Abstract: An apparatus and a system include a multiplier circuit for receiving a sensed voltage and current of a of a load resistance coupled to a rectified voltage from a transformer's output whose input is from a DC-to-AC converter being supplied from a DC power generator having an internal resistance. The multiplier outputs a product of the sensed voltage and current. A differentiator circuit outputs a rate of change of the product. An integrator circuit outputs an integrated voltage indicating an accumulative rate of change of the product. A voltage-to-frequency converter circuit generates a voltage waveform having a frequency determined by the integrated voltage. A driver circuit uses the voltage waveform to output a control signal for controlling a frequency of the DC-to-AC power converter where the apparatus substantially matches an input resistance of the transformer to the internal resistance, thereby maximizing power transfer to the load resistance.

Abstract: An integrated circuit package includes a substrate having a recess formed along at least a portion of a perimeter of the substrate, and an optical die having opto-electric circuitry, the optical die coupled to the substrate such that a portion of the optical die with the opto-electric circuitry overhangs the recess. The integrated circuit package also includes an optical unit disposed in the recess such that optical signals emitted by the opto-electric circuitry are reflected away from the substrate and incident optical signals are reflected onto the opto-electric circuitry.

Abstract: A self-contained power source to charge a battery and/or power a load is provided. The power source does not utilize a connection to an external power supply, such as AC mains and/or an AC to DC converter. In one embodiment, the self-contained power source includes an ultra low voltage power generator, such as 0.3V of a single solar cell, or even lower to slightly above the GND potential, that provides a voltage to a rechargeable battery, a load or both. A voltage converter with boost topology is used to supply a voltage comparable to the voltage of the rechargeable battery. A first push circuit containing a zero threshold voltage switch, a MUX circuit and a one-pulse-control block is utilized to ensure initial and continued operation of the voltage converter.

Abstract: An apparatus includes a pass element comprising an input, an output and a control input. The pass element, with a first signal on the control input, passes a voltage from the input to the output and, with a second signal on the control input, blocks the voltage on the input from passing to the output. A differential amplifier includes a non-inverting input coupled to the input, an inverting input coupled to the output, an amplifier output coupled to the control input and a bias current connection. The differential amplifier, with a bias current supplied, supplies the first signal along with a closed feedback loop from the output and supplies the second signal in absence of the bias current. A current source is coupled to the bias current connection and an enable input. The current source supplies the bias current and, in absence of an enable signal, disables the bias current.

Abstract: An optical apparatus includes a first beam combining device arranged to receive a first optical beam having a first wavelength at a first location and a second optical beam output having a second wavelength at a second location. The second optical beam has a polarization that is substantially orthogonal to a polarization of the first optical beam. The first beam combining device configured to output a first combined beam that comprises a combination of the first optical beam and the second optical beam. An optical element is arranged to receive the first combined beam and a second combined beam and to transmit an output beam that includes a combination of the first combined beam and the second combined beam.

Abstract: An apparatus and a system include a multiplier circuit for receiving a sensed voltage and current of a of a load resistance coupled to a rectified voltage from a transformer's output whose input is from a DC-to-AC converter being supplied from a DC power generator having an internal resistance. The multiplier outputs a product of the sensed voltage and current. A differentiator circuit outputs a rate of change of the product. An integrator circuit outputs an integrated voltage indicating an accumulative rate of change of the product. A voltage-to-frequency converter circuit generates a voltage waveform having a frequency determined by the integrated voltage. A driver circuit uses the voltage waveform to output a control signal for controlling a frequency of the DC-to-AC power converter where the apparatus substantially matches an input resistance of the transformer to the internal resistance, thereby maximizing power transfer to the load resistance.

Abstract: A boost DC/DC power converter is disclosed that has a low voltage source, an inductor and a switching device that forms a series loop, a diode in series with a capacitor coupled across the switching device, a voltage divider coupled across the capacitor and a pulse width modulator that is coupled to the voltage divider. The boost converter includes a first push controller coupled across the switching device to provide a first push voltage of sufficient magnitude to turn the switching device on where the low voltage source by itself is not capable of generating a voltage of sufficient magnitude to operate the switching device.

