Preliminary User's Manual l TQMa8Xx UM 0002 l © 2018, TQ-Systems GmbH
Page 17
3.2.6.8
Power-Up sequence TQMa8Xx / carrier board
The TQMa8Xx meets the required sequencing of the i.MX 8X by using the PMIC (4).
Since the TQMa8Xx operates at 3.3 V and the 1.8 V I/O voltage of the CPU signals is generated on the TQMa8Xx, the carrier board
design must meet requirements regarding the chronological behaviour of the voltages generated on the carrier board.
The 3.3 V carrier board supply may only be enabled via TQMa8Xx output V_1V8 (X2-11, X2-12).
The following illustration shows the voltage regulator control of a carrier board.
Illustration 10: Block diagram power supply carrier board
Attention: Power-Up sequence
The TQMa8Xx I/O pins may not be driven by external components during power-up in order
to avoid cross-supply and thus errors during the power-up sequence.
To ensure a correct power-up, the following sequence must be met on the carrier board:
The supply voltage of 3.3 V for the TQMa8Xx is present and the carrier board supply of 3.3 V
is activated with TQMa8Xx voltage V_1V8, pins X2-11, and X2-12.
3.2.6.9
Power modes
(TBD)
3.2.6.10
PMIC
On the TQMa8Xx the PMIC PF8100 is assembled. The PF8100 is connected to a dedicated I
2
C bus of the i.MX 8X (PMIC_I2C)
intended for power management. Alternatively, the PF8200 can be assembled. The PF8200 offers additional safety and
monitoring functions that may be used as part of an ASIL requirement.
The following PMIC and power management signals are routed to the connectors:
Table 15:
Provided PMIC signals
Signal
I/O
Power domain
Remark
PMIC_PGOOD
O
V_1V8_ANA
•
PMIC power monitor output
•
Requires pull-up on carrier board
•
See PMIC data sheet (4)
PMIC_FSOB_EWARN
O
V_1V8_ANA
•
Assembly option: Connection to FSOB (standard) or EWARN of PMIC
•
See PMIC data sheet (4)
PMIC_I2C_SDA
PMIC_I2C_SCL
I/O V_1V8_ANA
•
Dedicated PMIC interface
•
Can be used for further power management on carrier board
PMIC_PWRON
I
V_SNVS_CAP
•
Enable signal for PMIC (High-Active)
•
Activated by default when V_3V3_IN is switched on
•
To activate: Float or with 3.3 V
•
To deactivate: Connect to GND
Attention: Malfunction or destruction
The PMIC can be controlled via the dedicated i.MX 8X I
2
C bus (PMIC_I2C).
Improper PMIC programming may cause the i.MX 8X or other peripherals on the TQMa8Xx
to operate outside their specification.
This can lead to malfunction, deterioration or destruction of the TQMa8Xx.
