NCV7750GEVB
8
Undervoltage lockout generation
There are two supply voltages for the NCV7750 chip;
VDD and VDDA. For normal operation, both VDD and
VDDA must be above a certain threshold voltage; 2.625 V
falling edge for VDD and 3.5 V for VDDA. The chip may
operate in LHI mode with only VDDA’s voltage above
threshold.
In order to generate a UVLO fault, which is not reported
to the LCD display and instead results in the chip turning off
all outputs, remove one or both of the UVLO jumpers in
Figure 12.
After a UVLO fault, the chip will turn back on with all
outputs off. EN will have to be toggled to return the chip to
the Ready state.
Overtemperature generation
There is no on
−
board method to generate an OTD fault. It
is not recommended to use an oven to generate these faults,
as certain components such as the LCD screen are prone to
permanent damage at temperatures even far below the OTD
fault threshold of the NCV7750.
Transmission error
When CSB is asserted low, a bit called TER is
immediately put onto the SO pin of the NCV7750. This bit,
when high, means that the chip has just exited LHI mode, a
UVLO fault, EN has just been set high, or that there was a
fault during SPI transmission.
This feature is not displayed on the evaluation board. It
may be observed with the use of an external SPI controller.
Arduino (ATMega328P)
The NCV7750GEVB is a self
−
contained board, meaning
that it requires no external connections other than power.
This is accomplished through the use of an ATMega328P
chip configured as an Arduino, with a program preinstalled.
The ATMega328P is able to read the user inputs, determine
the state of the NCV7750, and report this to the user on the
LCD screen that accompanies it. This makes for simple,
hassle
−
free use even when a computer is not present.
