Abstract: Various embodiments are described herein that relate to systems and methods for selectively providing current to power LEDs. The techniques introduced here can enable smooth dimming of the LEDs from maximum brightness down to “actual extinction” or “pseudo-extinction.” More specifically, the LEDs can be dimmed to extinction without any significant gaps in the levels of brightness (i.e., a noticeable drop rather than a smooth transition between brightness levels). Various pulse width modulation (PWM) and shunting techniques may be used to control the power provided to each color channel of an LED board. Conventionally, PWM often causes LEDs to produce an undesirable acoustic effect. However, by dithering the PWM signals between multiple predetermined positions once the frequency enters the audible range (e.g., below 25 kHz), the cumulative acoustic effect instead becomes white noise.

Abstract: Various embodiments are described herein that relate to systems and methods for selectively providing current to power LEDs. The techniques introduced here can enable smooth dimming of the LEDs from maximum brightness down to “actual extinction” or “pseudo-extinction.” More specifically, the LEDs can be dimmed to extinction without any significant gaps in the levels of brightness (i.e., a noticeable drop rather than a smooth transition between brightness levels). Various pulse width modulation (PWM) and shunting techniques may be used to control the power provided to each color channel of an LED board. Conventionally, PWM often causes LEDs to produce an undesirable acoustic effect. However, by dithering the PWM signals between multiple predetermined positions once the frequency enters the audible range (e.g., below 25 kHz), the cumulative acoustic effect instead becomes white noise.

Abstract: Light source systems and methods of operating the light source systems are disclosed. A light source system may include a combination of two lighting modules in communication with each other. The lighting modules can operate in concert, in parallel, or as master or slave. A printed circuit board assembly (PCBA) of the light source system includes electrical circuitry to drive a set of light emitting diodes (LEDs). The PCBA can include a communication interface for communication amongst the lighting modules. The PCBA can also include an optical sensor to provide color spectrum feedback to a controller module for self calibration. A master PCBA can receive sensor feedbacks, such as thermal and optical feedbacks from a slave PCBA. The sensor feedbacks can then be used to tune a color spectrum of a slave lighting module including calibrating the slave lighting module.

Abstract: Some embodiments include a LED-based light module. The LED-based light module can include a memory to store a color mixing plan; a regulator that receives a variable output voltage from a power supply; a voltage measurement component, coupled in parallel to the regulator and the power supply, configured to measure a voltage level of the variable output voltage; a logic component; and a driver circuit. The logic component can be configured to determine driving current profiles for LEDs in the LED-based light module to dim a light output of the LEDs based on the voltage level. The driver circuit can drive the LEDs according to the driving current profiles by drawing power from the power supply (e.g., through the regulator).

Abstract: An electrical circuit is described that comprises a first string and second LED string coupled in parallel, a first and second transistor, at least one bypass transistor, and a controller. The first transistor is coupled to the first LED string at a first terminal of the first transistor. The second LED string includes multiple LED color strings coupled in series. The second transistor is coupled to the second LED string at a first terminal of the second transistor. The bypass transistor is coupled to one of the color strings. A first terminal of the bypass transistor is coupled to a first terminal of the color string. The second terminal of the bypass transistor is coupled to a second terminal of the color string. The controller controls a gate voltage of the first and second transistors and the bypass transistor to operate all transistors in linear modes.

Abstract: An electrical circuit for driving a light emitting diode (LED) string is described. The electrical circuit includes a first LED string having one or more color LED strings. A first current control transistor is coupled in series with the first LED string. A color bypass transistor may couple in parallel to one of the one or more color LED strings. A second LED string may also be coupled to the first LED string at an anode terminal of both LED strings. The second LED string may be coupled in parallel with a string bypass transistor and in series with a second current control transistor. Connection interfaces to control terminals of the first current control transistor, the color bypass transistor, the second current control transistor, and the string bypass transistor enable a control device to operate these transistors in linear mode to drive the LED strings.

Abstract: An electrical circuit for driving a light emitting diode (LED) string is described. The electrical circuit includes a first LED string having one or more color LED strings. A first current control transistor is coupled in series with the first LED string. A color bypass transistor may couple in parallel to one of the one or more color LED strings. A second LED string may also be coupled to the first LED string at an anode terminal of both LED strings. The second LED string may be coupled in parallel with a string bypass transistor and in series with a second current control transistor. Connection interfaces to control terminals of the first current control transistor, the color bypass transistor, the second current control transistor, and the string bypass transistor enable a control device to operate these transistors in linear mode to drive the LED strings.

Abstract: Light source systems and methods of operating the light source systems are disclosed. A light source system may include a combination of two lighting modules in communication with each other. The lighting modules can operate in concert, in parallel, or as master or slave. A printed circuit board assembly (PCBA) of the light source system includes electrical circuitry to drive a set of light emitting diodes (LEDs). The PCBA can include a communication interface for communication amongst the lighting modules. The PCBA can also include an optical sensor to provide color spectrum feedback to a controller module for self calibration. A master PCBA can receive sensor feedbacks, such as thermal and optical feedbacks from a slave PCBA. The sensor feedbacks can then be used to tune a color spectrum of a slave lighting module including calibrating the slave lighting module.

