Maintaining the Resistor Divider Ratio During Start-up

摘要

Circuits and methods to maintain a resistive voltage divider ratio during start-up of an electronic circuit comprising a feed-forward capacitor across a feedback resistor using a dynamic start-up circuit are disclosed as e.g. a LDO or an amplifier. In a preferred embodiment of the disclosure is applied to an LDO. Modification of the resistive voltage divider ratio caused by the feed-forward capacitor during start-up is prevented while the voltage level of a voltage access point of the voltage divider on the feed-forward capacitor is maintained. Embodiments of the disclosure presented comprise using a start-up buffer or a start-up capacitor during the start-up phase.

主权项

1. A method to maintain a resistive voltage divider ratio during start-up of any electronic circuit comprising a feed-forward capacitor across a feedback resistor of a resistive voltage divider using a dynamic start-up circuit, comprising the following steps:
(1) providing an electronic circuit comprising a feed-forward capacitor across a first feedback resistor of a resistive voltage divider and a start-up circuit; (2) avoiding modification of resistive voltage divider ratio caused by feed-forward capacitor during start-up phase; (3) monitoring output voltage and finish start-up-phase when desired output voltage of the electronic circuit is reached; and (4) processing normal operation after start-up phase is finished wherein feed-forward capacitor is connected across the feedback resistor of the resistive voltage divider after end of start-up phase.