Patent ID: 6208197
Filing Date: 2001-03-27
Classification: H02M

Abstract:
A charge pump formed in and on a semiconductor substance, the charge pump comprising:a first pump circuit having an output lead and having a first switch formed in and on a well, the well having a conductivity different from a conductivity of the substance, the first pump circuit being coupled to receive an external supply voltage, wherein the first pump circuit is configured to cause the output lead to have an output voltage with a level higher than the level of the external supply voltage, and wherein the first switch comprises a P-channel transistor formed in an N-well, the drain of the P-channel transistor of the first switch being coupled to the output lead;a second pump circuit being coupled to receive the external supply voltage, wherein the second pump circuit is configured to cause the well to have a voltage lever equal to or higher than the level of the output voltage;a first clamp circuit coupled to the output lead and to the well, wherein the first clamp circuit is configured to provide a current path from the well to the output lead when the voltage level of the well reaches a first predetermined threshold; anda second clamp circuit coupled to the output lead and to an internal node wherein the internal node is coupled to the second pump circuit, wherein the second pump circuit is configured to provide a current path from the internal node to the output lead when a voltage level of the internal node reaches a second predetermined threshold.