving driver systems disclosed in detail above or below. The lighting system further comprises at least one LED.

[0009] In another aspect of the present disclosure, a method for bypassing at least one LED is disclosed. The method is performed by using at least one circuit according to any of the embodiments involving electronic circuits disclosed in detail above or below. The method comprises at least the following steps:

[0010] a) When the output voltage V out drops to the detection circuit threshold voltage V th The bypass circuit is activated by using the detection circuit when:

[0011] b) By using a bypass circuit to reduce the driver current I D At least a portion of the LED is bypassed.

[0012] Those skilled in the art will recognize additional features and advantages upon reading the following detailed description, and upon viewing the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The present disclosure is illustrated by way of example and not by way of limitation, and similar reference numerals refer to similar or identical elements in the various figures of the accompanying drawings. The elements of the accompanying drawings are not necessarily drawn to scale with respect to each other. The features of the various illustrated examples may be combined unless they are mutually exclusive.

[0014] Figure 1 illustrates a circuit diagram of an exemplary lighting system;

[0015] Figure 2 and Figure 3 illustrates experimental results of measurements on a lighting system;

[0016] Figures 4 to 7 illustrates a circuit diagram of a further exemplary lighting system; and

[0017] Figure 8 A flow chart of an exemplary method for bypassing at least one LED is illustrated.

[0018] Special embodiments

[0019] In a first aspect of the present disclosure, a circuit is disclosed. The term "electronic circuit" as generally used herein is a broad term and should be given its ordinary and commonly used meaning to a person of ordinary skill in the art, without being limited to a special or customized meaning. Without limitation, an electronic circuit may particularly be or may include at least one electronic component that may be connected to at least one other electronic component, for example, other electronic components within the electronic circuit or electronic components of other electronic circuits. An electronic circuit may be a combination of at least two electronic components that are at least partially interconnected by conductive elements. As an example, an electronic component may include a resistor, an inductor, a capacitor, a diode and / or a transistor. As an example, a conductive element may include wires and / or traces. An electronic circuit may be or may include at least one integrated circuit. Therefore, an electronic circuit or at least a portion of an electronic circuit may be arranged on at least one piece of semiconductor material, especially silicon.

[0020] The electronic circuit can be divided into a plurality of electronic subcircuits, such as bypass circuits and / or detection circuits and / or other circuits, which will be outlined in detail below. In other words, the electronic circuit may include a plurality of electronic subcircuits. The electronic subcircuit itself may be an electronic circuit, in particular an electronic circuit as defined above. Therefore, the electronic subcircuit may in particular be at least one electronic component, which may be connected to at least one other electronic component, such as other electronic components of other electronic subcircuits within a superior electronic circuit. The electronic subcircuit may be configured to perform a task or function, in particular within a superior electronic circuit. One or more electronic subcircuits may at least partially work together or act together to perform a task or function. One or more electronic subcircuits may at least partially share electronic components and / or conductive elements. As shown, one or more electronic subcircuits may be electrically connected to each other.

[0021] The electronic circuit is configured to be connected to at least one LED. The term "LED" is short for "light emitting diode" and is generally used herein as a broad term and should be given its ordinary and usual meaning to a person of ordinary skill in the art, and is not limited to a special or customized meaning. Without limitation, an LED can be a semiconductor device configured to emit light when an electric current passes through it. In particular, the LED can be configured for use in automotive applications, for example, as a taillight of a car or as a headlight of a car or at least as a part thereof. A plurality of LEDs can be connected in series to form an LED string. A plurality of LED strings can be arranged in parallel to form an LED matrix.

[0022] The electronic circuit is further configured to be connected to at least one driver circuit. The driver circuit is configured to provide a driver current I D The term "driver circuit" is generally used herein as a broad term and should be given its ordinary and customary meaning to a person of ordinary skill in the art, and is not limited to a special or customized meaning. Without limitation, a driver circuit may be a circuit configured to provide a suitable current (e.g., a driver current I D ). The driver circuit may be configured to adjust the driver current, in particular to adjust the driver current relative to a requirement of a device such as at least one LED. The driver circuit may include at least one of a current sink, in particular a constant current sink, and a current source, in particular a constant current source. The driver circuit may be or may include at least one integrated circuit.

[0023] The electronic circuit includes a circuit configured to cause the driver current I D A bypass circuit that bypasses at least a portion of the LED. The term "bypass circuit" is generally used herein as a broad term and should be given its ordinary and usual meaning to a person of ordinary skill in the art, and is not limited to a special or customized meaning. Without limitation, the bypass circuit can be an electronic circuit or more particularly an electronic subcircuit configured to provide a bypass, particularly to provide a bypass within a high-level circuit. In other words, the bypass circuit can be an electronic subcircuit configured to provide a bypass within a circuit. The bypass circuit can be configured to bypass at least one component within the bypass circuit, particularly at least one LED. The bypass circuit can be configured to direct a current, particularly a driver current I D Or driver current I D The bypass circuit may be configured to bypass all I D The bypass circuit can be configured to bypass the driver current I D only a portion of, and therefore in particular not the entire driver current ID .

[0024] The electronic circuit also includes a detection circuit. The term "detection circuit" is generally used herein as a broad term and should be given its ordinary and usual meaning to a person of ordinary skill in the art, and is not limited to a special or customized meaning. Without limitation, the detection circuit can be an electronic circuit or more particularly an electronic subcircuit configured to detect or identify at least one physical entity or state. The detection circuit can also be configured to trigger at least one event, particularly triggering the activation of at least one other electronic component when a physical entity or state is detected.

[0025] The detection circuit defines the threshold voltage V th The term “threshold voltage” is also referred to as “V th " " is generally used as a broad term in this document and should be given its ordinary and customary meaning to those of ordinary skill in the art and is not limited to a special or customized meaning. Without limitation, the threshold voltage V th It can be a voltage that triggers at least one event, in particular triggers the activation of at least one other electronic component. In other words, when the threshold voltage V th In particular, as will be outlined in detail below, the threshold voltage V th It can be the threshold voltage of a transistor, especially the threshold voltage of a field effect transistor (FET). Therefore, the threshold voltage V th It can be the minimum gate-source voltage required to generate a conductive path between the source and drain of the FET. The conductive path can generally cause an increase in the current flowing through the FET. Therefore, the increased current can trigger an event.

[0026] The detection circuit is configured to detect when the output voltage V out drops to the threshold voltage V th The bypass circuit is activated when the threshold voltage V th The minimum output voltage of the driver circuit V out,min The terms "output voltage" and "minimum output voltage" are generally used herein as broad terms and should be given their ordinary and customary meanings to a person of ordinary skill in the art and are not limited to special or customized meanings. Without limitation, the output voltage may be the voltage at the output of a device or circuit, in particular a driver circuit. The minimum output voltage may be the minimum voltage required by the device or circuit, in particular by the driver circuit, for operation, in particular for normal operation or for error-free operation. Thus, the minimum output voltage may be the minimum voltage required by the driver circuit in order to provide (in particular to at least one LED) a sufficient driver current I D The minimum voltage required.

