PATENT DOCUMENT

Publication Number: US-8542472-B2
Application Number: US-201113191275-A
Country: US
Kind Code: B2

Title: Protection circuitry for reversible connectors

Abstract:
An electronic device may include a connector port that accommodates reversible connector plugs. The connector port may include protection circuitry that protects other components in the electronic device from undesired power supply voltages. The protection circuitry may form a first branch and a second branch opposite to the first branch. The protection circuitry may receive control signals from power polarity detection circuitry. The power polarity detection circuitry may detect the presence of power supply voltages at the first branch and the second branch. In response to detecting the presence of a power supply voltage at a given branch, the power polarity detection circuitry may disable a power supply signal path through the opposite branch and enable a power supply signal path through the given branch.

Claims:
What is claimed: 
     
       1. Connector port power protection circuitry coupled between electrical components and first and second contacts in a first connector, wherein the first connector is configured to mate with a second connector having third and fourth contacts in a first orientation in which the first contact is coupled to the third contact and the second contact is connected to the fourth contact and a second orientation in which the first contact is coupled to the fourth contact and the second contact is connected to the third contact:
 a first circuit branch coupled between the first contact and the electrical components; 
 a second circuit branch coupled between the second contact and the electrical components; and 
 connector orientation detection circuitry coupled to the first and second connector contacts, wherein the connector orientation detection circuitry provides control signals to the first and second circuit branches so that the first circuit branch isolates the first contact from the electrical components in response to detection of the first orientation and so that the second circuit branch isolates the second contact from the electrical components in response to detection of the second orientation. 
 
     
     
       2. The connector port power protection circuitry defined in  claim 1  further comprising a power supply node and a ground node coupled to the electrical components, wherein the first circuit branch comprises a first reverse voltage protection circuit coupled between the first contact and power supply node and wherein the second circuit branch comprises a second reverse voltage protection circuit coupled between the second contact and the power supply node. 
     
     
       3. The connector port power protection circuitry defined in  claim 2  wherein the first circuit branch comprises a first over-voltage protection circuit coupled between the first contact and power supply node and wherein the second circuit branch comprises a second over-voltage protection circuit coupled between the second contact and the power supply node. 
     
     
       4. The connector port power protection circuitry defined in  claim 3  wherein the first circuit branch comprises a first intermediate node, wherein the first over-voltage protection circuit is coupled between the power supply node and the first intermediate node, wherein the first reverse voltage protection circuit is coupled between the first intermediate node and the first contact, wherein the second circuit branch comprises a second intermediate node, wherein the second over-voltage protection circuit is coupled between the power supply node and the second intermediate node, and wherein the second reverse voltage protection circuit is coupled between the second intermediate node and the second contact. 
     
     
       5. The connector port power protection circuitry defined in  claim 4  further comprising control signal paths over which the connector orientation detection circuitry provides the first and second over-voltage protection circuits and the first and second reverse voltage protection circuits with control signals. 
     
     
       6. The connector port power protection circuitry defined in  claim 4  wherein the first reverse voltage protection circuit has a first terminal coupled to the first contact, a second terminal that receives control signals from the connector orientation detection circuitry, and a third terminal coupled to the first intermediate node, a diode coupled between the first intermediate node and the first contact, wherein the diode is configured to block current flow when the first contact has a lower voltage than the first intermediate node and wherein the second reverse voltage protection circuit has a first terminal coupled to the second contact, a second terminal that receives control signals from the connector orientation detection circuitry, and a third terminal coupled to the second intermediate node, a diode coupled between the second intermediate node and the second contact, wherein the diode is configured to block current flow when the second contact has a lower voltage than the second intermediate node. 
     
     
       7. The connector port power protection circuitry defined in  claim 4  wherein the first reverse voltage protection circuit further comprises a transistor that is coupled between the first contact and the first intermediate node and that receives control signals from the connector orientation detection circuitry and wherein the second reverse voltage protection circuit further comprises a transistor that is coupled between the second contact and the second intermediate node and that receives control signals from the connector orientation detection circuitry. 
     
     
       8. The connector port power protection circuitry defined in  claim 7  wherein the first reverse voltage protection circuit further comprises a Zener diode coupled between the second and third terminals of the first reverse voltage protection circuit and wherein the second reverse voltage protection circuit further comprises a Zener diode coupled between the second and third terminals of the second reverse voltage protection circuit. 
     
