Robust reference generation circuit for A/D converter
OwnerSangbeom Parkinventor
Life of this patent
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Abstract
Two reference generation circuits for A/D converter of the present invention generates a plurality of reference voltages characterized by voltage increments between two fixed reference voltages. These generated reference voltages greatly reduces unbalanced charge injection errors that any fully differential architecture can not remove. The inaccuracy of A/D converters caused by the corrupted reference voltages is greatly minimized.
Claims20
A reference generation circuit for A/D converter for generating reference voltages for A/D conversion, comprising:
- a resistor string for generating a plurality of reference voltages wherein the n resistors are coupled in series between the two fixed reference voltages;
- two MOS transistors for functioning as source-follower stages wherein the NMOS transistor is coupled to the most positive node of the resistor string and the PMOS transistor is coupled to the most negative node of the resistor string;
- and
- two amplifiers for making the positive input and negative input equal wherein each positive input receives a reference voltage and each negative input is coupled to the source of each NOS transistor.
A reference generation circuit for A/ D converter for generating reference voltages for A/D conversion, comprising:
- a resistor string for generating a plurality of reference voltages wherein the n resistors are coupled in series between the two fixed reference voltages;
- two MOS transistors for functioning as source-follower stages wherein the NMOS transistor is coupled to the most positive node of the resistor string and the PMOS transistor is coupled to the most negative node of the resistor string;
- two amplifiers for making the positive input and negative input equal wherein each positive input receives a reference voltage and each negative input is coupled to the source of each NOS transistor;
- and
- two switches for making dual modes wherein each switch is coupled between the negative input and the output of each amplifier.
Dependencies are inferred from the claim text.