High-accuracy low-power current sensor with large dynamic range
AssigneeSendyne Corporation
InventorVictor Marten
Life of this patent
Estimating the term…
Abstract
A current sensing approach makes use of two shunts in series, embedded in a switching fabric, each shunt the object of a differential measurement of voltage drop across the shunt. Methodical make-before-break cycling of the switches in the switching fabric permit real-time or very near-real-time measurement of nearly all of the errors such as offset errors present in each differential-measurement path. Additional differential measurement paths can be connected with the shunts, with RFI filtering at shorter time constants to serve electronic fuse needs.
Claims32
A system for measuring current passing through distinct first and second input terminals, the system comprising:
- a first switch and a first shunt in series, connected between the first input terminal and a node;
- a second switch and a second shunt in series, connected between the node and the second input terminal;
- a third switch connected between the first input terminal and the node, the third switch thereby in parallel with the first switch and the first shunt in series;
- a fourth switch connected between the node and the second input terminal, the fourth switch thereby in parallel with the second switch and the second shunt in series;
- a first data path measuring voltage across the first shunt and providing a first output;
- a second data path measuring voltage across the second shunt and providing a second output;
- and
- a control means selecting one or the other of the first and second outputs, communicating information indicative of the selected output external to the system.
A method for measuring current passing through distinct first and second input terminals, the method comprising the steps of:
- providing a first switch and a first shunt in series, connected between the first input terminal and a node;
- providing a second switch and a second shunt in series, connected between the node and the second input terminal;
- providing a third switch between the first input terminal and the node, the third switch thereby in parallel with the first switch and the first shunt in series;
- providing a fourth switch between the node and the second input terminal, the fourth switch thereby in parallel with the second switch and the second shunt in series;
- closing the third switch and opening the first switch, at a time when the second switch is closed and the fourth switch is open, and measuring the first output, thereby deriving first correction information;
- making use of the first correction information to correct the first output;
- closing the fourth switch and opening the second switch, at a time when the first switch is closed and the third switch is open, and measuring the second output, thereby deriving second correction information;
- and
- making use of the second correction information to correct the second output.
Dependencies are inferred from the claim text.