Low voltage analog-to-digital converters with internal reference voltage and offset
AssigneePhotobit Corporation
InventorsAlexander I. Krymski, Kwang-Bo (Austin) Cho
Life of this patent
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Abstract
An A-to-D converter system having programmed reference signal levels using only supply signal provided by a power supply is disclosed. The converter system includes a comparator configured to provide comparison of an analog input signal with an adjustable reference level. The converter system also includes a logic circuit and an adjustable capacitor.
Claims21
An A-to-D converter system receiving power from at least two supply signals, comprising:
- a comparator having inputs, configured to compare an analog input signal with an adjustable reference level, said adjustable reference level generated from at least one of said supply signals;
- a logic circuit coupled to a first one of said comparator inputs, said logic circuit having a plurality of differently-sized capacitors and a plurality of switches, each capacitor connected to at least one switch, said at least one switch configured to successively connect said each capacitor to different levels of said supply signal;
- and
- an adjustable capacitor coupled between the first one of said comparator inputs and a first one of said supply signals, said capacitor configured to provide additional capacitance, said additional capacitance adjustable to change a full swing level of said adjustable reference level, such that the change enables said logic circuit to operate with said supply signals.
A successive approximation A-to-D converter receiving power from at least two supply signals, comprising:
- a comparator having at least two inputs, to compare an input signal with a programmable reference level;
- and
- an adjustable capacitor coupled between one of said at least two comparator inputs and a first one of the supply signals, said adjustable capacitor providing a capacitive divider that changes a full swing of said programmable reference level, such that the change allows reference level programming to operate with a second one of the supply signals.
A method of converting analog signal to digital signal, comprising:
- adjusting a reference capacitor at an input signal node to change a full swing level of a reference level;
- selectively coupling conversion capacitors between the input signal node and a supply signal to program the reference level;
- comparing an input signal to said programmed reference level;
- and
- reading a digital output value if the comparison results in a match.
Dependencies are inferred from the claim text.