     
       9. The connector port power protection circuitry defined in  claim 4  wherein the first over-voltage protection circuit has a diode coupled between the first intermediate node and the power supply node and wherein the second over-voltage protection circuit has a diode coupled between the second intermediate node and the power supply node. 
     
     
       10. The connector port power protection circuitry defined in  claim 9  wherein the first over-voltage protection circuit has a transistor coupled between the first intermediate node and the power supply node and wherein the second over-voltage protection circuit has a transistor coupled between the second intermediate node and the power supply node. 
     
     
       11. A method of protecting internal device components that are coupled by protection circuitry to a connector that is operable to receive a mating connector in first and second orientations, comprising:
 with the connector, receiving the mating connector; 
 monitoring the connector port with connector orientation detection circuitry; 
 using the connector orientation detection circuitry to direct a first branch of the protection circuitry to block current flow in response to detecting that the mating connector is in the first orientation; and 
 using the connector orientation detection circuitry to direct a second branch of the protection circuitry to block current flow in response to detecting that the mating connector is in the second orientation. 
 
     
     
       12. The method defined in  claim 11  wherein the connector has first and second contacts, wherein the first branch is coupled between the first contact and the internal device components, wherein the second branch is coupled between the second contact and the internal device components, and wherein monitoring the connector port comprises monitoring voltages on the first and second contacts with the connector orientation detection circuitry. 
     
     
       13. The method defined in  claim 12  wherein using the connector orientation detection circuitry to direct the first branch of the protection circuitry to block current flow in response to detecting that the mating connector is in the first orientation comprises controlling a transistor in a reverse voltage protection circuit in the first branch and wherein using the connector orientation detection circuitry to direct the second branch of the protection circuitry to block current flow in response to detecting that the mating connector is in the second orientation comprises controlling a transistor in a reverse voltage protection circuit in the second branch. 
     
     
       14. The method defined in  claim 13  further comprising:
 in response to detecting that the mating connector is in the first orientation, using the connector orientation detection circuitry to direct the second branch of the protection circuitry to pass current between the second contact and the internal device components; and 
 in response to detecting that the mating connector is in the second orientation, using the connector orientation detection circuitry to direct the first branch of the protection circuitry to pass current between the first contact and the internal device components. 
 
     
     
       15. Protection circuitry coupled between a connector in an electronic device and internal device components in the electronic device, wherein the connector has at least first and second contacts and a ground contact, wherein the connector is configured to mate with a mating connector having third and fourth contacts and a mating ground contact in a first orientation in which the first contact is connected to the third contact, the second contact is connected to the fourth contact, and the ground contact is connected to the mating ground contact and a second orientation in which the first contact is connected to the fourth contact, the second contact is connected to the third contact, and the ground contact is connected to the mating ground contact, comprising:
 a power supply node and a ground node configured to supply power to the internal device components, wherein the ground node is coupled to the ground contact; 
 a first protection circuit branch coupled between the power supply node and the first contact; 
 a second protection circuit branch coupled between the power supply node and the second contact; and 
 connector orientation detection circuitry coupled to the first and second contacts and configured to detect whether the mating connector has the first orientation or the second orientation, wherein the connector orientation detection circuitry provides control signals to the first and second circuit branches, 
 wherein the first and second protection circuit branches each include a corresponding over-voltage protection circuit. 
 
     
     
       16. The protection circuitry defined in  claim 15  wherein the first and second protection circuit branches each include a corresponding reverse voltage protection circuit. 
     
     
       17. Protection circuitry coupled between a connector in an electronic device and internal device components in the electronic device, wherein the connector has at least first and second contacts and a ground contact, wherein the connector is configured to mate with a mating connector having third and fourth contacts and a mating ground contact in a first orientation in which the first contact is connected to the third contact, the second contact is connected to the fourth contact, and the ground contact is connected to the mating ground contact and a second orientation in which the first contact is connected to the fourth contact, the second contact is connected to the third contact, and the ground contact is connected to the mating ground contact, comprising:
 a power supply node and a ground node configured to supply power to the internal device components, wherein the ground node is coupled to the ground contact; 
 a first protection circuit branch coupled between the power supply node and the first contact; 
 a second protection circuit branch coupled between the power supply node and the second contact; and 
 connector orientation detection circuitry coupled to the first and second contacts and configured to detect whether the mating connector has the first orientation or the second orientation, wherein the connector orientation detection circuitry provides control signals to the first and second circuit branches, 
 wherein the connector orientation detection circuitry is configured to: 
 generate control signals that direct the first protection circuit branch to block current flow through the first connector in response to detection of the mating connector in the first orientation; and 
 generate control signals that direct the second protection circuit branch to block current flow through the second connector in response to detection of the mating connector in the second orientation. 
 