[0027] The term "activation", including its grammatical variants, is generally used herein as a broad term and should be given its ordinary and customary meaning to a person of ordinary skill in the art and is not limited to a special or customized meaning. Without limitation, activation may be or may include the start or initiation of at least one event or series of events. In particular, activating the bypass circuit may include guiding the current, in particular the driver current I D At least a portion of the LED may be passed through the bypass circuit (e.g. bypassing at least one LED). In other words, before activation, no current may be passed through the bypass circuit, and after activation, current may be passed through the bypass circuit. After activation, the current through the bypass circuit may be changed, in particular increased, more in particular increased stepwise or gradually, as will be outlined in detail below. Thus, activation may in particular be an initial activation into a non-constant or variable state, in particular a state of increasing the current through the bypass circuit.

[0028] The term "matching", including its grammatical variants, is generally used herein as a broad term and should be given its ordinary and usual meaning to a person of ordinary skill in the art, and is not limited to a special or customized meaning. Without limitation, matching may refer to an exact match, such as an exact match of two physical quantities, in particular two voltages. Alternatively, matching may refer to an approximate match. Therefore, there may be a special tolerance for the deviation of the physical quantities, in particular two voltages. In other words, the first physical quantity may be slightly greater than the second physical quantity. In particular, the threshold voltage V th can be slightly higher than the minimum output voltage V out,min . Threshold voltage V th Exceeding the minimum output voltage V out,min The amount of V may be less than 1 V, in particular less than 0.5 V, and more particularly less than 0.25 V. Thus, it can be ensured that the driver circuit receives sufficient operating voltage (at V out,min above).

[0029] For a better understanding, the following non-limiting example may be considered. A battery may be used as a voltage supply for a string of LEDs and a corresponding driver circuit. Over time, the battery voltage may decrease. Each LED may cause a particular voltage drop. Therefore, as the battery voltage decreases, there may be a point in time when the driver is no longer able to provide sufficient voltage, which would result in functional errors or failures. As a precaution, the threshold voltage V th can be chosen to be slightly higher than the driver circuit’s minimum output voltage V out,min, for example, by selecting corresponding electronic components, in particular corresponding transistors. Thus, the detection circuit can activate the bypass circuit in good time and, for example, can bypass one LED in the electronic circuit. As a result, the total voltage drop across the LED string can be reduced and the remaining voltage can be sufficient for accurate operation of the driver circuit. Thus, malfunctions of the driver circuit can be prevented without the need for additional battery monitoring circuits. By doing so, changes in the voltage drop across the LED, for example due to temperature, aging effects or binning, can also be automatically taken into account. Furthermore, it is even possible to keep the driver circuit operational in the event of a low battery voltage.

[0030] The detection circuit may be configured to control the bypass circuit by using negative loop feedback. In particular, the detection circuit may be configured to continuously control or adjust the bypass circuit, in particular the current passing through the bypass circuit, by using negative loop feedback. The term "negative loop feedback" is generally used as a broad term in this article and should be given its ordinary and commonly used meaning to those of ordinary skill in the art, and is not limited to a special or customized meaning. Without limitation, negative loop feedback may include feeding back at least a portion of the output of a device or system (in particular by using a loop) as an input, thereby reducing the fluctuation of the output. The loop may be configured to redirect at least a portion of the output back to the input. In particular, the output and / or input may be or may include current. In particular, the device or system may be an electronic circuit or a part of an electronic circuit. Negative loop feedback may include a loop within an electronic circuit, such as a loop that starts at a node in the electronic circuit and ends again at the node, and the loop may include at least one electronic component and / or a conductive element. The term "negative loop feedback" may refer to "negative feedback", "balance feedback", "adjustment feedback" or "negative feedback loop".

[0031] The electronic circuit is configured to continuously adjust the output voltage V by gradually bypassing the LEDs. out In other words, the electronic circuit can be configured to continuously adjust the output voltage V by gradually bypassing the LEDs. out The electronic circuit can be configured so that when the output voltage V out drops to the threshold voltage V th Below, as the output voltage V out The decrease of the bypass LED driver current I D In particular, the circuit can be configured to detect the output voltage V out When it drops to the threshold voltage V th In the following, in particular, by using a detection circuit. As mentioned above, the threshold voltage V th With minimum output voltage V out,min When the output voltage V out drops to the threshold voltage V thBelow this, the bypass circuit can be activated and the driver current I D At least a portion of the output voltage V can be directed to the vicinity of at least one LED, so that sufficient voltage can still be provided to the driver circuit. out The further reduction of the driver current I D The bypassed portion is continuously increased as described above. This may in particular distinguish the proposed electronic circuit from a bypass switch, which may generally only be set to two discrete states, i.e. fully off and fully on, and which therefore generally cannot provide continuous adjustment. In contrast, as described above, the proposed electronic circuit may apply a negative loop feedback to continuously control the bypass circuit, and in particular to control the current through the bypass circuit. In other words, due to the negative loop feedback, the bypass effect may increase with the output voltage V out Therefore, the output voltage V out In other words, at least within the predetermined voltage range, the electronic circuit can be configured to maintain the output voltage V out The predetermined voltage range may particularly refer to a predetermined voltage range of a supply voltage, such as a battery voltage. In particular, the electronic circuit may be configured to maintain the output voltage V at least after activating the bypass circuit (eg after starting to bypass at least one LED). out Constant until, even if the LEDs are all bypassed, the supply voltage is still too low to power the driver circuit. Therefore, because of the negative loop feedback, the bypass effect can increase as the supply voltage decreases.

[0032] At least one of the bypass circuit and the detection circuit may be an analog circuit. Therefore, the bypass circuit and / or the detection circuit may include analog components and particularly only analog components. The bypass circuit and / or the detection circuit may be configured to process analog signals and particularly only analog signals, more particularly to process continuous currents and / or voltages. In other words, at least one of the bypass circuit and the detection circuit may be a non-digital circuit. Therefore, the bypass circuit and / or the detection circuit may not use digital components. However, other options are also feasible. In principle, at least one of the bypass circuit and the detection circuit may also include at least one digital component.

[0033] The electronic circuit may include at least one capacitor configured to stabilize the electronic circuit. The capacitor may define a low pass filter in the electronic circuit. Thus, the capacitor may be configured and / or arranged to filter out high frequency signals (particularly high frequency currents) in the electronic circuit to stabilize the electronic circuit. The capacitor may have a capacitance value from 1 nF to 10 nF.

