New universal serial bus (USB) power-delivery (PD) and Type-C specifications have been released that enable delivery of higher power over USB cables and connectors. The intent for this technology is to create a universal power plug for laptops, tablets, and so forth. The USB-PD specification defines a communication link between ports connected via USB-PD cables and connectors. The communication is designed to be half-duplex and packet-based. The packets include various information that enables the two ports to communicate and negotiate the voltage and current the source port will provide to the sink port. This communication happens independently from normal USB communications that route through the same cable but use different wires.
This disclosure relates to circuits and methods to delegate power to multiple universal serial bus (USB) ports based on priority of device access to the respective USB ports. A port manager operating on or with a controller monitors requested port power from each of a plurality of USB ports. The port manager sets a separate port variable for each of the USB ports that indicates a priority in which each of the USB ports have requested port power. For example, if device (A) plugs into USB port (A) before another device (B) plugs into USB port (B), then device (A) can be assigned a higher priority than device (B). The controller monitors the separate port variables from the port manager for each of the USB ports. The controller then delegates power to the USB ports based on the priority assigned by the port manager. In one example, the highest priority device (device (A) in this example) can be allocated full power for charging and/or other power needs whereas devices assigned lower priority can be allocated power levels less than full power. This type of priority control mitigates users from receiving more combined power from multiple USB ports than should be supplied from the power supply driving the respective USB ports. In some examples, devices can negotiate for less power on power-up which can be used to supply other devices of lower priority that may request more power. In yet other examples, if a higher priority device has disconnected, remaining connected devices can dynamically renegotiate their current power allocation with the port manager based on their previously assigned priority.
As used herein, the term “circuit” can include a collection of active and/or passive elements that perform a circuit function, such as an analog circuit or control circuit. Additionally or alternatively, for example, the term “circuit” can include an integrated circuit (IC) where all and/or some of the circuit elements are fabricated on a common substrate (e.g., semiconductor substrate, such as a die or chip).
In an example, the port manager 110 can analyze the requested port power from each of the plurality of USB ports 1-N and determine an allocation of the port power for each of the USB ports based on the priority and an amount of power requested from each of the USB ports. The port manager 110 can set a separate power variable (see e.g.,
In another example, the controller 130 delegates a greater amount of power to devices having a higher priority as set by the port manager 110 and negotiated by the negotiation interface with each of the USB ports 1-N. In this manner, overall power requested from the collection of USB ports can be controlled. In yet another example, the controller 130 delegates a greater amount of power to devices having a lower priority as set by the port manager 110 and negotiated by the negotiation interface with each of the USB ports 1-N if a device of higher priority is disconnected from its respective USB port. In some examples, a negotiation can occur when devices are plugged into a respective USB port where a given device can notify the port manager 110 that less than full power is requested. In such example, the controller 130 can delegate a greater amount of power to devices having a lower priority as set by the port manager 110 and negotiated by the negotiation interface with each of the USB ports if a device of higher priority negotiates a lower power from its respective USB port than a device of lower priority negotiates from its respective USB port.
For other examples, the negotiation interface renegotiates the amount of power delegated by the controller 130 to each remaining device connected to the respective USB ports 1-N if a given device is disconnected from its respective USB port. The negotiation interface sends or receives power allocation data on a configuration channel (see e.g.,
The circuits and methods described herein mitigates the condition of the user from configuring USB ports to be able to pull unsuitably high levels of power at one time. Therefore, such circuits and methods can reduce power to USB ports based on which or how many ports are currently in use. For example, in a system that contains two USB type C ports, if one port is currently in use, the other port power can be reduced thus preventing the user from drawing a full 15 W from both available USB type C ports and in an effort to limit the amount of power being collectively consumed by the USB ports. This also allows more power headroom to be available for more important resources or tasks running on the central processing unit (CPU). This in turn allows for smaller power supplies due to the increased power headroom. Also, the circuits and methods described herein facilitates from having high current spikes generated during runtime caused by the USB ports. The USB ports alone in current systems can be configured to consume more power than the rating of the power supply, for example. By managing port charging, the total amount of power consumed by the ports can be decreased.
