Circuit, method and system for supplying power to two or more chains of LEDs

Abstract

A circuit configured to control current through one or more chains of light-emitting diodes, LEDs, (160, 170; 260, 270; 360, 370; 460, 470; 560, 570; 660, 670; 760, 770), the circuit comprising: a power converter unit (130; 230; 330; 430; 530; 630; 730) configured to receive an input signal from a power source (110; 210; 310; 410; 510; 610; 710) and to generate a first output signal having a first voltage; a charge pump (140; 240; 340; 440; 540; 640; 740) configured to receive at least a portion of the first output signal from the power converter unit (130; 230; 330; 430; 530; 630; 730) and to generate a second output signal having a second voltage; and a linear regulator (150; 250; 350; 450; 550; 650; 750) configured to receive the second output signal from the charge pump (140; 240; 340; 440; 540; 640; 740) and to generate a third output signal having a third voltage.

Description

[0001] This disclosure relates to circuits for driving and controlling chains of light-emitting diodes.

[0002] Drivers are often used to control a voltage, current, or power at a load. For example, a light-emitting diode (LED) driver can control the power supplied to a string of light-emitting diodes. Some drivers may include a direct current (DC)-to-DC power converter, such as a buck-boost, step-down, boost, or other DC-to-DC converter. Such DC-to-DC power converters can be used to control and possibly change the power to the load based on a characteristic of the load. DC-to-DC power converters can be particularly useful for regulating current through LED strings. In some cases, LED driver circuits can accept an input signal with an input current and an input voltage and provide an output signal with an output current and an output voltage.In some such cases, an LED driver circuit may control at least some aspects of the input signal and the output signal, such as controlling the output current output by the LED driver circuit.

[0003] US 2017 / 0339765 A1 discloses in Fig. 8 a circuit designed to drive an LED chain and comprising a power converter and a charge pump.

[0004] US 2011 / 0204797 A1 discloses a circuit configured to drive multiple LED chains. The circuit comprises a first voltage source, a second voltage source, and a charge pump connected to the second voltage source. The LED chains are each connected between the first voltage source and multiple outputs of the charge pump.

[0005] US 2004 / 0080301 A1 discloses a circuit configured to drive multiple LEDs. The circuit comprises a first linear regulator and a charge pump connected to the first linear regulator, as well as several additional linear regulators. The LEDs are each connected between the charge pump and one of the additional linear regulators.

[0006] This disclosure is generally directed to devices, systems, and techniques for a circuit for driving two or more different light-emitting diode (LED) strings. For example, the circuit may include a power converter, one or more charge pumps, and a linear regulator. The power converter, the one or more charge pumps, and the linear regulator may be configured to generate one or more output signals so that the circuit can support one or more lighting modes using the corresponding two or more LED strings. The circuit is designed in a manner that can eliminate an additional power converter to reduce a level of complexity of the circuit compared to a circuit that includes the additional power converter.Additionally, the circuit is designed in a manner that can limit the amount of power dissipated by the linear regulator, thereby reducing the amount of energy lost by the circuit compared to a circuit in which a corresponding linear regulator dissipates a larger amount of power. According to this disclosure, for example, the circuit can deliver the output signals to the two or more LED strings in a highly power-efficient manner while limiting circuit complexity by limiting the number of power converters included in the circuit.

[0007] One embodiment of the invention relates to a circuit according to claim 1. The circuit is configured to control current through one or more chains of LEDs. The circuit includes a power converter unit configured to receive an input signal from a power source and generate a first output signal having a first voltage, a charge pump configured to receive at least a portion of the first output signal from the power converter unit and generate a second output signal having a second voltage, and a linear regulator configured to receive the second output signal from the charge pump and generate a third output signal having a third voltage.

[0008] A further embodiment of the invention relates to a method according to claim 16. The method comprises receiving an input signal from a power source by a power converter unit of a circuit configured to control current through one or more chains of LEDs, generating a first output signal having a first voltage by the power converter unit, receiving at least a portion of the first output signal from the power converter unit by a charge pump, generating a second output signal having a second voltage by the charge pump, receiving the second output signal from the charge pump by a linear regulator of the circuit, and generating a third output signal having a third voltage by the linear regulator.

[0009] Another embodiment of the invention relates to a system according to claim 17. The system comprises a power source, a first chain of LEDs, a second chain of LEDs, and a circuit configured to control current through the first chain of LEDs and the second chain of LEDs. The circuit includes a power converter unit configured to receive an input signal from the power source and generate a first output signal having a first voltage, a charge pump configured to receive at least a portion of the first output signal from the power converter unit and generate a second output signal having a second voltage, and a linear regulator configured to receive the second output signal from the charge pump and generate a third output signal having a third voltage.

[0010] The overview is intended to provide an overview of the subject matter described in this disclosure. It is not intended to provide an exclusive or exhaustive explanation of the systems, devices, and methods described in detail within the accompanying drawings and the description below. Further details of one or more examples of this disclosure are set forth in the accompanying drawings and in the description below. Other features, objects, and advantages will be apparent from the description and drawings and from the claims. Fig. 1 is a block diagram illustrating an example system including a power source, a light emitting diode (LED) driver circuit, first LEDs, and second LEDs according to one or more techniques of this disclosure. Fig. 2 is a circuit diagram illustrating a system having circuitry for supplying power to a first string of LEDs and a second string of LEDs using a synchronous power boost converter unit, a single-stage charge pump unit, and a linear regulator unit according to one or more techniques of this disclosure. Fig. 3 is a circuit diagram illustrating a system including circuitry for supplying power to a first string of LEDs and a second string of LEDs using a synchronous power boost converter unit, a multi-stage charge pump unit, and a linear regulator unit according to one or more techniques of this disclosure. Fig. 4 is a circuit diagram illustrating a system having circuitry for supplying power to a first string of LEDs and a second string of LEDs using an asynchronous power boost converter unit, a single-stage charge pump unit, and a linear regulator unit according to one or more techniques of this disclosure. Fig. 5 is a circuit diagram illustrating a system having circuitry for supplying power to a first string of LEDs and a second string of LEDs using an asynchronous power boost converter unit, a multi-stage charge pump unit, and a linear regulator unit according to one or more techniques of this disclosure. Fig. 6 is a circuit diagram illustrating a system including circuitry for supplying power to a first string of LEDs and a second string of LEDs using a buck-boost power converter unit, a first single-stage charge pump unit, a linear regulator unit, and a second single-stage charge pump unit in accordance with one or more techniques of this disclosure. Fig. 7 is a circuit diagram illustrating a system including circuitry for supplying power to a first string of LEDs and a second string of LEDs using a buck-boost power converter unit, a first multi-stage charge pump unit, a linear regulator unit, and a second multi-stage charge pump unit in accordance with one or more techniques of this disclosure. Fig. 8 is a flowchart illustrating an example operation for generating one or more output signals to provide power to control one or more strings of LEDs, according to one or more techniques of this disclosure.

[0011] The same reference symbols refer to the same elements throughout the description and figures.

[0012] Some systems may use a power converter, such as a direct current (DC)-to-DC converter, to control power supplied to a string of light-emitting diodes (LEDs). This disclosure is directed to a circuit for driving two or more different LED strings that can be controlled according to one or more lighting modes. For example, a first string of LEDs may provide one or more first lighting modes, and a second string of LEDs may provide one or more second lighting modes. The circuit may provide one or more output signals to the first string of LEDs and the second string of LEDs such that each output signal of the one or more output signals corresponds to a respective one of the one or more first lighting modes and the one or more second lighting modes.In some cases, the one or more output signals may each include a corresponding voltage magnitude and current magnitude. The techniques and circuits described herein may be particularly useful in transportation lighting applications that include multiple strings of LEDs.

