TDK-Lambda CM4 Application Notes page 12

Power Good Signals (PG1-PG4 [Output])
Each output module provides a power good (PG) signal to indicate when the output
voltage is above approximately 90% of the pre-set voltage for that module. Each
PG signal on an output module is internally connected through an opto-isolator to
the signals circuit, which provides and open collector output, as shown.
The LED on the front of each module gives a visual confirmation of the PG status.
Note that remote adjustments of the output voltage using the V
pins do not change the PG signal threshold. The PG threshold is always
approximately 90% of the voltage set with the manual potentiometer.
Output Inhibits (INH1-INH4 [Input])
The signals circuit provides an inhibit input to disable each output module individually. Each inhibit input is internally connected through an opto-
isolator to the respective output modules. The basic internal electrical circuit and timing diagrams are shown below.
Internal circuit
Internal Temperature sensor (T
An internal temperature sensor is embedded in the transformer module. The output voltage of this sensor gives a measurement of the internal
transformer temperature and can be used to control external cooling systems or to provide a warning of impending over temperature protection.
The sensor output voltage is related to temperature as follows,
V = 0.4 + 0.0195*T
The sensor will accurately measure temperatures in the range -10⁰C to
+125⁰C.
The internal temperature should never exceed 120⁰C (2.74V)
CM4 App Note 260424 issue 2.1.docx
and I
CONTROL
[Output])
SNS
Document No. 260424
CONTROL
Timing: Typically, t
OFF
120
T output voltage Vs Internal Temperature
SNS
100
80
60
40
20
0
-20
0 0.5 1
= 100 μs and t
= 8 ms.
ON
1.5 2 2.5
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