Reference voltage generator using a pair of complementary-to-absolute temperature voltages

Abstract

Disclosed are a structure and method for generating a reference voltage (VREF) that remains essentially constant in response variations in temperature and/or variations in a positive supply voltage. The structure can include a VREF generation circuit with a first stage for generating a first complementary-to-absolute temperature voltage (V_CTAT), a second stage for generating a second complementary-to-absolute temperature voltage (V_CTAT) higher than but exhibiting the same temperature-dependent rate of change as V_CTAT, and an output stage for generating VREF as a function of the difference between V_CTATand V_CTAT(e.g., VREF can be approximately equal to V_CTATminus V_CTAT). In this structure, the same bias voltage (VBIAS) is employed for each stage and all transistors can be metal oxide semiconductor field effect transistors (MOSFETs). With the disclosed configuration, a more stable VREF across a wider temperature range and/or VDD range is achievable and the structure may consume less chip area.