Datasheet

LTC3734
25
3734fa
TYPICAL APPLICATION
Figure 9 shows a typical application using the LTC3734
to power the mobile CPU core. The input can vary from
5V to 24V; the output voltage can be programmed from
0.7V to 1.708V with a maximum current of 20A. By only
modifying the external MOSFET and inductor selection,
higher load current capability can be achieved.
The power supply in Figure 9 receives a VRON signal for
ON/OFF control. After soft-start, the output voltage is set
at 1.2V until the assertion of the MCH_PG signal. After
about a 50µs delay, the VID5-VID0 bits gain the control
over the output voltage and program it between 0.7V and
1.708V. When the STP_CPUB signal is low, a deep sleep
state is indicated and the output voltage is decreased
by about 1.04%. When the DPRSLPVR signal is high,
a deeper sleep state is indicated and the output voltage
becomes 0.748V regardless of the states of the VID bits.
Active voltage positioning is accomplished with a resistive
divider across the I
TH
pin. Lower resistance yields a steeper
AVP slope while higher resistance provides a flatter slope.
Finally, the PGOOD output is masked for 110µs during VID
change or state transition.
Figure 9. 5V to 24V Input, 0.7V to 1.708V Output, 20A IMVP-IV Compatible Power Supply
MCH_PG
DPRSLPVR
STP_CPUB
PSIB
FREQSET
VID0
VID1
VID2
VID3
VID4
VID5
PGOOD
I
TH
RUN/SS
SGND
V
FB
PV
CC
BOOST
TG
SW
BG
PGND
SENSE
+
SENSE
–
RBOOT
RDPRSLP
RDPSLP
V
OA
+
OAOUT
V
OA
–
MCH_PG
DPRSLPVR
STP_CPUB
PSIB
VID0
VID1
VID2
VID3
VID4
VID5
27
30
4
32
31
13
14
15
17
18
19
26
11
10
5
28
22
25
24
23
21
20
6
7
12
8
9
1
3
2
1M
1%
PGOOD
249k
3.3V
3.3V
1M
3k
100pF
0.47µF
BAT54
SW
680pF
100pF
5V
4.7µF
X5R
1µF
X5R
V
OUT
V
OA
+
3.3V
V
OA
+
5V
LTC3734
0.002Ω
1µF
Q1
Q2
D1
L1
0.8µH
C5: PANASONIC SP EEFSX0R181R OR
SANYO POSCAP 2R5TPE220MG
D1: B340A
L1: SUMIDA CEP125-0R8
Q1: IRF7811W(SO8) OR FDS7860DP
Q2: IRF7811W OR FDS7856DP(SO8) ×2
13.3k
10Ω
10Ω
12.7k
1%
1.27M
56.2k
13.3k
1.27M
3734 F09
1nF
C1
10µF ×5
35V X5R
V
IN
5V TO 24V
V
OUT
0.7V TO 1.708V
AT 20A
C5
270µF ×3
2V
1µF
+
SV
CC
0.1µF
X5R
5V
29
RBOOT
1000pF
100k
2k
VRON
VRON
Si1034X
470pF
MMBT3904 MMBT3904
2N7002
80.6k
2k
PGOOD
1.9k
RBOOT
1M
1µF
CLKEN#
4.12k
43.2k
IMPV4_PG