Abstract: A reference voltage circuit corrects for bandgap voltage shifts induced during fabrication. The reference voltage circuit generates a reference voltage using first and second base-emitter pairs. The reference voltage circuit sums the voltage across the first base-emitter pair with a difference voltage. During a first time period, the difference voltage is the voltage across the first base-emitter pair minus the voltage across the second base-emitter pair, and during a second time period, the difference voltage is the voltage across the second base-emitter pair minus the voltage across the first base-emitter pair.

Abstract: A reference voltage circuit corrects for bandgap voltage shifts induced during fabrication. The reference voltage circuit generates a reference voltage using first and second base-emitter pairs. The reference voltage circuit sums the voltage across the first base-emitter pair with a difference voltage. During a first time period, the difference voltage is the voltage across the first base-emitter pair minus the voltage across the second base-emitter pair, and during a second time period, the difference voltage is the voltage across the second base-emitter pair minus the voltage across the first base-emitter pair.

Abstract: A color correcting device driver is configured to vary the equivalent current into light emitting elements (e.g., LEDs) with the frequency of the AC input current (e.g., 120 Hz). In implementations that include a fly-back controller with a power factor correction (PFC) controller on the primary side, the color correcting device driver performs the method of: 1) turning on the loads (e.g., white and CA strings of LEDs); 2) determining if the voltage supplied to the loads has dropped by a first threshold amount; 3) turning off the loads; and 4) determining if the voltage supplied to loads has recovered by a second threshold amount (or waiting for a fixed amount of time). The method is repeated. In implementations that do not include a PFC controller on the primary side, the color correcting device driver can create a pulse width modulated (PWM) signal.

Abstract: The disclosed implementations utilize the voltage drop inherent in the device string to power a device control IC. In some implementations, current is drawn from the bottom of the device string and applied to a voltage supply pin of the device control IC. In some implementations, current is drawn from some other location in the device string (e.g., near the bottom or midpoint of the device string) using a switch. In some implementations, current is drawn from near the bottom and the bottom of the device string at different times, such that less current is drawn from the bottom of the device string as the duty cycle of the device string increases and more current is drawn from near the bottom of the device string as the duty cycle of the device string increases.

Abstract: A color correcting device driver is configured to vary the equivalent current into light emitting elements (e.g., LEDs) with the frequency of the AC input current (e.g., 120 Hz). In implementations that include a fly-back controller with a power factor correction (PFC) controller on the primary side, the color correcting device driver performs the method of: 1) turning on the loads (e.g., white and CA strings of LEDs); 2) determining if the voltage supplied to the loads has dropped by a first threshold amount; 3) turning off the loads; and 4) determining if the voltage supplied to loads has recovered by a second threshold amount (or waiting for a fixed amount of time). The method is repeated. In implementations that do not include a PFC controller on the primary side, the color correcting device driver can create a pulse width modulated (PWM) signal.

Abstract: A primary side PFC driver circuit is disclosed that includes a switch control circuit for commanding a switch to allow an inductor coupled to an output load (e.g., LEDs) to transfer energy provided by an input voltage source. The switch control circuit provides two signals for commanding the switch. A first signal having a first frequency, with a duty cycle in proportion to the input voltage amplitude, commands the switch to allow the average input current to be proportional to the input voltage amplitude. A second signal having a second frequency higher than the first frequency pulses the output load with substantially constant current pulses based on a value of the first signal (e.g., while the first signal is high). The current pulses produce a substantially constant current in the output load.

Abstract: The disclosed implementations utilize the voltage drop inherent in the device string to power a device control IC. In some implementations, current is drawn from the bottom of the device string and applied to a voltage supply pin of the device control IC. In some implementations, current is drawn from some other location in the device string (e.g., near the bottom or midpoint of the device string) using a switch. In some implementations, current is drawn from near the bottom and the bottom of the device string at different times, such that less current is drawn from the bottom of the device string as the duty cycle of the device string increases and more current is drawn from near the bottom of the device string as the duty cycle of the device string increases.

Abstract: In one novel aspect, driving a string of light emitting elements, such as LEDs, includes applying a drive signal to circuitry that regulates a voltage appearing at a source of a transistor whose drain is coupled to one end of the string of light emitting elements and whose source is coupled to ground through a resistive element. Sequencing of the drive signal and a voltage supply signal for the light emitting elements is controlled such that the voltage supply signal is not increased above a predetermined allowable voltage for the transistor until the transistor is turned on, and such that the supply voltage is not decreased below the allowable voltage for the transistor until the transistor is turned off.