     
     
       18. The protection circuitry defined in  claim 17  wherein the first protection circuit branch includes at least two transistors and wherein the second protection circuit branch includes at least two transistors. 
     
     
       19. The protection circuitry defined in  claim 18  wherein the connector comprises six contacts in addition to the ground contact and wherein the six contacts include the first and second contacts.

Description:
BACKGROUND 
     This relates generally to electronic devices with connector ports, and more particularly, electronic devices with reversible connector ports that have protection circuitry. 
     Handheld electronic devices and other portable electronic devices are becoming increasingly popular. Examples of handheld devices include handheld computers, tablet computers, media players, cellular telephones, and hybrid devices that include the functionality of multiple devices of this type. 
     Electronic devices such as handheld electronic devices often include connector ports. For example, some cellular telephones include 30-pin connector ports. Connector ports such as these may be used as input-output data ports and may receive connector plugs (sometimes referred to herein as mating plugs). Electronic devices may use a connector port to communicate with accessories such as audio speaker systems, computing docks, and power adapters. 
     Conventional connector ports (e.g., female connectors) are designed to receive connector plugs (e.g., male connectors) with a predetermined orientation. However, this may be inconvenient for users who must determine the appropriate orientation before inserting a conventional connector plug into a corresponding conventional connector. 
     Therefore, it would be desirable to provide improved connector ports for electronic devices. 
     SUMMARY 
     Electronic devices may include connector ports that accommodate reversible connector plugs (sometimes referred to herein as female connectors). Connector ports may be 6-pin connector ports that receive corresponding 6-pin connector plugs (sometimes referred to herein as male connectors or mating plugs). A reversible connector plug may be inserted into a connector port of an electronic device with a first orientation and a second orientation. The connector port may convey and receive data signals and power supply voltages from the connector plug over conductive paths (e.g., contacts). The connector port may provide the data signals and power supply voltages to other components of the electronic device. 
     The connector port may include associated connector circuitry. The connector circuitry may include protection circuitry that protects the other components from undesired power supply voltages. The protection circuitry may include reverse voltage protection circuitry that protects the components from negative power supply voltages. The protection circuitry may include over-voltage protection circuitry that protects the other components from undesired positive power supply voltages. 
     The protection circuitry may form a first branch and a second branch opposite to the first branch. The first branch may be coupled to a first power supply path of the connector plug. The second branch may be coupled to a second power supply path of the connector plug. 
     The protection circuitry may receive control signals from power polarity detection circuitry. The power polarity detection circuitry may detect the presence of power supply voltages at the first branch and the second branch. In response to detecting the presence of a power supply voltage at a given branch, the power polarity detection circuitry may disable a power supply signal path through the opposite branch and enable a power supply signal path through the given branch. 
     Further features of the present invention, its nature and various advantages will be more apparent from the accompanying drawings and the following detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram of an illustrative electronic device with a connector port that may be coupled to an accessory device via a mating connector in accordance with an embodiment of the present invention 
         FIG. 2  is a schematic diagram of an illustrative reversible 6-pin connector port in accordance with an embodiment of the present invention. 
         FIG. 3A  is a schematic diagram of an illustrative reversible 6-pin mating connector with a first orientation in accordance with an embodiment of the present invention. 
         FIG. 3B  is a schematic diagram of an illustrative reversible 6-pin mating connector with a second orientation in accordance with an embodiment of the present invention. 
         FIG. 4  is a schematic diagram of a conventional 30-pin connector port. 
         FIG. 5  is a schematic diagram of illustrative power protection circuitry that may be used in a reversible connector port. 