[0034] The detection circuit may include at least one transistor. As already indicated above, the threshold voltage V thCan be the threshold voltage of the transistor. The term "transistor" is generally used as a broad term in this article, and should be given its ordinary and commonly used meaning for ordinary technicians in the field, and is not limited to a special or customized meaning. Without limitation, it refers to a semiconductor device configured to switch and / or amplify electrical signals and / or electrical power. The transistor may particularly include at least three contacts, also referred to as electrodes or terminals. The transistor can be constructed in such a way that the voltage and / or current applied to the first pair of contacts can control the current passing through the second pair of contacts. The transistor can particularly be a field effect transistor (FET) including a gate contact, a drain contact and a source contact, and more particularly a metal oxide semiconductor field effect transistor (MOSFET). The transistor can be arranged (particularly within a circuit) so that the output voltage V out is applied to the gate contact of the transistor. The transistor may be selected from the group consisting of: N-type enhancement MOSFET, P-type enhancement MOSFET, N-type depletion MOSFET, P-type depletion MOSFET.

[0035] The bypass circuit may include at least one transistor, in particular at least one FET, the FET including a gate contact, a drain contact and a source contact. The transistor may be selected from the group including: an N-type enhancement MOSFET, a P-type enhancement MOSFET, an N-type depletion MOSFET, a P-type depletion MOSFET. The electronic circuit may include at least one of a pull-up resistor and a pull-down resistor. A pull-up resistor may be a resistor that is arranged and / or configured to connect a signal line in a circuit to a higher voltage (e.g., a supply voltage) without other components (e.g., a switching transistor) actively bringing the signal line to a lower voltage (e.g., ground). A pull-down resistor may be a resistor that is arranged and / or configured to connect a signal line in a circuit to a lower voltage (e.g., ground) without other components (e.g., a switching transistor) actively bringing the signal line to a higher voltage (e.g., a supply voltage). The pull-up resistor and / or the pull-down resistor may be typically a high-ohmic resistor, such as a 100kΩ resistor. Therefore, overall, the proposed electronic circuit can in principle work with components that are highly available on the market, such as N-type enhancement-mode MOSFETs, capacitors, and electrical appliances.

[0036] In other aspects of the present disclosure, a driver system is disclosed. The driver system includes at least one electronic circuit according to any of the embodiments involving electronic circuits described in further detail above or below. The driver circuit also includes a circuit configured to provide a driver current I Dat least one driver circuit. In the driver system, the electronic circuit and the driver circuit can be connected, for example, via wires and / or traces. At least one of the bypass circuit and the detection circuit can be an external circuit relative to the driver circuit. As described above, the electronic circuit can include at least one integrated circuit. The detection circuit can be an integrated circuit. The bypass circuit can be an integrated circuit. The detection circuit and the bypass circuit can also be part of an integrated circuit together. In addition, the driver circuit can be a separate integrated circuit. Therefore, the bypass circuit and / or the detection circuit can be decoupled from the driver circuit. This can be particularly beneficial for modular combination and individual size design of components. However, the driver circuit, the bypass circuit and the detection circuit can also be part of an integrated circuit. The driver system can also include a circuit configured to at least sense the driver current I D at least one sense resistor.

[0037] In other aspects of the present disclosure, a lighting system is disclosed. The lighting system comprises at least one driver system according to any of the embodiments relating to the driver system described in detail above or below. The lighting system further comprises at least one LED. In the lighting system, the driver system and the LED may be electrically connected, for example, via wires and / or traces. The lighting system may comprise at least one voltage source, in particular at least one battery. In the lighting system, the driver system and the LED and the voltage source may be electrically connected, for example, via wires and / or traces.

[0038] In other aspects of the present disclosure, a method for bypassing at least one LED is disclosed. The method is performed by using at least one circuit according to any of the embodiments involving electronic circuits disclosed in detail above or below. The method comprises at least the following steps:

[0039] a) When the output voltage V out drops to the detection circuit threshold voltage V th The bypass circuit is activated when:

[0040] b) By using a bypass circuit, the driver current I D At least a portion of the LED is bypassed.

[0041] In particular, step a) may be performed before step b). More particularly, step a) may trigger step b). Other steps may be feasible. The detection circuit may control the bypass circuit by using negative loop feedback. When the output voltage V out drops to the threshold voltage V th When the output voltage V out The decrease in the bypass LED driver current I DAt least within a predetermined voltage range, the electronic circuit can maintain the output voltage V out For other definitions and embodiments of this method, reference may be made to the definitions and embodiments of the electronic circuit outlined above.

[0042] The apparatus and method disclosed in this article have considerable advantages in the present advanced field, as has been indicated by the description. By using the apparatus and method proposed in this article, it is particularly possible to avoid failures of driver systems for LEDs (e.g. automotive applications powered by battery voltage). As a result, safety can be increased, which can be of particular significance for road traffic. In addition, normal operation of the driver system can be maintained even at lower battery voltages. A battery monitoring circuit may not be required. The proposed electronic circuit may be insensitive to changes in the forward voltage of the LED, for example due to temperature. Additional pins in the driver system may not be required. It can even work with a driver system with a power unloading circuit. The proposed circuit may be generally applicable to multiple current sources and current sinks as driver circuits. There may also be a large number of components available for the electronic circuit in the market, such as N-type enhancement MOSFETs. The proposed electronic circuit or part thereof may be an external circuit, which can facilitate easy dimensioning of external components.

[0043] In summary, and without excluding other further possible embodiments, the following embodiments may be envisaged:

[0044] Embodiment 1: An electronic circuit configured to be connected to at least one light emitting diode (LED) and at least one driver circuit, wherein the driver circuit is configured to provide a driver current I D , the electronic circuit comprises:

[0045] The bypass circuit is configured to make the driver current I D bypassing at least a portion of the LEDs; and

[0046] Detection circuit, define the threshold voltage V th , wherein the detection circuit is configured to: when the output voltage V out drops to the threshold voltage V th The bypass circuit is activated when:

[0047] The threshold voltage V th The minimum output voltage of the driver circuit V out,min Match.

[0048] Embodiment 2: The electronic circuit according to the aforementioned embodiment 1, wherein the detection circuit is configured to control the bypass circuit by using a negative loop feedback.

[0049] Embodiment 3: An electronic circuit according to any of the preceding embodiments, wherein the circuit is configured to continuously adjust the output voltage V by gradually bypassing the LEDs out .

[0050] Embodiment 4: An electronic circuit according to any one of the preceding embodiments, wherein the circuit is configured to: when the output voltage V out drops to the threshold voltage V th Below, with the output voltage V out The decrease of the bypass LED driver current I D part.

