Charge transfer switch

Abstract: An efficient charge pump circuit. Increased efficiency compared to previous pump circuits is achieved through use of a novel charge transfer switch and associated clocking scheme which reduces the supply current required to operate the charge pump. Instead of repeatedly charging and discharging a stray capacitance of each pump stage capacitor, some of the charge stored in the stray capacitor on the clock driver side is transferred to the next pump stage. This serves to pre-charge the stray capacitor of the next stage, reducing the supply current required to operate the charge pump. The apparatus and method described can also be used to reduce the power consumed by a system or circuit which has internal signals or nodes which are in opposite phase to each other. This is accomplished by reducing the power used to charge and discharge a stray capacitance associated with the signals or nodes.

Abstract: In a photoelectric conversion device having a plurality of pixel cells each of which includes a photoelectric conversion element, a field effect transistor having the gate area for storing signal charge generated by the photoelectric conversion element and the source-drain path for outputting a signal corresponding to the signal charge stored in the gate, a first power supply line for supplying electric power to the field effect transistor, and a first switch connected between the field effect transistor and the first power supply line, when a reset voltage for resetting the gate of the field effect transistor is Vsig0, a threshold voltage of the field effect transistor is Vth, current flowing through the field effect transistor is Ia, a voltage applied via the first power supply line is Vc1, and a series resistance of the first switch is Ron, each pixel cell is configured to satisfy a condition determined by Vc1−Ron×Ia>Vsig0−Vth.

Abstract: A voltage generating circuit in accordance with the present invention includes a plurality of pump stages for alternatingly performing its pumping and pre-charging operation, and a pre-charge stage for pre-charging a first pump stage to a first reference voltage level (e.g., a power supply level). Each of the pump stages can include first and second pumps with a symmetrical structure for alternatingly performing a pumping operation and a pre-charging operation during a first clock cycle, and a charge transfer switch. The charge transfer switch is connected between the pumping capacitors of the first and second pumps, for thereby sharing the charge of each pumping capacitor of the first and second pumps before the first clock cycle is finished.