Patent ID: 11922892
Assignee: META PLATFORMS TECHNOLOGIES, LLC
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC G  H | IPC G

Claim 0:
1. A device, comprising:
a backlight unit comprising an arrangement of light-emissive elements; and
a driver circuit comprising:
a voltage boost circuit configured to receive a device input voltage and generate a backlight drive voltage; and
a pulse modulation circuit configured to provide a pulse modulation signal having a duty ratio to the voltage boost circuit, comprising:
a digital pulse width modulation controller;
a loop gain adjuster; and
an analog-to-digital converter configured to receive a headroom signal from a headroom processor and to provide a control signal to the loop gain adjuster thereby adjusting the digital pulse width modulation controller, wherein:
the device input voltage is between 3 V and 4.5 V;
the backlight drive voltage is between 20 V and 40 V;
the duty ratio is in a range of 5% to 20%;
the pulse modulation controller is configured to adjust the pulse modulation signal based on the headroom signal;
the device has an input power factor of greater than 0.9;
a loop gain of the pulse modulation controller is adjusted based on the headroom signal; and
the device is a head-mounted device.