Patent ID: 9742398
Date: 2017-08-22
CPC Classifications: G01R,H03K

Claim:
1. An apparatus, comprising: a power switch having a switch control input and having a current conduction path coupled between a voltage input and an output voltage terminal, configured for supplying current to a load responsive to a switch control signal coupled to the switch control input; a first isolation switch having a current conduction path coupled between the voltage input a first node, and having a control terminal coupled to an isolation switching control circuit; a comparator amplifier having a pair of differential inputs coupled to the first node and to a second node, and having at least one output, the comparator amplifier configured to output a voltage in response to the difference at the differential inputs; a first current source coupled between a positive supply voltage and the first node, and configured to output a first current responsive to the voltage output from the comparator amplifier; and wherein the first current is proportional to the current through the power switch and to a ratio of the on resistance of the power switch and the on resistance of the first isolation switch; further comprising: a second isolation switch coupled between the output voltage terminal and the second node; and a second current source coupled between the positive supply voltage and the second node.