[0051] Embodiment 5: The electronic circuit according to any one of the preceding embodiments, wherein, at least within a predetermined voltage range, the electronic circuit is configured to maintain an output voltage V out Constant.

[0052] Embodiment 6: The electronic circuit according to any one of the preceding embodiments, wherein at least one of the bypass circuit and the detection circuit is an analog circuit.

[0053] Embodiment 7: The electronic circuit according to any one of the preceding embodiments, further comprising at least one capacitor configured to stabilize the electronic circuit.

[0054] Embodiment 8: The electronic circuit according to any one of the preceding embodiments, wherein the capacitor defines a low pass filter in the electronic circuit.

[0055] Embodiment 9: The electronic circuit according to any one of the preceding embodiments, wherein the threshold voltage V th Exceeding the minimum output voltage V out,min The amount is less than 1V, particularly less than 0.5V, more particularly less than 0.25V.

[0056] Embodiment 10: The electronic circuit according to any one of the preceding embodiments, wherein the detection circuit comprises at least one transistor.

[0057] Embodiment 11: The electronic circuit according to embodiment 10, wherein the threshold voltage V th is the threshold voltage of the transistor.

[0058] Embodiment 12: An electronic circuit according to any one of embodiments 10 and 11, wherein the transistor is a field effect transistor (FET) comprising a gate contact, a drain contact and a source contact, wherein the transistor is arranged so that the output voltage V out Applied to the gate contact of the transistor.

[0059] Embodiment 13: An electronic circuit according to any one of embodiments 10-12, wherein the transistor is selected from the group consisting of: N-type enhancement metal oxide semiconductor field effect transistor (MOSFET), P-type enhancement MOSFET, N-type depletion MOSFET, P-type depletion MOSFET.

[0060] Embodiment 14: The electronic circuit according to any of the preceding embodiments, wherein the bypass circuit comprises at least one transistor, in particular at least one FET comprising a gate contact, a drain contact and a source contact.

[0061] Embodiment 15: An electronic circuit according to embodiment 14, wherein the transistor is selected from the group consisting of: N-type enhancement MOSFET (metal oxide semiconductor field effect transistor), P-type enhancement MOSFET, N-type depletion MOSFET, P-type depletion MOSFET.

[0062] Embodiment 16: The electronic circuit according to any one of the preceding embodiments, further comprising at least one of a pull-up resistor and a pull-down resistor.

[0063] Embodiment 17: A driver system, comprising at least one electronic circuit according to any of the preceding embodiments and a circuit configured to provide a driver current I D at least one driver circuit.

[0064] Embodiment 18: The driver system according to Embodiment 17, wherein at least one of the bypass circuit and the detection circuit is an external circuit relative to the driver circuit.

[0065] Embodiment 19: A driver system according to any of the preceding embodiments relating to a driver system, wherein the driver system comprises at least one current sink (in particular a constant current sink) and a current source (in particular a constant current source).

[0066] Embodiment 20: An electronic circuit according to any of the preceding embodiments relating to a driver system, further comprising a circuit configured to at least sense a driver current I D at least one sensing resistor.

[0067] Embodiment 21: A lighting system comprising at least one driver system according to any of the preceding embodiments with reference to the driving system and at least one LED.

[0068] Embodiment 22: The lighting system according to the aforementioned Embodiment 21 further comprises at least one voltage source, in particular at least one battery.

[0069] Embodiment 23: A method for bypassing at least one LED by using at least one electronic circuit according to any of the previous embodiments of the reference electronic circuit, the method comprising at least the following steps:

[0070] a) When the output voltage V out drops to the detection circuit threshold voltage V th activating the bypass circuit by using the detection circuit when:

[0071] b) By using a bypass circuit to reduce the drive current I D At least a portion of the LED is bypassed.

[0072] Embodiment 24: The method according to the aforementioned embodiment 23, wherein the detection circuit controls the bypass circuit by using negative loop feedback.

[0073] Embodiment 25: The method according to any of the preceding embodiments, wherein the electronic circuit continuously adjusts the output voltage V by gradually bypassing the LEDs. out .

[0074] Embodiment 26: A method according to any of the preceding embodiments, wherein when the output voltage V out drops to the threshold voltage V th When the output voltage V out The decrease of the bypass LED driver current I D part.

[0075] Embodiment 27: A method according to any of the preceding embodiments, wherein the electronic circuit maintains the output voltage V at least within a predetermined voltage threshold. out Constant.

[0076] More special optional functions and embodiments will be described in detail in the description of the subsequent embodiments in conjunction with the illustrations. Among them, as those skilled in the art will appreciate, various optional functions can be implemented in an independent manner or in any feasible combination. The scope of the present disclosure is generally not limited by the preferred embodiments. The embodiments may be schematically described only in the figures.

[0077] Figure 1 1 shows a circuit diagram of an exemplary lighting system 110. According to any of the embodiments involving driver systems described in further detail above or below, the lighting system 110 includes at least one driver system 112. The lighting system 110 also includes at least one LED 114. Figure 1As shown, the lighting system 110 may include, for example, three LEDs 114. The lighting system 110 may also include at least one voltage source 116, in particular at least one battery 118. The voltage source 116 may be configured to provide a supply voltage V s The driver system 112 comprises at least one electronic circuit 120 according to any of the embodiments involving electronic circuits described in further detail above or below. The driver system 112 also comprises a circuit configured to provide a driver current I D At least one driver circuit 122.

[0078] The electronic circuit 120 is configured to be connected to at least one LED 114 and is configured to provide a driver current I D At least one driver circuit 122. As shown, the electronic circuit 120 can be connected to at least one LED 114 and / or at least one driver circuit 122 by using wires and / or traces. In addition, the electronic circuit 120 can be configured to be connected to a voltage source 116. In particular, the electronic circuit 120 can be connected to the voltage source 116 by using wires and / or traces. Generally speaking, the electronic circuit 120 can be connected to other devices by using wires and / or traces. In addition, the components of the electronic circuit 120 can be at least partially interconnected to each other by using wires and / or traces.

[0079] The electronic circuit 120 includes a bypass circuit 124. The bypass circuit 124 is configured to make the driver current I D The bypass circuit 124 bypasses at least a portion of the LED 114. As shown, the bypass circuit 124 can bypass one LED 114. However, in principle, two or more LEDs 114 can also be bypassed by the bypass circuit 124. The electronic circuit 120 also includes a detection circuit 126. The detection circuit 126 is configured to detect when the output voltage V out drops to the threshold voltage V th When the threshold voltage V th The minimum output voltage V of the driver circuit 122 out,min Match.

