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4929B–AUTO–01/07
ATA6264 [Preliminary]
5.3.4 The Power-down Procedure for VVCORE is Programmed to be 1.88V
Phase1: If the ignition key is switched off, the K15 voltage will vanish at pin K15. If the serial
interface command KEYLATCH is not set, the EVZ regulator stops working. The external charge
pump is still working because EVZ is above VSAT and the VSAT regulator is not in the Perma-
nent-on mode. The charge-pump voltage still supplies the VSAT regulator and the VCORE
regulator. Because the EVZ regulator stops working, VCORE will be switched to EVZ.
Phase2: The EVZ capacitor will be discharged, and as soon as the voltage at pin VSAT drops
too low, the VSAT regulator will go into Permanent-on mode. If VSAT reaches Permanent-on
mode, the external charge pump stops working and the VSAT voltage falls analog to the EVZ
voltage. If the voltage at VSAT is below 6.27V to 7V, the VPERI regulator will be switched off.
Depending on the charge-pump voltage, the VCORE regulator stops working. The power
sequencing function for the VPERI regulator is still active and guarantees a maximum voltage
difference between VPERI and VCORE of 2.8V
Phase3: After VVPERI becomes lower than 1.1V to 1.55V, the VCORE regulator has to stop
working.
Phase4: When the voltage at the EVZ capacitor is lower than 5.5V to 6.2V, VSAT is switched
off.
Figure 5-5. Start-up and Power-down Procedure if VVCORE Programmed to Be 1.88V
3V to 4.15V3V to 4.15V
5.5V to 6.2V
too low EVZ voltage
VSAT goes into On Mode
charge pump deactivated
7.5V to 9V
7V to 6.27V6.77V to 7.2V
1.1V to 1.55V1.25V to 1.7V
VGEVZ
VEVZ
VVSAT
VK15
VK30
VVCORE
VVPERI
t
t
t
t
t
t
t