Control for voltage regulators

摘要

A mixed signal approach is applied to detect an output voltage condition as applied to a load. A current mode monitoring approach can be adopted and applied in discrete time using a mixed analog and digital approach. For application to various low drop-out voltage regulator situations, a sensing transistor can be connected in parallel with a feedback loop transistor of the low drop-out voltage regulator circuit to create a sensing current that is proportional to the current passing through the feedback loop transistor and thus the output current provided to the load. This sensing approach can be adapted to sense both overload and light load conditions to allow dynamic power control of the device.

主权项

1. An apparatus for detecting load on an input power, the apparatus comprising:
a low dropout voltage regulator circuit configured to provide an output voltage to a load; a current mode comparator circuit connected to the low dropout voltage regulator circuit to monitor a low dropout voltage regulator circuit current driven by the output voltage of the low dropout voltage regulator circuit; wherein the current mode comparator circuit is configured to monitor the low dropout voltage regulator circuit current in a discrete time mixed analog/digital approach; wherein the low dropout voltage regulator circuit comprises a feedback loop transistor connected to pass the low dropout voltage regulator circuit current driven by the output voltage; and wherein the current mode comparator circuit comprises: a sensing transistor connected in parallel with the feedback loop transistor and configured to output a sensing current proportional to the low dropout voltage regulator circuit current; a reference current source configured to provide a reference current;a comparator circuit configured to perform a comparison between the sensing current and the reference current and to output a comparison signal based on the comparison;
wherein the current mode comparator circuit comprises an n-bit digital to analog conversion circuit configured to control the reference current source to output a high reference current, wherein the comparator circuit is configured to output a digital flag signal in response to the sensing current exceeding the high reference current.