[0013] Fig. 1 is a block diagram illustrating an example system 100 including a power source 110, an LED driver circuit 120, first LEDs 160, and second LEDs 170 according to one or more techniques of this disclosure. As shown in Fig. 1, the circuit 120 includes a power converter unit 130, a charge pump unit 140, and a linear regulator unit 150.

[0014] Power source 110 is configured to supply operating power to circuit 120. In some examples, power source 110 includes a battery and power generation circuitry to generate the operating power. In some examples, power source 110 is rechargeable to enable extended operation. Power source 110 may include any one or more of several different battery types, such as nickel-cadmium batteries and lithium-ion batteries. In some examples, a maximum voltage output by power source 110 is approximately 12 V. In some examples, power source 110 supplies power in a range of 10 watts (W) to 15 W.

[0015] The circuit 120 may include circuit elements including resistors, capacitors, inductors, diodes, semiconductor switches, and other semiconductor elements. As shown in Fig. 1, the circuit 120 includes a power converter unit 130. The power source 110 may supply an input signal to the power converter unit 130 to thereby power the circuit 120. Furthermore, the power converter unit 130 may supply at least a portion of a first output signal to first LEDs 160, which may represent a load powered by the power converter unit 130. In some cases, the input signal may include an input current and an input voltage. Additionally, the output signal may include an output current and an output voltage. In some cases, the power converter unit 130 includes a DC-DC power converter configured to regulate the output signal provided to the first LEDs 160. In some examples, the DC-DC power converter includes a switch / inductor unit, such as an H-bridge.An H-bridge uses a set of switches, often semiconductor switches, to convert electrical power. In some examples, the switch / inductor unit acts as a buck-boost converter. For example, a buck-boost converter is configured to regulate the output voltage supplied to the first LEDs 160 using at least two operating modes, including a buck mode and a boost mode. The power conversion unit 130 can control semiconductor switches of the buck-boost converter to change the operating mode of the buck-boost converter (e.g., change the operating mode of the buck-boost converter from buck mode to boost mode and vice versa).

[0016] In a Fig. 1, the semiconductor switches of the power converter unit 130 may include transistors, diodes, or other semiconductor elements. In the buck mode of operation, the buck-boost converter of the power converter unit 130 may step down voltage and step up current from the input of the power converter unit 130 to the output of the power converter unit 130. In the buck mode of operation, the buck-boost converter of the power converter unit 130 may step up voltage and step up current from the input of the power converter unit 130 to the output of the power converter unit 130. In some examples, the power converter unit 130 is configured to regulate a current of the at least a portion of the first output signal supplied to the first LEDs 160 such that a current of the at least a portion of the first output signal remains substantially constant, while an LED control switching element (in Fig. 1 not shown) is activated.

[0017] In some examples, the charge pump unit 140 may include one or more capacitors that store charge to increase or decrease voltage from an entry point to an exit point of the charge pump unit 140. In this way, the charge pump unit 140 may be a power converter that accepts an electrical input signal and produces an electrical output signal having different parameter values than the electrical input signal. In some examples, the charge pump unit 140 represents a Dickson charge pump with one or more "stages," where each stage of the one or more stages corresponds to a multiplication factor of a voltage of the electrical input signal to the charge pump unit 140. In some examples, the charge pump unit 140 includes one stage, and the charge pump unit 140 multiplies a voltage of the electrical input signal by a factor of two.In some examples, the charge pump unit 140 includes two stages, and the charge pump unit 140 multiplies a voltage of the electrical input signal by a factor of 3. In some examples, the charge pump unit 140 includes three stages, and the charge pump unit 140 multiplies a voltage of the electrical input signal by a factor of four. Therefore, each additional stage included in the charge pump unit 140 represents an additional multiplication factor of the voltage of an electrical signal passing through the charge pump unit 140.

[0018] The charge pump unit 140 may receive at least a portion of the first output signal generated by the power converter unit 130. In some examples, the first output signal includes a first voltage. In this way, a voltage of the electrical signal received by the charge pump unit 140 may be substantially the same as a voltage of the electrical signal received by the first LEDs 160. For example, the voltage of the electrical signal received by the charge pump unit 140 may be within a range of 99% to 101% of the voltage of the electrical signal received by the first LEDs 160. The charge pump unit 140 may generate a second output signal having a second voltage. In some examples, the second voltage is within a range of 1.9 times the first voltage to 2.1 times the first voltage (e.g., 2.0 times the first voltage).In some examples, the second voltage is within a range of 2.9 times the first voltage to 3.1 times the first voltage (e.g., 3.0 times the first voltage).

[0019] In some examples, the linear regulator unit 150 is a circuit component that receives an electrical input signal and generates an electrical output signal, wherein the electrical output signal has a constant and predetermined voltage that does not change based on the voltage of the input of the linear regulator unit 150. For example, a resistance of the linear regulator unit 150 may change according to the voltage of the input of the linear regulator unit 150, allowing the linear regulator unit 150 to generate the output signal with the constant and predetermined voltage. The linear regulator unit 150 may receive the second output signal from the charge pump unit 140 and generate a third output signal. In some examples, the linear regulator unit 150 provides the third output signal to the second LEDs 170.

[0020] The first LEDs 160 may include a suitable semiconductor light source. In some examples, an LED may include a pn junction configured to emit light when activated. In some examples, the first LEDs 160 may be included in a headlight assembly for automotive applications. For example, the first LEDs 160 may include a matrix, a string, or more than one string of light-emitting diodes to illuminate a road ahead of a vehicle. As used herein, a vehicle may refer to motorcycles, trucks, golf carts, snowmobiles, heavy equipment, or any type of vehicle that uses directional lighting. In some examples, the first LEDs 160 include a first string of LEDs including a set of high beam (HB) LEDs and a set of low beam (LB) LEDs.In some cases, the system 100 may toggle between activating the set of LB LEDs, activating the set of HB LEDs, activating both the set of LB LEDs and the set of HB LEDs, and deactivating both the set of LB LEDs and the set of HB LEDs. The first LEDs 160 may include any number of LEDs. For example, the first LEDs 160 may include from 1 to 100 LEDs.

[0021] The second LEDs 170 may include any suitable solid-state light source. In some examples, the second LEDs 170 may be included in a headlight assembly for automotive applications. For example, the second LEDs 170 may include a matrix, a string, or more than one string of light-emitting diodes to emit light from a vehicle. In some examples, the second LEDs 170 include a second string of LEDs including a set of daytime running light (DRL) LEDs and a set of position light (POS) LEDs. In some cases, the system 100 may toggle between activating the set of DRL LEDs, activating the set of POS LEDs, activating both the set of DRL LEDs and the set of POS LEDs, and deactivating both the set of DRL LEDs and the set of POS LEDs.In some examples, the second LEDs 170 may include a single set of LEDs configured to switch between a DRL mode and a POS mode. In some examples, the DRL lighting (e.g., the DRL LEDs) is mounted on the front of a vehicle and is automatically activated once the vehicle itself is turned on. For example, the DRL lighting may be activated at any time the vehicle is started. In some cases, the DRL lighting may signal the presence of the vehicle to pedestrians and other vehicles by emitting primarily white light. In some examples, the POS lighting is only activated at nighttime. The POS lighting may be used by all-terrain vehicle (ATV) original equipment manufacturers (OEMs) to distinguish car models from one another.In some examples, the POS lighting represents dimmed DRL lighting (e.g., dimmed 10% of the DRL lighting). The second LEDs 170 may include any number of LEDs. For example, the second LEDs 170 may include from 1 to 100 LEDs.

[0022] In some examples, by using a single power converter unit 130 to supply power to both the first LEDs 160 and the second LEDs 170, a complexity of the circuit 120 may be reduced compared to a circuit that uses a first power converter unit and a second power converter unit to supply power to a first group of LEDs and a second group of LEDs, respectively. For example, because the circuit 120 includes only a single power converter unit, the circuit 120 may be smaller than a circuit that supplies power to two groups of LEDs and that includes two power converters. Additionally, processing circuitry (in Fig. 1) that controls the power converter unit 130 does not require as much processing power as the processing circuitry of a circuit that supplies power to two groups of LEDs and includes two power converters. It may be advantageous to integrate the charge pump unit 140 into the circuit 120 because the charge pump unit 140 limits the amount of energy dissipated by the linear regulator unit 150, thereby ensuring that the circuit 120 operates power-efficiently.

