Abstract: A module type distinguishing apparatus and method for differentiating between modules based upon the presence or absence of a pulling resistor at a specified pin connection of the modules. A high impedance pulling resistance is connected to the line and is subject to sensing while a tri-state mode of operation is initiated in the module. The presence or absence of the pulling resistor in the module is detected and recorded in a register. Differentiation between module types is accomplished based upon the binary state of the data in the register. In a particularized implementation, industry standard L2 cache modules are distinguished as to tag bit size depending on the presence or absence of a pulling resistor as detected during tri-state operation of a tag output pin.

Abstract: A power supply interface suitable to provide voltages of appropriate magnitude to a static random access memory (SRAM) device from a combination of independent sources including a main power supply, an auxiliary power supply, and a battery. The voltages from the interface are at levels consistent with the SRAM modes of operation. During limited voltage tolerance read and write access operations, main power supply voltage is provided through a low forward voltage drop switched metal oxide field effect transistor (MOSFET). Parasitic paths, potentially producible by the transistor and affecting the battery source of power, are eliminated through the use of a second, complementary MOSFET. The second MOSFET is directly responsive to a POWERGOOD signal from the main power supply, indicating both an "on" state and an appropriate voltage level of the main power supply.

Abstract: Systems and methods for reducing the thermal stresses between an integrated circuit package and a printed circuit board, each having different thermal coefficients of expansion, to minimize thermal fatigue induced by power management cycling. The thermal impedance of the convection cooling system used with the integrated circuit package is switched with the state of the power management signal. A fan on the integrated circuit package heat sink is energized when the integrated circuit is operated in a high power mode and disabled when the integrated circuit is in a low power mode initiated by the power management system. The switching is directly responsive to the power management system and without regard to integrated circuit package temperature. The switching of the fan alters the thermal impedance to reduce the extremes of the temperature excursion and to materially reduce the rate of change of temperature experienced by the integrated circuit package.