Programmable error amplifier for sensing voltage error in the feedback path of digitially programmable voltage sources

Abstract

A programmable error amplifier (PEA) that may be used as part of a voltage regulation subsystem to control the output of a digitally programmable voltage source is disclosed. According to various embodiments, the PEA comprises an amplification circuit, an analog voltage sampling circuit and a digital reference voltage sampling circuit. The amplification circuit may employ a negative feedback configuration, and include an amplifier and a plurality of feedback capacitors. The analog voltage sampling circuit is responsive to an analog input voltage (such as the output of the programmable voltage source) and is coupled to the amplification circuit. During a first operational phase (the sampling phase), the analog voltage sampling circuit stores a charge dependent upon the analog input voltage, and during a second operational phase (the conversion phase), the analog voltage sampling circuit transfers the charge to the feedback capacitors of the amplification circuit. The digital reference voltage sampling circuit is responsive to a digital programming word and also is coupled to the amplification circuit. During the first (sampling) phase, the digital reference voltage sampling circuit stores a charge dependent upon the digital programming word, and during the second (conversion) phase transfers the charge to the feedback capacitors of the amplification circuit. A differential voltage based on the difference between the analog voltage and a reference voltage determined by the digital programming word appears across the input terminals of the amplifier.