Depletion capacitance compensator
AssigneeHughes Aircraft Company
InventorPaul R. Prince
Life of this patent
Estimating the term…
Abstract
The capacitance of a compensating reverse biased diode is added to the capacitance of a pn junction formed by surface depletion and inversion in a charge coupled device having variations in depletion capacitance which are to be compensated. Because the compensating diode is connected in an opposite sense with respect to the pn junction, an increase in small signal variations in the potential across the pn junction causes a decrease in small signal variations in the potential across the compensating diode. The resulting change in the capacitance of the pn junction is accompanied by a corresponding opposite change in the capacitance of the compensating diode so that the combined capacitance of the two elements remains nearly constant during all small signal variations in potential.
Claims10
A charge coupled device formed on a semiconductive layer of a first conductivity type having a charge flow channel adapted for transfer therethrough of charge packets, having depletion capacitance compensation, comprising:
- a compensating diode formed in or near said layer adjacent to said channel, including a first conductivity type portion and a second conductivity type portion;
- a charge storage region of said second conductivity type formed in said channel adapted for storage of a charge packet therein;
- a conductor connected directly between said charge storage region and said first conductivity type portion of said compensating diode;
- and
- means for maintaining a reverse bias potential across said first and second conductivity type portions of said compensating diode.
A charge coupled device having depletion capacitance compensation, comprising:
- a semiconductive layer of a first conductivity type;
- a channel stop of said first conductivity type defining a charge flow channel in said layer;
- a first region of a second conductivity type in said layer;
- a channel stop disposed near the boundary of said first region;
- a diode comprising a portion of said first conductivity type disposed in said first region;
- a second region of said second conductivity type spanning at least a portion of said charge flow channel;
- and
- a conductor directly connecting said diode portion and said second region.
A charge coupled device having improved linearity, comprising:
- a semiconductive layer of a first conductivity type;
- a charge flow channel in said layer adapted for transfer therethrough of charge packets;
- a region of a second conductivity type formed in said channel adapted for storing a charge packet therein;
- a charge sensing floating electrode overlying said region and insulated therefrom;
- a depletion capacitance compensating diode having adjoining semiconductive portions of first and second conductivity types, the first conductivity type portion of said compensating diode being directly connected to said region by means of a conductor.
A charge coupled device transversal filter, having depletion capacitance compensation, comprising:
- a semiconductive layer of a first conductivity type;
- a charge flow channel in said semiconductive layer adapted for transfer therethrough of charge packets;
- a plurality of floating electrodes overlying said channel;
- at least one region of a second conductivity type formed in said channel underlying a corresponding one of said floating electrodes, said region adapted to store a charge packet therein;
- a depletion capacitance compensating diode disposed externally of said charge flow channel having first and second adjoining semiconductive portions of said first and second conductivity types respectively;
- and
- a conductor directly connecting said first conductivity type portion of said diode with said one region.
A charge coupled device transversal filter having depletion capacitance compensation. comprising:
- a semiconductive layer of a first conductivity type;
- a plurality of charge sensing floating electrodes overlying said layer;
- a plurality of regions of a second conductivity type underlying said plurality of floating electrodes;
- and
- a depletion capacitance compensating diode having first and second adjoining semiconductive portions of said first and second conductivity types respectively, said first conductivity portion being directly connected to at least one of said plurality of regions by means of a conductor.
Dependencies are inferred from the claim text.