[0023] Fig. 2 is a circuit diagram illustrating a system 200 having circuitry for supplying power to a first string of LEDs 260 and a second string of LEDs 270 using a synchronous power boost converter unit 230, a single-stage charge pump unit 240, and a linear regulator unit 250 according to one or more techniques of this disclosure. As shown in Fig. 2, the system 200 includes a power source 210, a power converter unit 230, a charge pump unit 240, a linear regulator unit 250, a first chain of LEDs 260, an LED control switching element 262, and a second chain of LEDs 270. The power converter unit 230 includes an inductor 232 and switching elements 234A-234D (collectively, "switching elements 234"). The charge pump unit 240 includes a first diode 242A and a second diode 242B (collectively, "diodes 242") and a first capacitor 244A and a second capacitor 244B (collectively, "capacitors 244"). The power source 210 may be an example of a power source 110 of Fig. 1. The power converter unit 230 may be an example of a power converter unit 130 of Fig. 1. The charge pump unit 240 may be an example of the charge pump unit 140 of Fig. 1. The linear regulator unit 250 may be an example of the linear regulator unit 150 of Fig. 1. The first chain of LEDs 260 can be an example of the first LEDs 160 of Fig. 1. The second chain of LEDs 270 may be an example of the second LEDs 170 of Fig. 1 act.

[0024] The power source 210 may supply an input signal to the power converter unit 230. The power converter unit 230 may include a switch / inductor unit operating as a synchronous boost converter (e.g., an H-bridge). The H-bridge may be represented by the inductor 232 and the switching elements 234. In some cases, each of the switching elements 234 may include power switches, such as, but not limited to, any type of field-effect transistor (FET) with any combination of metal-oxide-semiconductor field-effect transistors (MOSFETs), bipolar transistors (BJTs), insulated-gate bipolar transistors (IGBTs), junction field-effect transistors (JFETs), high electron mobility transistors (HEMTs), or other elements that use voltage for control.Additionally, switching elements 234 may include n-type transistors, p-type transistors, and power transistors, or any combination thereof. In some examples, switching elements 234 include vertical transistors, lateral transistors, and / or horizontal transistors. In some examples, switching elements 234 include other analog components, such as diodes and / or transistors. In some examples, switching elements 234 may operate as switches and / or analog components.

[0025] In some examples, each of the switching elements 234 includes three terminals: two load terminals and a control terminal. For MOSFET switches, each of the switching elements 234 may include a drain terminal, a source terminal, and at least one gate terminal, where the control terminal is a gate terminal. For BJT switches, the control terminal may be a base terminal. Current may flow between the two load terminals of each of the switching elements 234 based on the voltage at the respective control terminal. Therefore, electrical current may flow through the switching elements 234 based on control signals supplied to the corresponding control terminal of the switching elements 234. In some examples, when a voltage applied to the control terminals of the switching elements 234 is greater than or less than a voltage threshold, the switching elements 234 may be activated, allowing the switching element to conduct electricity.Furthermore, the switching elements 234 may be deactivated when a voltage applied to the respective control terminals of the switching elements 234 is below the threshold voltage, thereby preventing the switching elements 234 from conducting electricity. A controller (in . Fig. 2 not shown) may be configured to control the switching elements 234 independently, so that one, a combination, all, or none of the switching elements 234 may be activated at any one time.

[0026] The switching elements 234 may include various material components such as silicon, silicon carbide, gallium nitride, or any other combination of one or more semiconductor materials. In some examples, silicon carbide switches may experience lower switching power losses. Improvements in magnetics and faster switching, such as gallium nitride switches, may allow the switching elements 234 to draw short current pulses from the power source 210. These higher frequency switching elements may require that control signals (e.g., voltage signals generated by a controller (in Fig. 2 not shown) to the corresponding control terminals of the switching elements 234 are sent with more precise timing compared to lower frequency switching elements.

[0027] According to the Fig. In the example illustrated in Figure 2, inductor 232 may comprise a component of power conversion unit 230. Inductors are electrical circuit components that resist a change in the magnitude of the current flowing through the inductor. In some examples, inductors include a conductive wire wound into a coil. When current flows through the coil, a magnetic field is created in the coil, and the magnetic field induces a voltage across the inductor. An inductance defines an inductance value, and the inductance value is the ratio of the voltage across the inductor to the rate of change of the current flowing through the inductor.Therefore, when the inductor 232 is charged with a magnetic field and placed in series with the power source 210 and the first string of LEDs 260, the voltage across the inductor 232 is configured to increase the amount of voltage supplied to the first string of LEDs 260.

[0028] The switch / inductor unit (e.g., the inductor 232 and the switching elements 234) may be configured to regulate the output voltage supplied to the first chain of LEDs 260 using at least one mode of operation, including a boost mode. In the Fig. 2, the switching elements 234 may include transistors, diodes, or other semiconductor elements. In the boost mode, the switch / inductor unit may step up voltage and down current from the input of the power converter unit 230 to the output of the power converter unit 230. As such, the power converter unit 230 may receive an input signal from the power source 210 and generate a first output signal. The first output signal may include a first voltage and a first current, wherein the first voltage is greater than a voltage of the input signal and the first current is less than a current of the input signal when the power converter unit is in the boost mode.

[0029] In some examples, while the switch / inductor unit is in the boost mode of operation, switching element 234A is enabled, switching element 234B is disabled, and switching element 234D alternates between being enabled and disabled. When switching element 234D is enabled, an electrical current flows from power source 210 through switching element 234A, inductor 232, and switching element 234D, charging inductor 232. When switching element 234D is disabled, inductor 232 discharges and an electrical current flows from power source 210 through switching element 234A, inductor 232, and switching element 234C, thereby boosting (e.g., increasing) an output voltage of the first output signal provided to charge pump unit 240 and the first chain of LEDs 260. Additionally, the power converter unit 230 may step down a current of the first output signal during the boost mode.

[0030] The power converter unit 230 may provide at least a portion of the first output signal to the charge pump unit 240. In this way, although the first output signal is described as an 'output,' the first output signal may act as an 'input' to the charge pump unit 240. In some examples, the charge pump unit 240 may represent a Dickson charge pump that includes a multiplication stage (e.g., two diodes and two capacitors) that substantially doubles a voltage of the electrical signal flowing through the charge pump unit 240 from an entry point of the charge pump unit 240 to an exit point of the charge pump unit 240. In this way, the charge pump unit 240 may be referred to herein as a "voltage multiplier" because the charge pump unit 240 increases the voltage by an integer factor.For example, the charge pump unit 240 may generate a second output signal having a second voltage and a second current. In some cases, the second voltage may be within a range of 1.9 times the voltage of the first output signal generated by the power converter unit 230 to 2.1 times the voltage of the first output signal.

[0031] In some examples, the charge pump unit 240 receives a charge pump control signal from the power converter unit 230. The charge pump control signal may enable the charge pump unit 240 to increase the voltage of the electrical signal flowing through the charge pump unit 240. For example, the charge pump control signal may represent an electrical signal flowing from the node 236 to the first capacitor 244A, where the charge pump control signal controls when the first capacitor 244A discharges. The charge pump control signal may represent an electrical signal having one or more first phases and one or more second phases. During the one or more first phases, a voltage of the charge pump control signal may be less than a voltage of the charge pump control signal during the one or more second phases.In some examples, during a first phase of the one or more first phases, the capacitor 244A charges via a first diode 242A to a voltage of the first output signal generated by the power conversion unit 230. In response to the charge pump control signal transitioning to a second phase of the one or more second phases following the first phase, a voltage at an "upper plate" of the first capacitor 244A (e.g., the plate of the first capacitor 244A that is closer to the diodes 244 than the "lower plate" coupled to the capacitor 236) may increase to twice the voltage of the first output signal generated by the power conversion unit 230. Subsequently, the second capacitor 244B may charge via the second diode 242B to twice the voltage of the first output signal generated by the power conversion unit 230.Subsequently, the charge pump control signal may change to another first phase of the one or more first phases, causing the second capacitor 244B to discharge. In this way, a voltage of the second output signal generated by the charge pump unit 240 is twice the voltage of the first output signal generated by the power converter unit 230 because the second capacitor 244B charges to twice the voltage of the first output signal.

