BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying figures, in which like reference numerals refer to identical or functionally-similar elements throughout the separate views and which are incorporated in and form a part of the specification, further illustrate the present invention and, together with the detailed description of the invention, serve to explain the principles of the present invention.
FIG. 1 illustrates a side view of a rotary/angular position sensor system, which can be adapted for use in accordance with a preferred embodiment;
FIG. 2 illustrates a front view of the rotary/angular position sensor system depicted in FIG. 1 in accordance with a preferred embodiment;
FIG. 3 illustrates a schematic diagram of an electrical circuit that can be implemented in accordance with a preferred embodiment; and
FIGS. 4-7 respectively illustrates graphs that demonstrate the baseline CE Results and the improvement of using the current limiting open collector output (Current Mirror) circuit disclosed in FIG. 3.
DETAILED DESCRIPTION OF THE INVENTION
The particular values and configurations discussed in these non-limiting examples can be varied and are cited merely to illustrate at least one embodiment of the present invention and are not intended to limit the scope of the invention.
FIG. 1 illustrates a side view of a rotary/angular position sensor system 100, which can be adapted for use in accordance with a preferred embodiment. FIG. 2 illustrates a front view of the rotary/angular position sensor system 100 depicted in FIG. 1 in accordance with a preferred embodiment. System 100 generally includes a shaft 102 connected to a rotatable plate 106. A rotary/angular position sensor 104 is located on or proximate to shaft 102 or rotatable plate 106 in order to detect the rotation and/or angular position of shaft 102 or rotatable plate 106. Sensor 104 may be provided as a camshaft sensor or a crankshaft sensor.
FIG. 3 illustrates a schematic diagram of an apparatus or electrical circuit 300 that can be implemented in accordance with a preferred embodiment. Circuit 300 can be utilized in association with the system 100 depicted in FIGS. 1-2. Circuit 300 generally functions as a current limiting open collector output stage and is configured on or in the context of an integrated circuit. A sensor signal 304 can be output from the rotary/angular position sensor 104 depicted in FIGS. 1-2 and provided to circuit 100 at node A. A resistor 306 is also generally connected to node A for fall time and a di/dt adjustment. Sensor supply voltage 302 (i.e., sensor B+) is connected to resistor 306, while a sensor ground 309 (i.e., sensor RTN) is connected to ground GND. Two transistors 308 and 310 are also provided as a part of circuit 300 and are both also connected to ground in addition to the resistor 306 at node A. A sensor signal can then be output from the circuit at node B and sent to an ECM load.
Circuit 300 can be implemented in the context of an Integrated Circuit (IC). The configuration of circuit 300 can be applied by integrating a current limiting open collector output stage on an IC or adding the circuit 300 to an IC and using appropriate RC (Resistor-Capacitor) filter components. Circuit 300 generally meets and exceed required EMC and radiated emissions testing capabilities by using a current limiting open collector output configuration that slows down the fall time of sensor 104 and reducing di/dt and ringing produced on the output signal (i.e., sensor signal 304 provided to circuit 300 and output from sensor system 100). In slowing down the fall time and reducing di/dt and ringing on the line, conducted emissions (CE) capabilities are improved to the point of meeting necessary EMC testing requirements.
FIGS. 4-7 respectively illustrates graphs 400, 500, 600, 700 that demonstrate the baseline CE Results and the improvement of using the current limiting open collector output (Current Mirror) circuit 300 disclosed in FIG. 3. Graphs 400, 500, 600, 700 generally plot data indicative of amplitude versus frequency and are provided herein for illustrative purposes only and are not considered limiting features of the embodiments.
It is contemplated that the use of the present invention can involve components having different characteristics. It is intended that the scope of the present invention be defined by the claims appended hereto, giving full cognizance to equivalents in all respects.
Patent Application
20070277587
