Abstract: An expander circuit may be configured to control a plurality of driver circuits for driving light emitting diodes (LEDs). The expander circuit may comprise a bus interface circuit configured to receive control signals from a processor over a communication bus, and a plurality of modulation signal generators configured to generate modulation signals based on the control signals. The expander circuit may be configured to provide the modulation signals to the plurality of driver circuits for driving the LEDs.

Abstract: This disclosure includes systems, methods, and techniques for controlling delivery of power to one or more strings of light-emitting diodes (LEDs). For example, a circuit includes a power converter configured to generate an electrical current, a switching device, and a sensor. The sensor is configured to compare a magnitude of the electrical current to a threshold, and in response to the magnitude exceeding the threshold, cause the switching device to turn on in order to sink a portion of the electrical current to prevent the magnitude of the electrical current from exceeding the threshold. When the switching device is turned on, the electrical current is divided into an undesired electrical current that flows across the switching device and a desired electrical current that flows to the string of LEDs.

Abstract: This disclosure includes systems, methods, and techniques for controlling delivery of power to one or more strings of light-emitting diodes (LEDs). For example, a circuit includes a power converter configured to generate an electrical current, a switching device, and a sensor. The sensor is configured to compare a magnitude of the electrical current to a threshold, and in response to the magnitude exceeding the threshold, cause the switching device to turn on in order to sink a portion of the electrical current to prevent the magnitude of the electrical current from exceeding the threshold. When the switching device is turned on, the electrical current is divided into an undesired electrical current that flows across the switching device and a desired electrical current that flows to the string of LEDs.

Abstract: This disclosure is directed to a light emitting diode (LED) circuit for driving two or more different LED strings, which may be controlled in a complimentary fashion. The LED circuit includes current monitoring capabilities that are configured to monitor current through the two or more different LED strings. The circuit is designed in a way that can reduce or eliminate excessive sensing pins that are otherwise needed for the current monitoring. According to this disclosure, for example, very accurate current monitoring can be achieved by using two or more sensing resistors while only using two sensing pins for the current monitoring through two or more different LED strings.

Abstract: This disclosure includes systems, methods, and techniques for controlling delivery of power to one or more strings of light-emitting diodes (LEDs). For example, a circuit is configured to monitor current through one or more strings of LEDs. The circuit includes a power converter unit, where the power converter unit is configured to receive an input signal from a power source, and where the power converter unit is configured to deliver an output signal to the one or more strings of LEDs, and a set point unit configured to deliver a set point signal to the power converter unit. Additionally, the circuit includes a correction unit configured to deliver, based on an input parameter value, an output parameter value, and a set point parameter value, a correction signal to the power converter unit.

Abstract: In one example, a system includes a load module, a power module, a series module, and a control module. The power module is configured to generate a supply power. The load module is configured to select a subset of light emitting diodes (LEDs) from a set of LEDs. The series module is configured to receive the supply power from the power module, dissipate a portion of the supply power, and output, to the subset of LEDs, a remaining portion of the supply power as a load power. The control module is configured to drive the series module to limit an amount of power at the subset of LEDs.

Abstract: In an example, a circuit includes one or more switches, wherein the circuit is configured to receive a battery voltage from a battery, deliver an input voltage to a controller, deliver an output voltage, and receive signals from the controller. The signals may activate the one or more switches and deactivate the one or more switches and activating the one or more switches and deactivating the one or more switches may control the input voltage to the controller.

Abstract: In one example, a method includes determining, by a device of a system, a voltage feedback value that represents a voltage level of a power signal being provided to a plurality of load elements that are selectively active. In this example, the method also includes adjusting, by the device and based on a quantity of load elements of the plurality of load elements that are active, the voltage level of the power signal such that the voltage feedback value remains less than or equal to an overvoltage threshold.

Abstract: A device for regulating a voltage includes a first branch switch, a second branch switch, and a control module. The control module is configured to determine an instruction to change from a first state to a second state. In response to the instruction, the control module is configured to activate the second branch switch, drive a power module to increase a supply voltage to provide a supply power for activating a second set of LEDs, drive the first branch switch to dissipate a portion of the supply power to provide a target power for activating a first set of LEDs in response to determining that a current at the second branch switch does not exceed a current threshold, and deactivate the first branch switch in response to determining that the current at the second branch switch exceeds the current threshold.

Abstract: In one example, a system includes a load module, a power module, a series module, and a control module. The power module is configured to generate a supply power. The load module is configured to select a subset of light emitting diodes (LEDs) from a set of LEDs. The series module is configured to receive the supply power from the power module, dissipate a portion of the supply power, and output, to the subset of LEDs, a remaining portion of the supply power as a load power. The control module is configured to drive the series module to limit an amount of power at the subset of LEDs.

Abstract: In one example, a method includes determining, by a device of a system, a voltage feedback value that represents a voltage level of a power signal being provided to a plurality of load elements that are selectively active. In this example, the method also includes adjusting, by the device and based on a quantity of load elements of the plurality of load elements that are active, the voltage level of the power signal such that the voltage feedback value remains less than or equal to an overvoltage threshold.

Abstract: A driver circuit for light-emitting diode (LED) headlight system includes a buck-boost converter connected in series to a first plurality of branches of LEDs. Each of the plurality of branches of LEDs includes a bypass switch configured to bypass the corresponding branch of LEDs. The buck-boost converter provides a constant current with an adjustable voltage to a selectable portion of the plurality of branches of LEDs, while bypassing each of the other branches of LEDs via the corresponding bypass switches. In some examples, the circuit delivers the current to the selectable portion of the first plurality of branches of LEDs during a first portion of a duty cycle, while delivering a digitally modulated current to a second plurality of branches during a second portion of the duty cycle.

Abstract: In one example, a system includes a load module, a voltage module, and a controller. The load module is configured to selectively bypass each load unit of a plurality of load units to form a series string of load units. The voltage module is configured to output a voltage across the series string of load units that is based on a target voltage. The controller is configured to output an indication of the target voltage, estimate a time delay for switching one or more load units of the plurality of load units, and output, after outputting the indication of the target voltage for the time delay, a control signal to switch one or more load units of the plurality of load units such that the series string of load units has the target quantity of load units.