[0032] The linear regulator unit 250 is configured to receive the second output signal generated by the charge pump unit 240. In some examples, the linear regulator unit 250 is a circuit component that receives an electrical input signal and generates an electrical output signal, wherein the electrical output signal has a constant and predetermined voltage that does not change based on the voltage and / or current of the input of the linear regulator unit 250. For example, a resistor of the linear regulator unit 250 may charge according to the voltage of the input of the linear regulator unit 250, enabling the linear regulator unit 250 to generate the output signal with the constant and predetermined voltage. The linear regulator unit 250 may receive the second output signal from the charge pump unit 240 and generate a third output signal with a third voltage and a third current.In some examples, the linear regulator unit 250 reduces (e.g., decreases) a voltage of the electrical signal flowing through the linear regulator unit 250. In this way, the voltage of the third output signal may be less than a voltage of the second output signal. In some examples, a difference between the voltage of the second output signal generated by the charge pump unit 240 and the voltage of the third output signal generated by the linear regulator unit 250 is less than a difference between the voltage of the first output signal generated by the power converter unit 230 and the voltage of the second output signal generated by the charge pump unit 240.

[0033] In some examples, it may be advantageous to limit a difference between the voltage of the second output signal and the voltage of the third output signal. For example, because the linear regulator unit 250 may include a resistor, energy is dissipated as heat when an electrical signal flows through the linear regulator unit 250. A first difference between the voltage of the second output signal and the voltage of the third output signal may correspond to a first amount of energy dissipation from the linear regulator unit 250, and a second difference between the voltage of the second output signal and the voltage of the third output signal may correspond to a second amount of energy dissipation from the linear regulator unit 250. If the first difference is greater than the second difference, the first amount of energy dissipation is greater than the second amount of energy dissipation.Energy dissipation leads to inefficiency because energy dissipated as heat cannot be used to power electrical components. Therefore, the power converter unit 230 and the charge pump unit 240 can limit the difference between the voltage of the second output signal and the voltage of the third output signal so that the difference remains below a voltage difference threshold, allowing the linear regulator unit 250 to efficiently generate the third output signal.

[0034] In some examples, the power converter unit 230 is configured to supply at least a portion of the first output signal to the first chain of LEDs 260 while the LED control switching element 262 is activated. In some examples, the current of the electrical signal received by the first chain of LEDs 260 is within a range of 50 milliamperes (mA) to 1,500 mA. In some cases, the first chain of LEDs 260 may include a set of HB LEDs and a set of LB LEDs. In some cases, the system 100 may alternate between activating the set of LB LEDs, activating the set of HB LEDs, activating both the set of LB LEDs and the set of HB LEDs, and deactivating both the set of LB LEDs and the set of HB LEDs.In some examples, the first string of LEDs may include a single set of LEDs configured to operate in an LB mode, to operate in an HB mode, to operate in both the LB mode and the HB mode, or to operate in neither the LB mode nor the HB mode. The LED control switching element 262 may control whether the first string of LEDs 260 receives power from the power conversion unit 230. For example, if the LED control switching element 262 is deactivated, the first string of LEDs 260 may not receive sufficient power to provide LB illumination and / or HB illumination.When the LED control switching element 262 is activated, the first string of LEDs 260 may receive at least a portion of the first output signal generated by the power converter unit 230, wherein the first output signal includes sufficient power for the first string of LEDs 260 to provide LB illumination and / or HB illumination. A controller (in . Fig. 2 not shown) may be configured to switch the first chain of LEDs 260 between one, none, or both of the LB mode and the HB mode.

[0035] In some examples, the linear regulator unit 250 is configured to provide at least a portion of the third output signal to the second chain of LEDs 270. In some examples, the third output signal includes a current within a range of 50 mA to 1,500 mA. In some cases, the second chain of LEDs 270 may include a set of daytime running light (DRL) LEDs and a set of position (POS) LEDs. In some cases, the system 200 may switch between activating the set of DRL LEDs, activating the set of POS LEDs, activating both the set of DRL LEDs and the set of POS LEDs, and deactivating both the set of DRL LEDs and the set of POS LEDs. In some examples, the second chain of LEDs 270 may switch between a DRL mode of operation and a POS mode of operation. In some examples, the DRL lighting (e.g.The DRL LEDs (also known as DRLs) are mounted on the front of a vehicle and are automatically activated when the vehicle itself is turned on. For example, the DRL lighting can be activated at any time the vehicle is started. In some cases, the DRL lighting can signal the presence of the vehicle by emitting primarily white light. In some examples, the POS lighting is only activated at night. POS lighting can be used by off-road vehicle (ATV) original equipment manufacturers (OEMs) to differentiate car models. In some examples, the POS lighting represents dimmed DRL lighting (e.g., dimmed 10% of the DRL lighting).

[0036] Fig. 3 is a circuit diagram illustrating a system 300 having circuitry for supplying power to a first string of LEDs 360 and a second string of LEDs 370 using a synchronous power boost converter unit 330, a multi-stage charge pump unit 340, and a linear regulator unit 350 according to one or more techniques of this disclosure. As shown in Fig. 3, the system 300 includes a power source 310, a power converter unit 330, a charge pump unit 340, a linear regulator unit 350, a first chain of LEDs 360, an LED control switching element 362, and a second chain of LEDs 370. The power converter unit 330 includes an inductor 332 and switching elements 334A-334D (collectively, "switching elements 334"). The charge pump unit 340 includes a first diode 342A, a second diode 342B, a third diode 342C, and a fourth diode 342D (collectively, "diodes 342"), and a first capacitor 344A, a second capacitor 344B, a third capacitor 344C, and a fourth capacitor 344D (collectively, "capacitors 344"). The power source 310 may be an example of the power source 110 of Fig. 1. The power converter unit 330 may be an example of the power converter unit 130 of Fig. 1. The charge pump unit 340 may be an example of the charge pump unit 140 of Fig. 1. The linear regulator unit 350 may be an example of the linear regulator unit 150 of Fig. 1. The first chain of LEDs 360 can be an example of the first LEDs 160 of Fig. 1. The second chain of LEDs 370 may be an example of the second LEDs 170 of Fig. 1. The system 300 may be substantially similar to the system 200 of Fig. 2, except that the charge pump unit 340 contains more than one multiplication stage, whereas the charge pump unit 240 of Fig. 2 contains a single multiplication level.

[0037] The power converter unit 330 may provide at least a portion of a first output signal to the charge pump unit 340. In this way, although the first output signal is described as an 'output,' the first output signal may act as an 'input' to the charge pump unit 340. In some examples, the charge pump unit 340 may represent a Dickson charge pump that includes two multiplication stages (e.g., four diodes and four capacitors) that substantially triple a voltage of the electrical signal flowing through the charge pump unit 340 from an entry point of the charge pump unit 340 to an exit point of the charge pump unit 340. In this way, the charge pump unit 340 may be referred to herein as a voltage multiplier because the charge pump unit 340 increases a voltage by an integer factor.For example, the charge pump unit 340 may generate a second output signal having a second voltage and a second current. In some cases, the second voltage may be within a range of 2.9 times the voltage of the first output signal generated by the power converter unit 330 to 3.1 times the voltage of the first output signal. For example, the second voltage may be 3.0 times the voltage of the first output signal.

