CBM100S Series
Application Note
Page 6
4. Main Features and Functions
6. Applications
6.1 CBM100S Series Derating Curve
The operating temperature range of CBM100S series is -25
0
C to +85
0
C
When operating the CBM100S series, proper derating is needed. The
maximum ambient temperature under any operating condition should not
exceed 85
0
C.
The following chart is the derating curve of CBM100S series.
Example:
::
:
What is the maximum ambient temperature of CBM100S120 operating at
Vin=115Vac and 50% rated load with heat sink M-B012?
Typical Thermal Resistance (Rca)
Heat Sink M-B012 Natural
Convection 20ft./min.(0.1m/s) 2.07℃/W
No Heat Sink Natural Convection
20ft./min.(0.1m/s) 5.0℃/W
Solution:
Given:
Heat sink M-B012 thermal resistance 2.07
0
C/W
Vin=115Vac, Vo=12Vdc
When Io=4.2A, efficiency=88.6% (see chapter 6.5)
Determine Power dissipation (Pd):
Pd=Pi-Po=Po(1-η)/η
=12×4.2×(1-0.886)/0886=6.4Watts
Determine maximum ambient temperature:
Given: Pd=6.4W
Then check above Power derating curve
The maximum ambient temperature is about Ta=71℃
Verify:
Maximum temperature rise △T = Pd × Rca=6.4×2.07=13.248℃
Maximum ambient temperature Ta=Tc-△T=85-13.248=71.752℃
Where:
The Rca is thermal resistance from case to ambience.
The Ta is ambient temperature and the Tc is case temperature.
4.1 Operating Temperature Range
The highly efficient design of Cincon’s CBM100S series
power module has resulted in their ability to operate within
ambient temperature environments from -20
0
C to 85
0
C. The
derating curve was drawn from the CBM100S power module.
Over current protection (OCP)
CBM100S Series provide fully continuous short-circuit
protection. The unit will auto recover until the short circuit is
removed. To provide a protection in a fault condition, the unit is
equipped with internal OCP. The unit will operate normally until
the fault condition is removed. The power module will go to hiccup
mode if output current reaches the condition of OCP, 130% to
200% rated current.
Over voltage protection (OVP)
All different voltage models have a fully continuous OVP. The
power module will supply OVP, and the maximum voltage of OVP
is 140% rated voltage. In the event of happen the OVP, the
converter will shut down, and then It must recycle AC input to
restart the converter.
5. EMC & Safety
CB IEC 60950-1
TUV EN 60950-1
UL/cUL UL60950-1
CE EN 55022 Class B,
FCC Part 15 for a Class B, CISPR 22