Electronic device and power reception control method thereof

Abstract

Embodiments of the present disclosure relate to an electronic device and a power reception control method thereof. When a USB Type-C legacy cable is used, a sink makes an excessive power reception request. The electronic device includes a first terminal and a second terminal connected to the cable, a detection circuit for detecting a voltage of the first terminal and the second terminal, and the first terminal or the second terminal detected by the detection circuit. It is provided with a controller that determines the type of the cable based on the terminal voltage, and according to the type of the cable, confirms the power supply capability of an external electronic device connected via the cable.

Description

[0001] Cross-reference to related applications

[0002] The publication of Japanese Patent Application No. 2019-194773, filed on October 25, 2019 (including the specification, drawings and abstract), is incorporated herein by reference in its entirety. Technical Field

[0003] The present invention relates to an electronic device, and more specifically, to an electronic device having USB (Universal Serial Bus) Type-C control functionality, and to a system using the electronic device. Background Technology

[0004] The technology of using communication cables to provide power between devices is becoming increasingly common. For example, USB (Universal Serial Bus) is one of the standards used to connect peripheral devices to information devices such as computers, and it can provide power while the information devices are communicating.

[0005] The standards specify the electrical power that can be provided by USB. For example, in the USB 2.0 standard, the power that can be provided by the standard is defined as 5V voltage and 500mA current. Furthermore, in the USB 3.x standard (x is any one of 0, 1, and 2, and is the same below), the electrical power that can be provided by the standard is defined as 5V voltage and 900mA current. When providing electrical power equal to or higher than that specified by the USB 2.0 and USB 3.x standards, standards such as USB BC (Battery Charging Specification) and USB PD (Power Delivery) are required.

[0006] The specification stipulates that when providing and receiving power equal to or higher than the standard power supplied as specified in the USB 2.0 and USB 3.x standards, a USB Type-C to USB Type-C cable with USB Type-C connectors at both ends should be used, instead of USB BC or USB PD. USB Type-C is one of the standards for USB cables and connectors, and is compatible with data input / output, power supply, and video output.

[0007] In USB Type-C, a configuration channel signal (hereinafter referred to as the CC signal) is defined, and a terminal (configuration channel terminal) for the CC signal is provided in the USB Type-C connector. To determine its role, the source is a power supply device that connects the configuration channel terminal (hereinafter referred to as the CC terminal) to the power supply line using a pull-up resistor, and the destination is a power receiving device that connects the CC terminal to the GND line using a pull-down resistor. Therefore, the power sending and receiving devices corresponding to USB Type-C detect the connection status by monitoring the voltage of the CC terminal.

[0008] Similarly, USB Type-C compliant sources are limited to standard power supply: 5V-1.5A or 5V-3A. The pull-up resistor values ​​correspond to these power supply capacities. For example, the pull-up resistor is 56kΩ for standard power supply; 22kΩ for 5V-1.5A; and 10kΩ for 5V-3A. On the other hand, the sink's pull-down resistor is limited to 5.1kΩ. Therefore, the sink detects the connection to the source and confirms the source's power supply capability by measuring the voltage level at the CC terminal.

[0009] The following is a publicly available technology.

[0010] [Non-Patent Literature 1] USB Type-C™ Cable and Connector Specification Revision 1.4 Summary of the Invention

[0011] In USB Type-C, in addition to the USB Type-C to USB Type-C cables described above, USB cables with a USB Type-C connector at one end and an existing USB connector (USB 2.0 connector or USB 3.x connector) at the other end are also defined (hereinafter referred to as USB Type-C legacy cables) to ensure connectivity with existing USB ports. Examples include "USB Type-C to Standard-A cables." These USB Type-C legacy cables are used, for example, to connect a host device with a pre-existing interface to a peripheral device with a USB Type-C port. Power supply using USB Type-C legacy cables is limited to USB standard power supply.

[0012] As mentioned above, in a source corresponding to USB Type-C, the CC terminal is connected to a pull-up resistor, but a source corresponding to USB Type-C does not have a CC terminal. Therefore, in USB Type-C, when using a USB Type-C legacy cable to connect a USB Type-C incompatible source to a USB Type-C compatible destination, the USB Type-C compatible destination is limited to connecting a pull-up resistor to a signal line, which is then connected to the CC terminal within the USB Type-C legacy cable, to verify the source's power supply capability. As mentioned above, since the power tolerance when using a USB Type-C legacy cable is limited to the standard USB supply power, the pull-up resistor in the cable must have a resistance value of 56kΩ, corresponding to the standard USB supply power.

[0013] However, if the pull-up resistor value does not meet the power supply limits specified by the USB standard—for example, if the pull-up resistor value is less than 56kΩ—the receiver may demand excessive power. As a result, the source may be overloaded, leading to source failure.

[0014] Other objects and novel features will become apparent from the description and accompanying drawings in this specification.

[0015] According to one embodiment, the electronic device is connected to an external power supply device via a cable, a first terminal and a second terminal are connected to the cable, a detection circuit is used to detect the voltage of the first terminal and the second terminal, the type of cable is determined by the detection circuit based on the voltage of the first terminal or the second terminal, and a controller is used to perform a power supply capability verification of the external power supply device according to the type of cable.

[0016] An electronic device according to one embodiment can perform safe power reception without making a power reception request to an external power supply device at excessive power. Attached Figure Description

[0017] Figure 1 This is a block diagram illustrating an example configuration of a power feed system according to the first embodiment.

[0018] Figure 2 This is a block diagram illustrating the configuration of a receiver with a standard USB Type-C port.

[0019] Figure 3 This is a block diagram illustrating an example configuration of a power receiving device according to a first embodiment.

[0020] Figure 4 This is a state transition diagram illustrating an example of the state transitions of a power receiving device according to a first embodiment.

