BOOT SEQUENCE IN COLD TEMPERATURES

Systems and methods are disclosed for boot sequences in cold temperatures. For example, methods may include accessing a temperature measurement from a temperature sensor; responsive to the temperature measurement being below a threshold, setting a clock frequency for a clock signal used by an integrated circuit to a first frequency; and executing boot code in the integrated circuit using the clock signal at the first frequency, wherein the first frequency is lower than a second frequency that the integrated circuit is configured to use when executing the boot code at higher temperatures. In some implementations, an idle mode is used to heat up a device to achieve a temperature needed to support a use case for the device.

TECHNICAL FIELD

This disclosure relates to boot sequences for cold temperatures.

DETAILED DESCRIPTION

A faster boot sequence of a camera may improve a user experience when the user is pressing the shutter bottom to start recording. But in some circumstances, when internal device temperature is very low (e.g., below 0° C.), it may happen that the device may not be able to boot or to start recording because the battery is not able to deliver enough power to the system to run properly. In such circumstances, a modified boot sequence may be employed to make do with lower power available from the battery until the battery heats up.

In some implementations, a boot sequence starts by enabling functions gradually in the system at a rate that is a function of the temperature of the battery, to reach a common state of the device, named the idle state. Second, when in the idle state, the process continues by running a sequence that will increase the internal temperature of the device since the components of the camera are going to be activated gradually and therefore dissipate some heat. By doing so, the battery temperature may be increased. When the internal battery temperature reaches a given value, the battery will be able to deliver enough power for tasks to be executed. In some implementations, a characterization of power to be delivered per camera use case may be used to allow for reduction of the warm-up sequence time, for example, as some use cases require less power.

A system may be configured to smooth power demand during the boot sequence. For example, a boot sequence of a system (e.g., a camera) may be controlled by two components, a microcontroller (MCU) and a system-on-a-chip (SoC). The MCU may perform a basic check to ensure that a power management integrated circuit (PMIC) is operational. The PMIC is a component that transforms the voltage delivered by the battery into several low voltage values required by the various integrated circuits of the system, such as DRAM, display, image sensors, and Embedded Multi Media Card (eMMC), for example. After the MCU performs a basic check, then the SoC will boot.

For example,FIG.8illustrates an overall current, delivered by the battery, during a boot sequence for an SoC. To ensure a safe boot sequence, the temperature of the battery may be measured. When the temperature measured is below a given threshold (e.g., below 0° C.), the boot sequence may be performed gradually, with special care. Special boot sequences for use in cold conditions may include one or more aspects listed below.1) In some implementations, a boot sequence may optionally avoid enabling per domain power supplies that are not necessary when a cold condition is detected. For example, an MCU may be configured to selectively enable power domains in a device based on one or more temperature measurements.2) In some implementations, when the SoC is under reset, special care may be used during SoC design to reduce power consumption, such as by reducing a number of registers that need to be enabled under a reset condition, and/or by activating clock gaters to minimize clock tree power consumption since some data paths may be not functional in this particular state or use case.3) In some implementations, a bootup sequence (e.g., a phase during which the bootstrap of the eMMC is loaded into internal SRAM) may be performed in a degraded mode, such as by increasing time for bootup in exchange for reduction of peak current drawn.4) In some implementations, a clock frequency used to run boot code is set based on one or more temperature measurements. For example, all clocks in a system may be set to their minimal values of frequency (i.e., values less than expected during a normal boot sequence) when a cold temperature below a predetermined threshold is detected.5) In some implementations, Automatic Voltage Scaling (AVS) may be applied early in a boot sequence. The application of AVS may allow control of voltage of a digital domain of the SoC that can support voltage adaptation based on intrinsic SoC characteristic (e.g., internal speed).6) In some implementations, a boot sequence may be adjusted to avoid parallel actions. For instance, if the SoC is populated with several DDR channels, each channel can be configured to perform its own training sequence in parallel. When a low temperature condition is detected, all DDR channel training sequences can be performed in a serial mode to spread out or spread apart in time the value of current drawn.7) In some implementations, code transfer from the eMMC (e.g., the non-volatile storage) to the DDR (e.g., the volatile storage) may be slowed down to spread out or spread apart in time the value of current drawn.8) In some implementations, when an idle state of a system (e.g., the camera) is reached, all clocks can be set to their nominal value.

