33811 Datasheet, PDF (12/18 Pages) Freescale Semiconductor, Inc – Solenoid Monitor Integrated Circuit (IC)

FUNCTIONAL DESCRIPTION
FUNCTIONAL INTERNAL BLOCK DESCRIPTION
FUNCTIONAL INTERNAL BLOCK DESCRIPTION
Figure 7. Functional Internal Block Diagram
POWER SUPPLY AND OSCILLATOR
The 33811 is designed to operate from 10.5V to 15.5V on
the VPWR pin. The VPWR pin supplies power to the internal
regulator which, in turn, supplies the analog circuit blocks.
The VDD Supply is used internally to supply the logic
circuitry. The VSPI supply is used for setting the SPI
communication threshold levels by supplying power to the
SO driver and the SI and CS input buffers. The on-chip
oscillator is used to set the solenoid sample period window
and sample rate.
MCU INTERFACE:
The 33811 device directly interfaces to a 3.3V or 5.0V
micro controller unit (MCU) using 16 bit Serial Peripheral
Interface (SPI) protocol. SPI serial clock frequencies up to
3.2MHz may be used when programming and reading output
status information. The RESET pin is used to place the 33811
into the Reset Mode. Normally the RESET pin is held at logic
0 by the MCU. When the MCU raises the RESET pin to a
logic 1, the 33811 enters the reset Mode. The reset initializes
the 5 fault outputs.
SOLENOID MONITORS: SOLM1 - SOLM5
These are the five solenoid monitor inputs that are
connected to the external solenoid driver output pins. The IC
has the ability to determine the correct movement of solenoid
armatures by analyzing the variation in the voltage profile,
across the solenoid driver MOSFET, which represents the
actual solenoid current profile.
33811
12
Analog Integrated Circuit Device Data
Freescale Semiconductor