# US 2013/0278242 A9 · Current sensing system and method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0278242 A9 - Document ID: US20130278242A9 - Status: Published application - Kind: A9 - Application number: 13/676,342 - Filed: 2012-11-14 - Published: 2013-10-24 - Earliest claimed: 2007-06-14 - Assignees: Panasonic Automotive Systems Company of America, Division of Panasonic Corporation of North America - Inventors: Harold Arthur Smith - Web page: https://patentgrep.com/patent/US20130278242A9 ## CPC - G01R 19/0092: {Measuring current only} - G01R 19/15: Indicating the presence of current - G01R 19/25: using digital measurement techniques - Y02T 10/70: Energy storage systems for electromobility, e.g. batteries - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract There is provided a current sense circuit (134). An exemplary current sense circuit (134) comprises a voltage-to-current converter circuit (218) that is adapted to receive a voltage that is proportional to a load current drawn from a battery (110) by a load (202) and to produce a current proportional to the load current, and a current-to-voltage converter circuit (228) that is adapted to receive the current proportional to the load current and to produce a voltage proportional to the load current based on a regulated voltage source (230). ## Claims ### Claim 1 A motorized vehicle comprising an entertainment system that includes a current sense circuit, the current sense circuit comprising: a voltage-to-current converter circuit that is adapted to receive a voltage that is proportional to a load current through a load and to produce a current proportional to the load current; and a current-to-voltage converter circuit that is adapted to receive the current proportional to the load current and to produce a voltage proportional to the load current based on a regulated voltage source. ### Claim 2 (depends on 1) The motorized vehicle recited in claim 1, wherein the voltage-to-current converter circuit comprises a Junction Field Effect Transistor (JFET) transistor that produces the current proportional to the load current. ### Claim 3 (depends on 1) The motorized vehicle recited in claim 1, comprising a current sense resistor having a voltage drop that is applied differentially to the voltage-to-current converter circuit. ### Claim 4 (depends on 1) The motorized vehicle recited in claim 1, comprising an analog-to-digital converter that is adapted to produce a digital output corresponding to the voltage proportional to the load current. ### Claim 5 (depends on 1) The motorized vehicle recited in claim 1, wherein the current-to-voltage converter circuit is adapted to produce an output voltage that falls as the current proportional to the load current increases. ### Claim 6 (depends on 1) The motorized vehicle recited in claim 1, wherein the load comprises an active antenna. ### Claim 7 (depends on 1) The motorized vehicle recited in claim 1, wherein the current sense circuit comprises a portion of a vehicle audio subsystem. ### Claim 8 (depends on 1) The motorized vehicle recited in claim 1, wherein the voltage-to-current converter circuit comprises a single Junction Field Effect Transistor (JFET) transistor that solely produces the current proportional to the load current. ### Claim 9 A method of sensing current drawn by a load within a motorized vehicle, the method comprising: receiving a voltage that is proportional to a load current drawn by a load within the vehicle; producing a current proportional to the load current; receiving the current proportional to the load current; and producing a voltage proportional to the load current based on a regulated voltage source. ### Claim 10 (depends on 9) The method recited in claim 9, wherein the current proportional to the load current is produced by a Junction Field Effect Transistor (JFET). ### Claim 11 (depends on 9) The method recited in claim 9, comprising differentially applying a voltage drop to produce the current proportional to the load current. ### Claim 12 (depends on 9) The method recited in claim 9, comprising producing a digital output corresponding to the voltage proportional to the load current. ### Claim 13 (depends on 9) The method recited in claim 9, comprising causing the voltage proportional to the load current to fall in response to a rise in the current proportional to the load current. ### Claim 14 (depends on 9) The method recited in claim 9, wherein the current proportional to the load current is produced solely by a single Junction Field Effect Transistor (JFET). ### Claim 15 A motorized vehicle (10) comprising: a chassis (18); an engine (12) that is supported by the chassis (18); a power train (14) adapted to be driven by the engine (12); control electronics (16) that are adapted to control the engine (12) and the power train (14); and an entertainment system (20) that includes an audio subsystem (22), the audio subsystem (22) being adapted to provide audio programming to occupants of the motorized vehicle (10), the audio subsystem (22) having a current sense circuit (134), the current sense circuit (134) comprising: a voltage-to-current converter circuit (218) that is adapted to receive a voltage that is proportional to a load current drawn from a battery (110) by a load (202) and to produce a current proportional to the load current; and a current-to-voltage converter circuit (228) that is adapted to receive the current proportional to the load current and to produce a voltage proportional to the load current based on a regulated voltage source (230). ### Claim 16 (depends on 15) The motorized vehicle (10) recited in claim 15, wherein the voltage-to-current converter circuit (218) comprises a JFET (216) that produces the current proportional to the load current drawn from the battery (110). ### Claim 17 (depends on 15) The motorized vehicle (10) recited in claim 15, comprising a current sense resistor (204) having a voltage drop that is applied differentially to the voltage-to-current converter circuit (218). ### Claim 18 (depends on 15) The motorized vehicle (10) recited in claim 15, comprising an analog-to-digital converter (132) that is adapted to produce a digital output corresponding to the voltage proportional to the load current. ### Claim 19 (depends on 15) The motorized vehicle (10) recited in claim 15, wherein the current-to-voltage converter circuit (228) is adapted to produce an output voltage that falls as the current proportional to the load current increases. ### Claim 20 (depends on 15) The motorized vehicle (10) recited in claim 15, wherein the load (202) comprises an active antenna (104).