[0021] Figure 5 This is a block diagram illustrating an example configuration of a USB Type-C to Type-C cable.

[0022] Figure 6A This is a flowchart illustrating an exemplary power receiving control of a power receiving device according to a first exemplary embodiment.

[0023] Figure 6B This is a flowchart illustrating an exemplary power receiving control of a power receiving device according to a first exemplary embodiment.

[0024] Figure 7 This is a flowchart illustrating an example of power reception control of a modified power receiving device according to the first embodiment.

[0025] Figure 8 This is a block diagram illustrating an example configuration of an electronic device according to a second embodiment.

[0026] Figure 9 This is a state transition diagram illustrating an example of the state transitions of an electronic device according to a second embodiment.

[0027] Figure 10A This is a flowchart illustrating an example of power receiving control of an electronic device according to a second embodiment.

[0028] Figure 10B This is a flowchart illustrating an example of power receiving control of an electronic device according to a second embodiment. Detailed Implementation

[0029] In the following description, an electronic device according to one embodiment will be described in detail with reference to the accompanying drawings. In the specification and drawings, identical or corresponding components are indicated by the same reference numerals, and repeated descriptions thereof are omitted. In the drawings, calibrations may be omitted or simplified for ease of description. Furthermore, at least a portion of each embodiment can be arbitrarily combined with each other.

[0030] (Example 1)

[0031] In the following description, Embodiment 1 will be described with reference to the accompanying drawings.

[0032] Figure 1 This is a block diagram of a power supply system 1 according to a first embodiment. The power supply system 1 includes an electronic device 200 and an electronic device 300. The electronic device 200 is a power supply device (hereinafter referred to as source 200), and the electronic device 300 is a power receiving device (hereinafter referred to as receiver 300). The source 200 and receiver 300 are connected via a detachable USB cable 100.

[0033] The USB cable 100 has a connector, at least one end of which corresponds to USB Type-C. In addition to the VBUS line and GND line, the USB cable 100 also includes a CC line as a signal line. Figure 1 The following diagram illustrates a USB Type-C legacy cable, which has a USB Type-C-enabled connector at one end and a pre-existing USB connector (USB 2.0 or USB 3.x) at the other end. As described above, the CC line of the USB cable 100 is connected to a pull-up resistor Rpc to determine the connection status of USB Type-C compatible devices, etc., based on the voltage at the CC terminal.

[0034] Source 200 has a USB Type-C incompatible port. For example, a port that does not support USB Type-C is a USB 2.0 port or a USB 3.x port. Source 200 can be a USB host or a USB charger (AC adapter) with or without host functionality.

[0035] The device 300 includes a USB Type-C compatible port and a controller 303. The USB Type-C port has a VBUS terminal, a ground terminal, a first configuration channel terminal (CC1 terminal), and a second configuration channel terminal (CC2 terminal). The VBUS terminal and GND terminal are connected to the VBUS line and GND line of the USB cable 100. One of the CC1 and CC2 terminals is connected to the CC line of the USB cable 100. Figure 1 In the middle, the CC1 terminal is connected to the CC line. The SU300 can be a USB peripheral device.

[0036] First, refer to Figure 2 This describes the general configuration of a receiver with a USB Type-C port. Receiver 30 includes pull-down resistors Rd1 and Rd2, a controller 33, a detection circuit 33, a VBUS terminal, a GND terminal, a CC1 terminal, a CC2 terminal, and data terminals (D+ and D- terminals) corresponding to USB 2.0. The CC1 and CC2 terminals are terminated at ground potential GND via pull-down resistors Rd1 and Rd2. In the USB Type-C standard, the resistance of pull-down resistors Rd1 and Rd2 is limited to 5.1kΩ. The voltage at the CC1 and CC2 terminals is detected by the detector 32. The controller 33 identifies the connection status with the source based on the voltage levels of the CC1 and CC2 terminals. Furthermore, the controller 33 confirms the source's power supply capability based on the voltage connected to either the CC1 or CC2 terminal on the CC line and executes a power reception request corresponding to the source's power supply capability.

[0037] Figure 3This diagram illustrates the configuration of a receiver 300 with a USB Type-C port according to a first embodiment. Similar to receiver 30, receiver 300 includes pull-down resistors Rd1 and Rd2, a detector 302, a controller 303, a CC1 terminal, a CC2 terminal, and data terminals (D+ terminal, D- terminal). Receiver 300 also includes pull-up resistors Rp1 and Rp2, switches SW1 and SW2, and a register 304. Receiver 300 according to the first embodiment is an electronic device that only supports receiver functions corresponding to USB Type-C and does not support source functions. The CC1 terminal can be considered as the first terminal, and the CC2 terminal as the second terminal.

[0038] Terminal CC1 is connected to either the first pull-up resistor Rp1 or the first pull-down resistor Rd1 via the first switch SW1. Terminal CC2 is connected to either the second pull-up resistor Rp2 or the second pull-down resistor Rd2 via the second switch SW2. Switches SW1 and SW2 are controlled by controller 303. It should be noted that pull-down resistors Rd1 and Rd2 are used to identify the destination and are limited to 5.1kΩ according to the USB Type-C standard.

[0039] Detector 302 is connected to terminals CC1 and CC2, and detects the terminal voltages of terminals CC1 and CC2 respectively.

[0040] Controller 303 controls switches SW1 and SW2 to determine the connection status and cable type based on the terminal voltages of terminals CC1 and CC2 detected by detection circuit 302. Furthermore, controller 303 makes a power reception request based on the connection status and cable type.

[0041] Register 304 stores information indicating whether a connection to the source has been detected and whether the cable type has been determined.

