33810_11 Datasheet, PDF (23/37 Pages) Freescale Semiconductor, Inc – Automotive Engine Control IC Quad injector driver with Parallel/SPI control

FUNCTIONAL DEVICE OPERATION
OPERATIONAL MODES
Table 11. Nominal Current DAC Select
DAC Command
Bits<4,3,2,1,0>
NOMI
Current (A)
Differential
Voltage
(mV
Rs = 20 mΩ
Differential
Voltage
(mV
Rs = 40 mΩ
00000
00001
00010
00011
00100
00101
00110
00111
01000
01001
01010
01011
01100
01101
01110
01111
10000
10001
10010
10011
(Gain = 2) (Gain = 1)
3.00
60
120
3.25
65
130
3.50
70
140
3.75
75
150
4.00
80
160
4.25
85
170
4.50
90
180
4.75
95
190
5.00
100
200
5.25
105
210
5.50
110
220
5.75
115
230
6.00
120
240
6.25
125
250
6.50
130
260
6.75
135
270
7.00
140
280
7.25
145
290
7.50
150
300
7.75
155
310
Table 11. Nominal Current DAC Select
DAC Command
Bits<4,3,2,1,0>
NOMI
Current (A)
Differential
Voltage
(mV
Rs = 20 mΩ
Differential
Voltage
(mV
Rs = 40 mΩ
10100
10101
10110
10111
11000
11001
11010
11011
11100
11101
11110
11111
8.00
8.25
8.50
8.75
9.00
9.25
9.50
9.75
10.00
10.25
10.50
10.75
(Gain = 2)
160
165
170
175
180
185
190
195
200
205
210
215
(Gain = 1)
320
330
340
350
360
370
380
390
400
410
420
430
MAXI DAC BITS
The MAXI control block provides a means to shut off all the
ignition coil drivers if the current reaches a SPI
programmable maximum level. Control is achieved by
comparing the output of the current sense amplifier with a SPI
programmed DAC value.
The MAXI comparator disables all gate drivers configured
as ignition drivers when the DAC MAXI setting is exceeded.
When a MAXI event occurs, the MAXI bit in the fault status
register is set and the MAXI pin is asserted (High).
When using a 20mΩ resistor as the current sense resistor,
the gain select of the differential amplifier connected to RSP
and RSN, should be set to a gain of 2, via the SPI Command
Message Spark Command (Command 0100, hex 4), Control
bit 6 =1.
When using a 40mΩ resistor as the current sense resistor,
the gain select of the differential amplifier connected to RSP
and RSN, should be set to a gain of 1, via the SPI Command
Message Spark Command (Command 0100, hex 4), Control
bit 6 =0. This is also the default value.
The MAXI fault bit in the SPI fault status register is cleared
when the MAXI condition no longer exists and the SPI fault
status register has been read by the MCU.
In V10 Mode, the MAXI pin is configured as an input to
receive the MAXI signal from a second MC33810 device in
the system. In this mode a input MAXI signal has effectively
the same control as an internal MAXI signal. Further
information is provided in the V10 Mode application section
of this specification.
Analog Integrated Circuit Device Data
Freescale Semiconductor
33810
23