Automotive test system with input protection
AssigneeSPX Corporation
InventorsPeter A. Puetz, John Hintz
Life of this patent
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Abstract
An input protection circuit protects a multiplexer used in an automotive breakout box for coupling to an electronic control module (ECM) of an automotive vehicle. The input protection circuit includes resistors connected between the input and the multiplexer and a negative feedback amplifier connected to the output of the multiplexer. The negative feedback amplifier provides a virtual ground. Additionally, the inputs to the multiplexer are clamped to within one diode forward voltage drop of electrical ground by diode pairs.
Claims17
A test system capable of coupling to an electronic control module (ECM) of an automotive vehicle for testing various electrical components of the automotive vehicle, wherein the ECM is electrically connected to the electrical components of the automotive vehicle, the test system comprising:
- connector means having a plurality of pins for coupling the test system to the ECM;
- a multiplexer coupled to the connector means for selecting one of the pins of the connector means and including a multiplexer output;
- high impedance means electrically connected between the ECM and the multiplexer;
- a negative feedback amplifier coupled to the multiplexer output, the negative feedback amplifier providing a virtual ground at the multiplexer output;
- and
- sensor means coupled to the negative feedback amplifier for sensing an electrical characteristic of an electrical component of the automotive vehicle.
A test system capable of coupling to an electronic control module (ECM) of an automotive vehicle for testing various electrical components of the automotive vehicle, wherein the ECM is electrically connected to the electrical components of the automotive vehicle, the test system comprising:
- connector means having a plurality of pins for coupling the test system to the ECM;
- a plurality of high impedance elements, each of which is coupled to one of the pins of the connector means;
- a multiplexer having an output and having a plurality of inputs each of which is coupled to one of the high impedance elements;
- virtual ground means coupled to the output of the multiplexer for providing a virtual electrical ground at the multiplexer output;
- and
- test means coupled to the virtual ground means for testing a selected electrical component of the automotive vehicle.
A test system for testing electrical components of an automotive vehicle, the test system capable of being electrically connected to an electronic control module of an automotive vehicle which is electrically connected to the electrical components of the vehicle, the test system comprising:
- sensor means for measuring the electrical characteristics of an electrical component coupled to an input of the sensor means;
- multiplexer means having an input for electrical connection to the electronic control module and having an output which is electrically connected to the input of the sensor means, the multiplexer means being capable of coupling a selected electrical component of the automotive vehicle to the input of the sensor means;
- and
- protection means, electrically connected to the multiplexer means, for limiting the voltage applied to the input of the multiplexer means, the protection means comprising a high impedance means for connection between the electronic control module and the input of the multiplexer means, and an amplifier means for electrical connection to the multiplexer means, the amplifier means providing a virtual ground at the multiplexer means output.
Dependencies are inferred from the claim text.