Fan speed control from adaptive voltage supply

An electronic system comprising:

• a thermal diode connected to a voltage source,
• an addressing circuit connected to be incremented by a system clock,
• a digital temperature table connected to the addressing circuit to provide a temperature value represented by a voltage for each incremented address from said addressing circuit,
• a comparator connected to the digital temperature table and to the thermal diode and providing a signal indicating when the address temperature voltage of the temperature table is equal to a voltage of the thermal diode,
• a frequency response table connected to the output of the digital temperature table,
• a voltage scaling signal circuit connected to the frequency response table,
• a voltage supply providing voltage to the electronic system in response to a voltage scaling signal received from the voltage scaling signal circuit, and
• a fan control circuit controlling a speed of a cooling fan according to a the voltage of the thermal diode and the digital temperature table.

An electronic system comprising:

• a plurality of temperature measuring circuits located upon the surface of an integrated circuit and each providing a temperature signal and each circuit including:
• a thermal diode connected to a voltage source,
• an addressing circuit connected to be incremented by a system clock,
• a digital temperature table connected to the addressing circuit to provide a temperature value represented by a voltage for each incremented address from said addressing circuit,
• a comparator connected to the digital temperature table and to the thermal diode and providing a signal indicating when the address temperature voltage of the temperature table is equal to a voltage of the thermal diode,
• a fan control circuit controlling a speed of a cooling fan according the plurality of temperatures signals.

A computer program product stored in a computer operable media, the computer operable media containing instructions for execution by a computer, which, when executed by the computer, cause the computer to implement a method for controlling the speed of a cooling fan provided to cool an integrated circuit comprising the steps of:

• receiving a first voltage from a thermal diode on the circuit;
• addressing a table of digital temperature representations by incrementing an address every cycle of a circuit clock,
• converting the addressed data to a second voltage representing the addressed temperature,
• comparing the first voltage with the second voltage,
• providing a corresponding temperature value when both the first and second voltages are equal,
• adjusting the fan speed according to the corresponding temperature.