         FIG. 6  is a flow chart of illustrative steps that may be performed by power polarity detection circuitry to configure power protection circuitry to accommodate a reversible connector. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of the present invention relate to electronic devices with connector ports. Electronic devices such as laptop computers, tablet computing devices, cellular telephones, music players, or other portable electronic devices may contain connector ports for communicating with other electronic devices. A given connector port (sometimes referred to herein as a female connector) may receive a connector plug (sometimes referred to herein as a male connector) with a corresponding connector cable that may electrically couple the given connector port to the connector port of another electronic device. Each port may contain conductive paths (e.g., metal traces, conductive pins, or contacts) through which data signals or power supply signals may be transferred between the port and corresponding conductive paths of the connector plug. For example, a tablet computing device may contain a connector port used to communicate with a speaker dock (e.g., by providing audio signals to the speaker dock and receiving power supply signals from the speaker dock). The speaker dock may contain power supply circuitry that provides power supply voltages to the tablet computing device through conductive paths of the connector port, connector cable, and connector plug. 
     Conventional connector ports receive connector plugs with a predetermined orientation. In other words, the conductive paths of the connector port couple to predetermined pins on a connector plug. For proper operation, each of the 30 conductive paths (e.g., pins or metal contacts) of a conventional 30-pin connector port couple to predetermined locations (e.g., pins or metal contacts) of a conventional 30-pin connector plug (e.g., a male mating connector). 
     It may be desirable to provide connector ports that accommodate reversible connector plugs (i.e., connector ports that accommodate connector plugs with multiple orientations). Connector ports that accommodate reversible connector plugs may sometimes be referred to herein as reversible connector ports. An illustrative electronic device  10  with a reversible connector port  20 A is shown in  FIG. 1 . 
     As shown in  FIG. 1 , electronic device  10  may include a display  12  and a button  14 . Electronic device  10  may include a reversible connector port  20 A suitable for receiving a reversible connector plug  22 A. Reversible connector port  20 A may be a 6-pin connector port (e.g., a 6-pin female connector) suitable for receiving a 6-pin mating connector. Mating connector  22 A may have conductive traces  23  (or contacts) for electrically coupling connector plug  22 A to connector port  20 A (e.g., connector port  20 A may contain conductive contacts that electrically couple with conductive contacts  23  when mating connector  22 A is inserted into connector port  20 A). Connector plug  22 A may be coupled to a connector plug  22 B via connector cable  24 . Connector cable  24  may convey signals from connector plug  22 A to connector plug  22 B. Connector plug  22 B may be an independent connector plug or built in to an accessory device  30 . For example, connector plug  22 B may be coupled to a connector port  20 B or built into accessory device  30 . Accessory device  30  may be a device suitable for communicating with or supplying power to electronic device  10 . Examples of suitable accessory devices include audio speaker docks, laptop computers, alternating current (AC) power adapters, etc. Accessory device  30  may convey data signals or power supply signals to electronic device  10  via connector plug  22 B, connector cable  24 , and connector plug  22 A. 
     An illustrative reversible connector port  20 A for receiving reversible 6-pin connector plugs is shown in  FIG. 2 . As shown in  FIG. 2 , reversible connector port  20 A may contain conductive paths P 1 _A, Dx_A, B_A, A_A, Dy_A, and P 2 _A. Conductive paths Dx_A, B_A, A_A, and Dy_A may be used to convey signals such as data signals from reversible connector port  20 A to a connector plug  22 . Conductive paths P 1 _A and P 2 _A (sometimes referred to herein as power supply paths) may be used to receive power supply signals from an accessory device  30 . For example, an accessory device  30  that is coupled to electronic device  10  via connector plug  22 A and reversible connector port  20 A may supply a power supply voltage via conductive paths P 1 _A or P 2 _A. A ground signal may be provided for connector port  20 A through a metal grounding shell  40 . Metal grounding shell  40  may provide structural support for receiving a connector plug  22 A. 
     An illustrative 6-pin connector plug  22 A for use with reversible connector port  20 A is shown in  FIGS. 3A and 3B . 6-pin connector plug  22 A may contain conductive paths P 1 _B, Dx_B, B_B, A_B, Dy_B, and optional power supply path P 2 _B for coupling to a connector port  20 A. To convey a ground signal between connector plug  22 A and connector port  20 A, connector plug  22 A may contain a metal grounding shell  42  that couples to metal grounding shell  40  of connector port  20 A. 
