Lighting circuit for controlling micro LED clusters in pixelated light sources

Abstract

The invention relates to a lighting circuit for controlling micro LED clusters in pixelated light sources. A method of controlling a cluster of micro-LEDs within a larger matrix of micro-LEDs may include receiving a reference current at a current-to-voltage converter circuit and generating a reference voltage based on the reference current. The method may also include receiving a reference current at the NxM micro LED driver circuits and generating a regulation current for each of the NxM micro LEDs, where M and N represent positive integers.

Description

Technical Field

[0001] This disclosure relates to circuitry for driving and controlling pixelated light sources, such as circuitry for vehicle headlights comprising a matrix of light-emitting diodes (LEDs). Background Technology

[0002] Driver circuits are commonly used to control voltage, current, or power at a load. For example, a light-emitting diode (LED) driver can control the power supplied to one or more LEDs. LED drivers may include voltage regulators, line regulators, or DC-DC power converters (such as buck-boost, buck, boost, or another DC-DC power converter). DC-DC power converters can be particularly useful for LED drivers to regulate the current through an LED string.

[0003] Some LED circuits consist of a large number of individually controllable LEDs arranged in a two-dimensional matrix. These individually controllable “miniature” LEDs can be driven to provide different lighting for different driving conditions (e.g., high beam or low beam) or to provide advanced lighting effects.

[0004] An advanced vehicle headlight system is an example application of such a matrix LED circuit, whereby the lighting effects associated with vehicle operation can be used to improve the driving experience and enhance vehicle safety. Summary of the Invention

[0005] Generally, this disclosure relates to circuitry for controlling and driving pixelated light sources, such as those used in advanced vehicle headlight systems, for example, so-called miniature light-emitting diode (micro-LED) matrices. The circuitry of this disclosure can be configured to control clusters of micro-LEDs. Individual circuits can be configured to receive a reference current and generate a reference voltage based on that reference current. Instead of implementing a current-to-voltage conversion for each individual micro-LED, a single current-to-voltage conversion can be used to generate a reference voltage for the entire N×M LED cluster, where N and M are positive integers. A corresponding number of N×M micro-LED driver circuits can then be configured to receive the reference voltage and generate a regulating current for each of the N×M micro-LEDs. The reference current and reference voltage can define a regulating loop (e.g., a closed-loop loop) for the entire cluster, while each individual micro-LED can still be controlled or adjusted via another regulating loop (e.g., an open-loop loop) within each of the N×M micro-LED driver circuits.

[0006] In one example, this disclosure describes a lighting circuit configured to control an N×M cluster of microLEDs. The lighting circuit may include: a current-to-voltage converter circuit configured to receive a reference current and generate a reference voltage based on the reference current; and an N×M microLED driver circuit configured to receive the reference voltage and generate an adjustable current for each of the N×M microLEDs, where M and N represent positive integers.

[0007] In another example, this disclosure describes a method comprising: receiving a reference current at a current-to-voltage converter circuit and generating a reference voltage based on the reference current; and receiving the reference voltage at an N×M miniature LED driver circuit and generating an regulated current for each of the N×M miniature LEDs, wherein M and N represent positive integers.

[0008] In another example, this disclosure describes a system including a matrix of micro-LEDs and a plurality of lighting circuits. Each of the lighting circuits can be configured to control an N×M cluster of micro-LEDs, and each of the lighting circuits can include: a current-to-voltage converter circuit configured to receive a reference current and generate a reference voltage based on the reference current; and N×M micro-LED driver circuits configured to receive the reference voltage and generate an adjustable current for each of the N×M micro-LEDs, where M and N represent positive integers.

[0009] Details of these and other examples are set forth in the accompanying drawings and the following description. Other features, objects, and advantages will be apparent from the description and drawings, as well as from the claims. Attached Figure Description

[0010] Figure 1 The diagram is a block diagram of a system including lighting circuitry and a processor, consistent with this disclosure.

[0011] Figure 2 This is a conceptual diagram showing a miniature LED driver matrix and a close-up view of a driver circuit connected to a miniature LED.

[0012] Figure 3A and Figure 3B This is a circuit diagram showing some example LED and driver arrangements.

[0013] Figure 4 This is a block diagram illustrating an example LED driver that can provide output current (Iout) to a single LED.

[0014] Figure 5 This is a circuit diagram showing the current reference routed to the micro LED driver circuit.

[0015] Figure 6This is a block diagram showing a matrix LED system, from which a current reference generator can generate a reference current for routing to the micro-LEDs.

[0016] Figures 7A-7C This is a conceptual diagram illustrating different ways of routing signals associated with a reference current to different LED drivers.

[0017] Figure 8 This is a block diagram illustrating one way of routing a current reference signal to multiple LED driver circuits, each including a reference voltage generator.

