Signalling - TDK-Lambda CM4 Application Notes

7. Signalling

Global Signals
To reduce cabling in the end system, all major input and output signals and the global 5V bias supply are wired to a single signals circuit that is
accessed through connector J3 on the transformer module as shown in the diagram below.
All the signals are referenced to the bias supply common rail (COM) and external control and/or monitoring circuits can be easily powered and
interfaced to the PSU through this connector. The entire signals circuit is fully medically isolated and can be considered a SELV output. The table
below lists the isolation voltages.
Signals to Input
Signals to Chassis
Signals to Output
Bias Supply (+5V [Power])
The CM4 series has one isolated bias supply located on the transformer module (J3) beside slot 4. The output side bias supply generates 5V and
is rated up to 1A. The supply is available whenever the AC mains voltage is connected and the input module is operating correctly. A shutdown
through the standby control on J2 or any of the following abnormal conditions will disable the 5V bias supply:

Over temperature of any part of the unit

Over voltage on any output module

Internal over current (device failure)
AC Mains Signal (ACOK [Output])
An ACOK signal is provided to indicate to the user that the AC mains voltage is applied and the input module is operating correctly. The output
signal is driven from an internal operational amplifier. Under normal operating conditions this signal gives a warning of 5 ms before the output
voltage falls below the power good threshold. A shutdown through the standby control on J2 or any of the following abnormal conditions may
cause the unit to turn off without the minimum 5 ms ACOK warning:

Over temperature of any part of the unit

Over voltage on any output module

Internal over current (device failure)
CM4 App Note 260424 issue 2.1.docx
12
2
Signals isolation voltages
4000
500
500
Document No. 260424
J3 – Global Signals
Pin Name
1 PG4
2 INH4
3 PG3
4 INH3
5 PG2
6 INH2
7 PG1
11
8 INH1
9 T
SNS
10 ACOK
1
11 +5V
12 COM
V
AC
V
DC
V
DC
Description
Slot 4 Power Good
Slot 4 Inhibit
Slot 3 Power Good
Slot 3 Inhibit
Slot 2 Power Good
Slot 2 Inhibit
Slot 1 Power Good
Slot 1 Inhibit
Temperature sense
AC mains signal
5V Bias supply
Common
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