     Connector port  20 A may receive 6-pin connector plug  22 A with a first orientation shown in  FIG. 3A . In the arrangement of  FIG. 3A , the conductive paths of connector port  20 A may be coupled to corresponding conductive paths of connector plug  22 A (i.e., conductive path P 1 _A may be coupled to conductive path P 1 _B, conductive path Dx_A may be coupled to conductive path Dx_B, conductive path B_A may be coupled to conductive path B_B, conductive path A_A may be coupled to conductive path A_B, and conductive path Dy_A may be coupled to conductive path Dy_B). In this arrangement, a positive power supply voltage may be conveyed between connector port  20 A and connector plug  22 A via conductive paths (e.g., contacts) P 1 _A and P 1 _B, while conductive paths P 2 _A and P 2 _B may be left floating (i.e., not driven with a power supply voltage). 
     Connector port  20 A may receive a 6-pin connector plug  22 A with a second orientation shown in  FIG. 3B . The second orientation may correspond to a user physically rotating connector plug  22 A 180 degrees relative to the orientation of  FIG. 3A  (or vice versa). Inserting connector plug  22 A into connector port  20 A with the second orientation may be referred to as reversing connector plug  22 A. In this arrangement, the conductive paths of connector port  20 A may be coupled to different conductive paths of connector plug  22 A relative to the first orientation. As shown in  FIG. 3B , conductive path Dx_A may be coupled to conductive path Dy_B, conductive path B_A may be coupled to conductive path A_B, conductive path A_A may be coupled to conductive path B_B, conductive path Dy_A may be coupled to conductive path Dx_B, and power supply path P 2 _A may be coupled to power supply path P 1 _B, while power supply paths P 1 _A and P 2 _B may be left floating. 
     The conductive paths of connector port  20 A may be coupled to different paths of connector plug  22 A depending on the orientation of connector plug  20 B. When connector plug  22 A is connected with the first orientation, power supply path P 1 _A may be coupled to path P 1 _B and power supply path P 2 _A may be floating. When connector plug  22 B is connected with the second orientation, power supply path P 1 _A may be floating and power supply path P 2 _A may be coupled to path P 1 _B. A connector port  20 A that accommodates the first connector plug orientation and the second connector plug orientation may be referred to as a reversible connector or a connector port that supports reversible connections. 
     Conventional connector ports such as 30-pin connector ports do not support reversible connections. A conventional 30-pin connector port  100  receiving a 30-pin connector plug is shown in  FIG. 4 . As shown in  FIG. 4 , conventional 30-pin connector port  100  contains paths for receiving a ground voltage G and power supply voltage Vp from 30-pin connector plug  102 . Data signals are conveyed between the 30-pin connector plug and conventional connector port  100  via paths  104 . Conventional 30-pin connector port  100  contains reverse voltage protection circuitry  106 , control circuitry  108 , and over-voltage protection circuitry  110 . Reverse voltage protection circuitry  106  provides protection against a negative voltage Vp (relative to ground) received from 30-pin connector plug  102  (i.e., reverse voltage protection circuitry  106  prevents negative voltages Vp from passing through). Control circuitry  108  detects a voltage signal at the output of reverse voltage protection circuitry  106  and drives over-voltage protection circuitry  110  with an enable signal to allow the output of reverse voltage protection circuitry  106  to pass through over-voltage protection circuitry  110 . Over-voltage protection circuitry  110  protects against large voltages Vp (i.e., over-voltage protection circuitry  110  blocks large voltages Vp that could damage electronic components  112 ). Conventional connector port  100  conveys input power supply voltage Vp to electronic components  112  as an output power supply voltage Vbus. 
     Conventional 30-pin connector port  100  receives 30-pin connector plugs with a predetermined orientation. Conventional 30-pin connector ports require a power supply signal to appear at the input of reverse voltage protection circuitry  106  and data signals to appear at predetermined locations on paths  104 . If a conventional 30-pin connector port  100  receives a 30-pin connector plug with an incorrect orientation, electronic components  112  can be provided with inappropriate power supply signals that damage electronic components  112 . Conventional connector ports include mechanisms that physically protect against connector plugs that are inserted with incorrect orientations. 