Abstract: A linear light module that uses a thermally conductive housing for dissipating heat generated by a lighting source within the housing is described. Light is thermally coupled away from the lighting source via a thermally conductive heating block. The heating block is thermally coupled to a thermally conductive heat pipe that runs along the length of the housing, where the length of the housing is substantially the same length as the linear light module. The housing is extruded to include a channel that runs the length of the housing for holding the heat pipe. Because the housing is long, the heat is easily conducted from the housing.

Abstract: A linear light module having an optical coupling element and a light pipe is described. The optical coupling element receives light emitted by multiple light emitting diodes (LEDs) having different emission wavelengths and couples the light efficiently to a linear light pipe. The light from the LEDs is efficiently mixed by the optical coupling element and the light pipe to produce a linear light output that is uniform in color and intensity. Diffusers can be used with the optical coupling element and light pipe at various locations to further enhance the uniformity of the emitted light.

Abstract: An electrical circuit is disclosed. The electrical circuit comprises a plurality of color strings coupled in series, where each color string has at least one lamp, preferably a light emitting diode. The color strings may be of dissimilar length and may contain light emitting diodes of different colors. In one embodiment, a switch coupled in parallel with one of the color strings is configured to shunt power away from the color string to a power supply. In another embodiment, a switch coupled in parallel with one of the color strings is configured to shunt power away from the color string to one or more other color strings. In several embodiments, passive storage elements are utilized to store shunted power. In another embodiment, a current injector is configured to inject or remove current from a node adjacent to a color string. In several embodiments the invention is implemented as a light emitting diode driver integrated circuit or chip.

Abstract: An electrical circuit is disclosed for driving color strings that have at least one lamp, preferably a light emitting diode (LED). The color strings can be different lengths. In some embodiments, a switch is coupled in parallel to one of the LED strings to shunt power away from the LED string to a power supply or to one or more other LED strings. In some embodiments, a current injector is configured to remove current from or inject current into a node adjacent to an LED string. Methods are disclosed for producing a desired light output utilizing color strings that may be of dissimilar length and that may contain light emitting diodes of different colors.

Abstract: Head stack fixtures for securing head stack assemblies to spin stand testing systems, and spin stand testing systems incorporating such fixtures, are disclosed. Exemplary head stack fixtures comprise a base supporting a piezoelectric actuator. The base includes an attachment mechanism for securing the HSA in such a way that the HSA will pivot relative to the base. When the HSA is secured to the base, the piezoelectric actuator engages the HSA. The piezoelectric actuator is therefore able to pivot the HSA relative to the base for fine positioning of a head of the HSA.

Abstract: The disclosed device is directed towards an optical data storage system. The optical data storage system comprises an optical medium including a servo plane and at least one data plane. A first laser is positioned to generate a servo laser beam and address the servo plane with a first servo focus spot. A second laser is positioned to generate a read-write laser beam and address the data plane with a second read-write focus spot. A first servo system is associated with the first laser and is configured to provide focus and tracking error correction according to servo information associated with the servo plane. A second servo system is associated with the second laser and is configured to provide focus and tracking error correction according to servo information associated with the data plane.

Abstract: The disclosed device is directed towards an optical data storage system. The optical data storage system comprises an optical medium including a servo plane and at least one data plane. A first laser is positioned to generate a servo laser beam and address the servo plane with a first servo focus spot. A second laser is positioned to generate a read-write laser beam and address the data plane with a second read-write focus spot. A first servo system is associated with the first laser and is configured to provide focus and tracking error correction according to servo information associated with the servo plane. A second servo system is associated with the second laser and is configured to provide focus and tracking error correction according to servo information associated with the data plane.

Abstract: An optical information storage system using optical storage media including multiple data layers or stacks wherein each of the multiple data stacks has a storage density comparable to a conventional single layer optical disk. The optical data storage system comprises an optical medium having a single dedicated servo layer and multiple data stacks which each contain an embedded servo format, a servo laser beam positioned to maintain a first focus point on the dedicated servo reference layer, a read-write laser beam positioned to maintain a second focus point on one of the data stacks, a first, dedicated servo system which provides focus and tracking error correction according to error signals generated from the dedicated servo layer, and a second, embedded servo system which provides focus and tracking error correction according to error signals generated from the data stacks.

Abstract: A current driver for magnetic recording comprising a current source, a current steering bridge for directing the current in one of two directions through a magnetic recording head during the length of a data pulse and a head select switch which allows current to flow through the head only for several short pulses occurring during the data pulse such that the magnetic regions impressed by the short pulses form a nearly continuous magnetic region on the recording medium.