An idle state of a camera may be used to warm the camera to run a requested camera use case once a temperature (e.g., a temperature of a battery) reaches a threshold required for robust performance in the use case. A battery may be able to deliver a given amount of power depending on its own temperature. So, to run a specific use case for the camera, the internal battery temperature must be above a minimal or minimum threshold value in order to safely and reliably deliver enough power. To do so, a software sequence can be run until the minimal temperature of the battery has been reached. The software sequence may be designed in order to safely increase power consumption, leading to increased heat dissipation by components, leading to internal body temperature increase, and therefore to battery temperature increase.

FIGS.1A-Bare isometric views of an example of an image capture device100. The image capture device100may include a body102, a lens104structured on a front surface of the body102, various indicators on the front surface of the body102(such as light-emitting diodes (LEDs), displays, and the like), various input mechanisms (such as buttons, switches, and/or touch-screens), and electronics (such as imaging electronics, power electronics, etc.) internal to the body102for capturing images via the lens104and/or performing other functions. The lens104is configured to receive light incident upon the lens104and to direct received light onto an image sensor internal to the body102. The image capture device100may be configured to capture images and video and to store captured images and video for subsequent display or playback.

The image capture device100may include an LED or another form of indicator106to indicate a status of the image capture device100and a liquid-crystal display (LCD) or other form of a display108to show status information such as battery life, camera mode, elapsed time, and the like. The image capture device100may also include a mode button110and a shutter button112that are configured to allow a user of the image capture device100to interact with the image capture device100. For example, the mode button110and the shutter button112may be used to turn the image capture device100on and off, scroll through modes and settings, and select modes and change settings. The image capture device100may include additional buttons or interfaces (not shown) to support and/or control additional functionality.

The image capture device100may include a door114coupled to the body102, for example, using a hinge mechanism116. The door114may be secured to the body102using a latch mechanism118that releasably engages the body102at a position generally opposite the hinge mechanism116. The door114may also include a seal120and a battery interface122. When the door114is an open position, access is provided to an input-output (I/O) interface124for connecting to or communicating with external devices as described below and to a battery receptacle126for placement and replacement of a battery (not shown). The battery receptacle126includes operative connections (not shown) for power transfer between the battery and the image capture device100. When the door114is in a closed position, the seal120engages a flange (not shown) or other interface to provide an environmental seal, and the battery interface122engages the battery to secure the battery in the battery receptacle126. The door114can also have a removed position (not shown) where the entire door114is separated from the image capture device100, that is, where both the hinge mechanism116and the latch mechanism118are decoupled from the body102to allow the door114to be removed from the image capture device100.

The image capture device100may include a microphone128on a front surface and another microphone130on a side surface. The image capture device100may include other microphones on other surfaces (not shown). The microphones128,130may be configured to receive and record audio signals in conjunction with recording video or separate from recording of video. The image capture device100may include a speaker132on a bottom surface of the image capture device100. The image capture device100may include other speakers on other surfaces (not shown). The speaker132may be configured to play back recorded audio or emit sounds associated with notifications.

A front surface of the image capture device100may include a drainage channel134. A bottom surface of the image capture device100may include an interconnect mechanism136for connecting the image capture device100to a handle grip or other securing device. In the example shown inFIG.1B, the interconnect mechanism136includes folding protrusions configured to move between a nested or collapsed position as shown and an extended or open position (not shown) that facilitates coupling of the protrusions to mating protrusions of other devices such as handle grips, mounts, clips, or like devices.

The image capture device100may include an interactive display138that allows for interaction with the image capture device100while simultaneously displaying information on a surface of the image capture device100.

