PATENT DOCUMENT

Publication Number: US-11023007-B2
Application Number: US-201916541090-A
Country: US
Kind Code: B2

Title: Connection and moisture detection

Abstract:
Methods, structures, and apparatus that are able to detect the presence of a connection to a contact of an electronic device and are also able to detect the presence of moisture at the contact.

Claims:
What is claimed is: 
     
       1. An electronic system comprising:
 a docking station comprising: 
 a current source to provide a current into a contact of the docking station to generate a ramping voltage on the contact and to then stop providing the current into the contact to generate a decaying voltage on the contact; 
 a comparator having a first input to receive the voltage on the contact and a second input to receive a threshold voltage; and 
 a microcontroller to enable and disable the current source and to receive an output of the comparator, wherein responsive to the output of the comparator changing state in response to the ramping voltage on the contact and changing state in response to the decaying voltage on the contact, the microcontroller determines a presence or absence of an accessory and the presence or absence of excessive moisture at the contact of the docking station. 
 
     
     
       2. The electronic system of  claim 1  further comprising a charging circuit to provide a charging voltage to an accessory when the presence of an accessory is detected and the absence of excessive moisture is detected and to otherwise not provide a charging voltage. 
     
     
       3. The electronic system of  claim 2  wherein the microcontroller determines the presence or absence of an accessory by providing a current into the contact and determining whether the comparator changes state in a first time window. 
     
     
       4. The electronic system of  claim 3  wherein the microcontroller determines the presence or absence of excessive moisture by not providing the current into the contact and determining whether the comparator changes state before a first duration. 
     
     
       5. The electronic system of  claim 3  wherein the microcontroller provides the current into the contact by enabling the current source. 
     
     
       6. The electronic system of  claim 3  wherein the microcontroller does not provide the current into the contact by disabling the current source. 
     
     
       7. An electronic system comprising:
 a docking station comprising: 
 first circuitry to provide a current into a first contact of the docking station; 
 second circuitry to determine whether a ramp voltage generated by the current reaches a threshold voltage in a first time window; and 
 the first circuitry to further stop providing the current into the first contact of the docking station; 
 the second circuitry to, after the first circuitry stops providing the current, to determine if a decay of the ramp voltage reaches the threshold voltage after a first duration; and 
 charging circuitry, responsive to the ramp voltage reaching the threshold voltage in the first time window and the decay of the ramp voltage reaching the threshold voltage after the first duration, to provide a charging voltage to an accessory mated with the docking station. 
 
     
     
       8. The electronic system of  claim 7  wherein the charging voltage is provided to the accessory using the first contact of the docking station. 
     
     
       9. The electronic system of  claim 7  wherein the charging voltage is provided to the accessory using a second contact of the docking station. 
     
     
       10. The electronic system of  claim 7  wherein the first circuitry comprises a current source. 
     
     
       11. The electronic system of  claim 10  wherein the second circuitry comprises a comparator. 
     
     
       12. The electronic system of  claim 10  wherein the second circuitry comprises a comparator and a microcontroller. 
     
     
       13. The electronic system of  claim 12  wherein the microcontroller is configured to enable and disable the current source, to receive an output of the comparator, and to enable and disable a charging circuit. 
     
     
       14. An electronic system comprising:
 a docking station comprising: 
 a first contact; 
 detection circuitry to determine whether a capacitance at the first contact of the docking station is in a first range, the detection circuitry to, in response to determining whether the capacitance is in the first range, determine whether a resistance at the first contact of the docking station is in a second range; and 
 charging circuitry to provide power to an accessory mated with the docking station when the capacitance is in the first range and the resistance is in the second range, and otherwise to not provide power to the accessory. 
 
     
     
       15. The electronic system of  claim 14  wherein the power is provided to the accessory using the first contact of the docking station. 
     
     
       16. The electronic system of  claim 14  wherein the power is provided to the accessory using a second contact of the docking station. 
     