Abstract: A power conversion circuit of two feedback loops is disclosed that includes a feedback control circuit for ramping up or down a commanded voltage to a load (e.g., LEDs). The second feedback loop feeds into the first feedback loop, and the second feedback loop operates at a slower bandwidth than the first feedback loop. When ramping up or down the commanded voltage, a voltage overshoot results because of delay in the system. The overshoot can be compensated for by a final adjustment to the commanded voltage.

Abstract: A color correcting device driver is configured to vary the equivalent current into light emitting elements (e.g., LEDs) with the frequency of the AC input current (e.g., 120 Hz). In implementations that include a fly-back controller with a power factor correction (PFC) controller on the primary side, the color correcting device driver performs the method of: 1) turning on the loads (e.g., white and CA strings of LEDs); 2) determining if the voltage supplied to the loads has dropped by a first threshold amount; 3) turning off the loads; and 4) determining if the voltage supplied to loads has recovered by a second threshold amount (or waiting for a fixed amount of time). The method is repeated. In implementations that do not include a PFC controller on the primary side, the color correcting device driver can create a pulse width modulated (PWM) signal.

Abstract: The disclosed multi-channel driver equalizer circuit matches currents in multiple strings of illumination devices at low current levels by using an analog equalizer to sequentially couple the output of a reference amplifier in series with each current source amplifier in a current limit loop of the driver equalizer circuit to correct the offsets of the current source amplifiers, resulting in the matching of string currents on average.

Abstract: In one embodiment, a method includes displaying an input tool comprising a first touch icon and a first input icon. The first touch icon may be visually separated from the first input icon by a predetermined distance. The first input icon may provide a graphical indication of an input associated with the first touch icon. The method may include determining an input based on a touch at or substantially near a location on a touch sensor associated with the first touch icon. The method may also include effecting the input as determined.

Abstract: A primary side PFC driver circuit is disclosed that includes a switch control circuit for commanding a switch to allow an inductor coupled to an output load (e.g., LEDs) to transfer energy provided by an input voltage source. The switch control circuit provides two signals for commanding the switch. A first signal having a first frequency, with a duty cycle in proportion to the input voltage amplitude, commands the switch to allow the average input current to be proportional to the input voltage amplitude. A second signal having a second frequency higher than the first frequency pulses the output load with substantially constant current pulses based on a value of the first signal (e.g., while the first signal is high). The current pulses produce a substantially constant current in the output load.

Abstract: A primary side PFC driver circuit is disclosed that includes a switch control circuit for commanding a switch to allow an inductor coupled to an output load (e.g., LEDs) to transfer energy provided by an input voltage source. The switch control circuit provides two signals for commanding the switch. A first signal having a first frequency, with a duty cycle in proportion to the input voltage amplitude, commands the switch to allow the average input current to be proportional to the input voltage amplitude. A second signal having a second frequency higher than the first frequency pulses the output load with substantially constant current pulses based on a value of the first signal (e.g., while the first signal is high). The current pulses produce a substantially constant current in the output load.

Abstract: A ramp-up circuit for switched capacitor circuits with negative feedback to control the slew rate of in-rush current. Other embodiments are described and claimed.

Abstract: The present disclosure provides a method and apparatus for high performance class D audio amplifier circuit that includes: a modulator circuit for receiving a PWM input signal and generating a control signal, a driver control circuit, a switching circuit, and a feedback circuit. The driver control circuit is adapted to generate a drive signal for the switching circuit. The driving signal provides compensation for noise and distortions in a PWM output signal at each cycle by selecting either a first pulse signal or a second pulse signal based on the information of the control signal.

Abstract: The present disclosure provides a method and apparatus for high performance class D audio amplifier circuit that includes: a modulator circuit for receiving a PWM input signal and generating a control signal, a driver control circuit, a switching circuit, and a feedback circuit. The driver control circuit is adapted to generate a drive signal for the switching circuit. The driving signal provides compensation for noise and distortions in a PWM output signal at each cycle by selecting either a first pulse signal or a second pulse signal based on the information of the control signal.

Abstract: A ramp-up circuit for switched capacitor circuits with negative feedback to control the slew rate of in-rush current. Other embodiments are described and claimed.

Abstract: A system and method are provided for communicating data among chained circuits. In operation, a period of a signal communicated between a chain of circuits is identified. Additionally, a state of the signal is determined, based on the period of the signal.

Abstract: A relaxation oscillator for generating an oscillator output signal having a predetermined frequency. The relaxation oscillator includes an interleaved charge pump for providing a restoring charge to an integrator in response to at least one charge pump control signal. The relaxation oscillator further includes an integrator having an integrator input connected to the current summing node. The integrator is adapted to produce an integrator output signal having the predetermined frequency at an integrator output. A comparator having an input connected to the integrator output is adapted to generate the oscillator output signal having the predetermined frequency in response to the integrator output signal.