[0080] At least one of the bypass circuit 124 and the detection circuit 126 may be an analog circuit. As shown in the figure, for example, the bypass circuit 124 and the detection circuit 126 are both analog circuits. The detection circuit 124 may include at least one transistor 128. The threshold voltage V th V may be specifically a threshold voltage of transistor 128, unless another component is involved in the description. Transistor 128 may be specifically a FET 130 including a gate contact, a drain contact and a source contact. Transistor 128 may be arranged such that the output voltage Vout is applied to the gate contact of transistor 128. Lighting system 110 may include an output node 132 at the output of driver system 112. Thus, output voltage V out Can be applied to the output node 132. The detection circuit 126, in particular the gate contact of the transistor 128, can be connected to the output node 132. Therefore, the output voltage V out 134. The bypass circuit 124 may also include at least one transistor 136, in particular at least one FET 138, the FET 138 including a gate contact, a drain contact and a source contact. More particularly, the transistor 134 may be an N-type enhancement MOSFET 140.

[0081] The electronic circuit 120 may further include at least one pull-up resistor 142. The pull-up resistor 142 may provide a connection, in particular a high-ohmic connection, to the voltage source 116. The electronic circuit 120 may further include at least one capacitor 144 configured to stabilize the electronic circuit 120. The capacitor 144 may define a low-pass filter in the circuit 144. Thus, the capacitor 144 may be arranged in parallel with the transistor 124.

[0082] The driver circuit 122 may be a low-side driver circuit. Therefore, the driver circuit 122 may be a current sink 146, in particular a constant current sink 148. Therefore, the driver current I D The constant current may in particular be passed through the LED 114. In general, many options for implementing a constant current sink are known to the skilled person. For example, Figure 1 As shown in FIG. 1 , the constant current sink 148 may include an internal voltage source 150 configured to provide a reference voltage V connected to ground 152, an operational amplifier 154, and a transistor 156. ref The transistor 156 may be particularly a FET 158 and more particularly an N-type enhancement mode MOSFET 160. A number of other options are also generally possible to implement the driver circuit 122.

[0083] At least one bypass circuit 124 and the detection circuit 126 may be external circuits relative to the driver circuit 122. Thus, at least one bypass circuit 124 and the detection circuit 126 may be arranged on a separate substrate, such as a separate piece of semiconductor material, in particular silicon. For example, the driver circuit 122 may be a first integrated circuit, and the bypass circuit 124 and the detection circuit 126 may together form a separate second integrated circuit. Thus, the bypass circuit 124 and the detection circuit 126 may be decoupled from the driver circuit 122. This may be particularly advantageous for modular combination and individual dimensioning of components. Furthermore, the driver system 112 may include a circuit configured to at least sense the driver current I D At least one sensing resistor 162 is provided. The sensing resistor 162 may be arranged in particular as a shunt resistor. The sensing resistor 162 may be connected to ground 164.

[0084] As shown in the figure, a voltage source 116, in particular a battery 118, can provide a supply voltage V to the lighting system 110. s , and thus provides a supply voltage V to the LED 114 and to the driver circuit 122 s . LED 114 can cause the supply voltage V s Therefore, the output voltage V out can be present at the output node 132. Therefore, the output voltage V out can be applied to the driver circuit 122. Therefore, the output voltage V out Too low, for example, because the supply voltage V provided by the battery s This may cause the driver circuit 122 to malfunction. In addition, the output voltage V out It can also be applied to the detection circuit 126, in particular to the transistor 128, and more particularly to the gate contact of the N-type enhancement MOSFET 134. The threshold voltage V th may be slightly higher than the minimum output voltage V of the driver circuit 122. out,min , for example, the minimum output voltage required for error-free operation of the driver circuit 122. In particular, the threshold voltage V th can exceed the minimum output voltage V out,min The amount is less than 1V, particularly less than 0.5V, more particularly less than 0.25V.

[0085] When the output voltage V out Above the minimum output voltage V out,min and is therefore also higher than the threshold voltage V of the N-type enhancement MOSFET 134 thWhen the N-type enhancement MOSFET 134 is turned on, the N-type enhancement MOSFET 134 can be in the on state. Therefore, current can flow from the source contact of the N-type enhancement MOSFET 134 to the drain contact of the N-type enhancement MOSFET 134. The source contact of the N-type enhancement MOSFET 134 can be connected to the ground 166. The drain contact of the N-type enhancement MOSFET 134 can be connected to the supply voltage V through the pull-up resistor 142. s Therefore, when the N-type enhancement MOSFET 134 is in the on state, current can be dissipated toward the ground 166, which can pull the gate voltage of the N-type enhancement MOSFET 140 down to a lower voltage. In particular, this can keep the gate voltage of the N-type enhancement MOSFET 140 at the threshold voltage V th Therefore, when the output voltage V out Above the minimum output voltage V out,min , the N-type enhancement MOSFET 140 can be in the off state. Therefore, when the output voltage V out Above the minimum output voltage V out,min When the LED 114 is on, there may be no bypassing of the LED 114 via the bypass circuit 124. It should be noted that the on-state and the off-state may be variable states and not necessarily discrete states. In particular, the on-state may cover a continuous range of currents through the transistor.

[0086] When the output voltage V out Closer to the minimum output voltage V out,min and reaches the threshold voltage V th When the N-type enhancement mode MOSFET 134 is turned off, the N-type enhancement mode MOSFET 134 can be gradually turned off. In other words, the current passing between the source contact and the drain contact of the N-type enhancement mode MOSFET 134 can be gradually reduced. This can be achieved by using the pull-up resistor 142 to pull the gate voltage of the N-type enhancement mode MOSFET 140 to a higher voltage. In other words, this can thus increase the gate voltage of the N-type enhancement mode MOSFET 140, in particular, exceeding the threshold voltage V of the N-type enhancement mode MOSFET 140. th Therefore, the N-type enhancement MOSFET 140 can be gradually turned on and the bypass circuit 124 can be turned on. Therefore, a continuously increasing current can flow from the source contact to the drain contact of the N-type enhancement MOSFET 140. The source contact and the drain contact of the N-type enhancement MOSFET 140 can be connected to the cathode and the anode of the bypassed LED 114, respectively. Therefore, a continuously decreasing current, especially the driver current I DA successively smaller portion of can pass through the bypassed LED 114. Therefore, the total voltage drop across all LEDs 114 can be reduced, and the output voltage V out This may still be sufficient for error-free operation of the driver circuit 122 .

