A-to-D Converter of the successive-approximation type

An integrated circuit analog-to-digital converter comprising:

• substrate means having transistors and associated circuitry diffused therein;
• d-c power supply bus means for said substrate means and comprising a negative voltage bus, and a ground common bus;
• said transistors including a set of inverted mode transistors arranged as a successive-approximation control means and register means;
• said transistors further comprising current source means including a set of normal mode transistors serving as switch-controllable current sources;
• normal mode transistor switch means coupled to said successive-approximation control means for controlling said current sources so as to produce summation currents for comparison with an analog input signal whereby to determine the digital signals to be stored in said register means;
• first circuit means coupling said inverted mode transistors between said common bus and said negative bus to supply power thereto and arranged to operate said inverted mode transistors in a first voltage range;
• second circuit means coupling said normal mode transistors between said common bus and said negative bus to supply power thereto and arranged to operate said normal mode transistors in a second voltage range which is negative relative to said first voltage range;
• and
• third circuit means interconnecting said switch means with said set of normal mode transistors to provide control of the individual current sources in accordance with the operation of said successive-approximation control means and register means;
• the negative supply voltage for the successive-approximation control means permitting it to directly drive said switch means without the need for voltage level translators.

An analog-to-digital converter comprising a single monolithic chip formed with:

• a plurality of normal mode transistor current sources arranged to produce respective currents for summation into a composite signal;
• I.sup.2 L inverted mode transistor means including logic circuitry means defining successive-approximation control means arranged to carry out a successive-approximation algorithm;
• and
• normal mode transistor switch means responsive to said successive-approximation control means and serving to selectively control the outputs of said current sources to carry out said algorithm for developing a digital output corresponding to an unknown analog signal;
• power supply means comprising a ground terminal and a negative terminal;
• and
• circuit means interconnecting both said I.sup.2 L transistor means and said normal mode transistors between said ground terminal and said negative terminal to supply operating current thereto.

An analog-to-digital converter comprising a single monolithic chip formed with:

• a plurality of normal mode transistor current sources arranged to produce respective currents for summation into a composite signal;
• I.sup.2 L inverted mode transistor means including logic circuit means defining successive-approximation control means arranged to carry out a successive-approximation algorithm;
• power supply means comprising first and second terminals providing first and second potentials of fixed magnitudes with said second potential being less positive than said first potential;
• a current supply circuit comprising normal mode transistors;
• first circuit means coupling the negative-voltage side of said inverted mode transistors to the positive-voltage side of said current supply circuit transistors, in a common series connection therebetween;
• second circuit means coupling the positive-voltage side of said inverted mode transistors to said first terminal to establish the positive side of said logic circuit means at a fixed potential;
• and
• third circuit means coupling the negative-voltage side of said current supply circuit transistors to said second terminal, whereby negative current flows from said second terminal through said current supply circuit transistors, said common series connection, and said inverted mode transistors.

An analog-to-digital converter comprising a single monolithic chip formed with:

• a plurality of normal mode transistor current sources arranged to produce respective currents for summation into a composite signal;
• I.sup.2 L inverted mode transistor means including logic circuit means defining successive-approximation control means arranged to carry out a successive-approximation algorithm;
• switch means responsive to said successive-approximation control means and serving to selectively control the outputs of said current sources to carry out said algorithm for developing a digital output corresponding to an unknown analog signal;
• said inverted mode transistors and said normal mode current source transistors all being operated in a below-ground potential range with said current source transistors being operated in a range which is more negative than the potential range of said inverted mode transistors;
• means fixing the injector voltage for said inverted mode transistors;
• and
• means for supplying a negative current to the negative terminal of said logic circuit means;
• said means for supplying negative current comprising means connecting said negative logic terminal to the positive voltage side of a circuit comprising normal mode transistors, whereby the negative current flowing through said normal mode transistor circuit also flows through said inverted mode transistors.

An analog-to-digital converter comprising a single monolithic chip having both analog circuits and digital circuits for processing an analog input signal to a corresponding digital output signal, said chip comprising:

• normal-mode transistor means forming part of said analog circuits and including a set of current sources for producing an internally derived-signal for comparison with the analog input signal;
• switch means for controlling said current sources;
• I.sup.2 L inverted-mode transistor means forming part of said digital circuits and including switch control transistors coupled to said switch means without the interposition of level-translating means therebetween;
• said I.sup.2 L inverted-mode transistor means further comprising logic means for activating said switch control transistors to carry out a conversion algorithm;
• power supply means comprising a pair of terminals, one of said terminals being at ground potential and the other being negative with respect to ground;
• means providing a signal which is positive with respect to ground for controlling the operation of said logic means;
• and
• circuit means interconnecting said I.sup.2 L transistor means and said normal mode transistor means between said power supply terminals to supply operating current to both of said transistor means while maintaining both in a below ground voltage range.

An analog-to-digital converter comprising an integrated circuit chip, the combination of:

• analog circuitry comprising a first group of normal-mode transistors and an output terminal;
• said normal-mode transistors each having first and second main electrodes;
• first power supply terminal means connected to said normal-mode transistors to supply operating current through the main electrodes thereof;
• said first group of transistors having first circuit means operable therewith to control the flow of current through the main electrodes of one of said normal-mode transistors;
• means coupling said one transistor to said output terminal to develop thereon an output signal variable in accordance with changes in the flow of current through said one transistor;
• said analog circuitry including a second group of normal mode transistors including a set of switchable current sources;
• said output signal being coupled to said second group of normal mode transistors to provide a control signal for controlling the functioning thereof in accordance with said output signal;
• I.sup.2 L inverted mode transistors forming logic circuitry producing a digital output signal to control the switching of said set of current sources;
• second power supply terminal means for said inverted mode transistors;
• voltage supply means;
• and
• means connecting said first and second power supply terminal means serially with said voltage supply means to provide that current flowing through and used in the operation of said first group of normal mode transistors is used also to power said I.sup.2 L logic circuitry.

An intergrated circuit analog-to-digital converter comprising:

• substrate means having transistors and associated circuitry diffused therein;
• d-c power supply bus means for said substrate means and comprising a negative voltage bus and a ground common bus;
• said transistors including a set of inverted mode transistors arranged as a successive-approximation control means and register means;
• means providing a positive control singal for said successive-approximation control means;
• said transistors further including a set of normal mode transistors serving a switch-controllable current sources;
• transistor switch means coupled to said successive-approximation control means without the interposition of level translators therebetween, said transistor switch means being operable by said successive-approximation means for controlling said current sources so as to produce summation currents for comparison with an analog input signal, whereby to determine the digital signals to be stored in said register means;
• and
• circuit means coupling said sets of transistors between said common bus and said negative bus to supply operating power thereto.