Abstract: Disclosed herein is a microelectromechanical (MEMS) device, including a rotor and a first piezoelectric actuator mechanically coupled to the rotor. The first piezoelectric actuator is electrically coupled between a first signal node and a common voltage node. A second piezoelectric actuator is mechanically coupled to the rotor, and is electrically coupled between a second signal node and the common voltage node. Control circuitry includes a drive circuit configured to drive the first and second piezoelectric actuators, a sense circuit configured to process sense signals generated by the first and second pizeoelectric actuators, and a multiplexing circuit. The multiplexing circuit is configured to alternate between connecting the drive circuit to the first piezoelectric actuator while connecting the sense circuit to the second piezoelectric actuator, and connecting the drive circuit to the second piezoelectric actuator while connecting the sense circuit to the first piezoelectric actuator.

Abstract: A scanning laser projector includes an optical module with a housing defined by a top surface, a bottom surface, and sidewalls extending between the top surface and bottom surface to define an interior compartment within the housing. A given one of the sidewalls has an exit window defined therein. A first light detector is positioned at an interior surface of the given one of the sidewalls about a periphery of the exit window. A second light detector positioned at the interior surface of the given one of the sidewalls about the periphery of the exit window and on a different side thereof than the first light detector.

Abstract: An AC capacitor is coupled to a totem-pole type PFC circuit. In response to detection of a power input disconnection, the PFC circuit is controlled to discharge the AC capacitor. The PFC circuit includes a resistor and a first MOSFET and a second MOSFET coupled in series between DC output nodes with a common node coupled to the AC capacitor. When the disconnection event is detected, one of the first and second MOSFETs is turned on to discharge the AC capacitor with a current flowing through the resistor and the turned on MOSFET. Furthermore, a thyristor may be simultaneously turned on, with the discharge current flowing through a series coupling of the MOSFET, resistor and thyristor. Disconnection is detected by detecting a zero-crossing failure of an AC power input voltage or lack of input voltage decrease or input current increase in response to MOSFET turn on for a DC input.

Abstract: The present description concerns a circuit for converting from a first alternating voltage to a second voltage. The circuit includes: a first thyristor; a first control circuit of the first thyristor; a power factor correction circuit comprising a coil; and a first circuit configured to convert a third voltage into a fourth DC voltage. The third voltage corresponds to a difference between a potential at a first node connected to an output node of the coil and a reference potential. The fourth DC voltage is configured to supply the first control circuit of the first thyristor, and is referenced with respect to the same reference potential as the third voltage.

Abstract: A scanning laser projector includes an optical module and projection engine. The optical module includes a laser generator outputting a laser beam, and a movable mirror scanning the laser beam across an exit window defined through the housing in a scanning pattern wider than the exit window such that the laser beam is directed through the exit window in a projection pattern that is smaller than and within the scanning pattern. A first light detector is positioned about a periphery of the exit window such that as the movable mirror scans the laser beam in the scan pattern, at a point in the scan pattern where the laser beam is scanned across an interior of the housing and not through the exit window, the laser beam impinges upon the first light detector. The projection engine adjusts driving of the movable mirror based upon output from the first light detector.

Abstract: A method of operating a display includes performing a non-synchronized touch scan pattern on a display with a controller coupled to the display. The non-synchronized touch scan pattern schedules touch scans independent of a refresh rate of the display. Upon the controller detecting a first synchronization pulse from a display controller coupled to the controller and the display, a first pulse-checking timer is started. Upon detecting a second synchronization pulse from the display controller and before the first pulse-checking timer expires, a first display refresh rate for the display is obtained from an interval between the first synchronization pulse and the second synchronization pulse. A synchronized touch scan pattern is performed with the controller, and is scheduled to avoid touch scans coinciding with refreshes of the display performed at the first display refresh rate.