[0042] Incidentally, the pull-up resistors Rp1 and Rp2, the pull-down resistors Rd1 and Rd2, and the detection circuit 302 can be integrated into a single semiconductor chip along with the controller 303 and the register 304; these can be external components.

[0043] Reference Figure 4 Describe the state of the sink 300 according to this embodiment.

[0044] Status ST1 is (Unattached.SNK), indicating that source 200 is not connected to destination 300. Since source 200 is not connected, the terminal voltages of terminals CC1 and CC2 of destination 300, indicating the ground potential GND, are connected to pull-down resistors Rd1 and Rd2.

[0045] State ST2 is the AttachWait.SNK state, indicating that the Attach 300 has detected a connection to the Source 200. The Attach 200 detects a connection to the Source 200 when the terminal voltage of either the CC1 or CC2 terminal becomes equal to or higher than a predetermined voltage vRdmin. This state is the AttachWait (State ST2).

[0046] For example, when the external electronic device connected to the sink 300 via a USB cable is the source 200, either the CC1 or CC2 terminal is connected to the CC line in the USB cable. If the USB cable is a USB Type-C to USB Type-C cable, the CC line is connected to a pull-up resistor in the source 200. Similarly, if the USB cable is a USB Type-C legacy cable, the CC line will be connected to a pull-up resistor within the cable. Therefore, as... Figure 1 As shown, when the receiver 300 is connected to the source 200 via a USB cable 100, which is a USB Type-C conventional cable, the CC line is connected to the CC1 terminal of the receiver 300. Therefore, the voltage divided by the pull-down resistor Rd1 of the receiver 300 and the pull-up resistor Rpc in the USB Type-C conventional cable appears at the CC1 terminal of the receiver 300. Although not shown, when the receiver 300 is connected to the source 200 via a USB cable, which is a USB Type-C to USB Type-C cable, the voltage divided by the pull-down resistor Rd1 of the receiver 300 and the pull-up resistor of the source 200 appears at the CC1 terminal of the receiver 300. Therefore, when within a predetermined voltage range, the receiver 300 can determine that the terminal voltage of the CC1 terminal is connected to an external electronic device that is the source 200. Here, the source connection is detected by a voltage vRdmin that is equal to or greater than the lower limit of the predetermined voltage range. Incidentally, the voltage vRdmin is specified by the Type-C standard. For example, the voltage vRdmin is higher than the ground potential, i.e., GND, connected to the pull-down resistor Rd1 or Rd2.

[0047] State ST3 is the state where a connection to source 200 is detected for a certain period of time, and transitions upon detection of a VBUS supply from source 200. This state is defined as the destination connection establishment state (Attached.SNK), indicating that a connection as destination 300 has been established. Specifically, destination 300 confirms the destination connection establishment state when the terminal voltage of either the CC1 or CC2 terminal connected to the CC line is maintained above a predetermined voltage vRdmin for a predetermined period of time, and when the supply of the bus power supply voltage VBUS is detected. Upon transitioning to state ST3, destination 300 begins receiving power from source 200 and can operate as a normal USB device. Incidentally, when the supply of the bus power supply voltage VBUS is removed, destination 300 enters state ST1, and source 200 stops.

[0048] According to this embodiment, the receiver 300 also has a state ST4, which is used to confirm the type of USB cable. As a first state where pull-up resistors Rp1 and Rp2 are connected to terminals CC1 and CC2 of the receiver 300, state ST4 is a state that confirms the type of USB cable connected to the receiver 300 based on the terminal voltages of terminals CC1 and CC2. The transition to state ST4 can be made from state ST1 or from state ST2.

[0049] In state ST4, when the connected USB cable is detected to be a USB Type-C to USB Type-C cable (first cable), after transitioning between states ST1 and ST2, the receiver 300 re-enters state ST3. After confirming the power supply capability of the source 200, it makes a power receiving request based on the confirmed power supply capability. Conversely, in state ST4, if the USB cable is not detected to be a USB Type-C to USB Type-C cable, the receiver 300 enters state ST1. Then, after transitioning between states ST1 and ST2, the receiver 300 re-enters state ST3 without checking the power supply capability of the source 200. It executes the power receiving request at, for example, a predetermined power, such as the standard supply power (5V, 500mA) defined by the USB 2.0 standard or the USB 3.x standard power supply (5V, 900mA). Incidentally, in the following text, these are referred to as the USB 2.0 standard or USB 3.x. The standard supply power determined by the x standard is called the USB standard supply power.

[0050] This section describes USB Type-C to USB Type-C cables. For example... Figure 5As shown, a USB Type-C to USB Type-C cable 110 is provided, typically consisting of multiple devices 114 called E-tags. The E-tags 114 are built into the cable 110 to provide information about the characteristics of the cable 110, such as cable length, amount of supported power, etc. The USB Type-C to USB Type-C cable 110 is provided with a CC line and a VCONN line, and power is supplied from a source 200 to the E-tags 114 via the VCONN line. In USB PD-compatible USB systems, the E-tags 114 and the source 200 communicate with each other via the CC line, and the USB system ensures safe power supply by checking the characteristics of the cable. A pull-down resistor Ra connected to the VCONN line is mounted on the E-tag 114. Therefore, in Figure 5 In this configuration, the pull-down resistor Ra is detected by monitoring the voltage at the CC2 terminal connected to the VCONN line. Specifically, when the voltage at the CC2 terminal falls below voltage vRa, it is identified that the CC2 terminal is connected to the pull-down resistor Ra. Unlike pull-down resistors Rd1 and Rd2, according to the USB Type-C standard, the resistance of the pull-down resistor Ra is set to 800Ω to 1.2kΩ. The voltage vRa is specified by the Type-C standard and is lower than the voltage vRdmin.