     
       17. The electronic system of  claim 14  wherein the detection circuitry determines whether a capacitance at the first contact of the docking station in a first range by providing a charging current at the first contact of the docking station. 
     
     
       18. The electronic system of  claim 17  further comprising the accessory, wherein the accessory mates with the docking station using a first contact of the accessory, wherein the accessory comprises a capacitor connected between the first contact of the accessory and ground. 
     
     
       19. The electronic system of  claim 18  wherein the first contact of the accessory is a power contact.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. provisional patent application No. 62/828,423, filed Apr. 2, 2019, which is incorporated by reference. 
    
    
     BACKGROUND 
     The amount of data transferred between electronic devices has grown tremendously the last several years. Large amounts of audio, streaming video, text, and other types of data content are now regularly transferred among desktop and portable computers, media devices, handheld media devices, displays, storage devices, and other types of electronic devices. 
     Power and data can be provided from one electronic device to another over cables that can include one or more wire conductors, fiber optic cables, or other conductors. Connector inserts can be located at each end of these cables and can be inserted into connector receptacles in the communicating or power transferring electronic devices. Contacts in or on a connector insert can form electrical connections with corresponding contacts in a connector receptacle. Other devices can have contacts at a surface of a device. Pathways for power and data can be formed when devices are attached together or positioned next to each other and corresponding contacts are electrically connected to each other. 
     Once these pathways are formed, the connected devices can share power, data, or both. Accordingly, it can be desirable for a device to be able to detect when such a connection has been made. 
     These various contacts in connector inserts, in connector receptacles, or on a surface of a device, can be exposed to the local environment where they can encounter liquid, moisture, or other damaging contaminants. For example, liquids can be spilled on these contacts or a device can be set down such that its contacts land in a puddle of liquid. Users can swim or exercise while wearing or holding an electric device. These activities can put contacts for the electronic devices in a position to encounter various contaminants such as chlorinated water, sweat, or other moisture. 
     These liquids, moisture, or other contaminants can corrode and damage the contacts. This corrosion can be greatly exacerbated by the presence of an electric potential, such as when a voltage is applied to a contact. Accordingly, it can be desirable for a device to be able to detect the presence of moisture or other contaminant at a contact so that the possible damage can be mitigated. 
     Thus, what is needed are methods, structures, and apparatus that are able to detect the presence of a connection to a contact of an electronic device and are also able to detect the presence of moisture or contamination at the contact. 
     SUMMARY 
     Accordingly, embodiments of the present invention can provide methods, structures, and apparatus that can detect the presence of a connection to a contact of an electronic device and can also detect the presence of moisture or contamination at the contact. 
     An illustrative embodiment of the present invention can provide circuitry that can detect a connection of an accessory to an electronic device, such as a docking station. This circuity can also detect the presence or absence of moisture at the connection between the accessory and the docking station. The use of the same circuity to detect a connection and to detect moisture can reduce power consumption and conserve resources. 
     These and other embodiments of the present invention can provide a docking station having one or more recesses or receptacles for one or more accessories. The accessories can include one or more contacts to mate with one or more corresponding contacts on the docking station, for example in a corresponding recesses in the docking station. These contacts can be used to convey power, ground, data, or other signals, voltages, or bias lines. 
     These and other embodiments of the present invention can provide a current source that can provide a current into a contact of the docking station. An accessory can have a known capacitor connected to an accessory contact that mates with the docking station contact. When the accessory and the known capacitor are mated with the docking station, the current can generate a ramp voltage. This ramp voltage can then reach a threshold voltage in a time that is determined by the known capacitor and the current, which is also known. Accordingly, when the ramp voltage reaches the threshold voltage in a specific window of time, it can be determined that an accessory is mated to the docking station. Conversely, when the ramp voltage reaches the threshold voltage outside of the specific window of time (for example, earlier than the specific window of time), it can be determined that no accessory is mated to the docking station. 
