HIP9011ABZT Intersil, HIP9011ABZT Datasheet - Page 6

• Manufacturer Part Number: HIP9011ABZT
• Description: IC SENSOR ENGINE KNOCK 20-SOIC
• Manufacturer: Intersil
• Type: Engine Knock Signal Processorr

Specifications of HIP9011ABZT

• Input Type: Logic
• Output Type: Logic
• Interface: SPI
• Current - Supply: 8mA
• Mounting Type: Surface Mount
• Package / Case: 20-SOIC (7.5mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Description of the HIP9011 Operation
This IC is designed to be a universal digitally controlled, analog
interface between engine acoustical sensors or accelerometers
and internal combustion engine fuel management systems.
Two wideband input amplifiers are provided which will allow the
use of two sensors. These sensors be of the piezoelectric type,
that can be mounted in optimum locations on either in-line or V
type engine configurations.
Output from these input amplifiers are directed to a channel
select mux switch and then into a 3rd order antialiasing filter.
The output signal is then directed to two programmable gain
stages, where one stage inverts or shifts the knock signal 180
degrees. The gain stage signals are outputted to two
programmable bandpass filter stages. Outputs from the two
BPF stages are then full wave rectified before being digitally
integrated by the programmable integrator. The integrator
output is applied to a line driver for further processing by the
engine fuel management control system. The gain, bandpass
filter and integrator stage settings are programmable from a
microprocessor via the SPI Bus Interface
TRANSDUCERS
20pF
0.022µF
4MHz
FIGURE 3. SIMPLIFIED BLOCK DIAGRAM OF THE HIP9011 IN AN AUTOMOTIVE APPLICATION
20pF
R
R
in
in
+5V
1MΩ
R
R
F
F
6
V
VMID
GND
CH0NI
CH1NI
CH1IN
CH1FB
CH0IN
CH0FB
OSCIN
OSCOUT
DD
MICROPROCESSOR
CONVERTER
HIP9011
INTOUT
A/D
INT/HOLD
TEST
SCK
SO
CS
SI
HIP9011
SPI BUS
+5V
Broadband piezoelectric ceramic transducers used for the
engine signal pickup have device capacitances in the order
of 1100pF and output voltages that range from 5mV to 8V
RMS. During normal engine operation, a single input
channel is selected and applied to the HIP9011. The engine
background noise is typically well below in amplitude than
the pre-detonation noise. Therefore, the bandpass filter
stages can be optimized to further discriminate between
engine background and combustion noise and pre-
detonation noise.
A basic approach to engine pre-detonation systems is to
only observe engine background during the time interval
that noise is expected and if detected, retard timing. This
basic approach does not require the sensitivity and
selectivity that is needed for a continuously adjustable
solution. Enhanced fuel economy and performance is
obtainable when this IC is coupled with a microprocessor
controlled fuel management system.
Where:
When the Input Signal is Present for the Period t
INTOUT (Volts) =
V
IN
EXAMPLE CASE USING IDEAL SYSTEM EQUATION
INTOUT (Volts) =
200x10
×
G
V
IN
RESET
G
G
×
G
-3
DSE
t
G
BPF
V
INT
PR
*1* [2 * 0.19 * 0.318 * 2x10



IN
IN
t
G
C
BPR
= 200mV
= 1.0, Ratio of R
= 0.190
= 2.0 Ideal Gain Value
= 200µs
= 2ms
= 2.0 Ideal Gain Value
= 0.125V, Typical Value
2]+0.125
= 0.4833 + 0.125
= 0.608V
×
G
PR
P-P
×
, Continuous AC Signal
1
-- -
π
×
F
t
------- -
to R
int
t
c



IN
×
-3
G
/200x10
DSE
INT
+
-6
V
*
:
RESET
January 6, 2006
FN4367.2