ISL6558EVAL1Z Intersil, ISL6558EVAL1Z Datasheet - Page 9

• Manufacturer Part Number: ISL6558EVAL1Z
• Description: EVAL BOARD 1 FOR ISL6558
• Manufacturer: Intersil

Specifications of ISL6558EVAL1Z

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

SUMMARY OF DESIGN
Table 1 shows the calculation results of critical design
parameters for the reference design, a four-channel
interleaved DC-DC buck converter.
Table 2 summarizes an approximate power dissipation
analysis for the reference design.
PARAMETER
ESR(max)
Cin (min)
Co(min)
I
I
I
I
I
Lo,Peak
Q1,RMS
Q2,RMS
IN,RMS
Io
Lo,RMS
I
Fsw
Lo,PP
DISTRIBUTION AMONG OUTPUT INDUCTORS)
I
RMS
D
PP
DUTY CYCLE AND SWITCHING FREQUENCY
TABLE 1. CRITICAL DESIGN PARAMETERS
OUTPUT INDUCTORS (ASSUMING EQUAL
SYNCHRONOUS LOWER FETs
Istep = 100A, f(step) = 80mV
dI
Lo(Io) = 0.6µH, V
Lo(Io) = 0.6µH, V
Lo(Io) = 0.6µH, V
Lo(Io) = 0.6µH, V
Lo(Io) = 0.6µH, V
IN
RT = 226kΩ (measured)
V
f
OUTPUT CAPACITORS
c
V
INPUT CAPACITORS
Vo(Io = 0) = 1.564V,
/dt = 0.1A/us,
IN
= Fsw/10 = 12.5kHz,
IN
Δ
G= 0.75V
V
= 12.6V, Io = 100A
f step
= 12, Po = 152W,
CONDITION
(
IN TRAN
V
Io = 100A
V
IN
,
V
IN
IN
N = 4
= 12.6V
)
9
=11V
IN
+
= 12,
-
=
/V
+
95mV
-
=
RAMP_PP
IN
IN
IN
IN
IN
1.0V
η
= 12.6V,
= 12.6V
= 12.6V
= 12.6V
= 12.6V
=
ERROR AMP. [He(S)]
0.83
+
-
FIGURE 9. SIMPLIFIED LOOP MODEL
,
G
Application Note 1029
F
VALUE UNIT
= I
16700
REF.
1000
14.1
13.1
19.4
10.0
34.7
25.6
23.9
10.0
125
3.1
0.8
DROOP
/I
O
kHz
mΩ
µF
µF
%
(MAX)
A
A
A
A
A
A
A
A
Lo/N
LAYOUT CONSIDERATIONS
Other than the layout considerations discussed in the
ISL6558 data sheet, below are the two possible rules to
obtain the best ripple current cancellation effect and
Output Inductor Copper
Z
TABLE 2. FULL-LOAD POWER DISSIPATION BUDGET
Input Inductors Copper
Upper FETs Conduction
Lower FETs Conduction
Lower FETs Body-diode
MOSFET r
Upper FETs Switching
LO
Output Inductor Core
Input Inductors Core
Switching Frequency
Miscounted and Error
Per-Channel Output
Per-Channel Driver
Output Capacitors
(S)
RLo/N
Input Capacitors
Zo(S)
PCB Copper
ELEMENTS
Conduction
Inductor
TOTAL
DS(ON)
CALCULATION CONDITIONS
PER-CHANNEL LOSSES (xN)
ESR
ESL
Co
Value
OTHERS (x1)
Ro
POWER DISSIPATION AT 100A
Vo
0.573W
1.055W
0.784W
0.603W
0.432W
0.547W
0.752W
0.003W
3.033W
31.42W
2.215w
0.294w
3.25W
11V
0.600µH at Full load
at Tj = +60°C
Negligible
0.0039W
125kHz
0.528W
1.152W
2.250W
0.293W
0.785W
0.623W
0.432W
0.466W
0.771W
2.953W
31.55W
LOAD
3.1W
12V
0.0044W
July 31, 2009
0.503W
1.212W
2.270W
0.293W
0.786W
0.634W
0.432W
0.424W
0.776W
2.912W
31.72W
12.6V
3.09W
AN1029.3