A method of simulating the voltage-current characteristics of a short channel metal-oxide-semiconductor field effect transistor (MOSFET) by connecting a series of incremental MOSFETs of different threshold voltages. The threshold voltages near the source and the drain are reduced due to charge sharing. The substrate of each reduced threshold voltage incremental MOSFET is connected to its source. The reduction in threshold voltage can be obtained by Schwartz-Christoffel transformation of the depletion layer edges of the charge sharing region. From these threshold voltages one can calculate the incremental channel conductances and the voltage drops.

A thermal control system for variable speed microprocessor with a piecewise estimate of temperature change. The estimate is modeled after actual temperature change measurements of a microprocessor operating at low and high speeds and is recorded in a digital format in storage registers, one set of registers for each operating frequency. A counter counts sample microprocessor clock signals for a time over which the microprocessor speed is operating at a specific speed and provides a basic count signal. This basic count signal is incremented or decremented by comparison with stored values of the piecewise estimate of temperature change. As the basic signal increases or decreases, new slopes are provided to the counter for adjusting the basic count, upwards or downwards, depending on whether the system speed is high, intermediate or low. The adjusted counter output is also fed to comparators, which monitor a desired upper and lower temperature limit. As the upper limit is approached, control logic implements a throttling algorithm to maintain temperature in the desired range. The present invention takes into account the operating history of the system in a particular environment since the system powers on, including idleness of the system.

In a method for control of an installation for transmission of high-voltage direct current in dependence on at least one stress parameter for a valve in a converter included in the installation and controlled by control equipment (CE1, CE2), a value (PDR, PDI, UMAX, TRC, TTC) of the stress parameter is continuously calculated, based on predetermined relationships (f1, f2, g1R, g2R, g1I, g2I, h1, h2) and in dependence on measured values (UN, .alpha., .gamma., ID, TO, TI, RECT/INV) of the operating parameters of the installation. At least one influencing signal (HTH, HCC, HCR) is generated in dependence on a comparison between the calculated value and at least one comparison value for the parameter, and the influencing signal is supplied to the control equipment to influence this in a direction which limits the value of the stress parameter. The member (HAS) comprises a monitoring device (PD, UA, TR, TT) for calculating the value of the stress parameter.

A real-time thermal management apparatus and method for a computer employs a monitor (40) to determine whether a CPU may rest based upon real-time sampling of temperature levels and CPU activity levels within the computer. The monitor activates a hardware selector to carry out the monitor's determination. If the monitor determines the CPU may rest, the hardware selector reduces CPU clock time; if the CPU is to be active, the hardware selector returns the CPU to its previous high speed clock level. Switching back into full operation from its rest state occurs without a user having to request it and without any delay in the operation of the computer while waiting for the computer to return to a "ready" state. Furthermore, the monitor (40) adjusts the performance level of the computer in response to the real-time sampling of CPU activity and temperature levels. Such adjustments are accomplished within the CPU cycles and do not affect the user's perception of performance and do not affect any system application software executing on the computer.