The image capture device100ofFIGS.1A-Bincludes an exterior that encompasses and protects internal electronics. In the present example, the exterior includes six surfaces (i.e. a front face, a left face, a right face, a back face, a top face, and a bottom face) that form a rectangular cuboid. Furthermore, both the front and rear surfaces of the image capture device100are rectangular. In other embodiments, the exterior may have a different shape. The image capture device100may be made of a rigid material such as plastic, aluminum, steel, or fiberglass. The image capture device100may include features other than those described here. For example, the image capture device100may include additional buttons or different interface features, such as interchangeable lenses, cold shoes, and hot shoes that can add functional features to the image capture device100.

The image capture device100may include various types of image sensors, such as charge-coupled device (CCD) sensors, active pixel sensors (APS), complementary metal-oxide-semiconductor (CMOS) sensors, N-type metal-oxide-semiconductor (NMOS) sensors, and/or any other image sensor or combination of image sensors.

Although not illustrated, in various embodiments, the image capture device100may include other additional electrical components (e.g., an image processor, camera system-on-chip (SoC), etc.), which may be included on one or more circuit boards within the body102of the image capture device100.

The image capture device100may interface with or communicate with an external device, such as an external user interface device (not shown), via a wired or wireless computing communication link (e.g., the I/O interface124). Any number of computing communication links may be used. The computing communication link may be a direct computing communication link or an indirect computing communication link, such as a link including another device or a network, such as the internet, may be used.

In some implementations, the computing communication link may be a Wi-Fi link, an infrared link, a Bluetooth (BT) link, a cellular link, a ZigBee link, a near field communications (NFC) link, such as an ISO/IEC 20643 protocol link, an Advanced Network Technology interoperability (ANT+) link, and/or any other wireless communications link or combination of links.

In some implementations, the computing communication link may be an HDMI link, a USB link, a digital video interface link, a display port interface link, such as a Video Electronics Standards Association (VESA) digital display interface link, an Ethernet link, a Thunderbolt link, and/or other wired computing communication link.

The image capture device100may transmit images, such as panoramic images, or portions thereof, to the external user interface device via the computing communication link, and the external user interface device may store, process, display, or a combination thereof the panoramic images.

The external user interface device may be a computing device, such as a smartphone, a tablet computer, a phablet, a smart watch, a portable computer, personal computing device, and/or another device or combination of devices configured to receive user input, communicate information with the image capture device100via the computing communication link, or receive user input and communicate information with the image capture device100via the computing communication link.

The external user interface device may display, or otherwise present, content, such as images or video, acquired by the image capture device100. For example, a display of the external user interface device may be a viewport into the three-dimensional space represented by the panoramic images or video captured or created by the image capture device100.

The external user interface device may communicate information, such as metadata, to the image capture device100. For example, the external user interface device may send orientation information of the external user interface device with respect to a defined coordinate system to the image capture device100, such that the image capture device100may determine an orientation of the external user interface device relative to the image capture device100.

Based on the determined orientation, the image capture device100may identify a portion of the panoramic images or video captured by the image capture device100for the image capture device100to send to the external user interface device for presentation as the viewport. In some implementations, based on the determined orientation, the image capture device100may determine the location of the external user interface device and/or the dimensions for viewing of a portion of the panoramic images or video.

The external user interface device may implement or execute one or more applications to manage or control the image capture device100. For example, the external user interface device may include an application for controlling camera configuration, video acquisition, video display, or any other configurable or controllable aspect of the image capture device100.

The user interface device, such as via an application, may generate and share, such as via a cloud-based or social media service, one or more images, or short video clips, such as in response to user input. In some implementations, the external user interface device, such as via an application, may remotely control the image capture device100such as in response to user input.