[0018] Figure 9 This is a block diagram illustrating one method of routing a current reference signal to multiple LED driver circuits that share a reference voltage generator.

[0019] Figure 10 This is another conceptual diagram illustrating another way of routing a signal associated with a reference current to different LED drivers.

[0020] Figure 11 It is a circuit diagram used to illustrate the power savings that can be achieved according to this disclosure.

[0021] Figure 12 This is another block diagram illustrating one way to route a current reference signal to multiple LED driver circuits that share a reference voltage generator that can be controlled for additional power savings.

[0022] Figure 13 It is a flowchart consistent with one or more examples of this disclosure. Detailed Implementation

[0023] This disclosure relates to circuitry useful for advanced vehicle headlight systems or other systems implementing so-called pixelated light sources. The circuitry can be used to control and drive the light-emitting elements of the pixelated light source, such as a large number (e.g., greater than 2000) of miniature light-emitting diodes (micro-LEDs). This technology and circuitry can address the routing area challenges associated with high-density driver circuitry associated with high-density pixelated light sources.

[0024] Micro-LEDs are typically referenced to LEDs with lateral dimensions of less than 100 micrometers, and in some cases less than 50 micrometers. As the size of micro-LEDs and their corresponding driver circuits becomes increasingly smaller, challenges arise in routing electrical signals to the circuits. For example, when the distance between micro-LEDs and the distance between driver circuits become less than 100 micrometers, routing electrical signals to each of the micro-LEDs becomes particularly challenging. The problem becomes even more challenging when the distance between driver circuits becomes less than 50 micrometers, and multiple conductor layers may be required instead of a single conductor, which adds to the cost.

[0025] To control the microLEDs, signals can be routed to microLED driver circuits. Each microLED can have a corresponding microLED driver circuit attached to it. The circuits of this disclosure can be configured to perform a current-to-voltage step for the entire cluster of microLEDs, rather than controlling each microLED in a completely separate manner. Individual circuits can be configured to receive a reference current and generate a reference voltage based on that reference current. However, a single current-to-voltage conversion can be used to generate a reference voltage for the entire N×M microLED cluster, where N and M are positive integers, instead of performing a current-to-voltage conversion for each individual microLED. The corresponding number of N×M microLED driver circuits can then be configured to receive the reference voltage and generate a regulating current for each of the N×M microLEDs, where M and N represent positive integers. The reference current and reference voltage can define a regulating loop for the entire cluster, while each individual microLED can still be controlled or adjusted via another regulating loop within each of the N×M microLED driver circuits.

[0026] Figure 1 This is a block diagram illustrating a system consistent with this disclosure, including lighting circuitry 10 and processor 12. Processor 12 can provide control signals to lighting circuitry 10. Based on the control signals, LED driver circuitry 102 can provide individual control of LED 106. Control signals may include pulse modulation (PM) signals, such as pulse width modulation (PWM) signals or other types of modulation signals. LED driver circuitry 102 may include transistors controlled to operate as DC / DC converters to deliver regulated current to LED 106.

[0027] According to this disclosure, the lighting circuit 10 can be configured to control individual N×M micro LED clusters in a manner that reduces excessive electrical signals routed to different LED driver circuits 102. In particular, the lighting circuit 10 may include a current-to-voltage converter circuit (…). Figure 1(Not shown in the diagram), the current-to-voltage converter circuit is configured to receive a reference current and generate a reference voltage based on the reference current. The reference voltage can be shared with each of the N×M microLED driver circuits, forming a regulation loop for the cluster. Each of the LED driver circuits 102 can be configured to receive the reference voltage and generate a regulation current for each of the N×M microLEDs, where M and N represent positive integers. Thus, the second regulation loop is for each individual microLED in the cluster. The lighting circuit 10 may include vehicle headlights in some examples, although the lighting circuit 10 may also be used in various other setups. For the vehicle example, the processor 12 may include an electronic control unit (ECU) used to control electronics in the vehicle.

[0028] High-density pixel matrix drivers with dense micro-LED pitch (e.g., less than 100 micrometers and particularly less than 10 micrometers) face challenges in circuit layout. One particular challenge is the routing of auxiliary signals related to analog driving functions (e.g., routing to a reference voltage and then to a reference current signal for each driver circuit).

[0029] Figure 2 This is a conceptual diagram showing a miniature LED driver matrix 204 within an analog + digital core 202. Figure 2 Also included is a conceptual close-up view of a driver circuit 210 connected to a microLED 230. The microLED can be individually attached to a microLED driver, as illustrated by microLED 232, and arrows indicate the attachment of microLED 232 to the driver circuit 210 as a directly adjacent driver circuit. Driver circuit 210 (and other microLED driver circuits) includes a controllable transistor 212. A PM signal controls the ON-OFF state of transistor 212 to deliver a controllable amount of current through microLED 230. Power supply 220 can provide power via controllable transistor 212 to drive the current through microLED 230. The circuit of this disclosure can be implemented within an analog + digital core 202, such as... Figure 2 As shown.