     These and other embodiments of the present invention can disable the current source once the ramp voltage reaches a first voltage. A pull-down resistor can be connected to the docking station contact to ensure that the ramp voltage decays once the current source is disabled. If moisture is present, the moisture can provide an additional pull-down resistance, thereby causing the ramp voltage to decay more quickly. Accordingly, when the ramp voltage decays below the threshold voltage before a first duration, it can be determined that moisture is present at the connection to the accessory. Conversely, when the ramp voltage decays below the threshold voltage after the first duration, it can be determined that moisture (or more specifically, excessive moisture) is absent at the connection to the accessory. When an accessory is detected, and excessive moisture is absent, the docking station can charge the accessory, otherwise the docking station can prevent such charging to protect the contacts of the docking station and accessory. 
     In these and other embodiments of the present invention, the use of the term moisture can refer to excessive moisture, since some level of moisture is almost always present in air. Excessive moisture can be an amount of moisture that can cause corrosion to contacts of the docking station or accessory, and is subject to normal manufacturing tolerances. 
     These and other embodiments of the present invention can provide further refinements. For example, the presence or absence of moisture can be more accurately determined by using different durations as the first duration depending on whether or not the presence of an accessory is determined. For example, where no accessory is found, a shorter duration can be used as the first duration in determining the presence of excessive moisture, while when an accessory is found, a longer duration can be used as the first duration in determining the presence of excessive moisture. This can help to prevent the presence or absence of the accessory from desensitizing the determination of the presence of excessive moisture. 
     In these and other embodiments of the present invention, the connection detect circuit and the contamination detect circuit can be connected to the same contact. In these and other embodiments of the present invention, the connection detect circuit and the contamination detect circuit can be connected to separate and different contacts. Also, in these examples, the connection detect circuit and the contamination detect circuit can be connected to a power contact. 
     In these and other embodiments of the present invention, the connection detect circuit and the contamination detect circuit can be connected to a power contact or a contact other than a power contact. For example, either or both the connection detect circuit and the contamination detect circuit can be connected to another type of contact such as a contact used for an enable signal, low-frequency data signal, or other data, control, bias, supply, or other type of contact. 
     Embodiments of the present invention can provide connection and moisture detection for various types of devices, such as portable computing devices, tablet computers, desktop computers, laptops, all-in-one computers, audio devices, wearable computing devices, cell phones, smart phones, media phones, storage devices, portable media players, navigation systems, monitors, power supplies, video delivery systems, adapters, remote control devices, chargers, and other devices. The connection and moisture detection can be done over various types of contacts. These contacts can provide pathways for power and signals that are compliant with various standards such as one of the Universal Serial Bus (USB) standards including USB Type-C, High-Definition Multimedia Interface® (HDMI), Digital Visual Interface (DVI), Ethernet, DisplayPort, Thunderbolt™, Lightning®, Joint Test Action Group (JTAG), test-access-port (TAP), Directed Automated Random Testing (DART), universal asynchronous receiver/transmitters (UARTs), clock signals, power signals, and other types of standard, non-standard, and proprietary interfaces and combinations thereof that have been developed, are being developed, or will be developed in the future. 
     Various embodiments of the present invention can incorporate one or more of these and the other features described herein. A better understanding of the nature and advantages of the present invention can be gained by reference to the following detailed description and the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates an electronic system that can be improved by the incorporation of an embodiment of the present invention; 
         FIG. 2  illustrates connection and moisture detection circuitry according to an embodiment of the present invention; 
         FIG. 3  is a timing diagram illustrating the operation of  FIG. 2 ; 
         FIG. 4  is a flowchart illustrating the operation of the circuitry of  FIG. 2 ; 
         FIG. 5  is another timing diagram illustrating the operation of the circuitry of  FIG. 2 ; and 
         FIG. 6  is another flowchart illustrating the operation of the circuitry of  FIG. 2 . 
     
