ISL6444_07 Datasheet, PDF (14/19 Pages) Intersil Corporation – Dual PWM Controller with DDR Memory Option for Gateway Applications

ISL6444
ISL6444 DC/DC Converter Application
Circuits
Figures 9 and 10 show application circuits of a dual channel
DC/DC converter for a notebook PC.
The power supply in Figure 9 provides +V2.5S and +V1.8S
voltages for memory and graphic interface chipset from
+5.0V to +24VDC battery voltage.
Figure 10 shows the power supply that provides +V2.5S and
+V1.8S voltages for memory and graphic interface chipset
from +5.0V system rail.
Figure 11 shows an application circuit for a single-output split
input power supply with current sharing for advanced
graphic card applications.
Figure 12 and 13 show application circuits of a complete
power solution for DDR memory that becomes a preferred
choice in modern computers.
The power supply shown in Figure 12 generates +2.5V
VDDQ voltage from a battery. The +1.25V VTT termination
voltage tracks VDDQ/2 and is derived from +2.5V VDDQ. To
complete the DDR memory power requirements, the +1.25V
reference voltage is also provided. The PG2 pin serves as
an output for the reference voltage in this mode.
Figure 13 depicts the DDR solution in the case where the 5V
system rail is used as a primary voltage source.
For detailed information on the circuit, including a Bill-of-
Materials and circuit board description, see Application Note
AN9995. Also see Intersil’s web site (http://www.intersil.com)
for the latest information.
C1
C2
1μF
+
56μF
+5.0-24V_IN
GND
CR1
+V2_5S
(3A)
Q1
1/2 IRF7313
C6
0.1μF
L1
10μH
+
R3
C8
330μF
Q2
2/2 IRF7313
R5
C3
0.01μF
SOFT1
VIN
12 ¹⁴
VCC
28 ₁₇
C4
0.01μF
SOFT2
BOOT1
6
BOOT2
23
UGATE1
PHASE1
R1 _ISEN1
2k
LGATE1
PGND1
VSEN1
VOUT1
EN1
PG1
R7 OCSET1
5
24
4
25
7
22
ISL6444
2
27
3
26
10
19
9
20
8
21
15
16
11
1
18
13
UGATE2
PHASE2
ISEN2 ^R2
2k
LGATE2
PGND2
VSEN2
VOUT2
EN2
PG2/REF
OCSET2 R8
GND
DDR
CR2
+
C5
10μF
+5.0V_cc
Q3
1/2 IRF7313
C7
0.1μF
L2
10μH
+V1_8
(2A)
C9
Q4
330μF
2/2 IRF7313
+
R4
R6
FIGURE 9. DUAL OUTPUT APPLICATION CIRCUIT FOR ONE-STEP CONVERSION
14
FN9069.3
April 12, 2007