CM4 App Note 260424 issue 2.1.docx Document No.260424 Page 1 of 29
CM4
AC/DC Modular Power Supply Series
APPLICATION NOTES
CM4 App Note 260424 issue 2.1.docx Document No. 260424 Page 2 of 29
Contents
Contents 2
1. Theory of Operation 3
2. Input Module Operation 4
3. Input Module Protection 5
4. Efficiency Performance 6
5. Power Ratings 7
6. System Cooling 8
7. Signalling 11
8. Output Module Operation 13
9. Advanced Output Module Features 16
10. Series Connected Outputs 20
11. Parallel Connected Outputs 21
12. Mechanical Dimensions and Mounting 24
13. Connector details 25
14. EMC Compliance 26
15. Reliability 27
16. Output Modules 28
17. Accessories 29
CM4 App Note 260424 issue 2.1.docx Document No. 260424 Page 3 of 29
1. Theory of Operation
The diagram below outlines the topology and major internal components of a fully assembled CM4 configurable power supply. Four output slots
are provided and can be populated by any combination of output modules. The remaining components in the block diagram are housed in the
input and transformer modules.
The input module is responsible for receiving the AC mains line voltage and converting it to an appropriate DC voltage whilst providing protection
from AC line disturbances and preventing excessive EMI emissions and current harmonics. The integrated EMI filter attenuates high frequency
current emissions to levels below EN55032 class B. It also provides dual pole fusing, one fuse in each conductor and protection from line
disturbances as outlined in EN61000.
Inrush current is controlled by a resistive element upon initial connection to the AC line. Once the internal capacitances have been charged, the
resistive element is bypassed to reduce losses.
Active Power Factor Correction (PFC) is used to ensure an accurate input current waveform with extremely low harmonic content, exceeding the
requirements of EN61000. This stage also provides active input current limiting which prevents overloading of the input stage while maintaining
high power factor.
The output of the PFC stage charges the hold-up electrolytic capacitors which store enough energy to allow the CM4 configured product to
continue operating during minor line disturbances. Long lifetime and high temperature capacitors are used which ensures extended lifetime and
product reliability.
A highly efficient zero voltage switching circuit is used to drive the isolated transformer from the hold-up capacitors. The output modules connect
to the transformer secondary and provide safe isolated power to a high performance synchronous rectifier power converter. This power converter
is controlled using the latest analog control technology to produce superior output performance in a miniature size.
CM4 App Note 260424 issue 2.1.docx Document No. 260424 Page 4 of 29
2. Input Module Operation
Startup & Shut Down
The CM input module operates from a universal input voltage range and starts automatically upon application of adequate AC mains voltage
(>84Vrms). After a short delay, the global 5V bias supply starts and the ACOK signal goes high to indicate that the mains voltage is present and
input stage is operating correctly. Once the ACOK signal is high, the output modules turn on and deliver power to the application loads. The
power good signals will indicate that the output voltages are within specification. The diagram below shows the normal start up/shut down
sequence and gives typical timings.
Typical timing values: t
1
≤2000 ms, t2 ≤400 ms, t3 ≤600 ms, t4 ≥15 ms, t5 ≥5ms (minimum), t6 ≥100 ms
When the AC mains voltage is removed, the internal hold-up capacitors will supply power to the load for typically 20 ms (t4+t5) at maximum
power. The ACOK signal will go low at least 5 ms before the output voltages fall below the power good threshold level. This allows the application
to prepare for the impending loss of power. The 5V bias supply will remain on for typically 100 ms, after the output modules have turned off.
Standby control
The unit may be completely shut down by shorting (<10Ω) the terminals of J2. The unit will restart once the short is released.
The control uses transformer coupled pluses to detect the short and is fully isolated to 2xMOPP. The voltage present on J2 ranges from +3.3V to
-0.8V with a peak current of 15mA. In active mode, the control is pulsed every 1.3 ms while in standby mode the control is pulsed every 400 ms.
A signal MOSFET or switch may be used to activate this control. This shutdown will not generate the ACOK warning signal.
Programmable start-up state
The start-up and standby control logic can be inverted by shorting J11 with a jumper. The functionality is shown in the table below.
J11
J2
Operational mode
Comments
Open
Open
NORMAL
Default. Unit will start into NORMAL mode
Open
Closed
STANDBY
<1W power consumption
Closed
Open
STANDBY
Unit will start into STANDBY mode. <1W power consumption
Closed
Closed
NORMAL
J11 LOCATION
J2 LOCATION
- +
J11
J12
CM4 App Note 260424 issue 2.1.docx Document No. 260424 Page 5 of 29
Note - J12 is reserved for internal use. Do not short J12
Hold-up
For short line distubances (<20 ms), the output voltages will not be affected*. However, the ACOK signal may still go low to warn that there is an
impending loss of output power. The ACOK signal will return to the high state once the unit has recovered from the disturbance.