    
    
     DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS 
       FIG. 1  illustrates an electronic system that can be improved by the incorporation of an embodiment of the present invention. This figure, as with the other included figures, is shown for illustrative purposes and does not limit either the possible embodiments of the present invention or the claims. 
     In this example, three accessories  200  can be placed in openings or recesses  110  in docking station  100 . Docking station can also include optional lid  120 , which can be attached using hinge  122 . Accessories  200  can communicate with docking station  100  when mated with docking station  100 . In these and other embodiments of the present invention, accessories  200  can communicate with docking station  100  when accessories  200  are not docked in docking station  100 . Also, in various embodiments of the present invention, accessories  200  can communicate with each other through docking station  100  when docked. In these and other embodiments, accessories  200  can communicate with each other when they are not docked in docking station  100 . These communications can be wired or wireless. For example, they can be Bluetooth or other wireless communications. Docking station  100  can also provide charging power to one or more of the accessories  200 . 
     In this example, charging and communication between accessories  200  and docking station  100  can be one where data and a charging voltage are provided over the same contact. In a specific embodiment of the present invention, docking station  100  can provide a charging voltage on a first contact and a reference ground on a second contact of an interface between docking station  100  and an accessory  200 . Data can be transferred by modulating the charging voltage on the first pin. Docking station  100  can modulate the charging voltage to send data to accessory  200  and accessory  200  can modulate the charging voltage itself to send data to docking station  100 . More specifically, the modulation can be done by adding or omitting an intermediate frequency (IF) signal or radio frequency (RF) to the charging voltage. 
     In this example, three accessories  200  are shown, though in other embodiments, docking station  100  can support one, two, or more than three accessories  200 . Docking station  100  can have a relatively flat surface, it can be a case or other container having a lid, or it can have another appropriate form factor. Accessories  200  can be rechargeable batteries, speakers, Bluetooth headphones, headsets, or earbuds, wearable computing or media devices such as jewelry or watches, or other types of accessories. Docking station  100  can include one or more optional receptacles or other surfaces or recesses  110  for supporting accessories  200  during charging and data transfers. Charging and data transfers can occur over electrical connections formed between contacts on accessories  200  and contacts in or on recesses  110 . 
     Docking station  100  can be powered by an internal battery, external power source, or other appropriate source or combination thereof. Docking station  100  can provide power to one or more accessories  200 . Accessories  200  and docking station  100  can communicate with each other. Also, accessories  200  can communicate with each other via docking station  100 . These communications can include authentication and identification information, firmware and software updates, user provided preferences, or other information. 
     When accessory  200  is inserted in recesses  110  or otherwise mated with docking station  100 , docking station  100  can determine that it is mated to accessory  200 . Docking station can also detect whether or not moisture is present at the mating connection. These determinations can allow accessory  200  to be charged by docking station  100 . 
     Accessories  200  can be, or can include rechargeable batteries. Accordingly, docking station  100  can charge these rechargeable batteries when accessories  200  are inserted into recesses  110  in docking station  100 . Accordingly, embodiments of the present invention can provide circuitry to enable docking station  100  to determine that an accessory  200  has been inserted in a recess  110 . This charging can be done using a power or other contact, as well as a ground contact, on docking station  100 . To avoid corrosion, embodiments of the present invention can provide circuitry to prevent this charging from occurring in the presence of moisture on these contacts. An example is shown in the following figure. 
       FIG. 2  illustrates connection and moisture detection circuitry according to an embodiment of the present invention. In various embodiments of the present invention, this circuitry can be repeated for each recess  110  (shown in  FIG. 1 ) in docking station  100 . In these and other embodiments of the present invention, some or all of this circuitry, such as microcontroller  130 , can be shared among more than one recess  110 . 