[0051] Therefore, in Figure 4 In state ST4, the receiver 300 detects the pull-down resistor Ra to confirm the type of USB cable. Specifically, in state ST4, the receiver 300 connects terminals CC1 and CC2 to pull-up resistors Rp1 and Rp2, respectively, to monitor the voltage at terminals CC1 and CC2. When the connected USB cable is a USB Type-C to USB Type-C cable, the voltage at terminal CC1 or CC2 corresponds to the voltage division between pull-up resistor Rp1 (or Rp2) and the pull-down resistor Ra of the E-marker. Therefore, when the voltage at terminal CC1 or CC2 is equal to or lower than voltage vRa, the receiver 300 determines that the pull-down resistor Ra of the E-marker is present, i.e., the connected USB cable is a USB Type-C to USB Type-C cable. The detection result of pull-down resistor Ra is stored in register 304. The first state, with pull-up resistors Rp1 and Rp2 connected to terminals CC1 and CC2, is equivalent to the state where the electronic device is operating as a source. Therefore, this first state is called the Unattached.SRC state, where source 200 is not connected to destination 300.

[0052] refer to Figure 6A and Figure 6B This will describe the power reception control process of the SU300.

[0053] First, when power is supplied, sink 300 switches to a source-disconnected state. Figure 4 In state ST4, where the source is not connected, controller 303 controls switches SW1 and SW2 to connect pull-up resistors Rp1 and Rp2 to each of terminals CC1 and CC2 (step S1). Afterward, the process proceeds to step S2, and it is determined whether a predetermined time has elapsed. If the predetermined time has not elapsed (N in step S2), the process proceeds to step S3.

[0054] Next, the detection circuit 302 determines whether the terminal voltage of the CC1 or CC2 terminal is equal to or less than the voltage vRa (step S3). That is, it determines whether a pull-down resistor Ra with an E flag is present in the cable connected to the receiver 300. When the voltage of the CC1 or CC2 terminal is equal to or less than the voltage vRa (Y in step S3), the controller 303 identifies that the connected cable is a USB Type-C to USB Type-C cable, sets the cable type flag TYPC_CBL_FLG to 1b, and stores the cable type flag TYPC_CBL_FLG in register 304 (step S4). Incidentally, the voltage vRa is determined based on the resistance values ​​of the pull-up resistors Rp1 and Rp2 of the receiver 300. For example, if the resistance of the pull-up resistors Rp1 and Rp2 connected to the receiver 300 with a 5V power supply is 56kΩ, then the voltage vRa is set to 0.2V. When the pull-up resistors Rp1 and Rp2 of the AC300 have a resistance of 22kΩ, the voltage vRa is 0.4V. When the pull-up resistors Rp1 and Rp2 have a resistance of 10kΩ, the voltage vRa is set to 0.8V.

[0055] On the other hand, when both the voltage at terminal CC1 and terminal CC2 are greater than voltage vRa (No in step S3), it means that the pull-down resistor Ra is not detected. This indicates that the connected USB cable is not a USB Type-C to USB Type-C cable. At this time, since it is unknown whether source 200 is connected to destination 300, controller 303 reads the source connection detection flag SRC_DET_FLG from register 304. The source connection detection flag SRC_DET_FLG indicates that a connection with source 200 has been detected, and checks whether the connection with source 200 has been detected. If 1b is set in the source connection detection flag SRC_DET_FLG (Y in step S5), the state proceeds to step S6 to continue operating as destination 300 since a connection with source 200 has been detected. If 1b is not set in the source connection detection flag SRC_DET_FLG (N in step S5), the process returns to step S2.

[0056] After setting the cable type flag TYPC_CBL_FLG (step S4), or after confirming the 1b source connection detection flag SRC_DET_FLG (in step S5, Y), the controller 303 executes the connection confirmation process for the destination 300. That is, the destination 300 switches to the destination not connected state. Figure 4 In the state ST1)(S6). In the unconnected state, the controller 303 controls the switches SW1 and SW2, and controls the second state for connecting the pull-down resistors Rd1 and Rd2 to each of the CC1 and CC2 terminals.

[0057] Controller 303 checks the detection voltages of terminals CC1 and CC2 to confirm the connection status (step S7). When either terminal CC1 or CC2 is connected to the CC line, a voltage is generated by the voltage division between the pull-up resistor Rpc in the pull-up resistors or the cable 100 of source 200 and the pull-down resistors Rd1 or Rd2 of destination 300. When either terminal voltage of CC1 or CC2 is equal to or higher than voltage vRdmin (Y in step S7), controller 303 identifies that destination 300 is connected to source 200. This state corresponds to the destination connection standby state. Figure 4 (State ST2 in the diagram). The voltage vRdmin is determined based on the resistance value of the pull-up resistor in source 200 and the resistance value of the pull-up resistor Rpc in cable 100. For example, if the resistance value of the pull-up resistor in source 200 connected to the 5V power supply and the resistance value of the pull-up resistor Rpc in cable 100 are both 56kΩ, then the voltage vRdmin is set to 0.2V.

[0058] Subsequently, controller 303 checks whether the voltages at terminals CC1 and CC2 are equal to or higher than voltage vRdmin during a predetermined time period, and checks whether the bus power supply voltage VBUS is provided. As a result, controller 303 checks whether sink 300 is in a state of establishing a connection with source 200 (sink connection establishment state) (step S8).

[0059] When controller 303 confirms that it has transitioned to the destination connection establishment state ( Figure 4In state ST3 (Y in step S8), it reads the cable type flag TYPC_CBL_FLG from register 304. If 1b is set in the cable type flag (Y in step S9), the controller 303 determines the connection via USB Type-C to USB Type-C cable based on one of the terminal voltages of the CC1 and CC2 terminals connected to the CC line, and checks the power supply capability of the source 200 (step S10). On the other hand, when the cable type flag TYPC_CBL_FLG is not set (N in step S9), it is determined that the controller 303 is connected via a USB Type-C legacy cable, and the controller 303 does not check the power supply capability of the source 200, and makes a power reception request using USB standard power supply (step S11). That is, after transitioning to the sink connection established state, the controller 303 makes a request to receive power using USB standard power supply without checking the terminal voltages of the CC1 and CC2 pins.

