Abstract: The disclosed devices may include a driver circuit including a voltage boost circuit, a pulse modulation controller, and optionally a headroom processor. The voltage boost circuit may be configured to receive a device input voltage (such as a battery voltage) and generate a backlight drive voltage. The pulse modulation controller may be configured to provide a pulse modulation signal to the voltage boost circuit, and may include a digital circuit or an analog circuit. Example devices may include a backlight unit receiving the backlight voltage. The optional headroom processor may provide a headroom signal to the pulse modulation controller based on a headroom voltage determined from the backlight unit. Devices may further include a backlight unit including an arrangement of light-emissive elements, and may include display devices such as head-mounted devices. Various other methods, systems, and computer-readable media are also disclosed.

Abstract: The disclosed devices may include a driver circuit including a voltage boost circuit, a pulse modulation controller, and optionally a headroom processor. The voltage boost circuit may be configured to receive a device input voltage (such as a battery voltage) and generate a backlight drive voltage. The pulse modulation controller may be configured to provide a pulse modulation signal to the voltage boost circuit, and may include a digital circuit or an analog circuit. Example devices may include a backlight unit receiving the backlight voltage. The optional headroom processor may provide a headroom signal to the pulse modulation controller based on a headroom voltage determined from the backlight unit. Devices may further include a backlight unit including an arrangement of light-emissive elements, and may include display devices such as head-mounted devices. Various other methods, systems, and computer-readable media are also disclosed.

Abstract: A battery operated portable communication device (100) provides improved power up of converged functionality managed by a power arbitration module (PAM) (104), a baseband processor (BP) (108), and an applications processor (AP) (104). In response to a control switch (120) being turned on, the baseband processor generates a time delay and asserts a boot-line to the applications processor which prevents full power up of the applications processor and during which a battery impedance is read, thereby preventing simultaneous power up of the AP and BP. The boot-line from the baseband processor to the applications processor is released once the BP power up is complete and battery impedance is read.

Abstract: A system and method to determine a power-up parameter for a circuit board. The method includes electrically exciting a second-order circuit to generate an underdamped transient response. The method includes receiving, at a comparator coupled to the second-order circuit, the underdamped transient response. The method includes generating, in response to the underdamped transient response received at the comparator, a plurality of edges. The method includes receiving, at a single general purpose input/output pin of the electronic processor, the plurality of edges. The method includes determining a first response parameter based on a plurality of edges. The method includes determining a second response parameter based on the plurality of edges. The method includes determining the power-up parameter based on the first response parameter and the second response parameter.

Abstract: A system and method to determine a power-up parameter for a circuit board. The method includes electrically exciting a second-order circuit to generate an underdamped transient response. The method includes receiving, at a comparator coupled to the second-order circuit, the underdamped transient response. The method includes generating, in response to the underdamped transient response received at the comparator, a plurality of edges. The method includes receiving, at a single general purpose input/output pin of the electronic processor, the plurality of edges. The method includes determining a first response parameter based on a plurality of edges. The method includes determining a second response parameter based on the plurality of edges. The method includes determining the power-up parameter based on the first response parameter and the second response parameter.