Patent Application
20100212341
Devices may not operate properly and may be unreliable if they are operated above a certain temperature. Devices consume power and create heat, which tends to heat the devices. Often cooling systems that use fans are used to cool these devices. The cooling systems may help to ensure that the devices do not overheat, but the cooling systems may create noise and consume power.
Temperature information from the devices can be used to control the cooling systems so that the cooling systems are turned on less frequently. But, it may be hard to convey the temperature information to the cooling system. For example, the temperature information may be susceptible to electronic noise when being sent from the device to the cooling system. Additionally, lines that convey the temperature information may require pins on a device such as an integrated chip in order to send the temperature information to a cooling system and the lines that convey the temperature information may require space to route the signals from the device to the cooling system. For example, the lines that convey temperature information may require room on a printed circuit board.
One solution for conveying temperature information to the cooling system is to apply a voltage to a diode within the device and measure the current through the diode using a line from the device to the cooling system. The amount of current through the diode changes as the temperature changes. This solution has the disadvantage of the current being susceptible to electric noise before being conveyed to the cooling system, and thus not producing an accurate measure of the temperature of the device. Another solution used is a digital read-out from a thermal sensor attached to the device. The digital read-out has the disadvantage of using multiple lines and/or pins available to the device to convey the temperature information.
Therefore there is a need in the art for controlling a cooling system for a device that is less susceptible to electronic noise and that does not use multiple lines.
The accompanying drawings are included to illustrate and provide a further understanding of the disclosed embodiments. In the drawings:
a illustrates an embodiment of a digital signal indicating the temperature of the device.
b illustrates an embodiment of a digital signal indicating the temperature of the device.
c illustrates a table for an embodiment of the present invention for setting a fan speed based on the temperature of a device as indicated by a digital signal.
Embodiments of systems and methods receive a digital signal outputted from a single line of a device. Embodiments of systems and methods calculate the temperature of the device based on the digital signal. Embodiments of systems and methods generate a signal to a cooling system to cool the device when the calculated temperature of the device is higher than a predetermined temperature.
In operation, the heat generating device 110 may generate a digital signal on the line 120 indicating the temperature of the heat generating device 110. The cooling system controller 130 may calculate the temperature of the heat generating device 110 based on the digital signal generated on the line 120. The cooling system controller 130 may generate a signal on line 140. The cooling device 150 may receive the generated signal on line 140 and adjust the operation of the cooling device 150 based on the generated signal.
In an embodiment, the heat generating device 110 is an electronic device. In an embodiment, the heat generating device 110 is an integrated circuit with a processor and a predetermined number of pins for outputting signals. In an embodiment, the heat generating device 110 includes a circuit for determining the temperature of the heat generating device 110.
In an embodiment, line 120 and/or line 140 are signal lines on a printed circuit board. In an embodiment, line 120 and/or line 140 are copper wires.
In an embodiment, cooling system controller 130 is an integrated circuit with a pin for input of line 120 and at least one pin for output of line 140.
In an embodiment, cooling system 150 may include a fan 155 that operates in proportion to the received signal on line 140. In an embodiment, cooling system 150 is a system for cooling heat generating device 110 such as a cooling system 150 that operates a pump to move fluid to remove heat from heat generating device 110.
a illustrates an embodiment of a digital signal 250 indicating the temperature of the device. The vertical axis of the graph is voltage 210 and the horizontal axis of the graph is time 220. The signal 250 as illustrated is either high 240.1 or low 240.0. There are three full cycles 230 illustrated. In an embodiment, the digital signal 250 is a pulse width modulated signal with the temperature of the device indicated as a percentage of the time the signal is high 240.1 for a cycle 230. For example, in cycles 230.1, 230.2, and 230.3 the signals are at a zero (0) state 240.0 for twenty-five percent (25%) of the cycle 230 and at a one (1) state for seventy-five percent (75%) of the cycle 230. In an embodiment, cycles 230.1, 230.2, and 230.3 indicate that the temperature of the device is seventy-five percent (75%) of a maximum temperature. The percentage of time that a signal is high during a cycle may be called a duty cycle. It should be understood that the values stated herein, such as 25 percent, 75 percent, 100 percent, and the stated revolutions per minutes (RPM) can be at or approximate to those stated values.
b illustrates an embodiment of a digital signal 250 indicating the temperature of the device. Cycle 230.4 illustrates the signal 250 being at a zero (0) state 240.0 for fifty percent (50%) of the cycle 230.4 and being at a one (1) state 240.1 for fifty percent (50%) of the cycle 230.4. In an embodiment, cycle 230.4 indicates that the device is at fifty percent (50%) of a maximum temperature. Cycle 230.5 illustrates the signal 250 being at a zero state (0) for seventy-five percent (75%) of the cycle 230.5 and being at a one (1) state 240.1 for twenty-five percent (25%) of the cycle 230.5. In an embodiment, cycle 230.5 indicates that the device is at twenty-five percent (25%) of a maximum temperature. Cycle 230.6 illustrates the signal 250 being at a zero state (0) for one-hundred percent (100%) of the cycle 230.6 and being at a one (1) state for zero percent (0%) of the cycle. In an embodiment, cycle 230.6 indicates that the device is at zero percent (0%) of a maximum temperature.
c illustrates a table for an embodiment of the present invention for setting a fan 152 speed based on the temperature of a device as indicated by a digital signal. The table illustrates an embodiment for how a fan 152 speed may be set based on the percentage of a cycle that the signal is high. For example, in row 260.1 the percentage of the cycle that the signal is high is zero percent (0%) and the fan 152 speed is set to zero (0). For row 260.2, the percentage of the cycle that the signal is high is twenty-five percent (25%) and the fan 152 speed is set to 500. For row 260.3, the percentage of the cycle that the signal is high is fifty percent (50%) and the fan 152 speed is set to 1000 RPM. For row 260.4, the percentage of the cycle that the signal is high is seventy-five percent (75%) and the fan 152 speed is set to 1500 RPM.
Many different ways of conveying the temperature of the device digitally on the line are possible. For example, the percentage of time that the signal is high may represent a relative temperature, e.g. a percentage above a normal operating temperature. As another example, the percentage of time that the signal is high may represent a temperature related to a temperature scale such as the Celsius or Fahrenheit. For example, the percentage could be one-half the actual temperature of the device in the Celsius scale. As another example, the percentage of time that the signal is high may represent the percentage of the current temperature of the device the device is to a maximum operating temperature of the device. Additionally, there are many different ways for conveying a digital signal on a single line.
Embodiments have the advantage that since the temperature information is conveyed digitally, the temperature information is not highly sensitive to noise.
Embodiments have the advantage that since the temperature is conveyed on a signal line, less space may be used to convey the temperature information. Embodiments have the advantage that for integrated circuits that only a single pin of the integrated circuit is used to convey the temperature information.
Various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.