[0038] In some examples, the charge pump unit 340 receives a charge pump control signal from the power converter unit 330. The charge pump control signal may enable the charge pump unit 340 to increase the voltage of the electrical signal flowing through the charge pump unit 340. For example, the charge pump control signal may represent an electrical signal flowing from a node 336 to the first capacitor 344A and the third capacitor 344C, where the charge pump control signal controls when the first capacitor 344A and the third capacitor 344C discharge. The charge pump control signal may represent an electrical signal having one or more first phases and one or more second phases. During the one or more first phases, a voltage of the charge pump control signal may be less than a voltage of the charge pump control signal during the one or more second phases.In some examples, during a first phase of the one or more first phases, the capacitor 344A charges via the first diode 342A to a voltage of the first output signal generated by the power conversion unit 330. In response to the charge pump control signal transitioning to a second phase of the one or more second phases following the first phase, a voltage at an "upper plate" of the first capacitor 344A (e.g., the plate of the first capacitor 344A closer to the diodes 342 than the "lower plate" coupled to the node 336) may increase to twice the voltage of the first output signal generated by the power conversion unit 330. Thereafter, the second capacitor 344B may charge via the second diode 342B to twice the voltage of the first output signal generated by the power conversion unit 330.

[0039] Subsequently, the charge pump control signal may transition to another first phase of the one or more first phases, causing the second capacitor 344B to discharge, which charges the third capacitor 344C to twice the voltage of the first output signal generated by the power converter unit 330. The charge pump control signal may further transition to another second phase of the one or more second phases, causing a voltage at the top plate of the third capacitor 344C to increase to three times the voltage of the first output signal generated by the power converter unit 330. Thereafter, the fourth capacitor 344D may charge via the fourth diode 342D to three times the voltage of the first output signal generated by the power converter unit 330. After the charge pump control transitions to another first phase of the one or more first phases, the fourth capacitor 344D discharges.In this way, a voltage of the second output signal generated by the charge pump unit 340 is three times the voltage of the first output signal generated by the power converter unit 330, since the fourth capacitor 344D charges to three times the voltage of the first output signal.

[0040] Even if the charge pump unit 240 of Fig. 2 and the charge pump unit 340 of Fig. 1 are described as having one or two multiplication stages, at least some of the Fig. 2 - 3 systems not shown contain more than two or fewer than two multiplication stages.

[0041] Fig. 4 is a circuit diagram illustrating a system 400 having circuitry for supplying power to a first chain of LEDs 460 and a second chain of LEDs 470 using an asynchronous power boost converter unit 430, a single-stage charge pump unit 440, and a linear regulator unit 450 according to one or more techniques of this disclosure. As shown in Fig. 4, the system 400 includes a power source 410, a power converter unit 430, a charge pump unit 440, a linear regulator unit 450, a first chain of LEDs 460, an LED control switching element 462, and a second chain of LEDs 470. The power converter unit 430 includes an inductor 432, a switching element 434, and a diode 436. The charge pump unit 440 includes a first diode 442A and a second diode 442B (collectively, “diodes 442”) and a first capacitor 444A and a second capacitor 444B (collectively, “capacitors 444”). The power source 410 may be an example of the power source 110 of Fig. 1. The power converter unit 430 may be an example of the power converter unit 130 of Fig. 1. The charge pump unit 440 may be an example of the charge pump unit 140 of Fig. 1. The linear regulator unit 450 may be an example of the linear regulator unit 150 of Fig. 1. The first chain of LEDs 460 can be an example of the first LEDs 160 of Fig. 1. The second chain of LEDs 470 may be an example of the second LEDs 170 of Fig. 1. The system 400 may be substantially similar to the system 200 of Fig. 2, with the exception that the power converter unit 430 is a boost converter, whereas the power converter unit 230 of Fig. 2 represents a buck-boost converter.

[0042] The power converter unit 430 may be configured to regulate the output voltage supplied to the first chain of LEDs 460 using at least one mode of operation, including a boost mode of operation. Fig. 4, the switching element 434 may include transistors, diodes, or other semiconductor elements. In the boost mode, the power converter unit 430 may step up voltage and step down current from the input of the power converter unit 430 to the output of the power converter unit 430. As such, the power converter unit 430 may receive an input signal from the power source 410 and generate a first output signal. The first output signal may include a first voltage and a first current, where the first voltage is greater than a voltage of the input signal and the first current is less than a current of the input signal. In some examples, to increase the voltage of the electrical signal flowing through the power converter unit 430, the switching element 434 transitions between being enabled and being disabled.When the switching element 434 is activated, an electric current flows from the power source 410 through the inductor 432 and the switching element 434, thereby charging the inductor 432. When the switching element 434 is deactivated, the inductor 432 discharges and an electric current flows from the power source 410 through the inductor 432 and the diode 436, thus stepping up (e.g., increasing) an output voltage of the first output signal applied to the charge pump unit 440 and / or the first chain of LEDs 460. Additionally, the power converter unit 430 may step down a current of the first output signal.

[0043] Fig. 5 is a circuit diagram illustrating a system 500 having circuitry for supplying power to a first chain of LEDs 560 and a second chain of LEDs 570 using an asynchronous power boost converter unit 530, a multi-stage charge pump unit 540, and a linear regulator unit 550 according to one or more techniques of this disclosure. As shown in Fig. 5, the system 500 includes a power source 510, a power converter unit 530, a charge pump unit 540, a linear regulator unit 550, a first chain of LEDs 560, an LED control switching element 562, and a second chain of LEDs 570. The power converter unit 530 includes an inductor 532, a switching element 534, and a diode 536. The charge pump unit 540 includes a first diode 542A, a second diode 542B, a third diode 542C, and a fourth diode 542D (collectively, “diodes 542”) and a first capacitor 544A, a second capacitor 544B, a third capacitor 544C, and a fourth capacitor 544D (collectively, “capacitors 544”). The power source 510 may be an example of the power source 110 of Fig. 1. The power converter unit 530 may be an example of the power converter unit 130 of Fig. 1. The charge pump unit 540 may be an example of the charge pump unit 140 of Fig. 1. The linear regulator unit 550 may be an example of the linear regulator unit 150 of Fig. 1. The first chain of LEDs 560 can be an example of the first LEDs 160 of Fig. 1. The second chain of LEDs 570 may be an example of the second LEDs 170 of Fig. 1. The system 500 may be substantially similar to the system 300 of Fig. 3, except that the power converter unit 530 is a boost converter, whereas the power converter unit 330 of Fig. 3 represents a buck-boost converter.

[0044] The power converter unit 530 may be configured to regulate the output voltage supplied to the first chain of LEDs 560 using at least one mode of operation, including a boost mode of operation. Fig. 5, the switching element 534 may include transistors, diodes, or other semiconductor elements. In the boost mode, the power converter unit 530 may step up voltage and step down current from the input of the power converter unit 530 to the output of the power converter unit 530. As such, the power converter unit 530 may receive an input signal from the power source 510 and generate a first output signal. The first output signal may include a first voltage and a first current, where the first voltage is greater than a voltage of the input signal and the first current is less than a current of the input signal. In some examples, to increase the voltage of the electrical signal flowing through the power converter unit 530, the switching element 534 transitions between being enabled and being disabled.When the switching element 534 is activated, an electric current flows from the power source 510 through the inductor 532 and the switching element 534, thereby charging the inductor 532. When the switching element 534 is deactivated, the inductor 532 discharges and an electric current flows from the power source 510 through the inductor 532, and the diode 536 thereby steps up (e.g., increases) an output voltage of the first output signal supplied to the charge pump unit 540 and / or the first chain of LEDs 50. Additionally, the power converter unit 530 may step down a current of the first output signal.