The external user interface device, such as via an application, may display unprocessed or minimally processed images or video captured by the image capture device100contemporaneously with capturing the images or video by the image capture device100, such as for shot framing or live preview, and which may be performed in response to user input. In some implementations, the external user interface device, such as via an application, may mark one or more key moments contemporaneously with capturing the images or video by the image capture device100, such as with a tag or highlight in response to a user input or user gesture.

The external user interface device, such as via an application, may display or otherwise present marks or tags associated with images or video, such as in response to user input. For example, marks may be presented in a camera roll application for location review and/or playback of video highlights.

The external user interface device, such as via an application, may wirelessly control camera software, hardware, or both. For example, the external user interface device may include a web-based graphical interface accessible by a user for selecting a live or previously recorded video stream from the image capture device100for display on the external user interface device.

The external user interface device may receive information indicating a user setting, such as an image resolution setting (e.g., 3840 pixels by 2160 pixels), a frame rate setting (e.g., 60 frames per second (fps)), a location setting, and/or a context setting, which may indicate an activity, such as mountain biking, in response to user input, and may communicate the settings, or related information, to the image capture device100.

The image capture device100may be used to implement some or all of the techniques described in this disclosure, such as the technique500described inFIG.5, the technique600described inFIG.6, and/or the technique700described inFIG.7.

FIGS.2A-Billustrate another example of an image capture device200. The image capture device200includes a body202and two camera lenses204and206disposed on opposing surfaces of the body202, for example, in a back-to-back configuration, Janus configuration, or offset Janus configuration. The body202of the image capture device200may be made of a rigid material such as plastic, aluminum, steel, or fiberglass.

The image capture device200includes various indicators on the front of the surface of the body202(such as LEDs, displays, and the like), various input mechanisms (such as buttons, switches, and touch-screen mechanisms), and electronics (e.g., imaging electronics, power electronics, etc.) internal to the body202that are configured to support image capture via the two camera lenses204and206and/or perform other imaging functions.

The image capture device200includes various indicators, for example, LEDs208,210to indicate a status of the image capture device100. The image capture device200may include a mode button212and a shutter button214configured to allow a user of the image capture device200to interact with the image capture device200, to turn the image capture device200on, and to otherwise configure the operating mode of the image capture device200. It should be appreciated, however, that, in alternate embodiments, the image capture device200may include additional buttons or inputs to support and/or control additional functionality.

The image capture device200may include an interconnect mechanism216for connecting the image capture device200to a handle grip or other securing device. In the example shown inFIGS.2A and2B, the interconnect mechanism216includes folding protrusions configured to move between a nested or collapsed position (not shown) and an extended or open position as shown that facilitates coupling of the protrusions to mating protrusions of other devices such as handle grips, mounts, clips, or like devices.

The image capture device200may include audio components218,220,222such as microphones configured to receive and record audio signals (e.g., voice or other audio commands) in conjunction with recording video. The audio component218,220,222can also be configured to play back audio signals or provide notifications or alerts, for example, using speakers. Placement of the audio components218,220,222may be on one or more of several surfaces of the image capture device200. In the example ofFIGS.2A and2B, the image capture device200includes three audio components218,220,222, with the audio component218on a front surface, the audio component220on a side surface, and the audio component222on a back surface of the image capture device200. Other numbers and configurations for the audio components are also possible.

The image capture device200may include an interactive display224that allows for interaction with the image capture device200while simultaneously displaying information on a surface of the image capture device200. The interactive display224may include an I/O interface, receive touch inputs, display image information during video capture, and/or provide status information to a user. The status information provided by the interactive display224may include battery power level, memory card capacity, time elapsed for a recorded video, etc.

The image capture device200may include a release mechanism225that receives a user input to in order to change a position of a door (not shown) of the image capture device200. The release mechanism225may be used to open the door (not shown) in order to access a battery, a battery receptacle, an I/O interface, a memory card interface, etc. (not shown) that are similar to components described in respect to the image capture device100ofFIGS.1A and1B.

