Patent ID: 8760190

Claim:
A method to provide Process-Voltage-Temperature (PVT) compensation for an Input/Output (IO) interface, said IO interface having a bandgap reference voltage (V BGR ) and a reference frequency (F REF ), said method comprising: connecting said V BGR to a voltage reduction system; reducing said V BGR by substantially half at said voltage reduction system to produce V BGR /2; connecting said V BGR /2 to a current mirror system; connecting said current mirror system to a high supply voltage (V DD ); connecting a driver bit cell to a low supply voltage (V SS ); connecting said current mirror system to said driver bit cell such that a process-variable-temperature current (I PVT ) flows through said driver bit cell; connecting said current mirror system to a compensated current controlled oscillator; mirroring said I PVT at said current mirror system such that said compensated current controlled oscillator receives a control current (I CNTL ) that is proportional to said I PVT ; generating an oscillation frequency (F OSC ) at said compensated current controlled oscillator that is a function of said I CNTL ; connecting said F OSC to a digital system; connecting said F REF to said digital system; measuring, by said digital system, a desired count period based on F REF ; accumulating, by said digital system, a count of said F OSC at said digital system during said desired count period; looking up, by said digital system, a PVT control bit value that correlates to said accumulated count of said F OSC in a look-up table containing a predetermined correlation of potential count values of said F OSC to desired PVT control bit values; and providing, by said digital system, said looked up PVT control bit value to said IO interface.