[0030] A fundamental function of a high-density pixel matrix micro-LED driver is to absorb or provide regulated current from the cathode / anode of the micro-LED. Figure 3A and Figure 3B The illustration shows two different example layouts. Figure 3A The high-side configuration of the microLED 32 is shown, wherein a current source 302 is positioned between the microLED 32 and ground to deliver current through the microLED. Figure 3BThis shows a low-side configuration of the micro LED 32, where the current source 304 is positioned at the power node (V). DDP Between ) and micro LED 34.

[0031] Each individual microLED in the matrix of microLEDs may physically require a dedicated analog current signal (Iref) to generate a regulated output current (IOUTx), which can be determined by the formula: Where k is a constant "kilis" gain factor, and IREF is a reference current. The IREF value is typically roughly equal across all microLED drivers, and the IREF value can be varied or adjusted within a defined range. This feature allows for adjustment of the matrix luminous flux as analog dimming. DCx may include a dedicated digital control signal for each microLED driver. This DCx signal may include duty cycle information provided by an embedded digital dimming PWM engine. The DCx signal can be used, for example, to modulate the individual pixel brightness defined in the intensity value within a video frame by switching transistor 212 between ON and OFF states. Figure 3A and Figure 3B These are two different example layouts of the regulating loop used to regulate IREF, which can be used to define the Vref for the LED clusters described herein.

[0032] Similarly, in Figure 3A and Figure 3B The diagram shows two different examples of current source / sink regulation circuit designs. Figure 4 Showing with Figure 3A or Figure 3B An example of a consistent lighting circuit 40 for a single micro LED 44. The lighting circuit 40 may include a current-to-voltage converter 404, which includes a reference resistor 406. Furthermore, the lighting circuit 40 may include a pixel adjustment loop. The pixel adjustment loop is shown as an open-loop gain, where “Aol” 410 represents the open-loop gain factor. The output current is fed back to node 414 through output resistor 412 to achieve open-loop gain on the output signal “Iout”.

[0033] The input IREF current can be converted into a voltage reference VREF by a current-to-voltage converter 404, which is designated as the "IV-converter" sub-circuit. The current-to-voltage converter 404 can be implemented using a reference resistor (Rref) 406. The VREF voltage can then be regulated by an error amplifier with a defined open-loop gain Aol across the power stage resistor Rout to generate the output current Iout. Resistor Rout also represents the feedback element. In this current regulation loop, the Kilis gain factor can be defined as the ratio of the reference resistor to the power stage resistor (i.e., k = Rref / Rout).

[0034] The IREF current utilized by the matrix of miniature LED drivers can be generated by a precision current mirror generator, which is powered by a voltage source (e.g., V). DDP )powered by. Figure 5 An example circuit diagram is shown with a current reference routed to the micro-LED driver circuitry. From a layout planning perspective, the IREF current mirrors 58A, 58B, 58C, and 58D can be placed outside the micro-LED matrix. The reference current from the IREF current mirrors 58A, 58B, 58C, and 58D is routed to current sources 56A, 56B, 56C, and 56D, which regulate the individual currents of the micro-LEDs 54A, 54B, 54C, and 54D. The circuitry and techniques disclosed herein for generating the Vref of a micro-LED driver cluster can be applied in... Figure 5 The system shown is used to improve the routing of electrical signals and potentially reduce power consumption.

[0035] Figure 6 This is a block diagram illustrating a matrix LED system 60, whereby a current reference generator 62 can generate a reference current for routing to a micro-LED driver 64. Logic 66 may be included to facilitate control. Routing the IREF signal becomes challenging in high-resolution matrices with a high number of pixels. The circuitry and techniques disclosed herein can be applied to systems like... Figure 6 The system shown is used to improve the routing of electrical signals and potentially reduce power consumption.

[0036] Figures 7A-7C This is a conceptual diagram illustrating different ways of routing a signal associated with a reference current to different LED drivers. Figure 7A Example 70A is shown, in which 200 IREF vertical signals need to be routed to each micro-LED driver in a column with a conductor pitch of less than 50 micrometers. Figure 7A This demonstrates a single metal layer (M1) used for signal routing. However, for such a large number of signals, more dedicated metal layers might be needed, such as... Figure 7B Example 70B shows how to achieve sufficient signal routing. Figure 7B Examples include four metal layers (M1, M2, M3, and M4). However, the additional metal layers add undesirable costs to the circuitry. Another drawback is the reliability of long, thin metal buses, where defect density can have a greater impact on yield, as a minimum metal pitch is required to route such dense connections. Another technique that can theoretically reduce the number of layers is to split the current mirror into two parts physically located in different regions of the chip (e.g., a part on the top side and a part on the bottom side). Figure 7C The segmented signal is conceptually illustrated in Example 70C. Figure 7C Examples include two metal layers (M1 and M2). However, this approach can be challenging due to other circuit constraints, such as pixel matrix location, logic areas, or other circuit limitations.