In some embodiments, the image capture device200described herein includes features other than those described. For example, instead of the I/O interface and the interactive display224, the image capture device200may include additional interfaces or different interface features. For example, the image capture device200may include additional buttons or different interface features, such as interchangeable lenses, cold shoes, and hot shoes that can add functional features to the image capture device200.

FIG.2Cis a top view of the image capture device200ofFIGS.2A-BandFIG.2Dis a partial cross-sectional view of the image capture device200ofFIG.2C. The image capture device200is configured to capture spherical images, and accordingly, includes a first image capture device226and a second image capture device228. The first image capture device226defines a first field-of-view230and includes the lens204that receives and directs light onto a first image sensor232. Similarly, the second image capture device228defines a second field-of-view234and includes the lens206that receives and directs light onto a second image sensor236. To facilitate the capture of spherical images, the image capture devices226and228(and related components) may be arranged in a back-to-back (Janus) configuration such that the lenses204,206face in generally opposite directions.

The fields-of-view230,234of the lenses204,206are shown above and below boundaries238,240indicated in dotted line. Behind the first lens204, the first image sensor232may capture a first hyper-hemispherical image plane from light entering the first lens204, and behind the second lens206, the second image sensor236may capture a second hyper-hemispherical image plane from light entering the second lens206.

One or more areas, such as blind spots242,244may be outside of the fields-of-view230,234of the lenses204,206so as to define a “dead zone.” In the dead zone, light may be obscured from the lenses204,206and the corresponding image sensors232,236, and content in the blind spots242,244may be omitted from capture. In some implementations, the image capture devices226,228may be configured to minimize the blind spots242,244.

The fields-of-view230,234may overlap. Stitch points246,248proximal to the image capture device200, that is, locations at which the fields-of-view230,234overlap, may be referred to herein as overlap points or stitch points. Content captured by the respective lenses204,206that is distal to the stitch points246,248may overlap.

Images contemporaneously captured by the respective image sensors232,236may be combined to form a combined image. Generating a combined image may include correlating the overlapping regions captured by the respective image sensors232,236, aligning the captured fields-of-view230,234, and stitching the images together to form a cohesive combined image.

A slight change in the alignment, such as position and/or tilt, of the lenses204,206, the image sensors232,236, or both, may change the relative positions of their respective fields-of-view230,234and the locations of the stitch points246,248. A change in alignment may affect the size of the blind spots242,244, which may include changing the size of the blind spots242,244unequally.

Incomplete or inaccurate information indicating the alignment of the image capture devices226,228, such as the locations of the stitch points246,248, may decrease the accuracy, efficiency, or both of generating a combined image. In some implementations, the image capture device200may maintain information indicating the location and orientation of the lenses204,206and the image sensors232,236such that the fields-of-view230,234, the stitch points246,248, or both may be accurately determined; the maintained information may improve the accuracy, efficiency, or both of generating a combined image.

The lenses204,206may be laterally offset from each other, may be off-center from a central axis of the image capture device200, or may be laterally offset and off-center from the central axis. As compared to image capture devices with back-to-back lenses, such as lenses aligned along the same axis, image capture devices including laterally offset lenses may include substantially reduced thickness relative to the lengths of the lens barrels securing the lenses. For example, the overall thickness of the image capture device200may be close to the length of a single lens barrel as opposed to twice the length of a single lens barrel as in a back-to-back lens configuration. Reducing the lateral distance between the lenses204,206may improve the overlap in the fields-of-view230,234. In another embodiment (not shown), the lenses204,206may be aligned along a common imaging axis.

Images or frames captured by the image capture devices226,228may be combined, merged, or stitched together to produce a combined image, such as a spherical or panoramic image, which may be an equirectangular planar image. In some implementations, generating a combined image may include use of techniques including noise reduction, tone mapping, white balancing, or other image correction. In some implementations, pixels along the stitch boundary may be matched accurately to minimize boundary discontinuities.

The image capture device200may be used to implement some or all of the techniques described in this disclosure, such as the technique500described inFIG.5, the technique600described inFIG.6, and/or the technique700described inFIG.7.

