Charge-pump circuit and control method thereof
First Claim
1. A charge-pump circuit comprising:
- at least first and second electrical charge transfer devices connected in series;
first and second capacitors;
clock supplying means supplying clock to one end of the second capacitor;
first switching means for connecting said first and second capacitors to a connecting point of the first and second electrical charge transfer devices in series; and
second switching means for connecting said first and second capacitors to the connecting point of the first and second electrical charge transfer device in parallel, wherein at least said first switching means consists of a MOS transistor for control and the charge-pump circuit has means for biasing a substrate of the MOS transistor for control so that forward direction current does not flow substantially through a parasitic diode accompanying the MOS transistor for control.
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Accused Products
Abstract
A charge-pump circuit has means biasing electrical potential of a substrate of a MOS transistor for control M2 so that forward direction current does not flow substantially through a,parasitic diode Dp1. In the concrete, the substrate of the substrate of a MOS transistor for control M2 is biased by voltage of a connecting point of the substrate of a MOS transistor for control M2 and a capacitor 1 at the case that the substrate of a MOS transistor for control M2 is P-channel type. Thus, it is prevented that a parasitic diode is biased to forward direction in a charge-pump circuit carrying out voltage fluctuation with lower voltage step than power source voltage Vdd so as to carry out normally charge-pump operation.
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Citations
8 Claims
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1. A charge-pump circuit comprising:
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at least first and second electrical charge transfer devices connected in series;
first and second capacitors;
clock supplying means supplying clock to one end of the second capacitor;
first switching means for connecting said first and second capacitors to a connecting point of the first and second electrical charge transfer devices in series; and
second switching means for connecting said first and second capacitors to the connecting point of the first and second electrical charge transfer device in parallel, wherein at least said first switching means consists of a MOS transistor for control and the charge-pump circuit has means for biasing a substrate of the MOS transistor for control so that forward direction current does not flow substantially through a parasitic diode accompanying the MOS transistor for control. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for controlling of charge-pump circuit comprising the step of:
- at least first and second electrical charge transfer devices connected in series;
first and second capacitors;
clock supplying means supplying clock to one end of the second capacitor;
first switching means for connecting said first and second capacitors to a connecting point of the first and second electrical charge transfer devices in series; and
second switching means for connecting said first and second capacitors to the connecting point of the first and second electrical charge transfer device in parallel, in which at least said first switching means consists of a MOS transistor for control and the charge-pump circuit has means for biasing a substrate of the MOS transistor for control so that forward direction current does not flow substantially through a parasitic diode accompanying the MOS transistor for electrical charge transfer, said method for controlling further comprising a step of changing state of said clock by said clock supplying means after said first and second switching means turn off. - View Dependent Claims (8)
- at least first and second electrical charge transfer devices connected in series;
Specification