A Design of Low-dropout Regulator with Adaptive Threshold Voltage Technique

In this paper, the characteristics of Low Dropout Regulators to which the adaptive threshold voltage technique was applied were analyzed. For this analysis, fore types of LDO were fabricated. Also Proposed LDO is fabricated in 0.18 um BCD process. The first was a conventional LDO. For the second type of LDO, the adaptive threshold voltage technique was applied to the error AMP and voltage buffer; for the third type of LDO, the adaptive threshold voltage technique was applied to the pass TR and for the fourth type of LDO, the adaptive threshold voltage technique was applied to the error AMP, voltage buffer, and pass TR. The adaptive threshold voltage technique applies a separate voltage to the body terminal of transistor to reduce the threshold voltage (Vth) and increase the drain current. In this paper, the adaptive threshold voltage technique was applied to each block. Then the characteristics and areas of the four types were comparatively analyzed. The area of the current-mirror of the error AMP and voltage buffer proposed in this paper decreased by about 61% compared to the conventional current-mirror. Furthermore, the area of the pass TR proposed in this paper decreased by 5.5% compared to the conventional pass TR and the regulation characteristic of the LDO improved