Power systems of network devices (e.g., switches, routers, etc.) require high reliability. As a result, the power systems utilize two parallel, independent, direct current (DC) input voltage feeds in order to maintain input redundancy. Because the input DC input voltage feeds, usually, do not provide equal voltage, nearly all the current is drawn from only one of the two DC input voltage feeds with the higher voltage. The greater the amount of current that is drawn from one of the two DC input voltage feeds, the greater the power loss.
According to one aspect, a method may include: determining, by a device, a first received power via a first input feed of a circuit board of the device; determining, by the device, a second received power via a second input feed of the circuit board; determining, by the device, whether the first input feed and the second input feed are receiving power based on the first received power and the second received power; and opening, by the device, a switch, of the circuit board, when the first input feed and the second input feed are receiving power.
According to another aspect, a device may include a circuit board. The circuit board may include: a first input bus to receive a first power from a first power source; a second input bus to receive a second power from a second power source; a switch to connect, when the switch is closed, the first input bus to the second input bus; and a logic element. The logic element may determine whether the first input bus is receiving the first power, may determine whether the second input bus is receiving the second power, and may close the switch when the first input bus is not receiving the first power or when the second input bus is not receiving the second power.
According to yet another aspect, a logic element, of a printed circuit board (PCB), may include: a first input to receive a first input signal from a first input bus of the PCB; a second input to receive a second input signal from a second input bus of the PCB; and an output to transmit an output signal, based on the first input signal and the second input signal, to a control input of a switch that connects, when the switch is closed, the first input bus to the second input bus. The output signal may include an open control value, to open the switch, when the first input signal indicates that the first input bus is receiving power from a first power source and the second input signal indicates that the second input bus is receiving power from a second power source.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate one or more implementations described herein and, together with the description, explain these implementations. In the drawings:
The following detailed description refers to the accompanying drawings. The same reference numbers in different drawings may identify the same or similar elements.
An embodiment, described herein, may minimize power loss when a printed circuit board (PCB) has two input feeds (e.g., which are connected to two different power sources) that supply power. The PCB may include a first input bus, a second input bus, a logic element, and a switch between the first input bus and the second input bus. The first input bus may operate as a first input feed from a first power source. The second input bus may operate as a second input feed from a second power source, which is different from the first power source. The logic element may determine whether the PCB is receiving power via both the first input feed and the second input feed or only via one of the input feeds (e.g., via the first input feed or via the second input feed).
The logic element may open the switch when the PCB is receiving power via both the first input feed and the second input feed. When the switch is open, the PCB may receive a first half of the power needed by the PCB via the first input feed and a second half of the power needed by the PCB via the second input feed. As a result, the power loss is almost twice as less when the switch is open than when the PCB receives most of the power only via one of the input feeds. In other words, the power loss from drawing all the current from a single power source is about twice as great as drawing one half of the current from the first single power source and the other half of the current from the second single power source.
The logic element may close the switch when the PCB is receiving power only via one of the input feeds. When the switch is closed, the PCB may receive all of the power needed by the PCB via the one of the input feeds that is receiving power (e.g., via the power received by the first input bus from the first power source). The logic element may re-open the switch when the logic element determines that the PCB is (again) receiving power via both the first input feed and the second input bus (e.g., power is restored from one of the power sources and is now being received from both power sources).
Input bus 210 may include any component that may receive power (e.g., a current of voltage, I) from a power source and transmit the power to other components of the PCB (e.g., DC/DC power supply 240). In one implementation, input bus 210 may operate as an input feed. Input bus 210 may receive power from a source outside of the PCB (or from another portion of the PCB). The power may include, for example, an input voltage of a particular DC voltage. When switch 230 is open (
Input bus 212 may include any component that may receive power from a power source and transmit the power to other components of the PCB (e.g., DC/DC power supply 242). In one implementation, input bus 212 may operate as an input feed. Input bus 212 may receive power from a source outside of the PCB (or from another portion of the PCB) that is different from the source that provides power to the PCB via input bus 210. When switch 230 is open (
Resistors, including resistor R1 and resistor R2, may act as DC resistive impedance from one DC input voltage feed. Diode D1 may connect a first DC input voltage feed to the input of DC/DC power supply 240 via input bus 210. Diode D2 may connect a second DC input voltage feed to the input of DC/DC power supply 242 via input bus 212. In one implementation, diodes, including diode D1 and diode D2, may include “OR” diodes that isolate particular voltage(s). In another implementation, diodes, including diode D1 and diode D2, may prevent shorting between input bus 210 and input bus 220. In yet another implementation, diodes, including diode D3 and diode D4, may ensure that a full amount of (output) power, which is required to be provided from DC/DC power supply 240 and DC/DC power supply 242, is maintained at output bus 250.
DC/DC power supply 240 may include any component that functions as a DC/DC converter. In one implementation, DC/DC power supply 240 may receive power received by input bus 210 via diode D1. Resistor R1 may contribute to an impedance (e.g., “R”) of input bus 210 that results in a power loss (e.g., “P”). Power loss may equal a product of a value of the current received by input bus 210 and a value of the impedance (e.g., P=I2*R). DC/DC power supply 240 may convert a received input DC voltage into another output DC voltage. A current flow of the output voltage may move across diode D3 and to a different portion (e.g., different from portion 200)/other components of the PCB, via output bus 250. DC/DC power supply 240 may provide, via output bus 250, half of an amount of output DC voltage required by the other components.
