Back to results
US 2010/0244947 A1Published application
Method of forming a sensing circuit and structure therefor
AssigneeSemiconductor Components Industries, LLC
InventorsHarold L. Massie, Jarvis Leroy Carter, SR.
Life of this patent
Estimating the term…
Abstract
In one embodiment, a sensing circuit includes a sense transistor and a compensation circuit to improve the accuracy of a sensing signal formed by the sensing circuit.
Claims20
A method of forming a current sense circuit comprising:
- providing a semiconductor substrate;
- forming a main transistor on the semiconductor substrate with the main transistor having a source that is formed with a source area;
- forming a sense transistor on the semiconductor substrate with the sense transistor having a source that is formed with a source area, with a gate of the sense transistor coupled to a gate of the main transistor, and a drain of the sense transistor coupled to a drain of the main transistor wherein the source area of the sense transistor is less than the source area of the main transistor;
- forming a resistor divider on the semiconductor substrate, the resistor divider having a first resistor and a second resistor with a first terminal of the first resistor coupled to an input of the resistor divider, a second terminal of the first resistor coupled to a sense node, a first terminal of the second resistor coupled to the sense node, and the input of the resistor divider coupled to the source of the main transistor;
- coupling the input of the resistor divider and the source of the main transistor to a first connection pad on the semiconductor substrate;
- coupling the source of the sense transistor to a second connection pad on the semiconductor substrate;
- coupling the sense node to a third connection pad on the semiconductor substrate;
- coupling a second terminal of the second resistor to a fourth connection pad on the semiconductor substrate;
- and
- coupling the first connection pad to a first terminal of a semiconductor package, coupling the second connection pad to a second terminal of the semiconductor package, coupling the third connection pad to a third terminal of the semiconductor package, and coupling the fourth connection pad to a fourth terminal of the semiconductor package.
7 more elements
A sense circuit comprising:
- a main transistor and a sense transistor formed on a semiconductor substrate, the main transistor having a source with a source area, a gate, and a drain, the sense transistor having a source with a source area that is less than the source area of the main transistor, a gate coupled to the gate of the main transistor, and a drain coupled to the drain of the main transistor;
- a resistor divider formed on the semiconductor substrate, the resistor divider having an input, a sense node, a first resistor, and a second resistor, the input of the resistor divider coupled to the source of the main transistor, the first resistor having a first terminal coupled to the input of the resistor divider and a second terminal coupled to the sense node, the second resistor having a first terminal and having a second terminal coupled to the sense node;
- a first connection pad formed on the semiconductor substrate and coupled to the input of the resistor divider wherein the input of the resistor divider is positioned between the source of the main transistor and the first connection pad;
- and
- a semiconductor package attached to the semiconductor substrate, the semiconductor package having a first terminal electrically coupled to the first connection pad.
2 more elements
A method of forming a sensing circuit comprising:
- providing a main transistor having an on-resistance, a gate, and a drain and having a source that is formed with a source area wherein the main transistor is configured to conduct a main transistor current through the source of the main transistor;
- providing a sense transistor having an on-resistance, a gate coupled to the gate of the main transistor, a drain coupled to the drain of the main transistor and having a source area that is less than the source area of the main transistor wherein the sense transistor is configured to conduct a sense transistor current through the source of the sense transistor and wherein the sense transistor current is ratioed to the main transistor current by a ratio of the on-resistance of the main transistor to the on-resistance of the sense transistor;
- forming a current flow path for the main transistor current, the current flow path having a wiring resistance;
- and
- coupling a compensation circuit to the source of the main transistor wherein the compensation circuit is coupled in parallel with the wiring resistance of the current flow path of the main transistor and configuring the compensation circuit to form a sense signal that is representative of a voltage drop across the wiring resistance and that has a value that is less than the voltage drop across the wiring resistance.
2 more elements
Dependencies are inferred from the claim text.