Abstract: A self-contained power source to charge a battery and/or power a load is provided. The power source does not utilize a connection to an external power supply, such as AC mains and/or an AC to DC converter. In one embodiment, the self-contained power source includes an ultra low voltage power generator, such as 0.3V of a single solar cell, or even lower to slightly above the GND potential, that provides a voltage to a rechargeable battery, a load or both. A voltage converter with boost topology is used to supply a voltage comparable to the voltage of the rechargeable battery. A first push circuit containing a zero threshold voltage switch, a MUX circuit and a one-pulse-control block is utilized to ensure initial and continued operation of the voltage converter.

Abstract: A boost DC/DC power converter is disclosed that has a low voltage source, an inductor and a switching device that forms a series loop, a diode in series with a capacitor coupled across the switching device, a voltage divider coupled across the capacitor and a pulse width modulator that is coupled to the voltage divider. The boost converter includes a first push controller coupled across the switching device to provide a first push voltage of sufficient magnitude to turn the switching device on where the low voltage source by itself is not capable of generating a voltage of sufficient magnitude to operate the switching device.

Abstract: Various circuits are described herein where a series transistor used to control current through a string of LEDs, driven by a high voltage, is not subjected to the high voltage when the transistor is turned off pursuant to a PWM signal. To avoid the transistor experiencing the high voltage, the HV regulator is disabled shortly before the transistor is turned off and is enabled shortly after the transistor has turned back on. Control circuits for controlling the regulator and transistor include delay circuits and/or voltage sensing circuits to ensure that the transistor is always on prior to the voltage regulator being enabled pursuant to the incoming PWM signal, and the voltage regulator is always disabled when the first transistor is off pursuant to the incoming PWM signal.

Abstract: Various circuits are described herein where a series transistor used to control current through a string of LEDs, driven by a high voltage, is not subjected to the high voltage when the transistor is turned off pursuant to a PWM signal. To avoid the transistor experiencing the high voltage, the HV regulator is disabled shortly before the transistor is turned off and is enabled shortly after the transistor has turned back on. Control circuits for controlling the regulator and transistor include delay circuits and/or voltage sensing circuits to ensure that the transistor is always on prior to the voltage regulator being enabled pursuant to the incoming PWM signal, and the voltage regulator is always disabled when the first transistor is off pursuant to the incoming PWM signal.

Abstract: A dual-channel load switch circuit may be provided for switching between first and second sources that generate respective input voltages. The circuit may include first and second channels adapted to receive the respective input voltages and to supply respective output voltages to a load element based on the respective input voltages. The first and second channels may each include first and second switching elements and first and second control circuitry. The second channel may include a diode in parallel with the second switching element and may be coupled to the first control circuitry. The circuit may include a reservoir element coupled to the first and second channels and configured to store a potential when one of the first and second channels supplies a respective output voltage to the load element and to apply the potential to the load element when neither output voltage is being supplied to the load element.

Abstract: An LED driver drives one or more strings of series-connected LEDs. A feedback voltage at a sense resistor is detected by an op amp, and the op amp controls the conductivity of a MOSFET in series with the LEDs to regulate the peak current. The MOSFET is also controlled by a PWM brightness control signal to turn the LEDs on and off at the PWM duty cycle. A boost regulator provides an output voltage to the string of LEDs. A divided voltage at the end of the string of LEDs is regulated by the boost controller to keep the divided voltage constant. When an LED becomes an open circuit, the boost regulator controller is immediately decoupled from the regulator's switching transistor. If an LED shorts, the boost regulator reduces its output voltage, and the duty cycle of the brightness control signal is automatically increased.