     To accommodate reversible connections, a connector port may detect the orientation of an inserted connector plug and use the detected orientation to configure connector port circuitry. In the arrangement of  FIG. 5 , a connector port  20 A may be provided with power polarity detection circuitry  200  (sometimes referred to herein as connector orientation detection circuitry) and protection circuitry  202 A and  202 B to accommodate reversible connections. 
     Connector port  20 A may include a ground power supply path  40  that provides a power supply ground voltage at ground power supply node  261  for components  280 . Connector port  20 A may receive a mating connector (not shown) that provides a power supply voltage relative to the ground power supply voltage provided via ground supply path  40 . Ground power supply path  40  may be formed from a symmetrical grounding shell  40  that couples to a corresponding symmetrical grounding shell of the mating connector. Connector port  20 A may receive a mating connector in a first orientation and a second orientation. In the first orientation, the mating connector may provide a ground voltage via path  40  and a power supply voltage via power supply path P 1 _A. In the second orientation, the mating connector may provide a ground voltage via path  40  and a power supply voltage via power supply path P 1 _B. 
     A first branch B 1  may be formed from the circuitry associated with a power supply signal path between an input node  250  (e.g., an input power supply node) and an output node  260  (i.e., the circuitry associated with the signal path through reverse voltage protection circuitry  204 A and over-voltage protection circuitry  206 A). 
     Protection circuitry  202 A may be coupled between input node  250  (e.g., an input power supply node) and output node  260  (e.g., an output power supply node). Input node  250  may be coupled to power supply path P 1 _A of connector port  20 A. Protection circuitry  202 A may contain reverse voltage protection circuitry  204 A coupled between input node  250  and an intermediate node  252  (e.g., an intermediate power supply node). Protection circuitry  202 A may contain over-voltage protection circuitry  206 A coupled between output node  260  and intermediate node  252 . 
     Reverse voltage protection circuitry  204 A may include a diode D 1 A and a transistor P 1 A (e.g., a p-type transistor) coupled in parallel between input node  250  and intermediate node  252 . Reverse voltage protection circuitry  204 A may include an input control node  254  through which a control signal may be supplied to the gate of transistor P 1 A (e.g., a P 1 _DIS control signal supplied by power polarity detection circuitry  200 ). A diode D 2 A (e.g., a zener diode or other diodes with desirable reverse breakdown voltages) may be coupled between intermediate node  252  and control node  254 . A resistor R 1 A may be coupled between control node  254  and a ground terminal. 
     Over-voltage protection circuitry  206 A may include a diode D 3 A and an n-type transistor N 1 A coupled between output node  260  and intermediate node  252 . Over-voltage protection circuitry  206 A may be provided a control signal via the gate of transistor N 1 A (e.g., a P 1 _EN control signal may be provided to the gate of transistor N 1 A by power polarity detection circuitry  200 ). 
     A second branch B 2  may be formed from the circuitry associated with a signal path between an input node  270  (e.g., an input power supply node) and output node  260  (i.e., the circuitry associated with a signal path through reverse voltage protection circuitry  204 B and over-voltage protection circuitry  206 B). 
     Protection circuitry  202 B may be coupled between input node  270  and output node  260 . Input node  270  may be coupled to power supply path P 2 _A of connector port  20 A. Protection circuitry  202 B may contain reverse voltage protection circuitry  204 B coupled between input node  270  and an intermediate node  272 . Protection circuitry  202 B may contain over-voltage protection circuitry  206 B coupled between output node  260  and intermediate node  272  (e.g., an intermediate power supply node). 
     Reverse voltage protection circuitry  204 B may include a diode D 1 B and a transistor P 1 B (e.g., a p-type transistor) coupled in parallel between input node  270  and intermediate node  272 . Reverse voltage protection circuitry  204 B may include an input control node  274  through which a control signal may be supplied to the gate of transistor P 1 B (e.g., a P 2 _DIS control signal supplied by power polarity detection circuitry  200 ). A diode D 2 B (e.g., a zener diode) may be coupled between intermediate node  272  and control node  274 . A resistor R 1 B may be coupled between control node  274  and a ground terminal. 
     Over-voltage protection circuitry  206 B may include a diode D 3 B and an n-type transistor N 1 B coupled between output node  260  and intermediate node  272 . Over-voltage protection circuitry  206 B may be provided a control signal via the gate of transistor N 1 B (e.g., a P 2 _EN control signal may be provided to the gate of transistor N 1 B by power polarity detection circuitry  200 ). 