[0037] In some respects, Figure 7A The diagram illustrates a routing congestion problem. Figure 7B This demonstrates an undesirable solution that requires four metal layers to achieve routing, and Figure 7C An example is shown that can be useful but still requires signal segmentation of multiple conductors.

[0038] One aspect of this disclosure is the idea of ​​sharing a current-to-voltage converter (also known as an "IV converter") within an M×N LED cluster, with the aim of reducing or eliminating problems associated with long analog vertical signal routing. The described techniques and solutions can also help reduce overall system power consumption.

[0039] Figure 8 A less desirable example of system 80 is shown, where bus 802 is configured to send an IREF signal to separate sub-circuits 800A, 800B, 800C, each individual sub-circuit including a separate IV converter. Each separate sub-circuit 800A, 800B, 800C outputs an Iout signal to a driver controlling LEDs 84A, 84B, 84C. Therefore, each microLED regulation loop receives a dedicated IREF signal as input from a reference current generator module, and each microLED regulation loop includes a separate IV converter to generate a local VREF required to regulate the corresponding output current of each microLED 84A, 84B, 84C. This can cause significant signal routing problems for routing the signal to the microLED driver 850, as shown at 852.

[0040] With Figure 8Unlike the examples shown, in some examples of this disclosure, the "IV converter" can be shared within a cluster of M×N pixel unit conditioning loops, where the "IV converter" still generates a local VREF, but it can be utilized by all M×N pixel unit conditioning loops to generate M×N LED output currents.

[0041] Figure 9 The diagram illustrates a lighting circuit combined with miniature LEDs 94A, 94B, and 94C. Figure 9 In this system 900, the lighting circuit is configured to receive a reference current (I) on the signal line 902. REF The IV converter 904 includes a resistor 906 or another resistive element to generate a reference voltage based on a reference current. This reference voltage is then shared by multiple driver circuits 910A, 910B, and 910C. Each of the driver circuits 910A, 910B, and 910C is configured to receive the reference voltage and generate a regulating current for each of the N×M miniature LEDs, where M and N represent positive integers. Each of the driver circuits 910A, 910B, and 910C includes a separate pixel regulation loop. The pixel regulation loop is shown as an open-loop gain, where "Aol" in 910A, 910B, and 910C represents the open-loop gain factor. The output current is fed back to nodes 914A, 914B, and 914C via output resistors 912A, 912B, and 912C to achieve open-loop gain on the output signal "Iout". The gain for each adjustment loop can be defined by output resistors 912A, 912B, and 912C, which limit the gain based on the output resistor and the reference voltage. Therefore, with resistors 912A, 912B, and 912C having different resistances, the gain will be different for each LED 94A, 94B, and 94C. However, separate from the pixel adjustment loop is the IREF adjustment loop described above, which can adjust IREF and VREF for the entire cluster of LEDs 94A, 94B, and 94C within system 900.

[0042] Sharing an IV converter 904 within an M×N microLED cluster reduces the number of conductors 952 required to connect electrical signals to the driver circuitry of the cluster 960. Each cluster requires only one IREF line 902, instead of separate IREF lines for each individual microLED. Closed-loop control allows for digital dimming across the entire cluster, while separate pixel control loops can achieve different (or similar) illumination for each individual LED within the cluster. Each of the N×M microLED driver circuits is directly connected to a specific microLED within the N×M microLED cluster. In other words, a driver circuit is used for each microLED, and each individual microLED can be attached to its corresponding driver circuit, as shown in the diagram. Figure 2 As shown in the conceptual diagram.

[0043] Each of the N×M miniature LED driver circuits 910A, 910B, 910C is configured to generate a regulated output current based on a reference voltage. Some or all of the regulated output currents associated with each of the N×M miniature LED driver circuits 910A, 910B, 910C can be different, for example, by utilizing similar or different output resistors 912A, 912B, 912C to achieve similar or different outputs. Each of the N×M miniature LED driver circuits 910A, 910B, 910C includes output resistors 912A, 912B, 912C, whose gain is limited according to the specific output resistors 912A, 912B, 912C and the reference voltage generated by the IV converter 904 for the cluster of miniature LED driver circuits 910A, 910B, 910C.

