TIC10024-Q1 Datasheet, PDF (21/81 Pages) Texas Instruments – 24-Input Multiple Switch Detection Interface (MSDI) Device With Adjustable Wetting Current for Automotive Systems

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1^st Event
occurance
2^nd Event
occurance
/INT pin is not
asserted until
tINT_IDLE has expired
/INT
/CS
ttINT_IDLE
TIC10024-Q1
SCPS268 – SEPTEMBER 2017
Register READ
(INT_STAT register)
Register READ
(INT_STAT register)
Figure 14. INT Assertion Scheme With t_{INT_IDLE}
8.3.9.3 Microcontroller Wake-Up
Using a few external components, the INT pin can be used for wake-up purpose to activate a voltage regulator
via its inhibit inputs. An implementation example is shown in Figure 15. This implementation is especially useful
for waking up a microcontroller in sleep mode to allow significant system-level power savings.
Before the wake-up event, the INT pin is in high impedance state on the TIC10024-Q1. The microcontroller can
be kept in sleep state with all its GPIOs in logic low. Hence, Q2 remains off with its based in logic low state and
the base of Q1 is weakly pulled-high to the V_S level. This causes Q1 to remain off, and the LDO_EN signal is
pulled-down to logic low to disable the regulator's output. V_DD is therefore unavailable to both the TIC10024-Q1
device and the microcontroller and SPI communicaiton is not supported. Switch status monitoring, however, is
still active in the TIC10024-Q1.
When an event, such as switch status change, temperature warning, or overvoltage, occurs, the INT pin is
asserted low by TIC10024-Q1, causing Q1 to turn on to activate the voltage regulator. The microcontroller is then
reactivated, and the communication between the microcontroller and the TIC10024-Q1 is reestablished. The
microcontroller can then access stored event information using SPI communication. Note since the INT pin is de-
asserted after the INT_STAT register is read, the microcontroller is required to keep the regulator on by driving
the μC_LDO_EN signal high. This allows V_DD to stay high to provide power to the microcontroller and support
SPI communications.
The wake-up implementation is applicable only when the device is configured to use the static INT assertion
scheme.
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