[0045] Fig. 6 is a circuit diagram illustrating a system 600 having circuitry for supplying power to a first chain of LEDs 660 and a second chain of LEDs 670 using a power buck-boost converter unit 630, a first single-stage charge pump unit 640, a linear regulator unit 650, and a second single-stage charge pump unit 680 according to one or more techniques of this disclosure. As in Fig. 6, the system 600 includes a power source 610, a power converter unit 630, a first charge pump unit 640, a linear regulator unit 650, a first chain of LEDs 660, an LED control switching element 662, a second chain of LEDs 670, a second charge pump unit 680, and a charge pump capacitor 690. The power converter unit 630 includes an inductor 632 and switching elements 634A-634D (collectively, "switching elements 634"). The first charge pump unit 640 includes a first diode 642A and a second diode 642B (collectively, "diodes 642") and a capacitor 644 (collectively, "capacitors 644"). The second charge pump unit 680 includes a third diode 682A and a fourth diode 682B (collectively “diodes 682”) and a capacitor 684. The power source 610 may be an example of the power source 110 of Fig. 1. The power converter unit 630 may be an example of the power converter unit 130 of Fig. 1. The first charge pump unit 640, the second charge pump unit 680 and the charge pump capacitor 690 may be an example of the charge pump unit 140 of Fig. 1. The linear regulator unit 650 may be an example of the linear regulator unit 150 of Fig. 1. The first chain of LEDs 660 can be an example of the first LEDs 160 of Fig. 1. The second chain of LEDs 670 may be an example of the second LEDs 170 of Fig. 1. The system 600 may be substantially similar to the system 200 of Fig. 2, except that the system 600 includes a first charge pump unit 640 and a second charge pump unit 680, whereas the system 200 of Fig. 2 contains a single charge pump unit 240.

[0046] The power converter unit 630 may be configured to operate in a buck mode and a boost mode. When the power converter unit 630 operates in the boost mode, the first charge pump unit 640 may receive a first charge pump control signal from the power converter unit 630. The first charge pump control signal may enable the charge pump unit 640 to increase the voltage of the electrical signal flowing through the charge pump unit 640. For example, the first charge pump control signal may represent an electrical signal flowing from the node 638 to the capacitor 644, wherein the first charge pump control signal controls when the capacitor 644 discharges. The first charge pump control signal may represent an electrical signal having one or more first phases and one or more second phases.During the one or more first phases, a voltage of the first charge pump control signal may be less than a voltage of the first charge pump control signal during the one or more second phases. In some examples, during a first phase of the one or more first phases, the capacitor 644 charges via the first diode 642A to a voltage of the first output signal generated by the power converter unit 630. In response to the first charge pump control signal transitioning to a second phase of the one or more second phases following the first phase, a voltage at a top plate of the capacitor 644 (e.g., the plate of the capacitor 644 closer to the diodes 642 than the bottom plate coupled to the node 638) may increase to twice the voltage of the first output signal generated by the power converter unit 630.The charge pump capacitor 690 may then increase via the second diode 642B to twice the voltage of the first output signal generated by the power converter unit 630. Subsequently, the first charge pump control signal may change to another of the one or more first phases, causing the charge pump capacitor 690 to discharge. In this way, a voltage of the second output signal generated by the charge pump unit 640 is twice the voltage of the first output signal generated by the power converter unit 630 because the charge pump capacitor 690 charges to twice the voltage of the first output signal.

[0047] When the power converter unit 630 operates in the buck mode, the second charge pump unit 680 may receive a second charge pump control signal from the power converter unit 630. The second charge pump control signal may enable the second charge pump unit 680 to increase the voltage of the electrical signal flowing through the second charge pump unit 680. For example, the second charge pump control signal may represent an electrical signal flowing from the node 639 to the capacitor 684, wherein the second charge pump control signal controls when the capacitor 684 discharges. The second charge pump control signal may represent an electrical signal having one or more first phases and one or more second phases.During the one or more first phases, a voltage of the second charge pump control signal may be less than a voltage of the second charge pump control signal during the one or more second phases. In some examples, during a first phase of the one or more first phases, the capacitor 684 charges via the third diode 682A to a voltage of the first output signal generated by the power converter unit 630. In response to the second charge pump control signal transitioning to a second phase of the one or more second phases following the first phase, a voltage at the top plate of the capacitor 684 may increase to twice the voltage of the first output signal generated by the power converter unit 630. Thereafter, the charge pump capacitor 690 may charge via the fourth diode 682B to twice the voltage of the first output signal generated by the power converter unit 630.Subsequently, the second charge pump control signal may change to another first phase of the one or more first phases, causing the charge pump capacitor 690 to discharge. In this way, a voltage of the second output signal generated by the second charge pump unit 680 is twice the voltage of the first output signal generated by the power converter unit 630 because the charge pump capacitor 690 charges to twice the voltage of the first output signal.

[0048] In this way, the first charge pump unit 640 can be used to generate a second output signal that is provided to the linear regulator unit 650 when the power converter unit 630 is operating in the buck mode. Using the same token, the second charge pump unit 680 can be used to generate the second output signal that is provided to the linear regulator unit 650 when the power converter unit 630 is operating in the boost mode.

[0049] Fig. 7 is a circuit diagram illustrating a system 700 having circuitry for supplying power to a first chain of LEDs 760 and a second chain of LEDs 770 using a power buck-boost converter unit 730, a first multi-stage charge pump unit 740, a linear regulator unit 750, and a second multi-stage charge pump unit 780 according to one or more techniques of this disclosure. As in Fig. 7, the system 700 includes a power source 710, a power converter unit 730, a charge pump unit 740, a linear regulator unit 750, a first chain of LEDs 760, an LED control switching element 762, a second chain of LEDs 770, a second charge pump unit 780, and a charge pump capacitor 790. The power converter unit 730 includes an inductor 732 and switching elements 734A-734D (collectively, “switching elements 734”). The first charge pump unit 740 includes a first diode 742A, a second diode 742B, a third diode 742C, and a fourth diode 742D (collectively, “diodes 742”) and a first capacitor 744A, a second capacitor 744B, and a third capacitor 744C (collectively, “capacitors 744”).The second charge pump unit 780 includes a first diode 782A, a second diode 782B, a third diode 782C, and a fourth diode 782D (collectively, "diodes 782"), and a first capacitor 784A, a second capacitor 784B, and a third capacitor 784C (collectively, "capacitors 784"). The power source 710 may be an example of the power source 110 of FIG. Fig. 1. The power converter unit 730 may be an example of the power converter unit 130 of Fig. 1. The first charge pump unit 740, the second charge pump unit 780 and the charge pump capacitor 790 may be an example of the charge pump unit 140 of Fig. 1. The linear regulator unit 750 may be an example of the linear regulator unit 150 of Fig. 1. The first chain of LEDs 760 can be an example of the first LEDs 160 of Fig. 1. The second chain of LEDs 770 may be an example of the second LEDs 170 of Fig. 1. The system 700 may be substantially similar to the system 300 of Fig. 3, except that the system 700 includes a first charge pump unit 740 and a second charge pump unit 780, whereas the system 300 of Fig. 3 contains a single first charge pump unit 740.

[0050] The power converter unit 730 may be configured to operate in a buck mode and a boost mode. When the power converter unit 730 operates in the boost mode, the first charge pump unit 740 receives a first charge pump control signal from the power converter unit 730. The first charge pump control signal may enable the first charge pump unit 740 to increase the voltage of the electrical signal flowing through the first charge pump unit 740. For example, the first charge pump control signal may represent an electrical signal flowing from the node 738 to the first capacitor 744A and the third capacitor 744C, wherein the first charge pump control signal controls when the first capacitor 744A and the third capacitor 744C discharge. The first charge pump control signal may represent an electrical signal having one or more first phases and one or more second phases.During the one or more first phases, a voltage of the first charge pump control signal may be less than a voltage of the first charge pump control signal during the one or more second phases. In some examples, during a first phase of the one or more first phases, the capacitor 744A charges via the first diode 742A to a voltage of the first output signal generated by the power converter unit 730. In response to the first charge pump control signal transitioning to a second phase of the one or more second phases following the first phase, a voltage at a top plate of the first capacitor 744A may charge to twice the voltage of the first output signal generated by the power converter unit 730. Thereafter, the second capacitor 744B may charge via the second diode 742B to twice the voltage of the first output signal generated by the power converter unit 730.