*Output modules that are adjusted above the hold-up voltage (as detailed in Section 16), may experience a dip in voltage but never below the
hold-up voltage specified.
No Load Power/Standby Power Consumption
The no-load power consumption of the CM4 series power supply is extremely low when compared to similar configurable power supplies. With
the output modules enabled the unit typically only requires less than 15W with no output load. To reduce the no-load power further the outputs
can be disabled using the inhibit pins. With the outputs disabled the unit typically requires less than 10W. When the unit is in the standby (latched
off) state, the power consumption is less than 1W.
Peak Power capability
The input module can provide a peak output power of up to 750W for a period of up to 5 seconds, provided the input current remains below the
over current protection threshold. Peaks of power lower than 750W can be supported for longer times provided the excess watt-seconds are
equivalent. For example, 750W peak for 5 seconds is an excess power of 150W*5s = 750Ws. 650W can be supported for 750Ws/50W = 15s.
When using peak power capability, the user must ensure the average power remains within ratings. Note that input module de-ratings apply to
both rated power and peak power.
3. Input Module Protection
Over current protection (OCP)
The input module is protected from excessive input current by means of an over current protection circuit which limits the input current to
approximately 7Arms. If the OCP threshold is exceeded the unit may shut down and attempt to automatically restart. This shutdown will generate
the usual ACOK warning.
Under voltage protection (UVP) & Brown-Out Protection (BOP)
The input module is protected from excessively low input voltages by under voltage and brown out protection circuits that senses the input line
voltage. The under-voltage protection circuit maintains the unit in standby mode until the input voltage rises above the UVP threshold as detailed
in the datasheet. Once the unit is active, the brown out protection monitors the input voltage and shuts down the unit when input voltage goes
below approximately 60Vrms. This shutdown will generate the usual ACOK warning. The unit will restart once the input voltage increases above
the UVP threshold.
Over Temperature Protection (OTP)
The input module is protected from excessive temperatures by means of various internal temperature sensors. If temperature thresholds are
exceeded the entire unit may latch off, with no ACOK warning. To re-enable the unit, it must be allowed to cool, then either disconnect the AC
mains for approximately 20 seconds, or toggle the standby control on J2.
Over Power Protection (OPP)
The input module is protected from excessive power by means of an over power protection circuit. Should the rated power be exceeded the unit
will shut down and attempt to recover automatically. This shutdown will not generate the usual ACOK warning.
CM4 App Note 260424 issue 2.1.docx Document No. 260424 Page 6 of 29
4. Efficiency Performance
The efficiency of the configured CM4 product is dependent on parameters such as input line voltage, load level and on the combination of output
modules. The plots below show typical efficiencies of a CM4 product fitted with all modules S1, S2, S3 or S4. The plots cover the full load and
line voltage range. All modules are adjusted to nominal voltages and are equally loaded.
An estimate of the overall efficiency for any configured system may be obtained from these graphs.
CM4 App Note 260424 issue 2.1.docx Document No. 260424 Page 7 of 29
5. Power Ratings
CM4 series products must always be operated within stated operating limits. Equipment manufacturers and other users must take the appropriate
de-rating into account when specifying a unit for the intended application. If in doubt, contact TDK-Lambda for assistance.
There are three main de-ratings for the CM4 series of configurable power supplies when used in a conduction cooled application,
1. Ambient air temperature
(1)
Ambient air temperature de-ratings apply to the input
module rated and peak power only.
(3)
The input module must be de-rated by 2.5% per
degree Celsius above 50°C, up to a maximum of
70°C.
2. Baseplate temperature
(2)
Baseplate temperature de-ratings apply to output
module rated power, peak power and rated current,
and bias supply power.
The output module parameters must be de-rated by
2.5% per degree Celsius above 85°C, up to a
maximum of 105°C.
3. Input line voltage
Input line voltage de-ratings apply to the rated power
and peak power for both the input module and output
module.
(3)
All parameters must be de-rated by 2.5% for every 3
volts below 120Vrms, down to a minimum of 85Vrms.
Notes:
1. Ambient air temperature is the air temperature immediately surrounding the power supply.
2. Baseplate temperature is measured at baseplate temperature sensing location TS1 (see mechanical drawings for location.