[0044] The lighting circuitry within system 900 may include vehicle headlight lighting circuitry, in which case an N×M cluster of microLEDs, represented by microLEDs 94A, 94B, and 94C, may comprise part of a matrix of microLEDs forming a larger vehicle headlight. N×M may be less than 50. The size of the cluster with the goal of generating “local” VREF can be selected to keep VREF routes short and without any congestion within the cluster. Some example cluster sizes may be 1×4, 1×10, 2×2, 4×2, 8×2, 1×16, and 2×16. Any cluster size can work, although cluster sizes with N×M less than 50 are generally desirable. Similarly, each of the N×M microLED driver circuits may define a pixel unit adjustment loop for one microLED within the microLEDs, while the cluster adjustment loop is still defined to adjust the IREF and VREF of the cluster.

[0045] Figure 10 This is another conceptual diagram illustrating another way of routing a signal associated with a reference current to different LED drivers. Figure 10 An example with a 1×10 cluster is shown. In this case, the number of lines required for 10 individual driver circuits is reduced to allow for sufficient line formation on a single metal layer, even with a driver size of approximately 50 micrometers. Figure 10 In the example, only one metal layer (M1) is needed for signal routing with a driver size surface area dimension on the order of 1×10 clusters and 50 micrometers.

[0046] Figure 11 This is a circuit diagram used to illustrate the power savings achievable according to this disclosure. Figure 11 The example shown is consistent with the case where a separate IREF current is directly supplied to the LED driver circuit, although in Figure 11 Similar driver circuits shown in the diagram can also be used in scenarios where IREFs are shared and VREFs are generated for LED driver clusters. Figure 11 In this circuit, the first driver circuit includes an operational transconductance amplifier 1106, an output resistor 1108, and a power stage 1110 including a transistor controlled by a PM signal. The output pin 1130 of the first driver circuit is connected to a first LED 1112. Similarly, the second driver circuit includes an operational transconductance amplifier 1120, an output resistor 1118, and a power stage 1124 including another transistor controlled by a PM signal. The output pin 1132 of the second driver circuit is connected to a second LED 1128. Figure 11 The example shown also illustrates two separate current sources 1102, 1116 and two separate reference resistors 1104, 1114. Reference resistors 1104, 1114 may include current-to-voltage converters that convert the reference current to a reference voltage. However, it is worth noting that there are two separate Iref currents (and generally N×M Iref currents for a cluster). The circuitry and techniques of this disclosure can eliminate the additional Iref current and use only a single Iref current for the entire N×M LED cluster. This saves power by eliminating all currents except for one Iref current used for an N×M cluster.

[0047] and Figure 11 The total power consumption of the system can be given by the following formula: Among them, P TOT It is the total power consumed, P LED It is through the power of a micro LED, and P IREF This is the power consumed by providing the IREF current. The total power consumption related only to the generation of the reference current is given by the following formula: As in the example, in a 100k pixel matrix scene with IOUT of approximately 1 mA and k=50:

[0048] Therefore, in some examples, approximately 11% of the power budget is wasted solely on reference current generation. The techniques and circuitry described herein can be employed to reduce power consumption caused by reference current generation in HD pixel matrix drivers with fine micro-LED pitch. For example, in scenarios where IV converter circuitry is added within each 1×10 cluster, the power consumption associated with the reference current generator can be reduced by a factor of 10:

[0049] Another way to further reduce power consumption is to add a logic enable / disable feature to the IV converter circuit, which is driven by PWM on a signal of a corresponding cluster driver with a PWM drive scheme. In this case, the IV converter circuit can include a switch to enable and disable the IV converter, such that the IV converter is active only if the PWM signal is active (in the ON state) for at least one of the LEDs in the cluster. In this case, an enhanced PWM algorithm can be used to distribute the same phase shift to the IV converter, which is applied to the pixels of the cluster sharing the IV converter. This saves even more IREF power until P IREF It becomes negligible.

[0050] Figure 12 This is a block diagram illustrating one method of routing a current reference signal to multiple LED driver circuits that share a reference voltage generator, which can be controlled for additional power savings. Figure 12 The system shown is similar to that in many ways in Figure 9 The systems shown are similar. The micro LEDs 1204A, 1204B, and 1204C are similar to the micro LEDs 94A, 94B, and 94C, and the driver circuits 1205A, 1205B, and 1205C are similar to the driver circuits 910A, 910B, and 910C. Signal input line 1250 is used to provide a reference current to IV converter 1220. IV converter 1220 includes a reference resistor 1206 for converting the reference current received on line 1250 into a reference voltage.

