Patent ID: 6483282
Filing Date: 2002-11-19
Classification: H02M

Abstract:
A charge pump-type DC/DC converter regulated to a predefined output voltage and comprising n (n&gE;2) elementary stages each consisting of a charge pump capacitor and several controllable switches connected thereto via which the charge pump capacitor is connectable either parallel to the input voltage of the corresponding elementary stage so that it can be charged in the charging phase of a charge pump cycle maximally roughly to the input voltage of the corresponding stage or connected in series to the input voltage of the corresponding stage so that in the discharge phase of a charge pump cycle at the output of a the corresponding stage a voltage can be generated corresponding maximally roughly to twice the input voltage of the stage, whereby the input voltage of the DC/DC converter is applied to the input of the first stage, both electrodes of the charge pump capacitor of the kth stage are connectable via one of the controllable switches to the output of the (kâ€”1)th stage, k=2, . . . , n and the output of the nth stage forms the output of the DC/DC converter, characterized in that it in addition comprises one or more further controllable switches via which the electrode of the charge pump capacitor of the nth stage, which in the discharge phase is not connected to the output of the converter, is connectable to one or more outputs of the 1th stage (1=(nâˆ’2), . . . 1) and/or of the input voltage, and a control circuit which in the discharge phase of the charge pump cycle signals ON, as a function of the input voltage of the DC/DC converter, that switch of the array consisting of the one controllable switch via which the electrode of the charge pump capacitor of the nth stage can be connected to the output of the (nâˆ’1)th stage and the further controllable switches and connects the voltage applied thereto to the cited electrode of the charge pump capacitor of the nth stage at which the efficiency of the DC/DC converter is a maximum.