BC384A480T033FP Datasheet, PDF (10/16 Pages) Vicor Corporation – BCM Bus Converter

EFFICIENCY / DISSIPATION
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:
1. Transfer Function
a. No load condition
V_OUT = V_IN • K
Eq. 1
Where K (transformer turns ratio) is constant
for each part number
b. Loaded condition
V_OUT = Vin • K – I_OUT • R_OUT
2. Dissipated Power
The two main terms of power losses in the
BCM module are:
Eq. 2
- No load power dissipation (P_NL) defined as the power
used to power up the module with an enabled power
train at no load.
- Resistive loss (R_OUT) refers to the power loss across
the BCM modeled as pure resistive impedance.
P_DISSIPATED ^~~ P_NL + P_ROUT
Eq. 3
Therefore, with reference to the diagram shown in Figure 16
P_OUT = P_IN – P_DISSIPATED = P_IN – P_NL – P_ROUT
Eq. 4
Notice that R_OUT is temperature and input voltage dependent and P_NL is
temperature dependent (See Figure 16).
PRELIMINARY DATASHEET
INPUT
POWER
OUTPUT
POWER
P_NL
Figure 17 — Power transfer diagram
P _{R OUT}
The above relations can be combined to calculate the overall module efficiency:
η ₌ ^POUT ₌ ^{PIN – PNL – PROUT} ₌
P_IN
P_IN
V_IN • I_IN – P_NL – (I_OUT)² • R_OUT
V_IN • I_IN
( ) = 1 – PNL + (IOUT)2 • ROUT
V_IN • I_IN
Eq. 5
Bus Converter Module
BC384A480T033FP
vicorpower.com
Rev. 1.0
Page 10 of 16