Provide an electronic design for a 2 channel multiplexed inductive loop detector (LC Oscillator).
Design will include:-
1. Schematic, BOM, calculations, technical explanation of operation, spice modelling of circuit or equivalent
2. Electronic components to be sourced from digikey or equivalent, industrial temperature range and AEC-Q100 – automotive preference
3. Microcontroller will provide a 10Khz 50/50 square wave output (3.3V) for Enabling and sequencing the two channels
4. The sine wave output of the oscillator will be converted into a square wave. The square wave outputs of both channels need to be switched to a single timer capture input pin on the micro controller (micro controller design is not part of the scope)
5. The Detector electronics will be up to 10m from the sensor via a shielded cable
6. Inductance and capacitance of cable needs to be included in design calculations
7. The LC Oscillator will output a clean sine wave on the cable to the loop sensor with a maximum peek of +5V (negotiable < unregulated supply of 12V) at target frequency of 150 KHz.
8. A +5V, +3.3V and unregulated 12V supply is available
9. Prefer schematic to be submitted in Altium but not essential.
10. The LC oscillator will operate over ~100 KHz to ~1.1Mhz, have a fast start up/settling time. Micro controller will provide an oscillator start up window to ignore the first few samples.
11. Coil and target distance of up to 40mm, typical 25mm.
12. Provide design for the inductance PCB loop,
a. Support with calculations and or modelling
b. The pcb embedded loop will be approximately 120mm x 50mm in a racetrack type configuration, both channel coils will be in close proximity to each other.
c. Minimum of 0.2% change in inductance at 40mm in presence of ferrous material
13. Provide Line surge protection in design