[0060] Meanwhile, in step S2, the pull-down resistor Ra of the E-marker is not detected, and in step S5, the cable is not a USB Type-C to USB Type-C cable, or if the source connection detection flag SRC_DET_FLG is not set, the signal source 200 may be disconnected. Therefore, when the state in which the pull-down resistor Ra of the E-marker is not detected and the source connection detection flag SRC_DET_FLG is not set continues for a predetermined period of time, the receiver 300 transitions to the receiver disconnected state. Figure 4 In state ST1, so as to perform the connection confirmation process ( Figure 6B (Step S13). As described above, in the unconnected state, the controller 303 controls switches SW1 and SW2, and connects pull-down resistors Rd1 and Rd2 to terminals CC1 and CC2, respectively.

[0061] In the unconnected state of the destination in step S13, the detector circuit 302 detects the terminal voltages of terminals CC1 and CC2. When the detected terminal voltage of CC1 or CC2 is equal to or higher than voltage vRdmin (Y in step S15), the controller 303 sets Ib to the source connection detection flag SRC_DET_FLG (step S16) when the source 200 detects that the source 200 is connected. At this time, the destination 300 is not in a state of establishing a connection with the destination 300, but rather in a state where the connection of the source 200 is detected (destination connection standby state (state ST2)). After detecting that the source 200 is connected, the process returns to step S1 to confirm the cable type.

[0062] When the non-destination connection state in step S13 continues for a predetermined time period (Y in step S14), the process returns to step S1. The continuation of the destination non-connection state may be due to the fact that the cable is connected but the source 200 is not connected. Therefore, in order to determine the type of cable first, the destination 300 moves to the source non-connection state (state ST4). As a result, even when the source 200 is not connected, the type of cable can be determined first, and the time spent from establishing a connection to the destination to requesting reception can be shortened.

[0063] In this way, by connecting pull-up resistors Rp1 and Rp2 to the CC1 and CC2 terminals of the receiver 300 to the same state as when the source is not connected, the type of cable connected can be identified. When the receiver 300 is connected to the source 200 using a USB Type-C to USB Type-C cable, after confirming the power supply capability of the source 200 from the voltages of the CC1 and CC2 terminals, the receiver 300 makes a power reception request using the power corresponding to the confirmed power supply capability. On the other hand, if a cable other than a USB Type-C to USB Type-C cable is connected, the receiver 300 performs a reception request with a predetermined power (such as the USB standard supply power) regardless of the voltages of the CC1 and CC2 terminals, without confirming the power supply capability of the source 200. In other words, the receiver 300 confirms the power supply capability of the source 200 based on the type of cable connected. Therefore, even if the pull-up resistor value in the USB Type-C legacy cable is inappropriate, the sink 300 can safely receive power without requesting to connect the source 200 via the USB Type-C incompatible port to receive excessive power.

[0064] (Revise)

[0065] exist Figure 6A , Figure 6B In the power reception control process, since the connection of the USB Type-C to USB Type-C cable is confirmed first, the sink 300 starts from the source not connected state. Figure 4 The present invention is not limited to state ST4. It is preferable to check the source connection before checking the cable type.

[0066] Figure 7 The power reception control flow of sink 300 is shown, which prioritizes connection confirmation of source 200.

[0067] First, when power is supplied to the host 300, the host 300 is in a host-disconnected state. Figure 4 State ST1 in (step S21). Step S21 and Figure 6BStep S13 is the same as in step S22, and therefore its description is omitted. When the voltages at terminals CC1 and CC2 detected by detection circuit 302 are equal to or higher than voltage vRdmin (Y in step S22), controller 303 detects that source 200 is connected. Incidentally, according to Figure 6A and Figure 6B In the power reception control process, controller 303 detects source connection, but in this modification, it is not necessary to set the source connection detection flag SRC_DET_FLG.

[0068] After detecting a source connection, controller 303 transitions to a source-disconnected state. Figure 4 In step S23, the controller 303 controls switches SW1 and SW2 to connect pull-up resistors Rp1 and Rp2 to terminals CC1 and CC2. In this case, detector 302 detects the terminal voltages of terminals CC1 and CC2. When the detected terminal voltage of CC1 or CC2 is equal to or less than voltage vRa (Y in step S24), the controller 303 identifies the connected cable as a USB Type-C to USB Type-C cable, sets Ib in the cable type flag TYPC_CBL_FLG, and stores it in register 304 (step S25). On the other hand, when both the terminal voltage of CC1 and the terminal voltage of CC2 are equal to or greater than voltage vRa (N in step S24), the controller identifies the connected cable as not a USB Type-C to USB Type-C cable, and the process proceeds to step S26 without setting the cable type flag TYPC_CBL_FLG.

[0069] Step S26 is Figure 4 State ST1, where the receiver is not connected. In step S26, controller 303 controls switches SW1 and SW2 to connect pull-down resistors Rd1 and Rd2 to terminals CC1 and CC2. The subsequent process is the same as that after step S7 in Figure 6, and the corresponding steps are given the same reference numerals, and their descriptions are omitted.

[0070] Similarly, in the modification of the first embodiment, by setting the sink 300 to the same state as the source not connected, the type of the connected cable can be identified. Therefore, when connected via a USB Type-C conventional cable, excessive power reception requests from the sink 300 to the source 200 can be prevented. Furthermore, in this modification, the process can be simplified since a source connection detection flag is not required.