[0087] Therefore, in general, the detection circuit 126 can be configured to control the bypass circuit 124 by using a negative loop feedback. As outlined above, as the output voltage V out The gate voltage of the N-type enhancement mode MOSFET 134 can be reduced, and the gate voltage of the N-type enhancement mode MOSFET 140 can be increased, so that the driver current I of the bypass LED 114 is D This can continue to reduce the voltage drop across LED 114 and thus increase V again. out Therefore, the electronic circuit 120 can be configured to control the bypass effect by using a negative loop feedback. Basically, the electronic circuit 120 can be configured to control the output voltage V by using a negative loop feedback. out The electronic circuit 120 may be configured to continuously adjust the output voltage V by gradually bypassing the LED 114. out The electronic circuit 120 may be configured to output voltage V out drops to the threshold voltage V th Below, as the output voltage V out The decrease in the driver current I of the bypass LED 114 increases D Therefore, as will be outlined in detail below, at least within a predetermined voltage range, the electronic circuit 120 can be configured to maintain the output voltage V out Constant.

[0088] Figure 2 and Figure 3 The diagram shows Figure 1 . In particular, Figure 2 shows experimental results obtained without using the proposed electronic circuit 120, and Figure 3 Experimental results obtained using the proposed electronic circuit 120 are shown. Figure 2 and Figure 3 Shows V out 、V s and I D Changes over time. out 、V s and I D The vertical scale values ​​are shown in mV / div, V / div and mA / div respectively. The time axis is shown in seconds. Figure 2As shown in FIG. , without using the proposed electronic circuit 120, the output voltage V out With the supply voltage V s When the supply voltage V s When it reaches 9.3V, I D starts to decrease because the output voltage V out This is no longer sufficient for normal operation of the driver circuit 122. Figure 3 As shown in FIG. 1 , in the case of using the proposed electronic circuit 120 , due to the regulation of the LED 114 through the step-by-step bypass, the output voltage V out Over a wide supply voltage V s In addition, until the driver current I D Starts to decrease, the supply voltage V s Can drop to 6.5V.

[0089] Figures 4 to 7 The circuit diagram of other exemplary lighting systems is shown. In particular, Figures 4 to 7 The diagram shows Figure 1 A variation of the electronic circuit 120 and the driver circuit 122 shown. More specifically, Figures 4 to 7 Variants using different kinds of MOSFETs in combination with high-side driver circuits or low-side driver circuits are shown. Therefore, further details can also be found, at least to a large extent, in Figure 1 Make.

[0090] Figure 4An exemplary lighting system 410 is illustrated, which can be similar to lighting system 110 at least to a large extent. Thus, the various system components can correspond to each other at least to a large extent and further details can be made with reference to the description above. In particular, driver system 412 can correspond to driver system 112. LED 414 can correspond to LED 114. Voltage source 416 can correspond to voltage source 116. Battery 418 can correspond to battery 118. Sense resistor 462 can correspond to sense resistor 162. Ground 464 and ground 466 can correspond to ground 164 and ground 166, respectively. Driver circuit 422 can correspond to driver circuit 122. In particular, current sink 446, current sink 448, voltage source 450, ground 452, operational amplifier 454, transistor 456 (which may be particularly FET 458 and more particularly N-type enhancement MOSFET 460), may respectively correspond to components of driver circuit 122. Electronic circuit 420 may correspond, at least to a large extent, to electronic circuit 120. In particular, output node 432 may correspond to output node 132, pull-up resistor 442 may correspond to pull-up resistor 142, and capacitor 444 may correspond to capacitor 144.

[0091] The bypass circuit 424 may correspond at least largely to the bypass circuit 124. The detection circuit 426 may correspond at least largely to the detection circuit 126. The bypass circuit 424 may include a transistor 436, in particular a FET 438, more particularly an N-type depletion MOSFET 440. In other words, the transistor 436 may be an N-type depletion MOSFET 440. In general, when their threshold voltage V th When V is applied to their gate contacts, N-type depletion MOSFETs can be in an on state. The detection circuit 426 can include a transistor 428, in particular a FET 430, and more particularly an N-type enhancement MOSFET 434. Therefore, as described above, when the output voltage V out The threshold voltage V of the N-type enhancement mode MOSFET 434 is reached. th When the N-type enhancement MOSFET 434 is gradually turned off, the gate voltage of the N-type depletion MOSFET 440 can be increased, especially when the threshold voltage V th Therefore, the N-type depletion-mode MOSFET 440 in the bypass circuit 424 can be gradually turned on.

[0092] Figure 5An exemplary lighting system 510 is illustrated, which may also be similar to the lighting system 110 at least to a large extent. Thus, the various system components may largely correspond to each other and further details may be made with reference to the description above. In particular, the driver system 512 may correspond to the driver system 112. The LED 514 may correspond to the LED 114. The voltage source 516 may correspond to the voltage source 116. The battery 518 may correspond to the battery 118. The sense resistor 562 may correspond to the sense resistor 162. The ground 564 may correspond to the ground 164. The driver circuit 522 may correspond to the driver circuit 122. In particular, the current sink 546, the constant current sink 548, the voltage source 550, the ground 552, the operational amplifier 554, the transistor 556 (which may be particularly a FET 558 and more particularly an N-type enhancement MOSFET 560) may correspond to the various components of the driver circuit 122. Electronic circuit 520 may correspond at least largely to electronic circuit 120. In particular, output node 532 may correspond to output node 132 and capacitor 544 may correspond to capacitor 144.

[0093] The bypass circuit 524 may correspond at least largely to the bypass circuit 124. The detection circuit 526 may correspond at least largely to the detection circuit 126. The bypass circuit 524 may include a transistor 436, in particular a FET 438, more particularly a P-type enhancement MOSFET 540. In other words, the transistor 436 may be a P-type enhancement MOSFET 540. The detection circuit 526 may include a first transistor 528, in particular a FET 530, more particularly an N-type enhancement MOSFET 534, and a second transistor 528', in particular a FET 530', more particularly an N-type enhancement MOSFET 534'. The source contact of the N-type enhancement MOSFET 534' may be connected to the ground 566'. The electronic circuit 520 may include a first pull-up resistor 542 connected to the drain contact of the N-type enhancement MOSFET 534, and a second pull-up resistor 542' connected to the drain contact of the N-type enhancement MOSFET 534'. The drain contact of the N-type enhancement MOSFET 534 can also be connected to the gate contact of the N-type enhancement MOSFET 534'. The threshold voltage V th can be slightly higher than the minimum output voltage V out,min Therefore, when the output voltage V out Reaching the minimum output voltage V out,minWhen the N-type enhancement MOSFET 534 is turned off, the N-type enhancement MOSFET 534 can be gradually turned off and the gradually decreasing current can be dissipated to the ground 566. By using the pull-up resistor 542, the voltage applied to the gate contact of the N-type enhancement MOSFET 534' can be increased, which can gradually turn on the N-type enhancement MOSFET 534'. Therefore, the current can be dissipated to the ground 566'. This can again reduce the gate voltage of the P-type enhancement MOSFET 540 applied to the bypass circuit 524. Therefore, the P-type enhancement MOSFET 540 can be gradually turned on to bypass the upper LED 514.