[0051] Subsequently, the first charge pump control signal may transition to another first phase of the one or more first phases, causing the second capacitor 744B to discharge, which charges the third capacitor 744C to twice the voltage of the first output signal generated by the power converter unit 730. The first charge pump control signal may further transition to another second phase of the one or more second phases, causing a voltage at the top plate of the third capacitor 744C to increase to three times the voltage of the first output signal generated by the power converter unit 730. The charge pump capacitor 790 may then charge via the fourth diode 742D to three times the voltage of the first output signal generated by the power converter unit 730.After the charge pump control switches to another first phase of the one or more first phases, the charge pump capacitor 790 discharges. In this way, a voltage of the second output signal generated by the first charge pump unit 740 is three times the voltage of the first output signal generated by the power converter unit 730, which charges the charge pump capacitor 790 to three times the voltage of the first output signal.

[0052] When the power converter unit 730 operates in the buck mode, the second charge pump unit 780 receives a second charge pump control signal from the power converter unit 730. The second charge pump control signal may enable the second charge pump unit 780 to increase the voltage of the electrical signal flowing through the second charge pump unit 780. For example, the second charge pump control signal may represent an electrical signal flowing from the node 739 to the first capacitor 784A and the third capacitor 784C, wherein the second charge pump control signal controls when the first capacitor 784A and the third capacitor 784C discharge. The second charge pump control signal may represent an electrical signal having one or more first phases and one or more second phases.During the one or more first phases, a voltage of the second charge pump control signal may be less than a voltage of the second charge pump control signal during the one or more second phases. In some examples, during a first phase of the one or more first phases, the capacitor 784A charges via the first diode 782A to a voltage of the first output signal generated by the power converter unit 730. In response to the second charge pump control signal transitioning to a second phase of the one or more second phases following the first phase, a voltage at the top plate of the first capacitor 784A may increase to twice the voltage of the first output signal generated by the power converter unit 730. Thereafter, the second capacitor 784B may charge via the second diode 782B to twice the voltage of the first output signal generated by the power converter unit 730.

[0053] Subsequently, the second charge pump control signal may transition to another first phase of the one or more first phases, causing the second capacitor 784B to discharge, charging the third capacitor 784C to twice the voltage of the first output signal generated by the power converter unit 730. The second charge pump control signal may further transition to another second phase of the one or more second phases, causing a voltage at the top plate of the third capacitor 784C to increase to three times the voltage of the first output signal generated by the power converter unit 730. Thereafter, the charge pump capacitor 790 may charge via the fourth diode 782D to three times the voltage of the first output signal generated by the power converter unit 730.After the charge pump control switches to another first phase of the one or more first phases, the charge pump capacitor 790 discharges. In this way, a voltage of the second output signal generated by the second charge pump unit 780 is three times the voltage of the first output signal generated by the power converter unit 730 because the charge pump capacitor 790 charges to three times the voltage of the first output signal.

[0054] In this way, the first charge pump unit 740 can be used to generate a second output signal that is provided to the linear regulator unit 750 when the power converter unit 730 is operating in the buck mode. Using the same token, the second charge pump unit 780 can be used to generate the second output signal that is provided to the linear regulator unit 750 when the power converter unit 730 is operating in the boost mode.

[0055] Fig. 8 is a flowchart illustrating an example operation for generating one or more output signals to provide power to control one or more strings of LEDs, according to one or more techniques of this disclosure. For convenience, Fig. 8 in relation to the system 100 of Fig. 1. However, the techniques of Fig. 8 by various components of the system 100 or by additional or alternative systems.

[0056] As in the example operation of Fig.8, the power converter unit 130 is configured to receive an input signal from the power source 110 (802). In some examples, the input signal includes a voltage and a current. In some cases, the power source 110 may be a rechargeable power source, such as a battery. The power converter unit 130 may generate a first output signal having a first voltage (804). In some examples, the power converter unit 130 represents a DC-DC converter. In some cases, the power converter unit 130 may operate according to a buck mode of operation. In some cases, the power converter unit 130 may operate according to a boost mode of operation. In some examples, the power converter unit 130 may operate according to both a buck mode of operation and a boost mode of operation.In this case, the first voltage of the first output signal generated by the power converter unit 130 may be greater than or less than the voltage of the input signal, depending on whether the power converter unit 130 is operating in the buck mode or the boost mode. For example, when the power converter unit 130 is operating in the boost mode, the first voltage may be greater than the voltage of the input signal. When the power converter unit 130 is operating in the buck mode, the first voltage may be less than the voltage of the input signal. In some examples, in response to an LED control switching unit being activated, the power converter unit 130 may supply at least a portion of the first output signal to a first chain of LEDs, which may represent HB lighting and LB lighting on a vehicle.The power converter unit 130 may generate the first output signal such that the first voltage is sufficient to power the first string of LEDs.

[0057] The charge pump unit 140 receives at least a portion of the first output signal from the power converter unit 130 (806). The charge pump unit 140 then generates a second output signal having a second voltage (808). In some examples, the charge pump unit 140 may be a Dickson charge pump that multiplies the voltage of the first output signal by an integer value. The charge pump unit 140 may receive a charge pump control signal that controls capacitors of the charge pump unit 140 to charge and discharge to generate the second output signal. The linear regulator unit 150 may receive the second output signal from the charge pump unit 140 (810) and generate a third output signal having a first voltage (812). The linear regulator unit 150 may generate the third output signal to have a constant voltage regardless of the input voltage of the linear regulator unit 150.The charge pump unit 140 may generate the second output signal such that a difference between the second voltage and the third voltage is relatively small compared to systems that do not include a power converter and a charge pump. In some examples, the linear regulator unit 150 supplies at least a portion of the third output signal to a second chain of LEDs representing DRL lighting and POS lighting on a vehicle.

[0058] The techniques described in this disclosure may be implemented, at least in part, in hardware, software, firmware, or any combination thereof. For example, various aspects of the described techniques may be implemented within one or more processors, including one or more microprocessors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or any other equivalent integrated or discrete logic circuit technology, as well as any combination of such components. The term "processor" or "operating circuit" may generally refer to a foregoing logic circuit technology alone or in combination with other logic circuit technology or any other equivalent circuit technology. A hardware control circuit may also perform one or more of the techniques of this disclosure.

[0059] Such hardware, software, and firmware may be implemented within the same device or within separate devices to support the various techniques described in this disclosure. In addition, any of the described units, modules, or components may be implemented together or separately as discrete but interoperable logic devices. The depiction of various 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, firmware, or software components. Rather, the functionality associated with one or more of the modules or units may be implemented by separate hardware, firmware, or software components, or within common or separate hardware, firmware, or software components.

