Settling Time and Effective Band Width for Op-Amps Using Miller Capacitance Compensation

摘要

An LDO/HDO circuit adds a supplementary current source to supply the output node. The current boosting section includes a digital comparator with a first input connected to the LDO's feedback loop and a second input connected to a reference level. The comparator then generates a digital output used to control the supplementary current source. This approach also can be used in a far-side implementation, where the local supply level for the load is boosted by the current source based a comparison of this local level and the output of the LDO. Miller capacitive compensation is also considered. Current in shunted to ground from a node in the Miller loop, where the level is controlled by the output of a digital comparator base on a comparison of the circuit's output voltage and a reference level.

主权项

1. A voltage regulation circuit, comprising:
a power transistor connected between an input supply voltage and an output supply node; an error amplifier having a first input connected to receive a first reference voltage and a second input connected to a feedback node, the error amplifier providing an output derived therefrom connected to control the gate of the power transistor; a voltage divider circuit connected between the output node and ground, the feedback node taken from a first node of the voltage divider; a capacitor and resistor connected in series between the output supply node and the output of the error amplifier; a current sinking circuit connected between ground and a node between the capacitor and the resistor; and a comparator having a first input connected to receive a second reference voltage and a second input connected to the output supply node, the comparator providing a digital output derived therefrom connected to the current source circuit, where the magnitude of the current provided to the output supply node is based on the comparator's output.