bcm48bh120t120a00 Vicor Corporation, bcm48bh120t120a00 Datasheet - Page 10

• Manufacturer Part Number: bcm48bh120t120a00
• Description: Bcmtm Bus Converter
• Manufacturer: Vicor Corporation

3.0 POWER, VOLTAGE, EFFICIENCY RELATIONSHIPS
Because of the high frequency, fully resonant SAC topology,
power dissipation and overall conversion efficiency of BCM
converters can be estimated as shown below.
Key relationships to be considered are the following:
Therefore, with reference to the diagram shown in Figure 15
Notice that R
and P
The above relations can be combined to calculate the overall module efficiency:
v i c o r p o w e r. c o m
1. Transfer Function
2. Dissipated Power
P
OUT
a. No load condition
V
Where K (transformer turns ratio) is constant
for each part number
b. Loaded condition
V
The two main terms of power losses in the
BCM module are:
- No load power dissipation (P
- Resistive loss (R
P
NL
DISSIPATED
OUT
OUT
used to power up the module with an enabled power
train at no load.
the BCM modeled as pure resistive impedance.
= P
is temperature dependent (See Figure 15).
IN
= V
= Vin • K – I
η =
– P
OUT
IN
~ P
~
DISSIPATED
• K
is temperature and input voltage dependent
P
P
NL
OUT
IN
+ P
OUT
OUT
=
R OUT
= P
) refers to the power loss across
V•I CHIP INC. (A VICOR COMPANY) 25 FRONTAGE RD. ANDOVER, MA 01810 800-735-6200
• R
P
IN
IN
OUT
– P
– P
NL
NL
P
IN
NL
– P
– P
) defined as the power
R OUT
R OUT
PRELIMINARY DATASHEET
=
Eq. 1
Eq. 2
Eq. 3
Eq. 4
V
IN
• I
IN
– P
V
BCM48BH120T120A00 - BCM48BH120M120A00
IN
NL
• I
– (I
IN
OUT
Figure 15 – Power transfer diagram
)
2
• R
OUT
= 1 –
POWER
INPUT
(
P
NL
+ (I
V
IN
OUT
• I
)
P
2
IN
NL
• R
OUT
)
P
OUTPUT
POWER
R
OUT
Eq. 5
Page 10 of 16
Rev. 2.0
12/10