Difference between revisions of "AURA SOM/AURA Hardware/Power and Reset/Power Supply Unit (PSU) and recommended power-up sequence"
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Depending on the kind of such loads, SOM_PGOOD might not be able to drive them properly. On AURA SOM this signal is driven by a push-pull output at NVCC_3V3 rail, with max 20 mA current. | Depending on the kind of such loads, SOM_PGOOD might not be able to drive them properly. On AURA SOM this signal is driven by a push-pull output at NVCC_3V3 rail, with max 20 mA current. | ||
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| + | ==== Note on CPU_PORn ==== | ||
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| + | Internally to the SOM, CPU_PORn is pulled-up with 100 kohm to NVCC_BBSM_1V8 rail. | ||
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[[Category:AURA]] | [[Category:AURA]] | ||
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Contents
Power Supply Unit (PSU) and recommended power-up sequence[edit | edit source]
Implementing correct power-up sequence for i.MX93 SOC processors is not a trivial task because several power rails are involved.
AURA SOM simplifies this task by embedding all the needed circuitry. The following picture shows a simplified block diagram of PSU/voltage monitoring circuitry:
The PSU is composed of two main blocks:
- power management integrated circuit (PMIC)
- additional generic power management circuitry that completes PMIC functionalities
The PSU:
- generates the proper power-up sequence required by the SOC processor and surrounding memories and peripherals
- synchronizes the powering up of carrier board to prevent back power
Power-up sequence[edit | edit source]
The typical power-up sequence is the following:
- VIN_SOM (+3.3V) main power supply rail is powered
- CPU_PORn (active-low) is driven low by PMIC; PMIC initiates power-up sequence needed by iMX93x processor
- SOM_PGOOD goes up when all CPU, memories and I/O power rail is ready
- finally PMIC releases CPU_PORn; this signal bring the processor out of reset
Note on SOM_PGOOD usage[edit | edit source]
SOM_PGOOD is generally used on carrier board to drive loads such as DC/DC enable inputs or switch on/off control signals.
Depending on the kind of such loads, SOM_PGOOD might not be able to drive them properly. On AURA SOM this signal is driven by a push-pull output at NVCC_3V3 rail, with max 20 mA current.
Note on CPU_PORn[edit | edit source]
Internally to the SOM, CPU_PORn is pulled-up with 100 kohm to NVCC_BBSM_1V8 rail.