DC/DC power supply 242 may include any component that functions as a DC/DC converter. In one implementation, DC/DC power supply 242 may receive power received by input bus 212 via diode D2. Resistor R2 may contribute to an impedance of input bus 212 that results in a power loss. Power loss may equal a product of a value of the current received by input bus 212 and a value of the impedance. DC/DC power supply 242 may convert a received input DC voltage into another output DC voltage. A current flow of the output voltage may move across diode D4 and to the different portion/other components of the PCB, via output bus 250. DC/DC power supply 242 may provide, via output bus 250, the other half of the amount of output DC voltage required by the other components.
Logic element 220 may include any component that controls whether switch 230 is open (
Switch 230 may include any component that opens or closes (e.g., turns on or off) a connection between first input bus 210 and second input bus 212. Logic element 220 may transmit output signal 222 to switch 230. Switch 230 may open (
For example, the value of first input signal 214 may equal one (1) when input bus 210 is receiving power from the first power source. The value of first input signal 214 may equal zero (0) when input bus 210 is not receiving power from the first power source. Similarly, the value of second input signal 216 may equal one (1) when input bus 212 is receiving power from the second power source. The value of second input signal 216 may equal zero (0) when input bus 212 is not receiving power from the second power source. When logic element 220 determines that the value of a signal (e.g., first input signal 214 or second input signal 216) is equal to 0, a signal/power may not have been received from an input bus (e.g., input bus 210 or input bus 212). Logic element 220 may associate the value of 0 with the receipt of power by the input bus that operates as an input feed.
Furthermore, in one implementation, logic element 220 may act as/include an AND gate. Logic element 220 may generate output signal 222 based on a product of the value of first input signal 214 and the value of second input signal 216. Accordingly, a value of output signal 222 may equal 1 when the value of first input signal 214 is equal to 1 and the value of second input signal 216 is equal to 1. The value of output signal 222 may equal 0 when either the value of first input signal 214 or the value of second input signal 216 is equal to 0. Switch 230 may receive, from logic element 220, output signal 222. Switch 230 may open when the value of output signal 222 is equal to 1. Conversely, switch 230 may close (
As shown in
A receipt of power via a first input feed may be determined (block 320). For example, input bus 220 may operate as a first input feed by receiving the power from the first power source. A first input of logic element 220 may receive input signal 214 from input bus 210. Logic element 220 may determine that the first input feed is receiving power when a value of input signal 214 is equal to a first particular value (e.g., 1). Logic element 220 may determine that the first input feed is not receiving power when the value of input signal 214 is equal to a second particular value (e.g., 0). A value associated with the receipt of power, via the first input feed, may equal the first particular value or the second particular value.
In another implementation, the first input, of logic element 220, may receive first power, as first input signal 214, from input bus 210. Logic element 220 may determine a first voltage measurement of the first power. Logic element 220 may determine that input bus 210 is receiving the power when the first voltage measurement is greater than zero.
Returning to
In another implementation, the second input, of logic element 220, may receive second power, as second input signal 216, from input bus 211. Logic element 220 may determine a second voltage measurement of the second power. Logic element 220 may determine that input bus 212 is receiving the power when the second voltage measurement is greater than zero.
Returning to
If both inputs are receiving power (block 340—YES), process 300 may include opening switch 230 (block 350). For example, switch 230 may be closed (
If both inputs are not receiving power (block 350—YES), process 300 may include closing switch 230 (block 355). For example, when logic element 220 determines that one of the first input feed and the second input feed is not receiving power, logic element 220 may generate an output signal with a close control value (e.g., the product, which equals 0). Logic element 220 may transmit, via the output of logic element 220, the output signal to the control input of switch 230. Switch 230 may close (
Power may be provided via output bus 250 (block 360). For example, when switch 230 is open (
When switch 230 is closed, DC/DC power supply 240 and DC/DC power supply 242 may receive all power from the same power source (e.g, the first power source or the second power source). One of DC/DC power supply 240 and DC/DC power supply 242 may receive the power via the closed switch 230 (
DC/DC power supply 240 and DC/DC power supply 242 may convert the received power into an output voltage. Output bus 250 may receive the output voltage from DC/DC power supply 240 and DC/DC power supply 242. Output bus 250 may transmit the output voltage to a portion/components of the PCB that utilize the output voltage.
Process 300 may repeat continuously as long as portion 200 receives power from at least one of the first power source or the second power source. Switch 230 may open when power is being received from both the first power source and the second power source. Switch 230 may close when power is being received from only of the first power source and the second power source.
The foregoing description of implementations provides illustration and description, but is not intended to be exhaustive or to limit the implementations to the precise form disclosed. Modifications and variations are possible in light of the above teachings or may be acquired from practice of these implementations.
For example, while a series of blocks has been described with regard to
While certain values have been used above (e.g., 0, 1), these values are merely provided as examples. In other implementations, the values may differ.
It will be apparent that example aspects, as described above, may be implemented in many different forms of software, firmware, and hardware in the embodiments illustrated in the figures. The actual software code or specialized control hardware used to implement these aspects should not be construed as limiting. Thus, the operation and behavior of the aspects were described without reference to the specific software code-it being understood that software and control hardware could be designed to implement the aspects based on the description herein.
Even though particular combinations of features are recited in the claims and/or disclosed in the specification, these combinations are not intended to limit the disclosure of the invention. In fact, many of these features may be combined in ways not specifically recited in the claims and/or disclosed in the specification. Although each dependent claim listed below may directly depend on only one other claim, the disclosure of the invention includes each dependent claim in combination with every other claim in the claim set.
No element, act, or instruction used in the present application should be construed as critical or essential to the invention unless explicitly described as such. Also, as used herein, the article “a” is intended to include one or more items. Where only one item is intended, the term “one” or similar language is used. Further, the phrase “based on” is intended to mean “based, at least in part, on” unless explicitly stated otherwise.
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