| 摘要 |
A current monitor ( 360 ) having a high performance, simple, and cost effective design that is independent of process, temperature and voltage is disclosed herein. The current monitor ( 360 ) includes a sensing transistor ( 340 ) that couples to the main transistor ( 312 ) of an adjoining voltage regulator. Specifically, the control and source nodes of each transistor couple to each other, respectively. The size of the main transistor ( 312 ) is a predetermined multiple integer n of the size of the sensing transistor. A first resistor (R<SUB>S3</SUB>) couples between a supply voltage and the drain node of the main transistor ( 312 ). A second resistor (R<SUB>S1</SUB>) couples between a supply voltage and the drain node of the sensing transistor ( 340 ), wherein the size of the second resistor (R<SUB>S1</SUB>) is equal to the size of the first resistor (R<SUB>S3</SUB>) multiplied by the predetermined multiple integer n. An inverting input of an amplifier ( 342 ) couples to the drain node of the sensing transistor ( 340 ), while a third resistor (R<SUB>S2</SUB>) connects between the supply voltage and a non-inverting input of the amplifier ( 342 ). The amplifier ( 342 ) drives a transistor ( 344 ) within a closed feedback loop to equalize the value of the voltages at both inputs of the amplifier ( 342 ). A feedback resistor (R<SUB>fdb2</SUB>) coupled between the source node of the transistor ( 344 ) and ground. A comparator ( 348 ) connects to the source node of the transistor ( 344 ) and between a current source and a reference resistor (R<SUB>ref</SUB>) to provide an output voltage.
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