[0071] (Example 2)

[0072] Next, Embodiment 2 will be described. The difference between Embodiment 2 and Embodiment 1 is that the electronic device acting as the receiver has a power operation mode with USB dual-role power.

[0073] USB Type-C defines three USB port source operation modes: source-only, destination-only, and dual-role power (hereinafter referred to as DRP) operation modes. Source 200 operates only as a power supply device, and destination 300 operates only as a power receiving device, but DRP can operate as both a power supply device and a power receiving device. In the second embodiment, power receiving control when the electronic device corresponding to the DRP operates as a destination will be described.

[0074] Figure 8 An exemplary configuration of a USB Type-C electronic device 400 with DRP capability is shown. The electronic device 400 includes pull-up resistors Rp1, Rp2 and pull-down resistors Rd1, Rd2, as it can also operate as a source 200 or as a sink 300. The electronic device 400 also includes a detection circuit 302, switches SW1, SW2, a controller 403, and a register 404. Switches SW1, SW2, and the detection circuit 302 can be connected to… Figure 3 The same reference numerals are shown here, and their descriptions will be omitted.

[0075] Controller 403 controls switches SW1 and SW2, periodically switching between a first state (where terminals CC1 and CC2 are connected to pull-up resistors Rp1 and Rp2) and a second state (where terminals CC1 and CC2 are connected to pull-down resistors Rd1 and Rd2). When an external electronic device, used as a source 200 of electronic device 400, is connected, electronic device 400 detects a connection when pull-down resistors Rd1 and Rd2 are connected to terminals CC1 and CC2 (second state). Conversely, when an external electronic device, used as a destination 300 of electronic device 400, is connected, electronic device 400 detects a connection when pull-up resistors Rp1 and Rp2 are connected to terminals CC1 and CC2 (first state).

[0076] Register 404 stores: source connection detection flag SRC_DET_FLG, which indicates whether source 200 has been detected; cable type flag TYPC_CBL_FLG, which indicates the cable type; and connection cable type determination execution flag CBL_CHK_FLG, which indicates whether the process of determining the type of the connected cable is executed.

[0077] Figure 9 This is a diagram showing the connection state transitions during the DRP operation of USB Type-C. (Refer to...) Figure 9The power reception control according to the second embodiment is described.

[0078] In DRP operation, the Destination Unattached state (Unattached.SNK, where pull-down resistors Rd1 and Rd2 are connected to CC1 and CC2 terminals) (state ST10) and the Source Unattached state (Unattached.SRC, where pull-up resistors Rp1 and Rp2 are connected to CC1 and CC2 terminals) (state ST40) switch at predetermined times as defined in the USB Type-C standard. In each state, the state transition is performed based on the detected voltage of the CC1 or CC2 pin. Typically, in the Destination Unattached state (state ST10), when a connection to source 200 is detected due to a voltage change at either the CC1 or CC2 terminal, the electronic device transitions to the Destination Attached Wait state (AttachedWait.SNK) (state ST20), and when predetermined conditions are met, the electronic device transitions to the Destination Attached Established state (Attached.SRC). On the other hand, in the source not connected state (state ST40), when the sink 300 is detected to be connected due to a change in the voltage of the CC1 terminal or the CC2 terminal, the electronic device switches to the source connected standby state (AttachWait.SRC) (state ST50), and when a predetermined condition is met, the electronic device switches to the sink connected state (Attached.SRC) (state ST60).

[0079] In the second embodiment, the data held in register 404 is used to cause the electronic device 400 to transition from a destination connection standby state (state ST20) to a destination connection established state (Attached.SNK) (state ST30). (See reference...) Figure 10A and Figure 10B The flowchart is used to describe the details.

[0080] Figure 10A and Figure 10B This is the power reception control process according to the second embodiment.

[0081] As described above, during DRP operation, the source is switched between the unattached state (Unattached.SNK, where pull-down resistors Rd1 and Rd2 are connected to the CC1 terminal and the CC2 pin) (state ST10) and the source is switched between the unattached state (Unattached.SRC, where pull-up resistors Rp1 and Rp2 are connected to the CC1 pin and the CC2 pin) (state ST40) within a predetermined time.

[0082] When pull-down resistors Rd1 and Rd2 are connected to terminals CC1 and CC2 (Y in step S100), similar to the first embodiment, the controller 403 determines that an external electronic device used as a source is connected when the terminal voltage of either terminal CC1 or CC2 is above voltage vRdmin (Y in step S101). That is, the electronic device 400 switches to a receiver-connected standby state. Figure 9 (State ST20 in the register). Controller 403 sets 1b and stores it in the source connection detection flag SRC_DET_FLG in register 404 (step S102). That is, the source connection detection flag SRC_DET_FLG is set when a connection with source 200 is detected when electronic device 400 indicates sink 300.

[0083] Then, the controller 403 reads the connection cable type determination implementation flag CBL_CHK_FLG stored in the register 404 to confirm whether Ib is set in the connection cable type determination implementation flag CBL_CHK_FLG (step S103). If the connection cable type determination implementation flag CBL_CHK_FLG is set to Ib (Y in step S103), the controller 403 continues the process as the sink 300. That is, the controller 403 checks whether it is in a state of establishing a connection with the source 200 (step S104).

[0084] When controller 403 enters the sink connection establishment state by establishing a connection with the source ( Figure 9 When the state ST30 is set (Y in step S104), it reads the cable type flag TYPC_CBL_FLG from register 404. If 1b is set (Y in step S105), the controller 403 recognizes that a connection is made via a USB Type-C to USB Type-C cable, and the connection is made to the CC line via either the CC1 or CC2 terminal. After confirming the power supply capability of the source 200, a power receiving request is executed (step S106). On the other hand, when the cable type flag TYPC_CBL_FLG is not set, since the connection is made via a USB Type-C legacy cable that is not a USB Type-C to USB Type-C cable, the controller 403 does not check the power supply capability of the source 200, but instead makes a power receiving request using the USB standard power supply (step S107).