     Capacitor C 1  and resistor R 1  can be fixed or discrete components in docking station  100 . They can be components on an integrated circuit that includes other circuits, such as some or all of the other circuits shown here. R 1  can be used to pull a voltage on CONTACT  1  to ground in the absence of other currents or voltages. Capacitor C 1  can provide a known capacitance for calibration purposes. Accessory  200  can include a capacitor CACC. Capacitor CACC can be a fixed known capacitor housed in or on the surface of accessory  200 . 
     When determining whether accessory  200  is present, microcontroller  130  can enable current source I 1   140  using the ENABLE signal. Current source I 1   140  can provide a current into CONTACT  1  of docking station  100 . When CONTACT  2  of accessory  200  is connected to CONTACT  1  of docking station  100 , current source I 1   140  can charge capacitors C 1  and CACC. When accessory  200 , and therefore capacitor CACC, is present, a voltage on CONTACT  1  can charge at a relatively slower rate. When accessory  200 , and therefore capacitor CACC, is absent, a voltage on CONTACT  1  can charge at a relatively faster rate. 
     The current provided by current source I 1   140  into CONTACT  1  docking station  100  can generate a ramp voltage. This ramp voltage can increase from ground, or near ground, to a voltage near VCC, which can be a power supply in docking station  100 , or other voltage. Comparator  150  can compare the ramp voltage on CONTACT  1  to a threshold voltage VDET and can provide a DETECT output to microcontroller  130 . When the ramp voltage on CONTACT  1  reaches the threshold voltage VDET, comparator  150  can provide a rising edge on the DETECT signal to microcontroller  130 , though a falling edge could be used in these and other embodiments of the present invention. Microcontroller  130  can then determine whether the ramp voltage has reached the VDET threshold within a certain time window. For example, when accessory  200 , and therefore capacitor CACC, is present, the current provided by current source I 1   140  into capacitor C 1  and CACC can provide a ramp voltage that reaches the threshold VDET at a specific time. This specific time can be determined by the magnitude of the current from current source I 1   140  and the capacitance values of the capacitors C 1  and CACC. The resistance of R 1  can act to slow the charge rate of these capacitors and can also be accounted for. Once determined, this specific time can be bracketed for manufacturing and other tolerances to generate a window. When microcontroller  130  determines that the ramp voltage has reached the VDET threshold within that time window, microcontroller  130  can determine that accessory  200  is present. When the ramp voltage on CONTACT  1  reaches the VDET threshold outside of that window, microcontroller  130  can determine that accessory  200 , and therefore capacitor CACC, are not present. 
     In these and other embodiments of the present invention, microcontroller  130  can follow other algorithms in determining whether accessory  200  is present. Again, when accessory  200 , and therefore capacitor CACC, is present, the current source I 1   140  can be expected to produce a ramp voltage at CONTACT  1  that reaches the VDET voltage threshold at a specific time. That specific time can be adjusted (shortened) for manufacturing and other tolerances and used to generate a first threshold duration. If the ramp voltage on CONTACT  1  reaches the VDET voltage threshold before that first threshold duration, microcontroller  130  can determine that capacitor CACC, and therefore accessory  200 , is absent. If the ramp voltage on CONTACT  1  reaches the VDET voltage threshold after that first threshold duration, microcontroller  130  can determine that accessory  200  is present. 
     Once it has been determined that accessory  200  is present, embodiments of the present invention can check whether moisture can be detected at CONTACT  1  of docking station  100 . If no such moisture is detected, charging circuit  160  can be enabled by microcontroller  130  to provide a charging voltage at CONTACT  1 , or other contact of docking station  100 . If moisture is detected at CONTACT  1 , microcontroller  130  can continue to disable charging circuit  160  until the moisture has been removed. 