FIG.3is a block diagram of electronic components in an image capture device300. The image capture device300may be a single-lens image capture device, a multi-lens image capture device, or variations thereof, including an image capture device with multiple capabilities such as use of interchangeable integrated sensor lens assemblies. The description of the image capture device300is also applicable to the image capture devices100,200ofFIGS.1A-Band2A-D.

The image capture device300includes a body302which includes electronic components such as capture components310, a processing apparatus320, data interface components330, movement sensors340, power components350, and/or user interface components360.

The capture components310include one or more image sensors312for capturing images and one or more microphones314for capturing audio.

The image sensor(s)312is configured to detect light of a certain spectrum (e.g., the visible spectrum or the infrared spectrum) and convey information constituting an image as electrical signals (e.g., analog or digital signals). The image sensor(s)312detects light incident through a lens coupled or connected to the body302. The image sensor(s)312may be any suitable type of image sensor, such as a charge-coupled device (CCD) sensor, active pixel sensor (APS), complementary metal-oxide-semiconductor (CMOS) sensor, N-type metal-oxide-semiconductor (NMOS) sensor, and/or any other image sensor or combination of image sensors. Image signals from the image sensor(s)312may be passed to other electronic components of the image capture device300via a bus380, such as to the processing apparatus320. In some implementations, the image sensor(s)312includes a digital-to-analog converter. A multi-lens variation of the image capture device300can include multiple image sensors312.

The microphone(s)314is configured to detect sound, which may be recorded in conjunction with capturing images to form a video. The microphone(s)314may also detect sound in order to receive audible commands to control the image capture device300.

The processing apparatus320may be configured to perform image signal processing (e.g., filtering, tone mapping, stitching, and/or encoding) to generate output images based on image data from the image sensor(s)312. The processing apparatus320may include one or more processors having single or multiple processing cores. In some implementations, the processing apparatus320may include an application specific integrated circuit (ASIC). For example, the processing apparatus320may include a custom image signal processor. The processing apparatus320may exchange data (e.g., image data) with other components of the image capture device300, such as the image sensor(s)312, via the bus380.

The processing apparatus320may include memory, such as a random-access memory (RAM) device, flash memory, or another suitable type of storage device, such as a non-transitory computer-readable memory. The memory of the processing apparatus320may include executable instructions and data that can be accessed by one or more processors of the processing apparatus320. For example, the processing apparatus320may include one or more dynamic random-access memory (DRAM) modules, such as double data rate synchronous dynamic random-access memory (DDR SDRAM). In some implementations, the processing apparatus320may include a digital signal processor (DSP). More than one processing apparatus may also be present or associated with the image capture device300.

The data interface components330enable communication between the image capture device300and other electronic devices, such as a remote control, a smartphone, a tablet computer, a laptop computer, a desktop computer, or a storage device. For example, the data interface components330may be used to receive commands to operate the image capture device300, transfer image data to other electronic devices, and/or transfer other signals or information to and from the image capture device300. The data interface components330may be configured for wired and/or wireless communication. For example, the data interface components330may include an I/O interface332that provides wired communication for the image capture device, which may be a USB interface (e.g., USB type-C), a high-definition multimedia interface (HDMI), or a FireWire interface. The data interface components330may include a wireless data interface334that provides wireless communication for the image capture device300, such as a Bluetooth interface, a ZigBee interface, and/or a Wi-Fi interface. The data interface components330may include a storage interface336, such as a memory card slot configured to receive and operatively couple to a storage device (e.g., a memory card) for data transfer with the image capture device300(e.g., for storing captured images and/or recorded audio and video).

The movement sensors340may detect the position and movement of the image capture device300. The movement sensors340may include a position sensor342, an accelerometer344, or a gyroscope346. The position sensor342, such as a global positioning system (GPS) sensor, is used to determine a position of the image capture device300. The accelerometer344, such as a three-axis accelerometer, measures linear motion (e.g., linear acceleration) of the image capture device300. The gyroscope346, such as a three-axis gyroscope, measures rotational motion (e.g., rate of rotation) of the image capture device300. Other types of movement sensors340may also be present or associated with the image capture device300.

