Chapter 5: Power Control; Pwr_Ok - Nexcom COM Express Type 6 ICES 673 User Manual

Chapter 5: Power Control

C 5: P
haPter ower
A. PWR_OK:
Input Power - Sequencing
COM Express input power sequencing requirements are as follows:
®
Start Sequence:
▪ VCC_RTC must come up at the same time or before VCC_5V_SBY
comes up.
▪ VCC_5V_SBY must come up at the same time or before VCC_12V
comes up.
▪ PWROK must be active at the same time or after VCC_12V comes
up.
Stop Sequence:
▪ PWROK must be inactive at the same time or before VCC_12V
goes down.
▪ VCC_12V must go down at the same time or before VCC_5V_SBY
goes down.
▪ VCC_5V_SBY must go down at the same time or before VCC_RTC
goes down.
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C
ontrol
VCC_RTC
VCC_5V_SBY
VCC_12V
PWROK
95%
T1
95%
T2
95%
T3
Figure 1: Power Sequencing
T1 VCC_RTC rise to VCC_5V_SBY rise
T2 VCC_5V_SBY rise to VCC_12V rise
T3 VCC_12V rise to PWROK rise
T4 PWROK fall to VCC_12V fall
T5 VCC_12V fall to VCC_5V_SBY fall
T6 VCC_5V_SBY fall to VCC_RTC fall
41
T6
T5
T4
≥ 0 ms
≥ 0 ms
≥ 0 ms
≥ 0 ms
≥ 0 ms
≥ 0 ms
ICES 673 User Manual