TPIC8101_05 Datasheet, PDF (1/20 Pages) Texas Instruments – KNOCK SENSOR INTERFACE

features
D Dual-Channel Knock Sensor Interface
D Programmable Input Frequency Prescaler
(OSC_IN)
D Serial Interface With Microprocessor (SPI)
D Programmable Gain
D Programmable Band-Pass Filter Center
Frequency
D External Clock Frequencies up to 24 MHz
− 4, 5, 6, 8, 10, 12, 16, 20, and 24 MHz
D Programmable Integrator Time Constants
D Operating Temperature Range −40°C to
125°C
TPIC8101
KNOCK SENSOR INTERFACE
SLIS110A − APRIL 2003 − REVISED MAY 2005
V_DD
GND
V_ref
OUT
NC
NC
INT/HOLD
CS
XIN
XOUT
DW PACKAGE
(TOP VIEW)
1
20
2
19
3
18
4
17
5
16
6
15
7
14
8
13
9
12
10
11
CH1P
CH1N
CH1FB
CH2FB
CH2N
CH2P
TEST
SCLK
SDI
SDO
applications
D Engine Knock Detector Signal Processing
D Analog Signal Processing With Filter
Characteristics
description
The TPIC8101 is a dual-channel signal processing IC for detection of premature detonation in combustion
engine. The two sensor channels are selectable through the SPI bus. The knock sensor typically provides an
electrical signal to the amplifier inputs. The sensed signal is processed through a programmable band-pass filter
to extract the frequency of interest (engine knock or ping signals). The band-pass filter eliminates any engine
background noise associated with combustion. The engine background noise is typically low in amplitude
compared to the predetonation noise.
The detected signal is full-wave rectified and integrated by use of the INT/HOLD signal. The digital output from
the integration stage is either converted to an analog signal, passed through an output buffer, or be read directly
by the SPI.
This analog buffered output may be interfaced to an A/D converter and read by the microprocessor. The digital
output may be directly interfaced to the microprocessor.
The data from the A/D enables the system to analyze the amount of retard timing for the next spark ignition timing
cycle.
With the microprocessor closed-loop system, advancing and retarding the spark timing optimize the load/RPM
conditions for a particular engine (data stored in RAM).
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
Copyright  2003 − 2005, Texas Instruments Incorporated
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