Lumileds LLC

Zhi Hua Song

Ronald Johannes Bonne

Antonio Lopez Julia

Toni Lopez

Wouter Anthon Soer

Claire Yue Gao

David Christopher Jansson

Wan-Ying Sau

An approach for controlling pixel turn on and turn off within an LED array is described. Turn-on delays for pixels within the LED array is based on the duty cycles of the pixels. The pixels are grouped based on corresponding duty cycles. The turn-on delay for each pixel is based on the group that includes the pixel, as well as position of the pixel within the group. The LED array is driven by circuitry in a CMOS backplane.

MicroLED array with adaptive PWM phase shift

A power supply system for a LED pixel array includes at least two power supplies respectively connectable to sub-arrays in a LED pixel array and providing adjustable power. A controller is connected to the at least two power supplies, with the controller able to make adjustments to the power supplied based on measured requirements of sub-arrays in the LED pixel array. In one embodiment, the LED pixel array is a microLED array.

Multiple power supply circuit for LED array

A light-emitting diode (LED) array includes an array of pixel assemblies and a pulse width modulator. The pulse width modulator generates pulse width modulation (PWM) signals for controlling a duty cycle of each of the pixels. The pixel assemblies each include an LED, a switching circuit, and a close loop circuit. The switching circuit receives a PWM signal and alternately turns on and off the LED based on the PWM signal. The close loop circuit regulates an LED current provided by the switching circuit to the LED based on a feedback signal received from the switching circuit. The close loop circuit in one pixel assembly may receive a reference current from a close loop circuit of another pixel assembly.

Current control for LED pixel arrays

A micro light emitting diode (LED) die can include a matrix of micro LEDs with a variety of forward voltages. A method of reducing a number of undriven or under driven uLEDs can include providing, by a power supply, an alternating current voltage (V) with a minimum voltage (V) and a maximum voltage (V), Vbeing sufficient to drive a plurality of micro light emitting diodes (uLEDs) of a uLED die using a plurality of uLED drivers, identifying, by a controller coupled to the uLED drivers, a uLED of the plurality of uLEDs with a forward voltage (V) greater than V, and altering, by the controller, a time of a rising edge of a pulse width modulation (PWM)-on time of the uLED such that Vof the uLED is less than Vfor the PWM-on time.

Voltage supply amplitude modulation driving outlier microLEDs

A lighting system includes an LED array having a plurality of LED pixels and a power controller. The power controller adjusts a supply voltage for powering the LED pixels based on one or more conditions of the LED array. The power controller may determine the supply voltage based on process data of the LED array. The power controller may adjust the supply voltage based on an operating temperature of the LED pixels and the amplitude of a current driving the LED pixels.

Dynamically regulated micro-LED pixel array

A control system for an LED array relies on defining a first and a second group of separately addressed LED pixels, with the first group including pixels with an average current no less than the current at a Q point and a second group including pixels with an average current less than the current at a Q point. An amplitude signal provided to the first group of separately addressed LED pixels is selectively modulated, while providing a DC mode 100% duty cycle. An amplitude signal provided to the second group of separately addressed LED pixels is fixed, and a modulated duty cycle is provided.

Micro-LED amplitude control system

A method for control of a pixel array based on a temperature estimate is provided. A method includes sampling an anode voltage of each LED of a plurality of pixels resulting in sampled voltages, determining an average voltage based on the sample voltages, and determining a total voltage to provide to the pixels based on the average voltage and voltage data from a memory coupled to the controller, the voltage data including one or more of a 3-sigma value, a driver headroom value, a resistance value, or a k-factor value.

LED driver voltage accounting for temperature estimate

A light-emitting diode (LED) array includes an array of pixel assemblies and a pulse width modulator. The pulse width modulator generates pulse width modulation (PWM) signals for controlling a duty cycle of each of the pixels. The pixel assemblies each include an LED, a switching circuit, and a close loop circuit. The switching circuit receives a PWM signal and alternately turns on and off the LED based on the PWM signal. The close loop circuit regulates an LED current provided by the switching circuit to the LED based on a feedback signal received from the switching circuit.

A LED controller for an LED pixel array includes a serial interface to an external data bus, along with an address generator connected to the serial interface and the LED pixel array. An image frame buffer is connected to the interface to receive image data and further connected to the address generator to receive an image frame buffer address. A command and control module is connected to the serial interface and configured to modify image frame buffer output signals. A calibration data storage module is connected to the command and control module to store calibration data related to pixel voltage response in the LED pixel array and enable modification of voltage provided by the dynamic power supply at least in part based on the image presented by the LED pixel array.

Universal asynchronous receiver/transmitter interface for light emitting diode system

A temperature monitor and control system for a pixel array includes a first driver connected to a first pixel connected to bus by a first switch, a second driver connected to a second pixel connected to a bus by a second switch, and a control block including connection to the first and second switches. The control block turns on the first switch and turns off the second switch, measures bus voltage, determines an LED forward voltage shift of the first pixel and corresponding temperature shift for the first pixel based on the determined forward voltage shift, and adjusts a driving current for first pixel based on the determined temperature shift.

Temperature sensing for a micro-LED array

Light-emitting devices are described herein. A device includes a packaging substrate having a top surface and a bottom surface and a hybridized device having a bottom surface on the top surface of the packaging substrate. The hybridized device includes a silicon backplane that includes input/output (I/O) pins and a light-emitting diode (LED) array having a bottom surface on a top surface of the silicon backplane. Passive components are disposed on the top surface of the packaging substrate. Conductive connectors are electrically coupled between the top surface of the hybridized device and the top surface of the packaging substrate.

Light-emitting diode lighting system with wirebonded hybridized device

Systems, devices and methods are described herein. A device includes a power stage circuit, a switch and a first circuit. The switch is electrically coupled to the power stage circuit. The first circuit is electrically coupled to the power stage circuit and the switch and has a single output. The first circuit is configured to provide a first circuit output voltage at the single output. The first circuit output voltage has a first level on a condition that the power stage circuit is conducting at a peak current level. The first circuit output voltage has a second level on a condition that the power stage circuit is not conducting.

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Palo Alto, CA, United States of America

Zhi Hua Song