[0094] Figure 6 An exemplary lighting system 610 is illustrated, which may also be at least largely similar to lighting system 110. Thus, the various system components may at least largely correspond to each other and further details may be made with reference to the description above. In particular, LED 614 may correspond to LED 114. The LED may be connected to ground 664. Voltage source 616 may correspond to voltage source 116. Battery 618 may correspond to battery 118. Sense resistor 662 may correspond to sense resistor 162. Driver system 512 may at least largely correspond to driver system 112.

[0095] In particular, the driver system 612 may include a driver circuit 622 that may be a high-side driver circuit. Thus, the driver circuit 622 may be a current source 646, in particular a constant current source 648. Thus, the driver current I D It can be a constant current through LED 614 in particular. Generally speaking, many options for implementing constant current source 648 are known to the skilled person. For example, Figure 6 As shown in FIG. 6 , the constant current source 648 may include a circuit configured to provide a reference voltage V to ground 652. ref The internal voltage source 650, the operational amplifier 654 and the operational amplifier 654', and the transistor 656. The transistor 656 can be particularly a FET 658 and more particularly a P-type depletion MOSFET 660. A number of other options are also generally used to implement the driver circuit 622.

[0096] The electronic circuit 620 may correspond at least largely to the electronic circuit 120. In particular, the output node 632 may correspond to the output node 132, and the capacitor 644 may correspond to the capacitor 144. The bypass circuit 624 may correspond at least largely to the bypass circuit 124. The detection circuit 626 may correspond at least largely to the detection circuit 126. The bypass circuit 624 may include a transistor 636, in particular a FET 638, more particularly a P-type enhancement MOSFET 640. In other words, the transistor 636 may be a P-type enhancement MOSFET 640. The detection circuit 626 may include a transistor 628, in particular a FET 630, more particularly a P-type enhancement MOSFET 634. In other words, the transistor 628 may be a P-type enhancement MOSFET 634. Therefore, in an exemplary embodiment, the driver system 620 may use only P-type enhancement MOSFETs. P-type enhancement MOSFETs may typically be MOSFETs with a gate-source voltage at their threshold voltage V th The gate-source voltage is below their threshold voltage V th The electronic circuit 620 is in the off state when the power is turned on or off. However, as mentioned above, other transistors, in particular other types of MOSFETs or mixed types of MOSFETs can also be used in general. The electronic circuit 620 can also include a pull-down resistor 642 in particular. The pull-down resistor 642 can provide a connection to the ground 666, in particular a high-ohmic connection. In other words, the pull-down resistor 642 can be connected to the ground 666.

[0097] In particular, the threshold voltage V th can be slightly higher than the minimum output voltage V out,min The source contact of the P-type enhancement mode MOSFET 634 can be connected to the supply voltage V s Therefore, when the output voltage V out Reaching the minimum output voltage V out,min , the P-type enhancement MOSFET 634 can be gradually turned off. Subsequently, the gate voltage of the P-type enhancement MOSFET 640 of the bypass circuit 624 can be pulled to a lower voltage by using a pull-down resistor 642 connected to ground 666. The source contact of the P-type enhancement MOSFET 640 can be connected to the output voltage V out Therefore, the P-type enhancement mode MOSFET 640 can be gradually turned on.

[0098] Figure 7An exemplary lighting system 710 is illustrated, which may also be at least largely similar to lighting system 110. Thus, the various system components may at least largely correspond to each other and further details may be made with reference to the description above. In particular, LED 714 may correspond to LED 114. The LED may be connected to ground 764. Voltage source 716 may correspond to voltage source 116. Battery 618 may correspond to battery 118. Sense resistor 762 may correspond to sense resistor 162. Driver system 612 may at least largely correspond to driver system 112.

[0099] Again, the driver system 712 may include a driver circuit 722 that may be a high-side driver circuit. Thus, the driver circuit 722 may be a current source 746, in particular a constant current source 748. Thus, the driver current I D Specifically, it may be a constant current through the LED 614. In the example shown, the constant current sink 748 may include a voltage source configured to provide a reference voltage V connected to the ground 752. ref The internal voltage source 750, the operational amplifier 754 and the operational amplifier 754' and the transistor 756. The transistor 756 can be particularly a FET 758 and more particularly a P-type enhancement MOSFET 760. As already described, a number of other options are also generally available for implementing the driver circuit 622.

[0100] The electronic circuit 720 may correspond at least largely to the electronic circuit 120. In particular, the output node 732 may correspond to the output node 132, and the capacitor 744 may correspond to the capacitor 144. The bypass circuit 724 may correspond at least largely to the bypass circuit 124. The detection circuit 726 may correspond at least largely to the detection circuit 126. The bypass circuit 724 may include a transistor 736, in particular a FET 738, more particularly an N-type enhancement MOSFET 640. In other words, the transistor 736 may be an N-type enhancement MOSFET 740. The source contact of the N-type enhancement MOSFET 740 may be connected to the ground 768. The detection circuit 726 may include a transistor 728, in particular a FET 730, more particularly a P-type enhancement MOSFET 734. The detection circuit 726 may further include a transistor 728', in particular a FET 730', more particularly a P-type enhancement MOSFET 734'. The electronic circuit 720 may also include, in particular, a pull-down resistor 742. The pull-down resistor 742 may be connected to the drain contact of the P-type enhancement MOSFET 734 and also to the ground 766. The drain contact of the P-type enhancement MOSFET 734 may also be connected to the gate contact of the P-type enhancement MOSFET 734'. The electronic circuit 720 may also include a pull-down resistor 742'. The pull-down resistor 742' may be connected to the drain contact of the P-type enhancement MOSFET 734' and also to the ground 766'.

[0101] The threshold voltage V of the P-type enhancement MOSFET 734 th can be slightly higher than the minimum output voltage V out,min The source contact of the P-type enhancement mode MOSFET 734 can be connected to V s Therefore, when the output voltage V out Reaching the minimum output voltage V out,min , the P-type enhancement MOSFET 734 can be gradually turned off. Subsequently, the gate voltage of the P-type enhancement MOSFET 734' can be pulled to a lower voltage by using a pull-down resistor 742 connected to ground 766. The source contact of the P-type enhancement MOSFET 734' can also be connected to V s Therefore, the P-type enhancement MOSFET 734' of the detection circuit 726 can be gradually turned on. Subsequently, the gate voltage of the N-type enhancement MOSFET 740 can be pulled to a higher voltage. Therefore, the N-type enhancement MOSFET 740 of the bypass circuit 724 can be gradually turned on.

