LTC3734_15 Datasheet, PDF (25/28 Pages) Linear Technology – Single-Phase, High Efficiency DC/DC Controller for Intel Mobile CPUs

LTC3734
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.
PGOOD
VRON
5V
3.3V
2k
5V
1000pF
100k
27
MCH_PG
30
DPRSLPVR
4
STP_CPUB
32
PSIB
31
Si1034X
100pF
V_OA+
1M
1%
13
VID0
14
VID1
15
VID2
17
VID3
18
VID4
19
VID5
26
11
680pF
3k
1M
10
470pF
5
100pF
28
1µF
V_OUT
X5R
22
BAT54
25
4.7µF
X5R
0.47µF
SW
MCH_PG
24
TG
DPRSLPVR
23
SW
STP_CPUB
21
BG
20
PSIB
PGND
FREQSET SENSE^{+ 6}
VID0
SENSE^{– 7}
1µF L1
Q1
0.8µH
Q2
D1
10Ω
1nF
10Ω
VID1
LTC3734
VID2
VID3
RBOOT
VID4 RDPRSLP
VID5
PGOOD
I_TH
RUN/SS
RDPSLP
V_OA+
OAOUT
V_OA–
RBOOT
12
12.7k
1%
8 ^56.2k
9
1.27M
1
3 ^13.3k
2
SGND
13.3k
V_OA+
1.27M
V_FB
PV_CC
BOOST
SV_CC ²⁹
5V
0.1µF
X5R
0.002Ω
V_IN
C1
5V TO 24V
10µF ×5
35V X5R
V_OUT
0.7V TO 1.708V
+ _C5
AT 20A
1µF
270µF ×3
2V
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
3.3V
249k 1M
PGOOD
MMBT3904
80.6k
RBOOT
CLKEN#
2k
3.3V
1.9k
2N7002 4.12k
43.2k
1µF
MMBT3904
IMPV4_PG
VRON
3734 F09
Figure 9. 5V to 24V Input, 0.7V to 1.708V Output, 20A IMVP-IV Compatible Power Supply
3734fa
25