3. A normalized value of 1 is equivalent to 100%.
4. Input line voltage de-ratings are cumulative with temperature de-ratings.
Examples of power ratings calculation for various input voltages, ambient temperatures and baseplate temperatures
1 2 3 4 5 6
7
VIN (V
RMS
)
120
85
85
120
120
100
120
Normalised VIN Rating [A]
1
0.708
0.708 1 1
0.833
1
T
AMBIENT
(⁰C)
70
50
70
50
60
60
50
Normalised T
AMBIENT
Rating [B]
0.5 1 0.5 1 0.75
0.75
1
T
BASE
(⁰C)
85
85
85
95
105
95
105
Normalised T
BASE
Rating [C]
1 1 1
0.75
0.5
0.75
0.5
Normalised Total input rating [A*B = D]
0.5
0.708
0.354 1 0.75
0.624
1
Normalised Total output rating [A*C = E]
1
0.708
0.708
0.75
0.5
0.624
0.5
Input module P
RATED/PEAK
[600W/750W*D]
300/375
424.8/531
212.4/265.5
600/750
450/562.5
374.4/468
600/750
Bias supply power [5W*C]
5 5 5
3.75
2.5
3.75
2.5
S1 P
RATED/PEAK
[125W/187.5W*E]
125/187.5
88.5/132.75
88.5/132.75
93.75/140.625
62.5/93.75
78/117
62.5/93.75
S1 I
RATED
[25A*C]
25
25
25
18.75
12.5
18.75
12.5
S2 P
RATED/PEAK
[150W/225W*E]
150/225
106.2/159.3
106.2/159.3
112.5/168.75
75/112.5
93.6/140.4
75/112.5
S2 I
RATED
[15A*C]
15
15
15
11.25
7.5
11.25
7.5
S3 P
RATED/PEAK
[150W/225W*E]
150/225
106.2/159.3
106.2/159.3
112.5/168.75
75/112.5
93.6/140.4
75/112.5
S3 I
RATED
[7.5A*C]
7.5
7.5
7.5
5.625
3.75
5.625
3.75
S4 P
RATED/PEAK
[150W/217.5W*E]
150/217.5
106.2/154
106.2/154
112.5/163.125
75/108.75
93.6/135.72
75/108.75
S4 I
RATED
[3.75A*C]
3.75
3.75
3.75
2.8125
1.875
2.8125
1.875
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
-40 -30 -20 -10 0 10 20 30 40 50 60 70
Normalised output power rating
Ambient Temperature (Celsius)
Ambient Temperature Derating
Derate at 2.5% per degree Celsius
above 50 degree Celsius
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
80 100 120 140 160 180 200 220 240 260 280
Normalised Output Power rating
Input Voltage (RMS)
Input Line voltage Derating
Derate at 2.5% per every
3 volts below 120Vrms
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
-40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 100 110
Normalised Power & Current Rating
Baseplate Temperature (Celsius)
Temperature Derating
Derate at 2.5% per degree Celsius
above 85 degree Celsius
CM4 App Note 260424 issue 2.1.docx Document No. 260424 Page 8 of 29
6. System Cooling
The power ratings shown in the previous section are for conduction cooling, however the unit may be operated with forced air cooling, convection
cooling or combinations of all three. To assist in specifying the product for these applications, the typical thermal performance has been
characterised under controlled conditions. The ratings achieved are based on maintaining the baseplate temperature within the conduction
cooled ratings specified in section 5.
CONVECTION PERFORMANCE
Natural Convection, No Heatsink, Free Air, Mounting Orientations A/B/C/D/E/F
CONVECTION PERFORMANCE WITH HEATSINK
(1)
Natural Convection, With Heatsink, Free Air, Mounting Orientations A/B/C/D/E/F
Orientation definitions
A B C D E
F
Orientation
definitions
Notes
1. Standard TDK-Lambda heatsinks type 1 and type 2 used. Type 1 used for mounting orientations A, B, E and F. Type 2 used for mounting orientations A, B, C and D.