     The first and second branches may provide paths through which a power supply voltage may be conveyed from ports P 1 _A or P 2 _A to other components  280  coupled to output node  260  (e.g., components such as processing circuitry, storage circuitry, communications circuitry, or other components of electronic device  10 ). For normal operation, components  280  may require power supply voltages that are within a predetermined range (e.g., power supply voltages between 4.25 V and 6 V). Reverse voltage protection circuitry  204  and over-voltage protection circuitry  206  may provide protection against power supply voltages that are outside of the predetermined range of voltages. 
     Reverse voltage protection circuitry  204  of each branch may provide protection against voltages that are negative. For example, the gate of p-type transistor P 1 A may be tied to ground through resistor R 1 A to prevent current flow through transistor P 1 A when the voltage at input node  250  is less than zero (i.e., the source-gate voltage may be insufficient to activate transistor P 1 A). At negative input voltages, diode D 1 A may be reverse-biased and prevent current flow between input node  250  and intermediate node  252 . 
     Over-voltage protection circuitry  206  of each branch may provide protection against power supply voltages that are larger than the predetermined voltage range. For example, if a large input voltage (e.g., a voltage larger than the predetermined voltage range) is supplied to input node  250  via power supply path P 1 _A, diode D 1 A may be forward-biased and convey the input voltage from input node  250  to intermediate node  252 . Over-voltage protection circuitry  206 A may prevent the large input voltage from being conveyed to output node  260 . To prevent the large input voltage from being conveyed to output node  260 , the gate of transistor N 1 A may be supplied with an appropriate voltage (e.g., 0 V) that prevents current from flowing between intermediate node  252  and output node  260  (i.e., the gate of n-type transistor N 1 A may be supplied with a voltage of 0 V so that the gate-source voltage is insufficient to activate transistor N 1 A). 
     Control signals may be provided by power protection circuitry  200  to over-voltage protection circuitry  206  to protect against power supply voltages that are between zero and the lower end of the predetermined voltage range (e.g., to protect against power supply voltages that are insufficient to properly power components  280 ). At these voltages, diode D 3 A may be reverse-biased and the current flow between intermediate node  252  and output node  260  may be determined by n-type transistor N 1 A (e.g., diode D 3 A may be reverse-biased by an input voltage of 2 V supplied by power supply path P 1 _A). To prevent current flow at these voltages, the gate of transistor N 1 A may be supplied with an appropriate voltage (e.g., 0 V) so that the gate-source voltage of transistor N 1 A is insufficient to activate transistor N 1 A. 
     It may be desirable to have different threshold voltages for activation of transistor N 1 A and deactivation of transistor N 1 A. For example, it may be desirable to provide a control signal to the gate of transistor N 1 A that activates transistor N 1 A when the power supply voltage is greater than 4.25 V and deactivates transistor N 1 A when the power supply voltage is less than 2.8 V. 
     Zener diodes D 2 A and D 2 B may protect respective transistors P 1 A and P 1 B from large input voltages. For example, if the power supply voltage at input P 1 _A is greater than the predetermined voltage range, the source-gate voltage of p-type transistor P 1 A may be determined by the reverse breakdown voltage of zener diode D 2 A. The use of zener diode D 2 A may protect transistor P 1 A by limiting the maximum voltage drop across the source terminal of transistor P 1 A and the gate terminal of transistor P 1 A. 
     The principles by which protection circuitry  202 A of branch B 1  are operated are applicable to protection circuitry  202 B of branch B 2 . It should be understood that protection circuitry  202 B may be operated in the same manner as protection circuitry  202 A to provide voltage protection in the case that a power supply voltage is provided to input node  270  (e.g., in the case that a connector plug  22 A is connected with a reversed orientation and power supply path P 1 _B is coupled to power supply path P 2 _A instead of power supply path P 1 _A). 
     Control signals may be provided to over-voltage protection circuitry and reverse voltage protection circuitry by power polarity detection circuitry  200 . Power polarity detection circuitry  200  may provide output control signals P 1 _EN to the gate of transistor N 1 A of branch  1 , P 1 _DIS to control node  254  of branch  1 , P 2 _EN to the gate of transistor N 1 B of branch  2 , and P 2 _DIS to control node  274  of branch  2 . Power polarity detection circuitry  200  may have inputs that are coupled to power supply paths P 1 _A and P 2 _A. 