[0051] With Figure 9 The examples in [the text] are different, in [the text] Figure 12In this configuration, IV converter 1220 is a switch 1230 configured to enable or disable IV converter 1220 based on whether some or all of the microLEDs in an N×M cluster of microLEDs are active. The activity of some or all of the N×M microLEDs can be defined by a PWM signal controlling the ON-OFF state of microLEDs 1204A, 1204B, and 1204C. Therefore, by implementing logic 1232 that receives the same PWM signal (e.g., from PWM engine 1240) used to control the ON-OFF state of microLEDs 1204A, 1204B, and 1204C, logic 1232 can be configured to control switch 1230 based on the PWM signal, thereby controlling whether IV converter 1220 is enabled based on whether some or all of the N×M microLEDs are active. In other words, switch 1230 can be controlled by logic 1232 based on the PM signal (in the N×M cluster of microLEDs) used to control the ON-OFF state of microLEDs 1204A, 1204B, and 1204C. Figure 12 The LEDs 1204A, 1204B, and 1204C are used to enable or disable the current-to-voltage converter circuit 1220.

[0052] Figure 13 This is a flowchart consistent with one or more examples in this disclosure. Figure 13 The steps shown and described below can be performed by lighting circuitry, such as an IV converter and N×M miniature driver circuits as described above. Figure 13 A consistent approach may include receiving a reference current at a current-to-voltage converter circuit (1301) and generating a reference voltage based on the reference current (1302). The reference voltage is output from the current-to-voltage converter circuit to N×M miniature LED driver circuits (1303). Each of the N×M miniature LED driver circuits receives the reference voltage and generates a regulated output current for each of the N×M miniature LEDs based on the reference voltage and N×M individual regulation loops. Again, M and N represent positive integers, and N×M can be less than 50.

[0053] Similarly, in various examples, the N×M microLEDs can comprise part of a matrix of microLEDs forming a larger vehicle headlight. Each of the N×M microLED driver circuits defines a pixel unit adjustment loop for one of the N×M microLEDs, and... Figure 12 The method shown may also include regulating the output current of each of the N×M microLEDs. In some cases, some or all of the regulated output currents associated with each of the N×M microLED driver circuits are different. In some cases, if similar output resistors are used, the regulated output currents associated with some or all of the N×M microLED driver circuits can be similar.

[0054] Each of the N×M miniature LED driver circuits includes an output resistor (e.g., Figure 9 Resistors 912A, 912B, and 912C are used, and their gain is limited by the output resistor and the reference voltage. In some cases, current-to-voltage converter circuits include switches (e.g., in...). Figure 12 The switch 1230 shown in this case, in Figure 12 The method shown may also include: controlling a switch to enable or disable the current-to-voltage converter circuit based on whether some or all of the N×M microLEDs are active. As explained herein, the switch 1230 within the IV converter 1220 may be based on a PM signal for the N×M microLEDs.

[0055] This disclosure also contemplates systems comprising circuits of this disclosure combined with microLEDs. Each of the N×M microLED driver circuits associated with a cluster of microLEDs may be directly connected to a specific microLED within the N×M microLED cluster. The system may include a matrix of microLEDs and multiple lighting circuits, wherein each of the lighting circuits is configured to control an N×M cluster of microLEDs. The entire matrix may include more than 2000 microLEDs divided into N×M clusters. The matrix may, for example, include approximately 4000 microLEDs, approximately 8000 microLEDs, approximately 16000 microLEDs, approximately 100000 microLEDs, or even more. In any case, consistent with this disclosure, the lighting circuits may be configured to control an N×M cluster of microLEDs using a shared current-to-voltage (“IV”) converter circuit.

[0056] Each component of the lighting circuit may include a current-to-voltage converter circuit and N×M miniature LED driver circuits. The current-to-voltage converter circuit is configured to receive a reference current and generate a reference voltage based on the reference current. The N×M miniature LED driver circuits are configured to receive a reference voltage and generate a reference current for each of the N×M miniature LEDs, where M and N represent positive integers. Each component of the lighting circuit may include a separate line for receiving the reference current from a reference current generator. The system includes a vehicle headlight module, although other lighting scenarios are also used for matrix lighting that includes a matrix of miniature LEDs.

[0057] The techniques described in this disclosure can be implemented in circuit arrangements. In various examples, the techniques can be implemented at least in part in circuit arrangements, hardware, software, firmware, or any combination thereof. For example, various aspects of the described techniques can be implemented within one or more logic elements, processors (including one or more microcontrollers, microprocessors, digital signal processors (DSPs)), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or any other equivalent integrated or discrete logic circuits, and any combination of such components. The terms "processor" or "processing circuit arrangement" can generally refer to any of the logic circuit arrangements described above, alone or in combination with other logic circuit arrangements or any other equivalent circuit arrangements. Control units, including hardware, can also perform one or more of the techniques disclosed herein.