     To detect moisture, or more specifically an excess amount of moisture, microcontroller  130  can disable current source I 1   140 . In the absence of moisture and when an accessory  200  is present, the voltage on CONTACT  1  can decay following an RC time constant determined by the product of the values of the resistance of the resistor R 1  and the sum of the capacitances of the capacitors C 1  and CACC. When moisture is present, the moisture can provide a leakage path from CONTACT  1  to ground (or other contact or voltage in or associated with recess  110 .) This leakage path can appear as a resistor in parallel with resistor R 1 . This parallel resistance can reduce the RC time constant at CONTACT  1  of docking station  100 , thereby leading to a faster decay time. Accordingly, comparator  150  can send an output DETECT signal to microcontroller  130  when the voltage on CONTACT  1  has decayed to the VDET threshold voltage. Again, in the absence of excessive moisture and when an accessory is present, an expected value for this decay can be determined by the resistance value of R 1  and the capacitance of the combination of capacitors C 1  and CACC. This expected time can be adjusted (shortened) for manufacturing and other tolerances and used to generate a second threshold duration. When microcontroller  130  determines that the decay time is greater than this second threshold duration, microcontroller  130  can determine that no moisture is present. When microcontroller  130  determines that the decay time is faster than this second threshold duration, microcontroller  130  can determine that excessive moisture is present and is forming a leakage path from CONTACT  1 . 
     Similarly, in the absence of moisture and when no accessory  200  is present, the voltage on CONTACT  1  can decay following an RC time constant determined by the product of the values of the resistance of the resistor R 1  and the capacitance of the capacitor C 1 . When moisture is present, the moisture can provide a leakage path from CONTACT  1  to ground (or other contact or voltage in or associated with recess  110 .) This leakage path can again appear as a resistor in parallel with resistor R 1 . This parallel resistance can reduce the RC time constant at CONTACT  1  of docking station  100 , thereby leading to a faster decay time. The new, shorter expected time can be adjusted (shortened) for manufacturing and other tolerances and used to generate a third threshold duration. When microcontroller  130  determines that the decay time is greater than this third threshold duration, microcontroller  130  can determine that no moisture is present. When microcontroller  130  determines that the decay time is faster than this third threshold duration, microcontroller  130  can determine that excessive moisture is present and is forming a leakage path from CONTACT  1 . 
     By utilizing the same comparator and threshold voltage for both connection detection and moisture detection, embodiments of the present invention can provide simplified circuitry that can reduce power consumption and conserve resources. In these and other embodiments of the present invention, different threshold voltages can be used for connection detection and moisture detection. For example, comparator  150  can be a hysteresis comparator. 
     A timing diagram showing the operation of this circuitry is shown in the following figure. 
       FIG. 3  is a timing diagram illustrating the operation of  FIG. 2  when an accessory and no excessive moisture are present at CONTACT  1  of docking station  100 . A specific time for when the ramp voltage on CONTACT  1  can reach the VDET threshold can be found given the values of resistor R 1 , capacitor C 1 , and capacitor CACC. This specific time can be adjusted for manufacturing and other tolerances to generate a window from time T 1  to T 2 . 
     At time T 0 , microcontroller  130  can enable current source I 1   140 . Current source I 1   140  can provide current into capacitors C 1  and CACC, thereby generating a ramp voltage on CONTACT  1 . The ramp voltage on CONTACT  1  can reach the VDET threshold voltage at time TR. This can cause the output DETECT of comparator  150  to go high at time TR. Since time TR is in the window from T 1  to T 2 , microcontroller  130  can determine that accessory  200  is present in docking station  100 . When time TR occurs before time T 1 , microcontroller  130  can determine that accessory  200 , and therefore capacitor CACC, is not present. Again, in these and other embodiments of the present invention, instead of a window, a duration threshold, which might or might not be the time from T 0  to T 1 , can be used instead of a window. 
     At time T 5 , microcontroller  130  can disable current source  140 . This can cause the voltage on CONTACT  1  to decay from a peak voltage back to ground through resistor R 1 . Since it was determined above that an accessory  200  is present, the decay time can be determined by the values of resistor R 1 , and the capacitors C 1  and CACC. An expected time can be found and adjusted (shortened) using manufacturing and other tolerances to generate a duration from T 5  to T 3 . When the voltage on CONTACT  1  falls to the VDET threshold voltage, the DETECT signal at the output of comparator  150  can go low at time TF. Since time TF occurs after the duration indicated by time T 3 , microcontroller  130  can determine that excess moisture is not present at CONTACT  1  of docking station  100 . If the following edge of the DETECT signal TF were to occur before time T 3 , microcontroller  130  could determine that excessive moisture is present and causing a leakage path from CONTACT  1 . 
