| 摘要 |
<p>A system and method for current sensing which is substantially consistent over device, temperature, and process variations is provided. The current sensing system and method are configured to provide a scaled down sense current of a known proportion to a load current being sensed. An exemplary current sensing system includes a first switch (301) coupled to one or more variable resistive elements (304, 305), wherein the resistive elements are configured to scale down the voltage across the first switch, with the scaled down voltage being provided to an input of an amplifier (308). The amplifier is coupled with the resistive elements and the second switch (302), and is configured to sense the scaled down voltage across the first switch, and force the voltage across the second switch to be equal to the scaled down voltage across the first switch, such that the current of known proportion to the load current can be provided at the output of the amplifier. To prevent the amplifier from providing an excessive slewing of current from the second switch to ground during the off period of the current sensing circuit, a driver and timing circuit (307) can be provided. The driver and timing circuitcan be configured to decouple a resistive switch connected to theinput of the amplifier to prevent the amplifier from excessive slewing when the voltage at the input node is low, e.g., when the first switch is not being driven. As a result, the current sensingcircuit can include the use of low voltage devices with a high voltage overlay in the amplifier to provide for higher speed and accuracy.</p> |
