| 摘要 |
A charge pump circuit has at least three stages: a pre-stage, a common stage and post stage. Each stage has three devices which are common. An NMOS device, which is called the charge injection device (CID), is controlled by a PMOS device during charge injection and an NMOS device during charge trapping. Also, each of the stages includes comparison stages for the CID in order to minimize the bulk to source voltage (Vbs) or bulk to drain voltage (Vbd). This greatly improves efficiency during the charge injection phase. Furthermore, the post-stage includes a comparison stage for the PMOS device since the threshold voltage increases as you increase the number of stages with the bulk tied to VPWR. The PMOS comparison stage should be inserted at the stage where the PMOS device begins to operate in the sub-threshold region, which is technology and voltage dependent.
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