Abstract: A control system includes a mirror controller generating horizontal and vertical mirror synchronization signals for a mirror based upon a mirror clock signal. Laser modulation circuitry generates horizontal and vertical laser synchronization signals as a function of first and second laser clock signals and generates control signals for a laser that emits a laser beam that impinges on the mirror. First synchronization circuitry receives the horizontal mirror synchronization signal and the horizontal laser synchronization signal, and modifies generation of the first laser clock signal to achieve alignment between the horizontal mirror synchronization signal and horizontal laser synchronization signal. Second synchronization circuitry receives the vertical mirror synchronization signal and the vertical laser synchronization signal, and modifies generation of the second laser clock signal to achieve alignment between the vertical mirror synchronization signal and vertical laser synchronization signal.

Abstract: A circuit includes two thyristors coupled in anti-series. An AC capacitor has first and second electrodes respectively coupled to two different electrodes of the two thyristors. The first and second electrodes are coupled to receive an AC voltage. A control circuit detects discontinuance of application of the AC voltage to the AC capacitor and in response thereto simultaneously applies same gate currents to the two thyristors. A current path through the two thyristors (one passing current in forward mode and the other in reverse mode) discharges a residual voltage stored on the AC capacitor.

Abstract: A light projection system includes a MEMS mirror operating on a mirror drive signal to generate a mirror sense signal resulting from operation of the MEMS mirror based on the mirror drive signal. A mirror driver generates the mirror drive signal from a drive control signal. A controller receives the mirror sense signal from the MEMS mirror, obtains a first sample of the mirror sense signal at a first phase thereof, obtains a second sample of the mirror sense signal at a second phase thereof, wherein the first and second phases are separated by a half period of the mirror drive signal, with the second phase occurring after the first phase, and generates the drive control signal based on a difference between the first and second samples to keep the mirror drive signal separated in phase from the mirror sense signal by a desired amount of phase separation.

Abstract: Mirror control circuitry operates to control a movable mirror. The mirror control circuitry includes drive circuitry for providing a drive signal to the movable mirror, and a processor. The processor causes the drive circuitry to generate the drive signal so as to have pulses with leading edges occurring an offset period of time after a maximum opening angle of the movable mirror and trailing edges occurring an offset period of time before a zero crossing of the movable mirror. The processor may sample a mirror sense signal from the movable mirror at times at which a derivative of capacitance of the movable mirror with respect to time is zero, and then perform an action based upon the samples.

Abstract: A scanning laser projector includes an optical module and projection engine. The optical module includes a laser generator outputting a laser beam, and a movable mirror scanning the laser beam across an exit window defined through the housing in a scanning pattern wider than the exit window such that the laser beam is directed through the exit window in a projection pattern that is smaller than and within the scanning pattern. A first light detector is positioned about a periphery of the exit window such that as the movable mirror scans the laser beam in the scan pattern, at a point in the scan pattern where the laser beam is scanned across an interior of the housing and not through the exit window, the laser beam impinges upon the first light detector. The projection engine adjusts driving of the movable mirror based upon output from the first light detector.

Abstract: A scanning laser projector includes an optical module with a housing defined by a top surface, a bottom surface, and sidewalls extending between the top surface and bottom surface to define an interior compartment within the housing. A given one of the sidewalls has an exit window defined therein. A first light detector is positioned at an interior surface of the given one of the sidewalls about a periphery of the exit window. A second light detector positioned at the interior surface of the given one of the sidewalls about the periphery of the exit window and on a different side thereof than the first light detector.

Abstract: A control system includes a mirror controller generating horizontal and vertical mirror synchronization signals for a mirror based upon a mirror clock signal. Laser modulation circuitry generates horizontal and vertical laser synchronization signals as a function of first and second laser clock signals and generates control signals for a laser that emits a laser beam that impinges on the mirror. First synchronization circuitry receives the horizontal mirror synchronization signal and the horizontal laser synchronization signal, and modifies generation of the first laser clock signal to achieve alignment between the horizontal mirror synchronization signal and horizontal laser synchronization signal. Second synchronization circuitry receives the vertical mirror synchronization signal and the vertical laser synchronization signal, and modifies generation of the second laser clock signal to achieve alignment between the vertical mirror synchronization signal and vertical laser synchronization signal.

