derivative at 404 fig5 shows another embodiment of a reference voltage generator reference voltage generator 500 comprises capacitor 502 differential pair 510 current source 520 current mirror 530 and current mirror 540 and desired reference voltage source 550 like in reference voltage generator 200 capacitor 502 is used to hold the reference voltage differential pair 510 is shown comprising pfet 512 and pfet 514 with one input tied to ground or v ss the other input is tied to the reference voltage current source 520 is shown comprising pfet 522 connected to a bias voltage current mirror 530 is shown comprising nfet 532 and nfet 534 current mirror 540 is shown comprising pfet 542 and pfet 544 with an output coupled to capacitor 502 desired reference voltage source 550 provides a desired reference voltage in the example shown here desired reference voltage source 550 is shown as provided by a voltage divider having resistors 552 and 554 however desired reference voltage source can be a bandgap voltage or a voltage divider having resistors and a buffer initially reference voltage generator 500 is activated by activating current source 520 such as by closing switch 524 when current source 520 is activated current flows through the differential pair through pfet 512 and pfet 514 the proportion of the current flowing through each pfet depends on the inherent resistance of each pfet and the voltage difference in order to minimize the initial discontinuity in the slope it is desirable for most of the current initially to flow through pfet 512 by doing so the amount of current used to charge capacitor 502 is small because the current.