An image formation device is provided which includes a variable resistor of which a resistance value changes in accordance with a user operation, an A/D converter that outputs information relating to a voltage applied to the variable resistor, and a pulse width modulation (PWM) controller that outputs a PWM signal having a duty ratio determined based on the information output by the A/D converter. The PWM controller outputs the PWM signal that has the duty ratio determined based on the information input with reference to a timing for inverting a logic state of the PWM signal.

A LED driving device is provided, which includes a LED string including at least one LED element, at least one channel connected to the at least one LED element, a current regulator configured to regulate a current flowing through the at least one channel according to at least one corresponding control voltage, and a control signal generating circuit configured to generate a control signal based on a difference between a reference voltage and a comparative voltage. The comparative voltage is determined based on a sensing voltage, and the sensing voltage corresponds to an LED current flowing through the LED string. The control signal generating circuit is further configured to generate the at least one corresponding control voltage based on the control signal.

In accordance with certain embodiments, lighting systems feature lightsheets including multiple illumination units or modules electrically interconnected such that unremoved illumination units or modules remain energized upon removal of at least a portion of one or more illumination units or modules.

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.

A color tuning system including a first plurality of LEDs having a first color temperature, a second plurality of LEDs having a second color temperature, a wave generator electrically connected to the first plurality of LEDs and the second plurality of LEDs, where the waveform generator transmits a first signal to the first plurality of LEDs for a first predetermined time and a second signal to the second plurality of LEDs for a second predetermined time.

An automotive headlight is disclosed including: an optical unit including a plurality of optical elements, each optical element having a different central direction; a segmented light-emitting diode (LED) chip including a plurality of LEDs that are separated by trenches formed on the segmented LED chip and arranged in a plurality of sections, each section being aligned with a different respective optical element, and each section including at least one first LED and at least one second LED; and a controller configured to: apply a forward bias to each of the first LEDs, apply a reverse bias to each of the second LEDs, and change a brightness of the first LEDs in any section based on a signal generated by the second LED in that section.

An automotive headlight is disclosed including: an optical unit including a plurality of optical elements, each optical element having a different central direction; a segmented light-emitting diode (LED) chip including a plurality of LEDs that are separated by trenches formed on the segmented LED chip and arranged in a plurality of sections, each section being aligned with a different respective optical element, and each section including at least one first LED and at least one second LED; and a controller configured to: apply a forward bias to each of the first LEDs, apply a reverse bias to each of the second LEDs, and change a brightness of the first LEDs in any section based on a signal generated by the second LED in that section.

The invention provides an interconnected string of three LED modules, having internal and external connections such that each LED in the string is fully individually addressable. LED biases and interconnects are oriented and configured such that individual addressability is achieved without the need for direct external signal connections to each LED in the string. Consequently embodiments are provided comprising pluralities of strings, arranged so as to form an array of LED modules, wherein wiring tracks running beneath, or along the intermediary spaces between, rows of LEDs are not required. Hence are provided LED devices comprising an array of individually addressable LED modules, having reduced spacing between rows and columns, and having optimal thermal path perpendicularly across the substrate layer. Provided devices have improved heat dissipation and greater achievable LED array density. Also provided are embodiments comprising one or more lens arrangements, suitable, for example, for adaptive beam-shaping applications.

The present invention discloses a full voltage segmented linear constant-current LED drive circuit in an auto switchover mode, comprising a minimum two groups of LEDs in parallel connection in proper sequence and a voltage detection and control circuit used for detection of power voltage; positive terminal of each group of LEDs is directly connected or indirectly connected to the power source via the change-over switch; negative terminal of each group of LEDs is grounded via corresponding control switch; wherein, one group of LEDs comprises a minimum two groups of LED units in series connection in proper sequence; negative terminal of each LED unit is grounded via corresponding control switch; the change-over switch and control switch are connected to and controlled by the voltage detection and control circuit to change inter-group parallel connection mode and ON/OFF of different LED units. The drive circuit according to the present invention can switch over series and parallel connection mode of LED, which can also easily adjust total load current in time according to voltage fluctuation mode, and thereby reduce harmonic distortion, and cater to power factor.

An LED driver circuit includes a rectifying module, a control unit, and at least two LED light strings. The control unit includes a voltage input detection terminal and a switch assembly. The voltage input detection terminal is configured to detect the waveform of the voltage input. The switch assembly changes the way of connection between the LED light strings according to the waveform of the voltage input.