ON Semiconductor NCV7750GEVB User Manual

NCV7750GEVB
NCV7750 Eval Board
User's Manual
Description
The NCV7750 is a quad low−side relay driver for
automotive applications, targeted for use in a Body Control
Unit (BCU) or Engine Control Unit (ECU). Communication
to the NCV7750 is accomplished through a SPI bus using the
SPI defined communication pins SI, SO, SCLK and CSB.
This evaluation board is set up to demonstrate the output
drivers, the protective features of the device, and the various
modes of operation that the device is capable of.
The NCV7750 has four independently controlled
channels. Each of these channels has Overcurrent Detection,
Overtemperature Detection, and Open Load Detection.
These conditions are reported back to the user through data
received during SPI communication.
Each of these four channels uses an NEC EX2 automotive
relay as a load that switches an LED load on the output of the
relay. Each relay has an accompanying button to generate an
Overcurrent condition, and a jumper to generate an Open
Load condition.
Output control is realized by DIP switches that may be set
by the user. There is a pushbutton to transmit the
configuration set by the DIP switches over SPI. There is also
a switch to allow for continuous transmission over SPI,
without the user needing to manually press the transmit
button. The state of the NCV7750 along with inputs and
outputs are displayed on the LCD. Silkscreened reference
tables are present on the board to give the user further
information about what is displayed on the LCD.
A demo mode may be accessed by pressing the transmit
button while continuous transmission is enabled.
Features
•
Demo Mode
•
Individual Output Drive Control
•
On−board Relay Demonstration
•
LCD Display for Input, Output and Chip State
•
Option for Off−board Operating Voltage and Input
Control
Application
The NCV7750 includes four low−side drivers. Each of
these drivers contains an internal clamping device which
permits safe switching of inductive loads. This clamp
voltage has a minimum specification of 36 V.
© Semiconductor Components Industries, LLC, 2017
September, 2017 − Rev. 0
EVAL BOARD USER'S MANUAL
Each power transistor output driver may sink 600 mA of
current, with the source of the transistor connected to the
ground pins and the drain connected to the output pin.
The primary target for this device is to control relay coils.
The output of the relay circuit may be connected to a wide
variety of devices, including but not limited to loads for a
BCU or ECU, windshield wipers, sunroof motor, cruise
control system, window defrosters, fog lights, HVAC fans,
ignition, headlights, tail lights, hazard lights, horn,
instrument cluster, heated mirror, keyless entry, fuel pump.
The NCV7750 may also be used to directly drive LEDs and
other devices with similar current requirements.
Communication
The NCV7750 uses SPI (Serial Peripheral Interface) for
communication while operating in "Normal Modes". SPI
uses the following four pins for communication:
•
SI – Serial Input
•
SO – Serial Output
•
SCLK – Clock
•
CSB – Chip Select Bar
When data is about to be transmitted to the NCV7750,
CSB goes low. Data is then clocked into the SI pin while data
is clocked out onto the SO pin simultaneously. Data is
clocked in on the negative edge of the clock; data is clocked
out on the positive edge of the clock. This is vital for correct
operation of the device, and may require specific
configuration of the device controlling the NCV7750. These
edges must also match properly if the NCV7750 is to be used
in daisy chain configuration with other NCV7750s or other
SPI controlled devices. It should also be noted that data on
SO is available as soon as CSB goes low, without needing to
wait for a clock edge. For more information on the specifics
of SPI communication with the NCV7750, see the
documentation entitled NCV7750/D.
1
www.onsemi.com
Publication Order Number:
EVBUM2507/D