Abstract: Methods and apparatuses for improving the power efficiency of boost converters that power illumination sources, such as lasers or LEDs, are described. An adaptive driving strength scheme that dynamically controls a switch-on current for a boost converter based on an output voltage of the boost converter, a temperature, and a state of an illumination source powered by the boost converter are utilized to improve the power efficiency of the boost converter. A resistance of a switch transistor for the boost converter may be adjusted over time by dynamically adjusting a gate voltage applied to the switch transistor.

Abstract: Examples are disclosed that relate to a power supply device for controlling a liquid crystal display (LCD) panel in a reliable and power efficient manner. In one example, the power supply device includes a positive-side switching converter, a negative-side switching converter, and a controller. In an active-bias mode, the controller controls the positive-side switching converter and the negative-side switching converter to alternate a polarity of a bias voltage across a positive output node and a negative output node by alternating between a forward-bias state and a reverse-bias state. In a neutral-bias mode, the controller provides a neutral bias voltage across the positive output node and the negative output node.

Abstract: A system includes a first sense circuit configured to provide a first output representative of sensed current provided by a first battery coupled to a first load. A second sense circuit is configured to provide a second output representative of sensed current provided by a second battery coupled to the first load. An input current controller is coupled to receive the respective first and second outputs and to couple between the second battery and the first load to control the current provided by the second battery.

Abstract: A system and method generate an alternating current (AC) input signal by a digitally controlled resonant drive circuit. The method includes driving a face tracking sensor with the input signal. An output signal is received from the face tracking sensor and an amplitude of the output signal is compared to a target amplitude. A duty cycle of the resonant drive circuit is modified based on the comparison to control the amplitude of the output signal about the target amplitude.

Abstract: A system includes a first sense circuit configured to provide a first output representative of sensed current provided by a first battery coupled to a first load. A second sense circuit is configured to provide a second output representative of sensed current provided by a second battery coupled to the first load. An input current controller is coupled to receive the respective first and second outputs and to couple between the second battery and the first load to control the current provided by the second battery.

Abstract: Examples are disclosed that relate to a power supply device for controlling a liquid crystal display (LCD) panel in a reliable and power efficient manner. In one example, the power supply device includes a positive-side switching converter, a negative-side switching converter, and a controller. In an active-bias mode, the controller controls the positive-side switching converter and the negative-side switching converter to alternate a polarity of a bias voltage across a positive output node and a negative output node by alternating between a forward-bias state and a reverse-bias state. In a neutral-bias mode, the controller provides a neutral bias voltage across the positive output node and the negative output node.

Abstract: The techniques disclosed herein may achieve efficient regulation of power delivered from one or more batteries to a circuit or system with a power control device that has two or more operating modes. In a first operating mode, the power control device may select a first power circuit to deliver power to a system load with a first quiescent current, while in a second operating mode the power control device may select at least one additional power circuit to deliver power to the system load with a second quiescent current. The first quiescent current is significantly less than the second quiescent current such that operation of the first power circuit corresponds to a lower power mode than the additional power circuits. An ideal diode circuit may be configured to selectively couple the outputs of each of the power circuits to the system load.

Abstract: A system includes a first sense circuit configured to provide a first output representative of sensed current provided by a first battery coupled to a first load. A second sense circuit is configured to provide a second output representative of sensed current provided by a second battery coupled to the first load. An input current controller is coupled to receive the respective first and second outputs and to couple between the second battery and the first load to control the current provided by the second battery.

Abstract: Examples are disclosed that relate to monitoring an emission state of light sources. One example provides a light emitting circuit comprising a power source, one or more light sources connected to an output of the power source, and a control circuit comprising a pulsed voltage source and a control transistor configured to regulate a current through the light sources based upon an output of the pulsed voltage source. The light emitting circuit further comprises a monitor transistor comprising a gate connected to an output of the light sources such that a voltage at the output of the light sources controls an output of the monitor transistor, and a monitor transistor detector connected to the output of the monitor transistor. The monitor transistor detector is configured to monitor a state of the one or more light sources based upon a state of the output of the monitor transistor.

Abstract: A system includes a first sense circuit configured to provide a first output representative of sensed current provided by a first battery coupled to a first load. A second sense circuit is configured to provide a second output representative of sensed current provided by a second battery coupled to the first load. An input current controller is coupled to receive the respective first and second outputs and to couple between the second battery and the first load to control the current provided by the second battery.

Abstract: A system and method generate an alternating current (AC) input signal by a digitally controlled resonant drive circuit. The method includes driving a face tracking sensor with the input signal. An output signal is received from the face tracking sensor and an amplitude of the output signal is compared to a target amplitude. A duty cycle of the resonant drive circuit is modified based on the comparison to control the amplitude of the output signal about the target amplitude.

Abstract: Examples are disclosed that relate to monitoring an emission state of light sources. One example provides a light emitting circuit comprising a power source, one or more light sources connected to an output of the power source, and a control circuit comprising a pulsed voltage source and a control transistor configured to regulate a current through the light sources based upon an output of the pulsed voltage source. The light emitting circuit further comprises a monitor transistor comprising a gate connected to an output of the light sources such that a voltage at the output of the light sources controls an output of the monitor transistor, and a monitor transistor detector connected to the output of the monitor transistor. The monitor transistor detector is configured to monitor a state of the one or more light sources based upon a state of the output of the monitor transistor.