     A flowchart illustrating the operation of the circuitry in  FIG. 2  is shown in the following figure. 
       FIG. 4  is a flowchart illustrating the operation of a docking station according to an embodiment of the present invention. In act  400 , a current can be provided into a contact, such as CONTACT  1 , of docking station  100 . In act  410 , it can be determined if a threshold voltage is reached between times T 1  and T 2 . If not, then no charging should occur in act  460 . When the threshold is reached at a time between T 1  and T 2 , it can be determined that an accessory is present. It can then be determined in act  420  if a decay time is less than a duration defined by time T 3  in act  420 . If it is not, then no moisture is detected and charging can proceed in act  440 . If the decay time to reach the VDET threshold voltage is less than the duration indicated by time T 3 , then moisture is detected and no charging should occur in act  430 . 
       FIG. 5  is another timing diagram illustrating the operation of the circuitry of  FIG. 2 . In this example, a ramp voltage on CONTACT  1  of docking station  100  reaches the VDET threshold voltage at time TR, thereby causing the output DETECT signal of comparator  150  to go high. Since TR occurs before times T 1  and T 2 , microcontroller  130  can determine that no accessory  200  is present in a corresponding recess  110  of docking station  100 . 
     Since accessory  200 , and therefore capacitor CACC, is absent, the voltage on CONTACT  1  can be expected to decay with the RC time constant determined by the product the resistance value of resistor R 1  and the capacitance value of capacitor C 1 . The voltage on CONTACT  1  can be expected to reach the VDET threshold voltage at a specific time. As before, this specific time can be adjusted (shortened) for manufacturing and other tolerances to generate a duration, indicated here as the duration from T 5  to T 4 . Again, when moisture is present at CONTACT  1 , it can appear as a resistance in parallel to R 1 , which can reduce the time constant present at CONTACT  1 . Accordingly, when a decay time is faster than the duration from T 5  to T 4 , microcontroller  130  can determine that moisture is present, and when the decay time is slower than the duration from T 5  to T 4 , microcontroller  130  can determine that no moisture, or specifically no excessive moisture, is present. 
     Accordingly, at time T 5 , microcontroller  130  can disable current source I 1   140 , and the voltage on CONTACT  1  can begin to decay to ground. The voltage on CONTACT  1  can again reach the VDET threshold voltage at time TF, thereby causing the output DETECT of comparator  152  fall. Since time TF occurs before the end of the duration from T 5  to T 4 , microcontroller  130  can determine that moisture is present at CONTACT  1 . A flowchart illustrating this is shown in the following figure. 
       FIG. 6  is another flowchart illustrating the operation of the circuitry of  FIG. 2 . In act  600 , a current is provided into CONTACT  1 . In act  610 , it can be determined whether a resulting ramp voltage on CONTACT  1  reaches a threshold voltage at a time between T 1  and T 2 . If it does, then microcontroller  130  can determine that an accessory is present. In act  620 , it can be determined whether a decay time is less than a first duration indicated by time T 3 . Again, this first duration can be determined using the time constant equal to the product of the resistance of R 1  and the capacitance of capacitors C 1  and CACC. If the decay time for the voltage on CONTACT  1  to reach the VDET threshold voltage is less than this first duration, then moisture is detected in act  630 . If the decay time is longer than this first duration, then no moisture is detected in act  640 . 
     In act  610 , since the voltage threshold is reached at a time outside of the window between T 1  and T 2 , it can be determined that no accessory is present in recess  110  of docking station  100 . In act  650 , it can be determined whether the voltage on CONTACT  1  reaches the VDET threshold voltage in less time than a second duration indicated by time T 4 . Again, this second duration can be determined using the time constant equal to the product of the resistance of R 1  and the capacitance of capacitor C 1 . If the decay time is less than this second duration, then moisture is detected in act  670 . If the decay time is longer than this second duration, then no moisture is detected in act  660 . 