[0085] On the other hand, when 1b is not set in the connection cable type determination execution flag CBL_CHK_FLG (N in step S103), the controller 403 controls switches SW1 and SW2 to connect terminals CC1 and CC2 to pull-up resistors Rp1 and Rp2 (step S109). That is, the controller 403 performs control to switch to the source-unconnected state. Figure 9 In step S101, if the voltages of terminals CC1 and CC2 are not equal to or greater than voltage vRdmin within a predetermined time (step S101, Y, step S108, Y), then the electronic device 400 is also operated as source 200, and the controller 403 controls switches SW1 and SW2 to switch to the source disconnected state.

[0086] When the electronic device 400 enters the source-disconnected state, the controller 403 reads the source connection detection flag SRC_DET_FLG from the register 404 (step S110). The fact that Ib is set in the source connection detection flag SRC_DET_FLG (Y in step S110) indicates that the electronic device 400, acting as the sink 300, has detected a connection to the source. Therefore, the controller 403 determines the cable type required for the device 400 to operate as the sink 300 in a subsequent process, sets Ib in the connection cable type determination implementation flag CBL_CHK_FLG, and stores it in the register 404 (step S111).

[0087] If 1b is not set in the source connection detection flag SRC_DET_FLG, meaning no source connection of electronic device 400 is detected (N in step S110), then electronic device 400 is not identified as operating as destination 300. Therefore, electronic device 400 continues the connection confirmation process as a source.

[0088] Next, the controller 403 checks whether the terminal voltage of either the CC1 or CC2 terminal is equal to or less than voltage vRa (step S112). In step S112, it checks whether the cable connected to the electronic device 400 is a USB Type-C to Type-C cable. If the electronic device 400, set to a source-unconnected state, is connected to the source 200 via a USB Type-C to Type-C cable, then since either the CC1 or CC2 terminal is connected to the cable pull-down resistor Ra, one of the terminal voltages of the CC1 and CC2 terminals will become below voltage vRa. On the other hand, when the terminal voltages of both the CC1 and CC2 terminals are higher than voltage vRa, this indicates that the connecting cable is a USB Type-C legacy cable. This is because USB Type-C legacy cables do not have an E-marker pull-down resistor Ra. Therefore, by checking whether the terminal voltage of either the CC1 or CC2 terminal is equal to or less than voltage vRa, the type of connecting cable can be determined.

[0089] If the voltage of one of the CC1 and CC2 terminals is equal to or less than voltage vRa (Y in step S112), i.e., the connection cable is identified as a USB Type-C to Type-C USB cable, then the controller 403 confirms that there is no connection to the destination 300 based on the voltage of the other terminal of the CC1 and CC2 terminals. Since the pull-up resistor is connected to the CC1 and CC2 terminals in step S109, the voltage of the other terminal of the CC1 and CC2 terminals connected to the destination 200 with the pull-down resistor Rd is within a predetermined voltage range (above voltage vRdmin, below voltage vRdmax). Therefore, if the voltage vRdmax is higher than the upper limit of the predetermined voltage range, it can be determined that the connected external electronic device is not the destination 300. Therefore, the controller 403 checks whether the voltage of the other terminal of the CC1 and CC2 terminals is higher than voltage vRdmax (step S113). If the voltage of the other terminal of the CC1 and CC2 terminals is higher than voltage vRdmax (Y in step S113), the controller 403 identifies that it is not connected to the destination. Incidentally, the voltage vRdmax is lower than the power supply potential connected to the pull-up resistors Rp1 and Rp2, which is, for example, limited by the Type-C standard.

[0090] Then, in step S112, controller 403 indicates that the connection cable is identified as USB Type-C to USB Type-C, and stores register 404 by setting 1b in the cable type flag TYPC_CBL_FLG (step S114).

[0091] On the other hand, when the voltage of the other terminal of CC1 and CC2 is equal to or less than the voltage vRdmax (N in step S113), the controller 403 recognizes that the electronic device 400 is connected to the sink 300, and the device 400 switches to a source-connected standby state. Figure 9 (ST50). Subsequently, when the connected state of the receiver 300 continues for a predetermined period of time, the electronic device 400 transitions to the source connection established state. Figure 9 (ST60 in the middle), and the controller 403 begins operation as source 200 (step S118).

[0092] If the terminal voltage of either CC1 or CC2 is not equal to or lower than voltage vRa (N in step S112), that is, if it is determined that the connecting cable is a USB Type-C legacy cable, then in step S115, the controller 403 detects whether the electronic device 400 is connected to the sink 300. Therefore, the controller 403 determines whether the terminal voltage of either CC1 or CC2 is equal to or lower than voltage vRdmax. If either CC1 or CC2 is not lower than voltage vRdmax (N in step S115), the controller 403 identifies that the electronic device 400 is not connected to the sink 300, and the process proceeds to step S116. On the other hand, if the terminal voltage of either CC1 or CC2 is equal to or lower than voltage vRdmax (Y in step S115), the controller 403 identifies that the electronic device 400 is connected to the sink 300, and operation of the source 200 begins (step S118).

[0093] Therefore, controller 403 confirms the type of the connection cable (step S112), and after determining that it is not connected to destination 300 (Y in step S113, N in S115), if a predetermined time has elapsed (Y in step S116), then electronic device 400, which is performing operations as destination 300, switches to a destination-unconnected state (step S117). That is, controller 403 performs control to connect the pull-down resistor to terminals CC1 and CC2, and returns to step S100.

