Patent ID: 7123077
Filing Date: 2006-10-17
Classification: H02M,H03K

Abstract:
1. A four-phase charge pump circuit with reduced body effect comprising: an input stage; an output stage, which outputs a boosted voltage; and multiple boosting stages coupled between the input stage and the output stage and driven by four phase clock signals; each boosting stage comprising an upper branch charge pump and a lower branch charge pump, each branch charge pump further comprising: a main pass transistor having a body, a gate terminal, a source terminal as a first node and a drain terminal as a second node, wherein the first node and the second node connect respectively to a front boosting stage and a rear boosting stage, and potential at the body is kept at a low level by the four phase clock signals; a pre-charge transistor having a gate terminal, a source terminal and a drain terminal, wherein the drain terminal and the source terminal of the pre-charge transistor are coupled to the gate terminal of the main transistor and the second node; the gate terminal of the pre-charge transistor is coupled to the first node of the main pass transistor; two capacitors coupled respectively to the gate terminal of the main pass transistor and the first node; and two substrate transistors, each of them having a body, a gate terminal, a source terminal and a drain terminal, wherein the source terminals and the bodies of the substrate transistors are connected together to the body of the main pass transistor, and the drain terminals of the substrate transistors are connected respectively to the first node and the second node of the main pass transistor; wherein the gate terminal of one substrate transistor, whose drain terminal connects to the first node of the main pass transistor, is connected to the second node of the main pass transistor, and the gate of the other substrate transistor is connected to the second node of the main pass transistor of the other branch charge pump.