     In these and other embodiments of the present invention, adjustments in the window and threshold durations can be made for manufacturing and other tolerances. These adjustments can compensate for errors in the current provided by I 1   140 , the VDET threshold voltage, stray resistances and capacitances of the contacts, traces, and components on or associated with interconnect illustrated in  FIG. 2  or otherwise described, components tolerances of capacitor C 1 , resistor R 1 , and capacitor CACC, delays through comparator  150  and microcontroller  130 , as well as other errors. 
     In these and other embodiments of the present invention, instead of determining whether an accessory is present by determining whether a threshold voltage is reached in a time window, or before a duration, a value of capacitance at a contact, such as CONTACT  1 , can be determined to be in a window or below (or above) a certain value. Since other components are known, the value of the capacitance at CONTACT  1  can be found using the same circuits and methods disclosed herein. Similarly, the presence of moisture can be determined by determining whether a resistance at CONTACT  1  is below a certain value. 
     In these and other embodiments of the present invention, the connection detect circuit and the contamination detect circuit can be connected to the same contact. In these and other embodiments of the present invention, the connection detect circuit and the contamination detect circuit can be connected to separate and different contacts. Also, in these examples, the connection detect circuit and the contamination detect circuit can be connected to a power contact. 
     In these and other embodiments of the present invention, the connection detect circuit and the contamination detect circuit can be connected to a contact other than a power contact. For example, either or both the connection detect circuit and the contamination detect circuit can be connected to another type of contact such as a contact used for an enable signal, low-frequency data signal, or other data, control, bias, supply, or other type of contact. 
     Embodiments of the present invention can provide connection and moisture detection for various types of devices, such as portable computing devices, tablet computers, desktop computers, laptops, all-in-one computers, wearable computing devices, audio devices, cell phones, smart phones, media phones, storage devices, portable media players, navigation systems, monitors, power supplies, video delivery systems, adapters, remote control devices, chargers, and other devices. The connection and moisture detection can be done over various types of contacts. These contacts can provide pathways for power and signals that are compliant with various standards such as one of the Universal Serial Bus (USB) standards including USB Type-C, High High-Definition Multimedia Interface® (HDMI), Digital Visual Interface (DVI), Ethernet, DisplayPort, Thunderbolt™, Lightning®, Joint Test Action Group (JTAG), test-access-port (TAP), Directed Automated Random Testing (DART), universal asynchronous receiver/transmitters (UARTs), clock signals, power signals, and other types of standard, non-standard, and proprietary interfaces and combinations thereof that have been developed, are being developed, or will be developed in the future. 
     The above description of embodiments of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form described, and many modifications and variations are possible in light of the teaching above. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications to thereby enable others skilled in the art to best utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. Thus, it will be appreciated that the invention is intended to cover all modifications and equivalents within the scope of the following claims.

Metadata:
Filing Date: 20190814
Publication Date: 20210601
Grant Date: 20210601
Priority Date: 20190402
Inventors: BECKHAM, BRANDON J.
SANCHEZ BARBA, GABRIEL
YILMAZ, ISIKCAN
Assignee: APPLE INC
CPC Classifications: [{"code": "G06F1/1632", "inventive": true, "first": true, "tree": "[]"}, {"code": "G01N27/048", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1632", "inventive": true, "first": true, "tree": "[]"}, {"code": "H02M3/158", "inventive": true, "first": false, "tree": "[]"}, {"code": "G01N27/223", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/28", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/30", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/182", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02M3/158", "inventive": true, "first": false, "tree": "[]"}, {"code": "G01N27/223", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1632", "inventive": true, "first": true, "tree": "[]"}, {"code": "G01N27/048", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 72663068