available the current industry standard practice is to drive the emitter with currents i e1 and i e2 whose ratio is m if u03b2 1 i e1 u03b2 2 i e2 then the collector ratio is also m and temperature is easily determined in high performance cmos processes it is unlikely that u03b2 1 u03b2 2 further in these processes u03b2 is typically very low 0 5 2 0 this is shown in the graph of fig3 by curve 301 in this case i e1 i e2 u2260 i c1 i c2 the problem is indicated if the equation for u03b4v be is modified to read u03b4 v be u03b7kt q ln i e2 u03b2 1 1 u03b2 2 i e1 u03b2 2 1 u03b2 1 if for example u03b2 1 0 7 and u03b2 2 0 8 we may record an error of 10 u00b0 c when using the industry approach of driving the emitter this error is not tolerable when system requirements are errors of 1 u00b0 c or less in accordance with a first method to correct for this error beta correction is utilized we wish to control i c2 i c1 m thus m i e2 u2212 i b2 i e1 u2212 i.