     When no accessory device  30  is connected to electronic device  10  (e.g., when no connector plug  22 A is coupled to connector port  20 A), power polarity detection circuitry  200  may set the P 1 _EN and P 2 _EN control signals to a ground voltage and the P 1 _DIS and P 2 _DIS control signals to high impedance (HiZ). By setting the P 1 _EN and P 2 _EN control signals to the ground voltage, transistor N 1 A of branch  1  and transistor N 1 B of branch  2  may be disabled. By setting the P 1 _DIS and P 2 _DIS control signals to high impedance (e.g., by disconnecting the P 1 _DIS and P 2 _DIS control signals), the gate voltage of transistor P 1 A may be determined by the breakdown voltage of zener diode D 2 A (at high input voltages) and grounding resistor R 1 A and the gate voltage of transistor P 1 B may be determined by the breakdown voltage of zener diode D 2 B and grounding resistor R 1 B. 
     When an accessory device  30  that supplies a valid power supply voltage (e.g., a power supply voltage within the normal operating voltage range of device  10 ) is connected to electronic device  10 , power polarity detection circuitry  200  may perform the steps of the flowchart shown in  FIG. 6 . 
     In step  302 , power polarity detection circuitry  200  may detect a power supply voltage on a first branch. For example, power polarity detection circuitry  200  may use comparator circuitry to determine if a power supply voltage is being provided on path P 1 _A to branch B 1  or if a power supply voltage is being provided on path P 2 _A to branch B 2 . 
     In step  304 , power polarity detection circuitry may drive a disable signal to the opposite branch in response to detecting a power supply voltage for the first branch. For example, if a power supply voltage with voltage 5 V is detected on path P 1 _A, power polarity detection circuitry may provide a P 2 _DIS control signal with voltage 5 V to input node  274 . By supplying input node  274  with a 5 V control signal, transistor P 1 B may be deactivated (i.e., the source-gate voltage of transistor P 1 B may be less than the activation voltage threshold of transistor P 1 B). 
     In response to detecting a power supply voltage for a branch, power polarity detection circuitry  200  may activate charge pump circuitry. The charge pump circuitry may provide a boosted voltage relative to the detected power supply voltage that may be used to drive the input gate of transistor N 1 A or transistor N 1 B. For example, if a 5 V power supply voltage was detected at the input to branch B 1  in step  302 , then the charge pump circuitry may provide a boosted voltage that is equal to the 5 V input power supply voltage plus the activation threshold voltage of transistor N 1 B (e.g., 6 V). 
     The charge pump circuitry may require time to stabilize (i.e., it may take time to stabilize the boosted voltage produced by the charge pump circuitry). In step  306 , after the charge pump circuitry output is stabilized, the first branch may be enabled (e.g., by sending a P 1 _EN) to allow the power supply voltage to be conveyed to other components of electronic device  10 . For example, if a power supply voltage within a predetermined operating range was detected at the input to branch B 1  in step  302 , then diode D 1 A and transistor P 1 A may convey the power supply voltage to intermediate node  252 . After the charge pump circuitry is stabilized, transistor N 1 A may be activated by the boosted voltage and the power supply voltage may be conveyed from intermediate node  252  to output node  260 . 
     By disabling the opposite branch in step  304 , protection may be provided against undesired current flow through the opposite branch. For example, when an output voltage is conveyed through a first branch (e.g., branch B 1 ) to output node  260 , the output voltage may be conveyed to intermediate node  272  of the opposite branch (i.e., a positive power supply voltage at output node  260  may forward bias diode D 3 B and be conveyed to intermediate node  272  of branch B 2  through diode D 3 B). Disabled transistor P 1 B may prevent undesired current flow from the intermediate node to input node  270 . 
     The foregoing is merely illustrative of the principles of this invention and various modifications can be made by those skilled in the art without departing from the scope and spirit of the invention.

Metadata:
Filing Date: 20110726
Publication Date: 20130924
Grant Date: 20130924
Priority Date: 20110726
Inventors: MULLINS SCOTT
Assignee: APPLE INC
CPC Classifications: [{"code": "H01R24/60", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01R13/64", "inventive": false, "first": false, "tree": "[]"}, {"code": "H02H11/002", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 46506629