Abstract: A Light-Emitting Diode (LED) driver circuit is disclosed that controls the brightness of light generated by a LED that is coupled between a first terminal and a second terminal in response to a user supplied brightness control signal. A constant current source generates a constant current that is supplied to the LED and to a shunt circuit, which his connected in parallel with the LED. A brightness control circuit generates a pulse signal having a duty cycle that is proportional to the brightness control signal, and controls the shunt circuit such that, when said pulse signal is high, the constant current is passed through the shunt circuit and the LED is turned off, and when the pulse signal is low, the constant current is passed through the LED. The duty cycle of the brightness control signal is adjusted to adjust the LED's brightness, while the LED color remains constant.

Abstract: System and techniques for reducing the polarization dependency of an optical component by combining the actions of a circulator and a polarization beam combiner to separate an optical signal into a plurality of orthogonally oriented polarization components; rotate at least one of the components so that the polarization orientation of the components are parallel; propagate the components through respective input ports of an optical component at substantially the same time; rotate at least one of a plurality of output components from the optical component so that the polarization orientation of the output components are orthogonal; and recombine the plurality of output components into an output optical signal.

Abstract: A high efficiency multi-mode charge pump based LED driver comprising a multi-mode charge pump and a LED driver controls the brightness level of at least one group of a plurality of LEDs, which is used as a backlight for a display device. The charge pump provides an output voltage to the plurality of LEDs. It includes at least three modes of operation, and allows automatic switching among modes. Mode selection and automatic mode switching determination are achieved by comparing derived voltages from input voltage and output voltage of the charge pump with an internal reference voltage. The LED driver provides regulated and well matched forward currents to the plurality of LEDs to adjust their brightness levels and ensure the backlight uniformity. The forward current for each LED is generated by amplifying the voltage differential of a voltage derived from an external control input, and a voltage derived from an internal current source.

Abstract: An integrated transceiver for achieving bi-directional communication along a single fiber-optic cable in a fiber-optic network. The transceiver includes an active part for transmit and receive portions of the transceiver. The active part includes a photo diode and a laser diode attached to a substrate. Bi-directional communication is achieved by using an optical circulator. The optical circulator may include components that limit back reflections into the active part of the transceiver. The optical circulator is attached to the substrate and connected optically to the active part.

Abstract: A multi-mode multi-phase inductor-less DC/DC regulator is powered by a voltage source and produces an output to a load. It includes at least two modes of operation, and allows automatic switching among modes. Each mode includes a charging phase and a transfer phase. Mode selection and automatic mode switching determination are achieved by comparing derived voltages from the voltage source with internal voltage references. Mode selection and automatic mode switching actuation are achieved by selectively actuating some or all of no more than eight switching and regulation elements. Charging and transfer phases alternate and phase change is achieved by changing the configurations of some or all of the switching and regulation elements to charge and discharge no more than two external flying capacitors to provide a voltage at the output. This voltage is then fed back to a voltage regulation circuit to produce a regulated output voltage to the load.

Abstract: A plug in communications module for achieving bi-directional communication along a single fiber-optic cable in a fiber-optic network. The plug in module is made such that it plugs directly into fiber-optic communication equipment of standard form factors. Bi-directional communication is achieved by using a low-cost circulator. The plug in module also has a receptacle that is used for attaching a patch cable between the fiber-optic network in the plug in module.

Abstract: A collimating device having adjustable features that facilitate proper optical alignment of components positioned within the collimator is disclosed. In one embodiment, the collimating device includes a collimating portion including a collimating element, a core portion containing an optical device, and at least one adapter portion. An engagement surface on one end of the collimating portion is shaped to engage a corresponding engagement surface on one end of the adapter portion to form an adjustment point. An additional adjustment point is defined between another end of the adapter portion and an end of the core portion. These adjustment points enable the collimating portion to be maneuvered with respect to the core portion in order to align the collimating device. Minimal clearances between the adjustment point surfaces minimize the amount of adhesive needed to bond the collimator portion together after alignment, thereby producing a more stable and secure collimating device.