[0102] Figure 8A flow chart of an exemplary method for bypassing at least one LED by using at least one electronic circuit according to any of the embodiments of the electronic circuit described in detail above or below is illustrated. The method comprises at least the following steps:

[0103] a) (indicated by reference numeral 810) when the output voltage V out The threshold voltage V th activating the bypass circuit by using the detection circuit when:

[0104] b) (indicated by reference numeral 812) by using a bypass circuit to reduce the driver current I D At least a portion of the LED is bypassed.

[0105] In particular, step a) may be performed before step b). More particularly, step a) may trigger step b). Further steps may be possible. The detection circuit may control the bypass circuit by using negative loop feedback. The electronic circuit may continuously adjust the output voltage V by gradually or gradually bypassing the LED. out . The output voltage V out drops to the threshold voltage V th Below, the electronic circuit can follow the output voltage V out The driver current I of the bypass LED 114 is continuously increased by decreasing D At least within a predetermined voltage range, the electronic circuit can maintain the output voltage V out Constant.

[0106] Although specific examples have been illustrated and described herein, those of ordinary skill in the art will appreciate that multiple options and / or equivalent implementations may be used to replace the specific examples shown and described without exceeding the scope of the present disclosure. This application is intended to cover any adjustments or changes to the specific examples discussed herein. Therefore, it is intended that the present disclosure is limited only by the claims and their equivalents.

[0107] It should be noted that the methods and apparatuses outlined in this disclosure, including preferred embodiments thereof, may be used alone or in combination with other methods or apparatuses disclosed in this document. Furthermore, features outlined in the context of an apparatus also apply to the corresponding method, and vice versa. Furthermore, all aspects of the methods and apparatuses outlined in this document may be combined arbitrarily. In particular, the features of the claims may be combined with each other in any manner.

[0108] It should be noted that the description and drawings illustrate only the principles of the provided methods and devices. Those skilled in the art may implement a variety of arrangements that, although not explicitly described or shown herein, embody the principles of the present disclosure and are included in its spirit and scope. In addition, all examples and embodiments outlined in this disclosure are clearly intended in principle to be merely illustrative purposes, to help the reader understand the principles of the proposed methods and systems. In addition, all descriptions of the principles, aspects, and embodiments of the present disclosure provided herein are intended to include their equivalents, as are the specific examples of the present disclosure.

Claims

1. An electronic circuit (120, 420, 520, 620, 720) configured to be connected to at least one light emitting diode LED (114, 414, 514, 614, 714) and configured to provide a driver current I D At least one driver circuit (122, 422, 522, 622, 722) of the electronic circuit (120, 420, 520, 620, 720) comprising: The bypass circuit (124, 424, 524, 624, 724) is configured to make the driver current I D bypassing at least a portion of the LEDs (114, 414, 514, 614, 714); as well as Detection circuit (126, 426, 526, 626, 726), defines a threshold voltage V th , wherein the detection circuit (126, 426, 526, 626, 726) is configured to: when the output voltage V at the driver circuit (122, 422, 522, 622, 722) out drops to the threshold voltage V th When the threshold voltage V th and the minimum output voltage V of the driver circuit (122, 422, 522, 622, 722) out,min Match.

2. The electronic circuit (120, 420, 520, 620, 720) according to the preceding claim, wherein the detection circuit (126, 426, 526, 626, 726) is configured to control the bypass circuit by using negative loop feedback.

3. The electronic circuit (120, 420, 520, 620, 720) according to any of the preceding claims, wherein the electronic circuit (120, 420, 520, 620, 720) is configured to continuously adjust the output voltage V by gradually bypassing the LED (114, 414, 514, 614, 714). out .

4. The electronic circuit (120, 420, 520, 620, 720) according to any one of the preceding claims, wherein the electronic circuit (120, 420, 520, 620, 720) is configured to: when the output voltage V out drops to the threshold voltage V th Below, as the output voltage V out The driver current I of the LED (114, 414, 514, 614, 714) is continuously increased by decreasing D of the said part.

5. The electronic circuit (120, 420, 520, 620, 720) according to any one of the preceding claims, wherein at least within a predetermined voltage range, the electronic circuit (120, 420, 520, 620, 720) is configured to maintain the output voltage V out Constant.

6. The electronic circuit (120, 420, 520, 620, 720) of any one of the preceding claims, wherein at least one of the bypass circuit (124, 424, 524, 624, 724) and the detection circuit (126, 426, 526, 626, 726) is an analog circuit.

7. The electronic circuit (120, 420, 520, 620, 720) according to any of the preceding claims, further comprising at least one capacitor (144, 444, 544, 644, 744) configured to stabilize the electronic circuit (120, 420, 520, 620, 720), wherein the capacitor (144, 444, 544, 644, 744) defines a low pass filter in the electronic circuit (120, 420, 520, 620, 720).

8. The electronic circuit (120, 420, 520, 620, 720) according to any one of the preceding claims, wherein the detection circuit (126, 426, 526, 626, 726) comprises at least one transistor (128, 428, 528, 628, 728), wherein the threshold voltage V th is the threshold voltage of the transistor (128, 428, 528, 628, 728).

9. The electronic circuit (120, 420, 520, 620, 720) according to claim 8, wherein the transistor (128, 428, 528, 628, 728) is a field effect transistor FET (130, 430, 530, 630, 730) comprising a gate contact, a drain contact and a source contact, wherein the transistor (128, 428, 528, 628, 728) is arranged so that the output voltage V out Applied to the gate contact of the transistor (128, 428, 528, 628, 728).

10. A driver system (112, 412, 512, 612, 712) comprising at least one electronic circuit (120, 420, 520, 620, 720) according to any one of the preceding claims and configured to provide a driver current I D at least one driver circuit (122, 422, 522, 622, 722).

11. A lighting system (110, 410, 510, 610, 710) comprising at least one reference driver system (112, 412, 512, 612, 712) according to any of the preceding claims relating to a driver system (112, 412, 512, 612, 712) and at least one LED (114, 414, 514, 614, 714).

12. A method for bypassing at least one LED (114, 414, 514, 614, 714) by using at least one electronic circuit (120, 420, 520, 620, 720) according to any of the preceding claims relating to an electronic circuit (120, 420, 520, 620, 720), the method comprising at least the following steps: When the output voltage V at the driver circuit (122, 422, 522, 622, 722) out drops to the threshold voltage V of the detection circuit (126, 426, 526, 626, 726) th When the bypass circuit (124, 424, 524, 624, 724) is activated by using the detection circuit (126, 426, 526, 626, 726); and By using the bypass circuit (124, 424, 524, 624, 724) to make the driver current I D At least a portion of the LED (114, 414, 514, 614, 714) is bypassed.

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