Patent ID: 6912159
Filing Date: 2005-06-28
Classification: G11C

Abstract:
1. A boosting circuit having charge pump circuits for generating a boosting voltage with respect to a predetermined potential by allowing charge to move through a charge transfer transistor in synchronization with a clock signal input through a capacitor, comprising: a first charge pump circuit group in which the charge pump circuits are connected in series of n stages (n is an integer of 2 or more) to each other; a second charge pump circuit group in which the charge pump circuits are connected in series of m stages (m is an integer of 2 or more) to each other; and a stage-number switching circuit for switching an output terminal of the first charge pump circuit group and an input terminal of the second charge pump circuit group between a connected state and an unconnected state in accordance with a stage-number switching control signal, in such a manner that the first charge pump circuit group and the second charge pump circuit group are connected in series with each other and the second charge pump circuit group outputs a first boosting voltage, or the first charge pump circuit group and the second charge pump circuit group are connected in parallel with each other and the first and second charge pump circuit groups output a second boosting voltage, wherein the stage-number switching circuit includes: in a case where the stage-number switching control signal is at a first voltage level, the switching transistor is turned on with a supplied clock signal, and in a case where the stage-number switching control signal is at a second voltage level, the switching transistor is turned off.