The power components350may receive, store, and/or provide power for operating the image capture device300. The power components350may include a battery interface352and a battery354. The battery interface352operatively couples to the battery354, for example, with conductive contacts to transfer power from the battery354to the other electronic components of the image capture device300. The power components350may also include an external interface356, and the power components350may, via the external interface356, receive power from an external source, such as a wall plug or external battery, for operating the image capture device300and/or charging the battery354of the image capture device300. In some implementations, the external interface356may be the I/O interface332. In such an implementation, the I/O interface332may enable the power components350to receive power from an external source over a wired data interface component (e.g., a USB type-C cable).

The user interface components360may allow the user to interact with the image capture device300, for example, providing outputs to the user and receiving inputs from the user. The user interface components360may include visual output components362to visually communicate information and/or present captured images to the user. The visual output components362may include one or more lights364and/or more displays366. The display(s)366may be configured as a touch screen that receives inputs from the user. The user interface components360may also include one or more speakers368. The speaker(s)368can function as an audio output component that audibly communicates information and/or presents recorded audio to the user. The user interface components360may also include one or more physical input interfaces370that are physically manipulated by the user to provide input to the image capture device300. The physical input interfaces370may, for example, be configured as buttons, toggles, or switches. The user interface components360may also be considered to include the microphone(s)314, as indicated in dotted line, and the microphone(s)314may function to receive audio inputs from the user, such as voice commands.

The image capture device300may be used to implement some or all of the techniques described in this disclosure, such as the technique500described inFIG.5, the technique600described inFIG.6, and/or the technique700described inFIG.7.

FIG.4is a block diagram of electronic components of an image capture device400configured to adjust a boot sequence based on a temperature of the image capture device. The image capture device400includes capture components410, including one or more image sensors412and one or more microphones414; a processing apparatus420including an integrated circuit (IC)422and a microcontroller (MCU)424; a battery450; and a temperature sensor452. For example, the processing apparatus420may be configured to access a temperature measurement from the temperature sensor452, and responsive to the temperature measurement being below a threshold, set a clock frequency for a clock signal used by an integrated circuit, e.g., the integrated circuit422, to a first frequency. The processing apparatus420may be configured to execute boot code in the integrated circuit422using the clock signal at the first frequency. The first frequency may be lower than a second frequency that the integrated circuit422is configured to use when executing the boot code at higher temperatures.

The battery450is configured to provide power to the processing apparatus420. In this example, the temperature sensor452is integrated with or within the battery450. In some implementations, the temperature sensor452may be positioned elsewhere in the image capture device400, for example, outside of the battery450.

In this example, the processing apparatus420includes the integrated circuit422(e.g., a system-on-a-chip (SOC)) and the microcontroller (MCU)424that is used to access the temperature measurement from the temperature sensor452and set the clock frequency for the clock signal. In some implementations, the integrated circuit422may be configured to access the temperature measurement and set the clock frequency for the clock signal during an early phase of a boot sequence for the integrated circuit422.

The integrated circuit422may include multiple power domains, and the processing apparatus420may be configured to select a first non-empty subset of the power domains in the integrated circuit422for activation based on one or more temperature measurements from the temperature sensor452, activate the first non-empty subset of the power domains for use during a boot sequence, and disable a second non-empty subset of the power domains, disjoint from the first non-empty subset, during the boot sequence.

In some implementations, the processing apparatus420is configured to activate a clock gater based on one or more temperature measurements from the temperature sensor452. In some implementations, the processing apparatus420is configured to, responsive to the temperature measurement being below the threshold, apply automatic voltage scaling to one or more power domains of the integrated circuit422.