In one specific example using three ports, three USB ports are provided that support high current charging. These ports have a full power state, a reduced power state, and a charging disabled state such as:
1. USB-C: Full power=15 W @ (5V, 3 A)
Reduced power=7.5 W @ (5V, 1.5 A)
Charging disabled=4.5 W @ (5V, 0.9 A)
2. USB-C: Full power=15 W @ (5V, 3 A)
Reduced power=7.5 W @ (5V, 1.5 A)
Charging disabled=4.5 W @ (5V, 0.9 A)
3. USB-A CHG: Full power=12.5 W @ (5V, 2.5 A)
Reduced power=7.5 W @ (5V, 1.5 A)
Charging disabled=4.5 W @ (5V, 0.9 A)
When the user performs the action to insert a device into any of the three ports, the other two ports enter into the reduced power state such as:
1. USB-C: Full power=15 W @ (5V, 3 A) Occupied
2. USB-C: Reduced power=7.5 W @ (5V, 1.5 A) Unoccupied
3. USB-A CHG: Reduced power=7.5 W @ (5V, 1.5 A) Unoccupied
From this state when the user performs the action to insert an additional device into the remaining two open ports, the last remaining port enters into the charging disabled state
1. USB-C: Full power=15 W @ (5V, 3 A) Occupied
2. USB-C: Reduced power=7.5 W @ (5V, 1.5 A) Occupied
3. USB-A CHG: Charging disabled=4.5 W @ (5V, 0.9 A) Occupied/Unoccupied
This procedure can be performed given that the user inputs a device into any of the open ports. Given how many ports are available (e.g., no device occupies the port) the power state is changed accordingly. Given that there are three USB ports (USB C 1, USB C 2, and USB A CHG) there are three possible configurations that can be obtained when the user performs the action to insert a device into one of the three available charging ports. The user can either insert the device into one of the USB-C or the USB-A CHG. Then the two ports that are not occupied enter into the reduced, half power state.
Thus, a summary of a configuration with only one device inserted into the unit includes:
There is one state available for each charging port:
If system has 3 charging ports, there are 3 possible state configurations.
The remaining, not occupied, ports only support up to half power.
A device cannot draw full power from a half power port. Other configurations are possible however.
Given that the users' first action is to insert a device into one of the three open ports the user can then insert an additional second device into one of the two open ports, this now results in six possible configurations.
Thus, a summary of a configuration with two devices inserted into the unit includes:
Only the first device inserted supports full power.
Only the second device inserted supports half power.
The remaining, not occupied, ports do not support charging (charging disabled).
These ports allow default, 0.9 A current, for example.
When, a device is removed, currently inserted devices can renegotiate to the highest allowed power configuration as mentioned previously. When considering the case where only one device has been inserted, and the configuration is one of three. Then by removing the device, respective charging USB devices return to a full power supported initial state.
Thus, a summary of a configuration when removing one device from the unit includes:
When the device is removed, respective charging ports allow full power.
This returns to the initial state where no devices occupy any of the charging ports.
When considering the case where there are two inserted devices, when one device is removed, the remaining devices can renegotiate to a higher allowed power state. For instance, consider the configuration where the user first inserted a device into USB-C which supported up to full power, then the user inserted a second device into the USB-A charger which supported up to half power. At this point, the user can either remove the USB-C device or the USB-A charger device. If the user removes the USB-C device, then a possible result is where USB-A charging device restores to full power and remaining unoccupied ports are allowed reduced power. In another example, the user can remove the second device in USB-A charger which results in USB-C device restores to full power (e.g., USB-C was the 1st device plugged in & already had full power, so does not need to “restore” full power) and remaining unoccupied ports are allowed reduced power.
When in a two-device state, for example, when one state is removed, the remaining occupied port can renegotiate power. This allows the remaining device the ability to consume full power from the port it occupies. Since this device now has the option to consume more power, an assumption can be made that the device may consume more power. This allows us to cover every case and simplify the state table.
Thus, a summary of a configuration when removing two devices from the unit includes:
When any of the two devices is removed, the charging ports return to a one device state.
This is achieved by renegotiating and allowing full power to the remaining port.
A negotiation interface 340 can be provided to negotiate the amount of power delegated by the controller 330 to devices connected with each of the USB ports 1-N. In one example, the controller 330 delegates a greater amount of power to devices having a higher priority as set by the port manager 310 and negotiated by the negotiation interface 340 with each of the USB ports 1-N. As shown, power negotiation can occur over configuration channels 350, where each USB port is assigned its own channel. In another example, the controller 330 delegates a greater amount of power to devices having a lower priority as set by the port manager 310 and negotiated by the negotiation interface 340 with each of the USB ports 1-N if a device of higher priority is disconnected from its respective USB port. In yet another example, the controller 330 delegates a greater amount of power to devices having a lower priority as set by the port manager 310 and negotiated by the negotiation interface 340 with each of the USB ports 1-N if a device of higher priority negotiates a lower power from its respective USB port than a device of lower priority negotiates from its respective USB port.
In view of the foregoing structural and functional features described above, an example method will be better appreciated with reference to
What have been described above are examples. It is, of course, not possible to describe every conceivable combination of components or methodologies, but one of ordinary skill in the art will recognize that many further combinations and permutations are possible. Accordingly, the disclosure is intended to embrace all such alterations, modifications, and variations that fall within the scope of this application, including the appended claims. As used herein, the term “includes” means includes but not limited to, the term “including” means including but not limited to. The term “based on” means based at least in part on. Additionally, where the disclosure or claims recite “a,” “an,” “a first,” or “another” element, or the equivalent thereof, it should be interpreted to include one or more than one such element, neither requiring nor excluding two or more such elements.
Filing Document | Filing Date | Country | Kind |
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PCT/US2018/037543 | 6/14/2018 | WO | 00 |