0
50
100
150
200
250
300
350
400
450
500
550
-40 -30 -20 -10 0 10 20 30 40 50 60 70 80
Pout
Ambient Temperature
S1 120Vin, 4x5Vout
A B CD EF
0
50
100
150
200
250
300
350
400
450
500
550
-40 -30 -20 -10 0 10 20 30 40 50 60 70 80
Pout
Ambient Temperature
S1 220Vin, 4x5Vout
A B CD EF
0
50
100
150
200
250
300
350
400
450
500
550
600
650
-40 -30 -20 -10 0 10 20 30 40 50 60 70 80
Pout
Ambient Temperature
S2/S3/S4 120Vin, 4x10/20/40Vout
A B CD EF
0
50
100
150
200
250
300
350
400
450
500
550
600
650
-40 -30 -20 -10 0 10 20 30 40 50 60 70 80
Pout
Ambient Temperature
S2/S3/S4 220Vin, 4x10/20/40Vout
A B CD EF
0
50
100
150
200
250
300
350
400
450
500
550
-40 -30 -20 -10 0 10 20 30 40 50 60 70 80
Pout
Ambient Temperature
S1 120Vin, 4x5Vout
A B CD EF
0
50
100
150
200
250
300
350
400
450
500
550
-40 -30 -20 -10 0 10 20 30 40 50 60 70 80
Pout
Ambient Temperature
S1 220Vin, 4x5Vout
A B CD EF
0
50
100
150
200
250
300
350
400
450
500
550
600
650
-40 -30 -20 -10 0 10 20 30 40 50 60 70 80
Pout
Ambient Temperature
S2/S3/S4 120Vin, 4x10/20/40Vout
A B CD EF
0
50
100
150
200
250
300
350
400
450
500
550
600
650
-40 -30 -20 -10 0 10 20 30 40 50 60 70 80
Pout
Ambient Temperature
S2/S3/S4 220Vin, 4x10/20/40Vout
A B CD EF
CM4 App Note 260424 issue 2.1.docx Document No. 260424 Page 9 of 29
FORCED AIR PERFORMANCE
No Heatsink, Air Direction X or Y at 2m/s/1.5m/s/1m/s/0.5m/s
FORCED AIR PERFORMANCE WITH HEATSINK
(2)
With Heatsink, Air Direction X or Y at 2m/s/1.5m/s/1m/s/0.5m/s
Airflow definitions
X Y Z
Notes
1. Each 0.5m/s is approximately 100LFM. Eg. 2m/s ≈ 400LFM, 1.5m/s ≈ 300LFM etc.
2. Standard TDK-Lambda heatsinks type 1 and type 2 used. Type 1 used for airflow direction X. Type 2 used for airflow direction Y.
The ratings provided above are for guidance only and all CM4 configured solutions must be evaluated in the end application to ensure the
conditions set out in the power ratings section are met.
0
50
100
150
200
250
300
350
400
450
500
550
-40 -30 -20 -10 0 10 20 30 40 50 60 70 80
Pout
Ambient Temperature
S1 120Vin, 4x5Vout
2MS-1 1.5MS-1 1MS-1 0.5MS-1
0
50
100
150
200
250
300
350
400
450
500
550
-40 -30 -20 -10 0 10 20 30 40 50 60 70 80
Pout
Ambient Temperature
S1 220Vin, 4x5Vout
2MS-1 1.5MS-1 1MS-1 0.5MS-1
0
50
100
150
200
250
300
350
400
450
500
550
600
650
-40 -30 -20 -10 0 10 20 30 40 50 60 70 80
Pout
Ambient Temperature
S2/S3/S4 120Vin, 4x10/20/40Vout
2MS-1 1.5MS-1 1MS-1 0.5MS-1
0
50
100
150
200
250
300
350
400
450
500
550
600
650
-40 -30 -20 -10 0 10 20 30 40 50 60 70 80
Pout
Ambient Temperature
S2/S3/S4 220Vin, 4x10/20/40Vout
2MS-1 1.5MS-1 1MS-1 0.5MS-1
0
50
100
150
200
250
300
350
400
450
500
550
-40 -30 -20 -10 0 10 20 30 40 50 60 70 80
Pout
Ambient Temperature
S1 120Vin, 4x5Vout
2MS-1 1.5MS-1 1MS-1 0.5MS-1
0
50
100
150
200
250
300
350
400
450
500
550
-40 -30 -20 -10 0 10 20 30 40 50 60 70 80
Pout
Ambient Temperature
S1 220Vin, 4x5Vout
2MS-1 1.5MS-1 1MS-1 0.5MS-1
0
50
100
150
200
250
300
350
400
450
500
550
600
650
-40 -30 -20 -10 0 10 20 30 40 50 60 70 80
Pout
Ambient Temperature
S2/S3/S4 120Vin, 4x10/20/40Vout
2MS-1 1.5MS-1 1MS-1 0.5MS-1
0
50
100
150
200
250
300
350
400
450
500
550
600
650
-40 -30 -20 -10 0 10 20 30 40 50 60 70 80
Pout
Ambient Temperature
S2/S3/S4 220Vin, 4x10/20/40Vout
2MS-1 1.5MS-1 1MS-1 0.5MS-1
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