The processing apparatus420may be configured to run the integrated circuit422in an idle mode after completing execution of the boot code. The idle mode includes instructions that cause components of the processing apparatus420to dissipate heat, compare one or more temperature measurements from the temperature sensor452to a threshold associated with a selected use case, and, responsive to the one or more temperature measurements exceeding the threshold associated with the selected use case, transition from the idle mode to an active mode that supports the selected use case.

FIG.5is a flowchart of an example of a technique500for booting a device such as a camera or an imaging device at a low temperature. The technique500includes accessing502a temperature measurement from a temperature sensor; responsive to the temperature measurement being below a threshold, setting504a clock frequency for a clock signal used by an integrated circuit to a first frequency; activating506a clock gater based on one or more temperature measurements from the temperature sensor; responsive to the one or more temperature measurements being below the threshold, applying508automatic voltage scaling to one or more power domains of the integrated circuit; and executing510boot code in the integrated circuit using the clock signal at the first frequency. The first frequency may be lower than a second frequency that the integrated circuit is configured to use when executing the boot code at higher temperatures.

In some implementations, the temperature sensor is integrated with a battery. In some implementations, the temperature sensor is disposed inside a camera body with the integrated circuit. In some implementations, the integrated circuit includes multiple power domains and a subset of the power domains may be selected for activation based on the temperature measurement. In some implementations, an idle mode may be used after the boot sequence at low temperature to heat up a device (e.g., the camera or the imaging device) that includes the integrated circuit to achieve a temperature (e.g., a battery temperature) needed to supply current sufficient for a selected use case for the device. The technique500ofFIG.5may be implemented with the technique600ofFIG.6and/or the technique ofFIG.7described herein.

FIG.6is a flowchart of an example of a technique600for booting at low temperature. The technique600includes selecting602a first non-empty subset of the power domains in the integrated circuit for activation based on one or more temperature measurements from the temperature sensor; activating604the first non-empty subset of the power domains for use during a boot sequence; and disabling606a second non-empty subset of the power domains, disjoint from the first non-empty subset, during the boot sequence. The technique600ofFIG.6may be implemented with the technique500ofFIG.5and/or the technique700ofFIG.7described herein.

FIG.7is a flowchart of an example of a technique700for warming up a device, such as an image capture device or camera, from a low temperature using an idle mode to support a use case requiring a higher temperature. The technique700includes running702an integrated circuit in an idle mode after completing execution of boot code, wherein the idle mode includes instructions that cause components to dissipate heat; comparing704one or more temperature measurements from a temperature sensor to a threshold associated with a selected use case; and, responsive to the one or more temperature measurements exceeding the threshold associated with the selected use case, transitioning706from the idle mode to an active mode that supports the selected use case.

In some implementations, the temperature sensor is integrated with a battery. In some implementations, the temperature sensor is inside an image capture device, such as inside a camera body adjacent to or with the integrated circuit. In some implementations, the integrated circuit includes multiple power domains and a subset of the power domains may be selected for activation based on the one or more temperature measurements. In some implementations, the technique700includes, responsive to one or more of the temperature measurements being below a threshold, applying automatic voltage scaling to one or more power domains of the integrated circuit. The technique700ofFIG.7may be implemented with the technique500ofFIG.5and/or the technique600ofFIG.6described herein.

FIG.8illustrates a graph800of overall current, delivered by a battery, during a normal boot sequence for an SoC of a camera. To execute a boot sequence effectively in cold temperatures, the techniques500,600,700ofFIGS.5to8may be employed. For example, a temperature of the battery may be measured. When the temperature measured is below a given threshold (e.g., below 0° C.), the boot sequence may be performed gradually, with special care. This gradual boot sequence may occur using a clock signal at a first frequency that is lower than a second frequency used when temperature measurements are above the given threshold. This gradual boot sequence may include running an integrated circuit of the camera in an idle mode after completing execution of boot cod. The idle mode includes instructions that cause components to dissipate heat, thus raising the temperature of the overall device that includes the components. By heating the components, a temperature needed to support a use case for the device, that is, the camera can be achieved.