[0058] Such circuit arrangements, hardware, software, and firmware can be implemented within the same device or integrated circuit or in separate devices to support the various operations and functions described in this disclosure. Furthermore, any of the described units, modules, or components can be implemented together or separately as discrete but interoperable logic devices. The description of different features as modules or units is intended to highlight different functional aspects and does not necessarily imply that such modules or units must be implemented by separate hardware or software components. Rather, one or more functions associated with a module or unit can be implemented by separate hardware or software components or integrated within common or separate hardware or software components.

[0059] One or more aspects of this disclosure can also be executed in software, for example, particularly for logic or decisions performed based on circuit outputs, in which case those aspects of the technology described in this disclosure can also be implemented or encoded in a computer-readable medium, such as a computer-readable storage medium containing instructions. Instructions implemented or encoded in a computer-readable storage medium can, for example, cause a processor to perform a method when executed. In this example, the instructions can be stored in memory, which may include random access memory (RAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), flash memory, or other computer-readable media.

[0060] The following terms may illustrate one or more aspects of this disclosure.

[0061] Clause 1: A lighting circuit configured to control an N×M cluster of miniature LEDs, the lighting circuit comprising: a current-to-voltage converter circuit configured to receive a reference current and generate a reference voltage based on the reference current; and an N×M miniature LED driver circuit configured to receive the reference voltage and generate an adjustable current for each of the N×M miniature LEDs, wherein M and N represent positive integers.

[0062] Clause 2: The lighting circuit according to Clause 1, wherein the lighting circuit includes a vehicle headlight lighting circuit and N×M micro-LEDs comprising part of a matrix of micro-LEDs forming a larger vehicle headlight.

[0063] Clause 3: Lighting circuits according to Clause 1 or 2, where N×M is less than 50.

[0064] Clause 4: A lighting circuit according to any one of Clauses 1-3, wherein each of the N×M miniature LED driver circuits defines a pixel unit adjustment loop for one miniature LED.

[0065] Clause 5: A lighting circuit according to any one of Clauses 1-4, wherein each of the N×M miniature LED driver circuits is configured to generate a regulated output current based on a reference voltage.

[0066] Clause 6: The lighting circuit according to Clause 5, wherein some or all of the regulated output currents associated with each of the N×M miniature LED driver circuits are different.

[0067] Clause 7: A lighting circuit according to any one of Clauses 1-6, wherein each of the N×M miniature LED driver circuits includes an output resistor that limits the gain based on the output resistor and a reference voltage.

[0068] Clause 8: A lighting circuit according to any one of Clauses 1-7, wherein the current-to-voltage converter circuit includes a switch configured to enable or disable the current-to-voltage converter circuit based on whether some or all of the N×M microLEDs are active.

[0069] Clause 9: Lighting circuits pursuant to Clause 8, wherein a switch is controlled by a bit to enable or disable a current-to-voltage converter circuit based on a PM signal for N×M miniature LEDs.

[0070] Clause 10: A lighting circuit according to any one of Clauses 1-9, wherein each of the N×M miniature LED driver circuits is directly connected to a specific miniature LED among the N×M miniature LEDs.

[0071] Clause 11: A method comprising: receiving a reference current at a current-to-voltage converter circuit and generating a reference voltage based on the reference current; and receiving the reference current at N×M miniature LED driver circuits and generating an regulated current for each of the N×M miniature LEDs, wherein M and N represent positive integers.

[0072] Clause 12: The method according to Clause 11, wherein the N×M micro-LEDs comprise part of a matrix of micro-LEDs forming a larger vehicle headlight.

[0073] Clause 13: The method of Clause 11 or 12, wherein N×M is less than 50.

[0074] Clause 14: The method according to any one of Clauses 11-13, wherein each of the N×M microLED driver circuits defines a pixel unit adjustment circuit for one of the microLEDs, the method further comprising: adjusting the output current for each of the N×M microLEDs.

[0075] Clause 15: According to the method of Clause 14, some or all of the currents of the regulated output currents associated with each of the N×M miniature LED driver circuits are different.

[0076] Clause 16: The method according to any one of Clauses 11-15, wherein each of the N×M miniature LED driver circuits includes an output resistor that limits the gain based on the output resistor and a reference voltage.

[0077] Clause 17: The method according to any one of Clauses 11-16, wherein the current-to-voltage converter circuit includes a switch, the method further comprising: controlling the switch to enable or disable the current-to-voltage converter circuit based on whether some or all of the N×M microLEDs are active.

[0078] Clause 18: The method according to Clause 17, wherein the control switch is based on a PM signal for N×M miniature LEDs.

