EVB-VF522R3 Platform User’s Guide, Rev. 0, 11/2014
6
Freescale Semiconductor, Inc.
Power management scheme
4.2
Switch-mode voltage regulator (U7)
An automotive-grade triple-output switch-mode voltage regulator generates:
•
1.5V to power the main MCU core voltage regulator (default), MCU DDR interface, and DDR
memory,
•
3.3V to power the main MCU core voltage regulator (to test low-power applications, e.g. without
DDR), main MCU supply, and EVB peripherals,
•
5V to power the MCU USB interface and EVB peripherals.
Each output has a “Power-Good” LED indicator as well as an inherent “Enable” feature.
4.3
Linear voltage regulators (U511, U1, U513)
Three voltages are generated using linear voltage regulators:
•
Optional 1.2V to power the MCU analog 1.2V blocks (instead of using filtered MCU core supply),
•
1.8V to power the audio/DSP circuitry,
•
Optional 3.3V to power the MCU analog 3.3V blocks and other EVB circuitry (instead of using
filtered MCU supply).
The 1.2V and 1.8V outputs have LED status indicators.
4.4
Power status LEDs (DS1 to DS6)
Five voltage outputs have green LED status indicators as shown in
.
If no LEDs are illuminated when power is applied to the EVB, it is possible that the external power source
polarity is incorrect. The EVB will not be damaged, though, thanks to the series diode D500 on the power
input.
Although all the voltage regulators have output overload protection, it is strongly recommended to prevent
their outputs from being shorted. If this happens, damage is likely to occur to the EVB and/or components.
4.5
Backup battery (BT500)
When the external power supply fails, the Secure Real-Time Clock (SecureRTC) module of the MCU
operates from the on-board coin cell battery. Its holder accommodates a 20 mm diameter 3V lithium-ion
Table 1. Power status LEDs
LED
Legend
Description
DS1
1.8VL
Linear 1.8V
DS3
1.2VL
Linear 1.2V
DS4
1.5VS
Switch-mode 1.5V “Power-Good”
DS5
3.3VS
Switch -mode 3.3V “Power-Good”
DS6
5VS
Switch -mode 5.0V “Power-Good”
