BCM6123X60E10A5YZZ Datasheet, PDF (23/29 Pages) Vicor Corporation – Fixed Ratio DC-DC Converter

Sine Amplitude Converter™ Point of Load Conversion
L_{PRI_IN_LEADS} ^{= 6.7 nH}
+
VV_PRINI
C_{PRI_INT_ESR}
0.75 mΩ
C_{PRI_INT}
11.2 µF
C_IN
RC_IN
I ^IPRI__QQ
140 mA
–
1/6 • I_SEC
I_O^IS_UEC_T
0.24 nH
V•I
++
5 mΩ
1/6 • V_PRI
––
K
BCM6123x60E10A5yzz
R_SEC
1_R.6_O2_UTmΩ
C_OUT
L_{SEC_OUT_LEADS} ^{= 0.64 nH}
RCC_{SEOC_UINTT_ESR}
81 µΩ
C_{SEC_INT}
202 µF
+
V^V_O^SE_U^C_T
–
Figure 19 — BCM module AC model
The Sine Amplitude Converter (SAC™) uses a high frequency
resonant tank to move energy from Primary to secondary and
vice versa. The resonant LC tank, operated at high frequency,
is amplitude modulated as a function of primary voltage and
secondary current. A small amount of capacitance embedded in
the primary and secondary stages of the module is sufficient for full
functionality and is key to achieving high power density.
The BCM6123x60E10A5yzz SAC can be simplified into the
preceeding model.
At no load:
The use of DC voltage transformation provides additional
interesting attributes. Assuming that R_SEC = 0Ω and I_{PRI_Q} = 0A,
Eq. (3) now becomes Eq. (1) and is essentially load independent,
resistor R is now placed in series with V_PRI.
R^R
+
V^V_Pⁱ_Rⁿ_{I –}
S^SA^AC^C™
K^K=⁼1¹/3^/62
V_So_Eu_C t
V_SEC = V_PRI • K
K represents the “turns ratio” of the SAC.
Rearranging Eq (1):
K = ^VSEC
VPRI
In the presence of load, V_SEC is represented by:
V_SEC = V_PRI • K – I_SEC • R_SEC
and I_SEC is represented by:
(1)
Figure 20 — K = 1/6 Sine Amplitude Converter
with series primary resistor
The relationship between V_PRI and V_SEC becomes:
(2)
V_SEC = (V_PRI – I_PRI ^• R) ^• K
(5)
Substituting the simplified version of Eq. (4)
(I_{PRI_Q} is assumed = 0A) into Eq. (5) yields:
(3)
V_SEC = V_PRI ^• K – I_SEC ^• R ^• K²
(6)
^{I SEC = IPRIK– IPRI_Q}
(4)
R_SEC represents the impedance of the SAC, and is a function of
the R_DSON of the primary and secondary MOSFETs and the winding
resistance of the power transformer. I_{PRI_Q} represents the quiescent
current of the SAC control, gate drive circuitry, and core losses.
BCM^® Bus Converter
Page 23 of 29
Rev 1.2
07/2016
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