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BCM6123X60E15A3YZZ Datasheet, PDF (22/28 Pages) Vicor Corporation – Fixed Ratio DC-DC Converter | |||
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Sine Amplitude Converter⢠Point of Load Conversion
LPRI_IN_LEADS = 6.7 nH
+
VVPRINI
CPRI_INT_ESR
0.75 mΩ
CPRI_INT
11.2 µF
CIN
RCIN
I IPRI_QQ
270 mA
â
1/4 ⢠ISEC
IOISUECT
0.53 nH
Vâ¢I
++
10 mΩ
1/4 ⢠VPRI
ââ
K
BCM6123x60E15A3yzz
RSEC
1R.9O6UTmΩ
COUT
LSEC_OUT_LEADS = 0.64 nH
RCCSEOC_UINTT_ESR
60.4 µΩ
CSEC_INT
140 µF
+
VVOSEUCT
â
Figure 16 â BCM module ACâmodel
The Sine Amplitude Converter (SACâ¢) 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 BCM6123x60E15A3yzz SAC can be simplified into the
preceeding model.
At no load:
interesting attributes. Assuming that RSEC = 0Ω and IPRI_Q = 0A,
Eq. (3) now becomes Eq. (1) and is essentially load independent,
resistor R is now placed in series with PRI.
RR
+
VVPiRnI â
SSAACCâ¢
KK==11/3/42
VSoEuC t
VSEC = VPRI ⢠K
(1)
K represents the âturns ratioâ of the SAC.
Rearranging Eq (1):
K = VSEC
VPRI
In the presence of load, VSEC is represented by:
VSEC = VPRI ⢠K â ISEC ⢠RSEC
and Iout is represented by:
Figure 17 â K = 1/4 Sine Amplitude Converter
with series primary resistor
(2)
The relationship between VPRI and VSEC becomes:
VSEC = (VPRI â IPRI ⢠R) ⢠K
(5)
Substituting the simplified version of Eq. (4)
(IPRI_Q is assumed = 0A) into Eq. (5) yields:
(3)
VSEC = VPRI ⢠K â ISEC ⢠R ⢠K2
(6)
I SEC = IPRIKâ IPRI_Q
(4)
RSEC represents the impedance of the SAC, and is a function
of the RDSON of the primary and secondary MOSFETs and the
winding resistance of the power transformer. PRI_Q represents the
quiescent current of the SAC control, gate drive circuitry,
and core losses.
The use of DC voltage transformation provides additional
This is similar in form to Eq. (3), where RSEC is used to represent the
characteristic impedance of the SACâ¢. However, in this case a real
R on the primary side of the SACâis effectively scaled by K2 with
respect to the secondary.
Assuming that R = 1Ω, the effective R as seen from the secondary
side is 62.5mΩ, with K = 1/4 .
BCM® Bus Converter
Page 22 of 28
Rev 1.2
07/2016
vicorpower.com
800 927.9474
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