Patent ID: 7714635

Claim:
In an integrated circuit having a substrate, an apparatus contained within the integrated circuit for providing a voltage scaling signal to adjust an internal voltage supplied to circuitry within the integrated circuit comprising: a temperature measurement circuit having a thermal diode positioned upon the substrate for measuring temperature, the thermal diode connected to a voltage source and having a thermal diode output connected to a first input of a comparator, an address counter connected to a system clock, and providing an incrementing address to a first digital to analog converter connected to a second input of the comparator, the address counter further connected to a comparator output, and an address counter output wherein the thermal diode provides a voltage to the comparator which is compared to a voltage from the digital to analog converter and when equal, the comparator provides its output to the address counter which provides a resulting incremented address signal representing a measured temperature value; an IR drop measurement circuit including: a first loop oscillator circuit having a first plurality of invertors connected in a loop and each first loop invertor connected to an integrated circuit voltage source, the first loop oscillator circuit having a first loop frequency output; a second loop oscillator circuit having a second plurality of invertors connected in a loop and each second loop invertor connected to a bandgap voltage source, the second loop oscillator circuit having a second loop frequency output; a first difference circuit connected to receive the first and second loop frequency outputs and storing an IR drop value signal output to an IR drop register, a frequency measurement circuit within the integrated circuit including a pulse width table connected to receive the resulting incremented address signal as an input address and providing a corresponding predetermined frequency output signal; a second difference circuit connected to receive the predetermined frequency analog signal and the second loop frequency output and storing a frequency difference value output to a process sensor register; a supervisor circuit connected to the IR drop register and the process sensor register and receiving user input values for either the IR drop register or the process sensor register and upon receiving the user input values, storing the received user input values to the IR drop register or the process sensor register in place of any previously stored values; and a summing circuit connected to the IR drop register and the process sensor register and summing the values from the IR drop register and the process sensor register to provide the voltage scaling signal.