[0094] As described above, even when a USB Type-C DRP-compatible electronic device operates as a destination 300, it performs power reception control after determining the cable type. Therefore, when USB Type-C DRP-enabled electronic devices operate as destination 300, they can prevent the external source 200 from requesting excessive power, even if they are connected via a USB Type-C legacy cable. As a result, power can be safely received in the power supply system using a USB Type-C legacy cable. Furthermore, USB Type-C DRP-compatible electronic products have pull-up and pull-down resistors to prevent excessive power reception requests without the need for additional components.

[0095] If all USB Type-C DRP-compliant electronic devices use this firmware to control the status of their USB Type-C ports, the type of cable can be checked without changing the hardware configuration.

[0096] The invention made by the inventors has been described above based on the embodiments, but the invention is not limited to the above embodiments, and needless to say, various modifications can be made without departing from its spirit.

Claims

1. An electronic device connected via a cable to an external power supply device, the electronic device comprising: A first terminal and a second terminal, wherein at least one of the first terminal and the second terminal is connected to a signal line of the cable; The detection circuit is configured to detect the voltage of the first terminal and the voltage of the second terminal; The controller is configured to: determine the type of the cable based on a detected voltage between the voltage of the first terminal and the voltage of the second terminal, and to confirm the power supply capability of the external power supply device based on the type of the cable; as well as First pull-up resistor, second pull-up resistor, first pull-down resistor, and second pull-down resistor. The type of cable is determined by connecting the first terminal and the second terminal to the first pull-up resistor and the second pull-up resistor, respectively; and After the type of the cable is determined, the power supply capability is confirmed by connecting the first terminal and the second terminal to the first pull-down resistor and the second pull-down resistor, respectively.

2. The electronic device according to claim 1, The controller is configured to: confirm the power supply capability, and when the controller determines that the cable type is a first type, request power reception using power according to the confirmed power supply capability; and The controller is configured to request power reception using a predetermined power level when the controller determines that the type of the cable is not the first type, without confirming the power supply capability.

3. The electronic device of claim 2, wherein the first type is a USB Type-C to Type-C cable.

4. The electronic device of claim 2, wherein the predetermined power is defined by the USB 2.0 standard or the USB 3.x standard.

5. The electronic device according to claim 1, The first terminal and the second terminal are configuration channel terminals according to the USB Type-C standard.

6. The electronic device according to claim 1, The electronic device mentioned above is a power receiving device.

7. An electronic device connected via a cable to an external power supply device, the electronic device comprising: A first terminal and a second terminal, wherein at least one of the first terminal and the second terminal is connected to a signal line of the cable; The detection circuit is configured to detect the voltage of the first terminal and the voltage of the second terminal; The controller is configured to: determine the type of the cable based on a detected voltage in the voltage of the first terminal and the voltage of the second terminal, and confirm the power supply capability of the external power supply device according to the type of the cable; The electronic device described herein can operate as a power supply device or a power receiving device; and When the electronic device detects a connection to the external power supply device, the electronic device switches its operation to that of the power supply device, and the controller determines the type of the cable based on the detected voltage of the voltage at the first terminal and the voltage at the second terminal.

8. The electronic device of claim 7, further comprising a register configured to store a type of cable determination flag, the cable determination flag indicating that the determination of the type of the cable has been performed; The controller is further configured to: When the electronic device detects a connection to the external power supply device, it confirms the type of the cable identification flag; When the type of the cable determination flag indicates that the determination has been performed, the operation is maintained as a power receiving device; and When the type of the cable identification flag indicates that the identification has not yet been performed, the operation of the electronic device is converted to the operation of the power supply device, and the type of the cable is determined based on the detected voltage of the voltage of the first terminal and the voltage of the second terminal.

9. The electronic device according to claim 8, The register is also configured to store a source connection detection flag, which indicates that the connection to the external power supply device has been detected. When the operation of the electronic device is converted to the operation of the power supply device, if the source connection detection flag indicates that the connection with the external power supply device is detected, the controller activates the type of the cable determination flag.

10. An electronic device, the electronic device being connected via a cable to an external power supply device and serving as a power receiving device, the electronic device comprising: The first terminal is connected to the cable and is connected to the first pull-up resistor or the first pull-down resistor via the first switch; The second terminal is connected to the cable and is connected to the second pull-up resistor or the second pull-down resistor via the second switch; The controller is configured as follows: When the first terminal and the second terminal are respectively connected to the first pull-up resistor and the second pull-up resistor, the type of cable is determined according to the voltage of the second terminal; When the first terminal and the second terminal are respectively connected to the first pull-down resistor and the second pull-down resistor, the connection with the external power supply device is determined according to the voltage of the first terminal; as well as Check the power supply capability of the external power supply device according to the type of cable.

11. A method for controlling power reception of an electronic device, the electronic device being connected via a cable to an external power supply device, wherein the electronic device is not operable as a power supply device; and wherein the electronic device includes a first terminal, a second terminal, a pull-up resistor, and a pull-down resistor, the first terminal and the second terminal being connected to the cable, the pull-up resistor and the pull-down resistor being respectively connected to the first terminal and the second terminal via switches, wherein the method comprises: The type of cable is determined based on the first terminal and the second terminal; The connection to the external power supply device is detected based on the voltage of the first terminal and the voltage of the second terminal. When the connection with the external power supply device is determined, the power supply capability of the external power supply device is confirmed. Before the type of the cable is determined, the pull-up resistor is connected to the first terminal and the second terminal respectively; as well as After the type of the cable is determined, the pull-down resistor is connected to the first terminal and the second terminal, respectively.

12. The method according to claim 11, The first terminal and the second terminal are configuration channel terminals according to the USB Type-C standard.

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