Abstract: A light projection system includes a microelectromechanical (MEMS) mirror configured to operate in response to a mirror drive signal and to generate a mirror sense signal as a result of the operation. A mirror driver is configured to generate the mirror drive signal in response to a drive control signal. A zero cross detector is configured to detect zero crosses of the mirror sense signal. A controller is configured to generate the drive control signal as a function of the detected zero crosses of the mirror sense signal.

Abstract: A control system for a laser scanning projector includes a mirror controller generating horizontal and vertical mirror synchronization signals for an oscillating mirror apparatus based upon a mirror clock signal, and laser modulation circuitry. The laser modulation circuitry generates horizontal and vertical laser synchronization signals as a function of a received laser clock signal, and generates control signals for a laser that emits a laser beam that impinges on the oscillating mirror apparatus. Synchronization circuitry generates the laser clock signal and sends the laser clock signal to the laser modulation circuitry, receives the horizontal and vertical mirror synchronization signals from the mirror controller, receives the horizontal and vertical laser synchronization signals from the laser modulation circuitry, and modifies the laser clock signal so as to achieve alignment between the horizontal and vertical mirror synchronization signals and the horizontal and vertical laser synchronization signals.

Abstract: A capacitive element has its terminals coupled together by two thyristors electrically in antiparallel. The discharge of the capacitive element is controlled by the application of a gate current to one thyristor of the two thyristors which is in a reverse-biased state in response to a voltage stored across the terminals of the capacitive element. The reverse-biased thyristor responds to the applied gate current by passing a leakage current to discharge the stored voltage.

Abstract: Disclosed herein is a microelectromechanical (MEMS) device, including a rotor and a first piezoelectric actuator mechanically coupled to the rotor. The first piezoelectric actuator is electrically coupled between a first signal node and a common voltage node. A second piezoelectric actuator is mechanically coupled to the rotor, and is electrically coupled between a second signal node and the common voltage node. Control circuitry includes a drive circuit configured to drive the first and second piezoelectric actuators, a sense circuit configured to process sense signals generated by the first and second pizeoelectric actuators, and a multiplexing circuit. The multiplexing circuit is configured to alternate between connecting the drive circuit to the first piezoelectric actuator while connecting the sense circuit to the second piezoelectric actuator, and connecting the drive circuit to the second piezoelectric actuator while connecting the sense circuit to the first piezoelectric actuator.

Abstract: A control circuit includes a first control circuit generating a first drive control signal from a pre-drive signal (that is a frequency at which an opening angle of the first and second mirrors is equal) for the first mirror. A second control circuit generates a second drive control signal from the pre-drive signal for the second mirror. First and second drivers generate first and second drive signals for the first and second mirrors from the first and second drive control signals. The first and second drive control signals are generated so that the first and second drive signals each have a same frequency as the pre-drive signal but are different in amplitude from one another to cause the first and second mirrors to move at a same frequency, with a same and substantially constant given opening angle as one another, and in phase with one another.

Abstract: A method is provided that is implemented by a first NFC device configured in reader mode. The method includes evaluating an information about the coupling between the first NFC device and a second NFC device configured in card mode, as a function of the position of an antenna of the first NFC device with respect to an antenna of the second NFC device. The method further includes indicating the information by a user interface of the first device.

Abstract: An optical package includes a beam combiner that combines laser light from a laser unit into a single laser beam, a movable mirror apparatus, and a fixed folding mirror which reflects the single laser beam toward the movable mirror apparatus. Beam equalizer optics cause increase of a slow axis divergence rate of the single laser beam such that its slow axis divergence rate is equal to its fast axis divergence rate. The movable mirror apparatus directs the single laser beam through an exit window. The beam equalizer optics include at least one negative spherical lens shaped such that a slow axis divergence rate of incident light is increased but a fast axis divergence rate of incident light is unaltered.