The HIP9011 is used to provide a method of detecting premature detonation often referred to as “Knock or Ping” in internal combustion engines.
The IC is shown in the Simplified Block Diagram. The chip can select between one of two sensors, if needed for accurate monitoring or for “V” type engines. Internal control via the SPI bus is fast enough to switch sensors between each firing cycle. A programmable bandpass filter processes the signal from either of the sensor inputs. The bandpass filter can be selected to optimize the extraction the engine knock or ping signals from the engine background noise. Further single processing is obtained by full wave rectification of the filtered signal and applying it to an integrator whose output voltage level is proportional to the knock signal amplitude. The chip is under microprocessor control via a SPI interface bus.

FEATUREs
• Two Sensor Inputs
• Microprocessor Programmable
• Accurate and Stable Filter Elements
• Digitally Programmable Gain
• Digitally Programmable Time Constants
• Digitally Programmable Filter Characteristics
• On-Chip Crystal Oscillator
• Programmable Frequency Divider
• External Clock Frequencies up to 24MHz
   - 4, 5, 6, 8, 10, 12, 16, 20, and 24MHz
• Operating Temperature Range -40oC to 125oC
• Pb-Free Plus Anneal Available (RoHS Compliant)

APPLICATIONs
• Engine Knock Detector Processor
• Analog Signal Processing Where Controllable Filter Characteristics are Required