Claims

[1] A circuit configured to control current through one or more chains of light-emitting diodes, LEDs, (160, 170; 260, 270; 360, 370; 460, 470; 560, 570; 660, 670; 760, 770), the circuit comprising: a power converter unit (130; 230; 330; 430; 530; 630; 730) configured to receive an input signal from a power source (110; 210; 310; 410; 510; 610; 710) and to generate a first output signal having a first voltage; a charge pump (140; 240; 340; 440; 540; 640; 740) configured to receive at least a portion of the first output signal from the power converter unit (130; 230; 330; 430; 530; 630; 730) and to generate a second output signal having a second voltage; and a linear regulator (150; 250; 350; 450; 550; 650; 750) configured to receive the second output signal from the charge pump (140; 240; 340; 440; 540; 640; 740) and to generate a third output signal having a third voltage. [2] The circuit of claim 1, wherein the power converter unit (230; 330; 430; 530; 630; 730) is further configured to: to supply at least a portion of the first output signal to a first chain of LEDs (260; 360; 460; 560; 660; 760) while an LED control switching element (262; 362; 462; 562; 662; 762) is activated. [3] The circuit of claim 2, wherein the power converter unit (230; 330; 430; 530; 630; 730) for supplying the at least part of the first output signal to the first chain of LEDs (260; 360; 460; 560; 660; 760) is configured to: to regulate a current of at least a portion of the first output signal supplied to the first chain of LEDs (260; 360; 460; 560; 660; 760) such that a current of at least a portion of the first output signal remains substantially constant while the LED control switching element (262; 362; 462; 562; 662; 762) is activated. [4] The circuit of claim 2 or 3, wherein the linear regulator (230; 330; 430; 530; 630; 730) is further configured to provide at least a portion of the third output signal to a second chain of LEDs (270; 370; 470; 570; 670; 770). [5] Circuit according to claim 2 or 3, wherein the linear regulator (230; 330; 430; 530; 630; 730) is further configured to: to supply at least a portion of the third output signal to a second chain of LEDs (270; 370; 470; 570; 670; 770) while the LED control switching element (262; 362; 462; 562; 662; 762) is deactivated. [6] Circuit according to one of the preceding claims, wherein the power converter unit (230; 330; 430; 530; 630; 730) comprises a power converter switching device (234A-234D; 334A-334D; 434, 436; 534, 536; 634A-634D; 734A-734D) and an inductor (232; 332; 432; 532; 632; 732), wherein the power converter unit (230; 330; 430; 530; 630; 730), while the power converter switching device (234A-234D; 334A-334D; 434, 436; 534, 536; 634A-634D; 734A-734D) is activated, is designed to: to charge the inductance (232; 332; 432; 532; 632; 732) while the power converter switching device (234A-234D; 334A-334D; 434, 436; 534, 536; 634A-634D; 734A-734D) is activated; and to discharge the inductance (232; 332; 432; 532; 632; 732) while the power converter switching device (234A-234D; 334A-334D; 434, 436; 534, 536; 634A-634D; 734A-734D) is deactivated to generate the first output signal, wherein the power converter unit (230; 330; 430; 530; 630; 730) increases a voltage of the input signal to generate the first output signal. [7] The circuit of claim 6, wherein the power converter unit (230; 330; 430; 530; 630; 730) is further configured to: to generate a charge pump control signal, wherein the charge pump control signal includes one or more first phases during which the power converter switching device (234A-234D; 334A-334D; 434, 436; 534, 536; 634A-634D; 734A-734D) is activated, and one or more second phases during which the power converter switching device (234A-234D; 334A-334D; 434, 436; 534, 536; 634A-634D; 734A-734D) is deactivated, and wherein the charge pump (240; 340; 440; 540; 640; 740) is configured to generate the second output signal based on the charge pump control signal, and, wherein the charge pump (240; 340; 440; 540; 640; 740) is configured to increase the first voltage of the first output signal in order to generate the second output signal. [8] The circuit of claim 7, wherein the charge pump (240; 340; 440; 540; 740) comprises a first capacitor (244A; 344A; 444A; 544A; 744A) and a second capacitor (244B; 344B; 444B; 544B; 744B), and wherein the charge pump (240; 340; 440; 540; 740) is configured to generate the second output signal: to charge the first capacitor (244A; 344A; 444A; 544A; 744A) to the first voltage during each first phase of the one or more first phases; and to charge the second capacitor (244B; 344B; 444B; 544B; 744B) to the second voltage during every second phase of the one or more second phases. [9] The circuit of claim 8, wherein the charge pump (240; 340; 440; 540; 740) comprises a multiplication stage and wherein the second voltage is within a range of 1.9 times the first voltage to 2.1 times the first voltage. [10] The circuit of claim 7, wherein the charge pump (240; 340; 440; 540; 740) has two multiplication stages and wherein the second voltage is within a range of 2.9 times the first voltage to 3.1 times the first voltage. [11] A circuit according to any one of the preceding claims, wherein the first output signal has a first current within a range of 50 milliamperes (mA) to 1,500 mA and wherein the third output signal has a second current within a range of 50 mA to 1,500 mA. [12] Circuit according to one of the preceding claims, wherein the linear regulator (150; 250; 350; 450; 550; 650; 750) is configured to reduce a voltage of the second output signal in order to generate the third output signal, wherein a difference between the second voltage and the third voltage is smaller than a difference between the first voltage and the second voltage. [13] The circuit of any preceding claim, wherein the charge pump (140; 240; 340; 440; 540; 640; 740) is configured to limit a difference between the second voltage and a third voltage such that the difference between the second voltage and the third voltage remains below a voltage difference threshold. [14] A circuit according to any one of the preceding claims, wherein the power converter unit (130; 230; 330; 430; 530; 630; 730) comprises a direct current to direct current (DC-DC) converter. [15] The circuit of claim 14, wherein the DC-DC converter comprises an H-bridge unit. [16] Method comprising: Receiving an input signal from a power source (110; 210; 310; 410; 510; 610; 710) by a power converter unit (130; 230; 330; 430; 530; 630; 730) of a circuit configured to control a current through one or more chains of light-emitting diodes, LEDs, (160, 170; 260, 270; 360, 370; 460, 470; 560, 570; 660, 670; 760, 770); Generating a first output signal having a first voltage by the power converter unit (130; 230; 330; 430; 530; 630; 730); Receiving at least a portion of the first output signal from the power converter unit (130; 230; 330; 430; 530; 630; 730) by a charge pump (140; 240; 340; 440; 540; 640; 740) of the circuit; Generating a second output signal with a second voltage by the charge pump (140; 240; 340; 440; 540; 640; 740); Receiving the second output signal from the charge pump (140; 240; 340; 440; 540; 640; 740) by a linear regulator (150; 250; 350; 450; 550; 650; 750) of the circuit; and Generating a third output signal with a third voltage by the linear regulator (150; 250; 350; 450; 550; 650; 750). [17] The method of claim 16, further comprising: Providing at least a portion of the first output signal to a first chain (260; 360; 460; 560; 660; 760) of LEDs while an LED control switching element (262; 362; 462; 562; 662; 762) is activated. [18] The method of claim 17, wherein the method further comprises: Supplying at least a portion of the third output signal to a second chain of LEDs (270; 370; 470; 570; 670; 770) through the linear regulator (250; 350; 450; 550; 650; 750). [19] The method of claim 17, wherein the method further comprises: Providing at least a portion of the third output signal to a second chain of LEDs (270; 370; 470; 570; 670; 770) while the LED control switching element (262; 362; 462; 562; 662; 762) is deactivated. [20] System that has: a power source (110; 210; 310; 410; 510; 610; 710); a first chain of LEDs (160; 260; 360; 460; 560; 660; 760); a second chain of LEDs (170; 270; 370; 470; 570; 670; 770); and a circuit configured to control current through the first chain of LEDs (160; 260; 360; 460; 560; 660; 760) and the second chain of LEDs (270; 370; 470; 570; 670; 770), the circuit comprising: a power converter unit (130; 230; 330; 430; 530; 630; 730) configured to receive an input signal from the power source (110; 210; 310; 410; 510; 610; 710) and to generate a first output signal having a first voltage; a charge pump (140; 240; 340; 440; 540; 640; 740) configured to receive at least a portion of the first output signal from the power converter unit (130; 230; 330; 430; 530; 630; 730) and to generate a second output signal having a second voltage; and a linear regulator (150; 250; 350; 450; 550; 650; 750) configured to receive the second output signal from the charge pump (140; 240; 340; 440; 540; 640; 740) and to generate a third output signal having a third voltage.

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