TDK-Lambda CM4, Application Notes

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CM4 App Note 260424 issue 2.1.docx Document No. 260424 Page 11 of 29
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.
J3
– Global Signals
Pin Name Description
1 PG4 Slot 4 Power Good
2 INH4 Slot 4 Inhibit
3 PG3 Slot 3 Power Good
4 INH3 Slot 3 Inhibit
5 PG2 Slot 2 Power Good
6 INH2 Slot 2 Inhibit
7 PG1 Slot 1 Power Good
8 INH1 Slot 1 Inhibit
9 T
SNS
Temperature sense
10 ACOK AC mains signal
11 +5V 5V Bias supply
12 COM Common
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 isolation voltages
Signals to Input 4000 V
AC
Signals to Chassis 500 V
DC
Signals to Output 500 V
DC
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)
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