PM6652 STMicroelectronics, PM6652 Datasheet - Page 29

• Manufacturer Part Number: PM6652
• Description: IC CTLR STEPDOWN SMPS 32VFQFPN
• Manufacturer: STMicroelectronics

Specifications of PM6652

• Applications: Controller, Intel IMVP-6.5™, VR11
• Voltage - Input: 4.5 V ~ 36 V
• Number Of Outputs: 1
• Voltage - Output: 0.3 V ~ 1.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 32-VFQFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

PM6652
8.3
8.4
8.5
Pulse-skip working mode
The PM6652 can obtain very high efficiency at light load if the low side MOSFET is turned
off when the inductor current becomes equal to zero. This feature is performed by the zero
crossing comparator (see the internal block diagram,
VR11 mode this feature is activated by asserting DPRSLPVR pin. In GFX render mode the
DPRSLPVR assertion implies also that the VDAC minimum slew-rate is 10mV/µs, for
increasing programmed output voltage, as required by IMPV6.5 specifications for render
suspend fast exit mode (refer to Voltage dynamic (VID) transitions for details).
Differential remote sensing
The PM6652 performs a differential remote sensing, between VSNS and GSNS pins. The
error between the sensed output voltage and the programmed one (VSNS - VDAC) and
between the remote ground and local one (GSNS - GND) are the other two inputs of the
integrator, as shown in
connected to the mobile processor differential feedback pins; only two catch resistors
(100Ω) are allowed to avoid any VR output voltage runaway, due to a lack of negative
feedback when the processor is not mounted.
Droop function
In order to reduce the output capacitance amount, the PM6652 performs a load dependent
behavior. The voltage sensed between pins CSNS and VOUT is proportional to the load
current:
Equation 6
Given the network shown in
Equation 7
From the previous equation the equivalent droop resistance performed by the switching
regulator is:
Equation 8
The sense resistor can be a dedicated precision resistor or the inductor's DCR as explained
in
Section 8.7: Current sensing on page 31
V
CORE
Figure 25 on page 28
_
R
SS
Figure 25 on page 28
DROOP
Doc ID 16867 Rev 3
−
V
C
GND
SNS
=
_
⎛
⎜ ⎜
⎝
−
SS
1
+
V
OUT
=
R
R
.
V
2
1
. The differential remote sense must be directly
DAC
⎞
⋅ ⎟ ⎟
⎠
=
R
R
SNS
−
SNS
, the resultant regulated output voltage is:
⎛
⎜ ⎜
⎝
1
+
=
⋅
Figure 24 on page 24
I
LOAD
R
G
R
2
1
D
⎞
⋅ ⎟ ⎟
⎠
⋅
R
R
SNS
SNS
⋅
I
LOAD
Device description
). In CPU and
29/53