Conventional LDO regulator analysis usually ignores the feedforward zero due to the pass transistor’s Cgd. In fact, Table I shows that the feedforward zero falls beyond the typical LDO’s open-loop unity gain frequency, and therefore, does not typically surface during the conventional LDO regulator ac analysis. However, it is worth mentioning that this RHP zero Z1 attracts complex poles to the right-hand side of the S-plane, degrading the loop’s stability. The presented external capacitorless LDO regulator requires a gain-bandwidth product of around 500 kHz. At those frequencies, the feedforward zero has noticeable effects at low load currents.
đang được dịch, vui lòng đợi..