[0079] Clause 19: The method according to any one of Clauses 11-18, wherein each of the N×M miniature LED driver circuits is directly connected to a specific miniature LED of the N×M miniature LEDs.

[0080] Clause 20: A system comprising: a micro-LED matrix; a plurality of lighting circuits, each of which is configured to control an N×M cluster of micro-LEDs, wherein each of the lighting circuits includes: a current-to-voltage converter circuit configured to receive a reference current and generate a reference voltage based on the reference current; and N×M micro-LED driver circuits configured to receive the reference voltage and generate an regulated current for each of the N×M micro-LEDs, wherein M and N represent positive integers.

[0081] Clause 21: A system pursuant to Clause 20, wherein each of the lighting circuits includes a separate line for receiving a reference current from a reference current generator.

[0082] Clause 22: A system pursuant to Clause 20 or 21, wherein the system includes a vehicle headlight module.

[0083] Various aspects have been described in this disclosure. These and other aspects are within the scope of the following claims.

Claims

1. A lighting circuit configured to control an N×M miniature light-emitting diode (LED) cluster, the lighting circuit comprising: A current-to-voltage converter circuit is configured to receive a reference current and generate a reference voltage based on the reference current; as well as N×M miniature LED driver circuits are configured to receive the reference voltage and generate a regulating current for each of the N×M miniature LEDs, where M and N represent positive integers.

2. The lighting circuit of claim 1, wherein the lighting circuit comprises a vehicle headlight lighting circuit, and the N×M micro-LEDs comprise part of a matrix of micro-LEDs forming a larger vehicle headlight.

3. The lighting circuit according to claim 1, wherein N×M is less than 50.

4. The lighting circuit of claim 1, wherein each of the N×M microLED driver circuits defines a pixel unit adjustment circuit for one of the microLEDs.

5. The lighting circuit of claim 1, wherein each of the N×M miniature LED driver circuits is configured to generate an regulated output current based on the reference voltage.

6. The lighting circuit of claim 5, wherein some or all of the regulated output currents associated with each of the N×M miniature LED driver circuits are different.

7. The lighting circuit of claim 1, wherein each of the N×M miniature LED driver circuits includes an output resistor, the output resistor defining a gain based on the output resistor and the reference voltage.

8. The lighting circuit of claim 1, wherein the current-to-voltage converter circuit includes a switch configured to enable or disable the current-to-voltage converter circuit based on whether some or all of the N×M microLEDs are active.

9. The lighting circuit of claim 8, wherein the switch is controlled to enable or disable the current-to-voltage converter circuit based on a pulse-modulated PM signal for the N×M microLEDs.

10. The lighting circuit of claim 1, wherein each of the N×M micro-LED driver circuits is directly connected to a specific micro-LED among the N×M micro-LEDs.

11. A method comprising: A reference current is received at the current-to-voltage converter circuit, and a reference voltage is generated based on the reference current; as well as The reference current is received at N×M miniature LED driver circuits, and an adjustment current is generated for each of the N×M miniature LEDs, where M and N represent positive integers.

12. The method of claim 11, wherein the N×M microLEDs comprise part of a matrix of microLEDs forming a larger vehicle headlight.

13. The method of claim 11, wherein N×M is less than 50.

14. The method of claim 11, wherein each of the N×M microLED driver circuits defines a pixel unit adjustment loop for one of the microLEDs, the method further comprising: The output current is adjusted for each of the N×M miniature LED driver circuits.

15. The method of claim 14, wherein some or all of the regulated output currents associated with each of the N×M miniature LED driver circuits are different.

16. The method of claim 11, wherein each of the N×M miniature LED driver circuits includes an output resistor, the output resistor defining a gain based on the output resistor and the reference voltage.

17. The method of claim 11, wherein the current-to-voltage converter circuit includes a switch, and the method further includes: The switch is used to enable or disable the current-to-voltage converter circuit based on whether some or all of the N×M microLEDs are active.

18. The method of claim 17, wherein controlling the switch is based on a pulse-modulated PM signal for the N×M microLEDs.

19. The method of claim 11, wherein each of the N×M microLED driver circuits is directly connected to a specific microLED of the N×M microLEDs.

20. A system comprising: Miniature LED matrix; Multiple lighting circuits, each of which is configured to control an N×M cluster of miniature LEDs, wherein each of the lighting circuits includes: A current-to-voltage converter circuit is configured to receive a reference current and generate a reference voltage based on the reference current; as well as N×M miniature LED driver circuits are configured to receive the reference voltage and generate a regulating current for each of the N×M miniature LEDs, where M and N represent positive integers.

21. The system of claim 20, wherein each of the lighting circuits includes a separate line for receiving the reference current from the reference current generator.

22. The system of claim 20, wherein the system includes a vehicle headlight module.

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