Electronic device with display and low-noise ambient light sensor with a control circuitry that periodically disables the display
First Claim
1. A method of gathering ambient light sensor data in an electronic device having a display, an ambient light sensor, and control circuitry with an integrating analog-to-digital converter, wherein the integrating analog-to-digital converter has an integrating input and wherein the control circuitry has transistor circuitry coupled between the integrating input and the ambient light sensor, the method comprising:
- with the control circuitry, disabling the display for sample periods and enabling the display for hold periods that are interspersed among the sample periods; and
during a first set of the sample periods, providing signals from the ambient light sensor to the integrating input through the transistor circuitry;
during a second set of the sample periods, using the transistor circuitry to prevent signals from the ambient light sensor from reaching the integrating input; and
with the control circuitry, producing an ambient light sensor signal using data gathered by the integrating analog-to-digital converter during the second set of sample periods and the data gathered by the integrating analog-to-digital converter during the first set of sample periods.
1 Assignment
0 Petitions
Accused Products
Abstract
An electronic device may be provided that has a display. The display may produce stray light when producing images for a user. The electronic device may have an ambient light sensor for measuring ambient light levels. Ambient light data may be used in adjusting display brightness. The display may be periodically disabled to prevent the stray light from interfering with the ambient light sensor. An integrating analog-to-digital converter may be used in gathering sensor data from the ambient light sensor. Control circuitry may be configured to remove background signals from ambient light sensor data. The background signals may be associated with leakage current that arises due to offset voltages in an operational amplifier in the integrating analog-to-digital converter. The operational amplifier may have an analog autozeroing capability or control circuitry may be used to subtract background data from ambient light sensor data.
45 Citations
20 Claims
-
1. A method of gathering ambient light sensor data in an electronic device having a display, an ambient light sensor, and control circuitry with an integrating analog-to-digital converter, wherein the integrating analog-to-digital converter has an integrating input and wherein the control circuitry has transistor circuitry coupled between the integrating input and the ambient light sensor, the method comprising:
-
with the control circuitry, disabling the display for sample periods and enabling the display for hold periods that are interspersed among the sample periods; and during a first set of the sample periods, providing signals from the ambient light sensor to the integrating input through the transistor circuitry; during a second set of the sample periods, using the transistor circuitry to prevent signals from the ambient light sensor from reaching the integrating input; and with the control circuitry, producing an ambient light sensor signal using data gathered by the integrating analog-to-digital converter during the second set of sample periods and the data gathered by the integrating analog-to-digital converter during the first set of sample periods. - View Dependent Claims (2, 3, 4, 5)
-
-
6. An electronic device, comprising:
-
a display; an ambient light sensor that receives ambient light; and control circuitry that periodically disables the display, wherein the control circuitry has an integrating analog-to-digital converter with an integrating input and has transistor circuitry that is controlled by the control circuitry to couple the ambient light sensor to the integrating input. - View Dependent Claims (7, 8, 9, 10, 11)
-
-
12. A method of gathering ambient light sensor data in an electronic device that has a display, an ambient light sensor, and control circuitry with an integrating analog-to-digital converter and transistor circuitry coupled between the ambient light sensor and the integrating analog-to-digital converter, the method comprising:
-
with the control circuitry, disabling and enabling the display during respective alternating first and second time periods; during the first time periods, using the control circuitry to configure the transistor circuitry to provide signals from the ambient light sensor to the integrating analog-to-digital converter; and during the second time periods, using the control circuitry to configure the transistor circuitry to gather background signals with the integrating analog-to-digital converter. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20)
-
Specification