ncp5392p ON Semiconductor, ncp5392p Datasheet - Page 26

• Manufacturer Part Number: ncp5392p
• Description: 2/3/4-phase Controller For Cpu Applications
• Manufacturer: ON Semiconductor

resulting gain generates constant output impedance from
DC up to the frequency where the ceramic takes over
holding the impedance below 1.0 mW. See the example of
the locations of the poles and zeros that were set to optimize
the model above.
starting compensation values can be found for a typical
mixed bulk and ceramic capacitor type output filter.
compensation in conjunction with thermistor R
and R
100 W for maximum phase boost, and the value of RF is
typically set to 3.0 kW.
Droop Injection and Thermal Compensation
output currents for each phase. A droop amplifier is added
to adjust the total gain to approximately eight. VDRP is
externally summed into the feedback network by the
resistor RDRP. This introduces an offset which is
proportional to the output current thereby forcing a
controlled, resistive output impedance.
2p @ CFB1 @ (RFB1 ) RFB)
2p @ CF @ RF
The goal is to compensate the system such that the
By matching the following equations a good set of
R
The VDRP signal is generated by summing the sensed
FB
ISO2
1
-100
should be set to provide optimal thermal
-20
-40
-60
-80
80
60
40
20
. With R
0
100
1
Zout Open Loop
Zout Closed Loop
Open Loop Gain with Current Loop Closed
Voltage Loop Compensation Gain
+
2p @ (RBRD ) ESR
FB
set to 1.0 kW, R
+
2p @ C
1000
1
Figure 14. NCP5392P Circuit Frequency Response
Cer
Bulk
FB1
@ (RBRD ) ESR
1mOhm
) @ C
is usually set to
1
Bulk
T2
10000
(eq. 10)
(eq. 11)
, R
http://onsemi.com
Bulk
ISO1
NCP5392P
)
Frequency
26
basic equation:
temperature according to the Equation 14:
RDRP determines the target output impedance by the
The value of the inductor's DCR is a function of
DCR (T) + DCR
RT
RL
100000
V
R
RSUM
I
RISO1
RDRP
RISO2
I Bias
out
out
DRP
RSx
Figure 15. Droop Injection and Thermal
+ Z
CSx
+
CSSUM
RNOR
R
out
Amp
Gain = 4
FB
Amp
Droop
+
25C
@ DCR @ A
1.3 V
Gain = 1
R
Compensation
+
+
-
-
@ (1 ) 0.00393 @ (T * 25))
FB
RFB1
+
-
1000000
@ DCR @ A
RFB
1.3 V
Z
1.3 V
out
CFB1
CSSUM
+
R
DRP
CSSUM
@ A
-
+
RF
Error
Amp
CH
DRP
CF
@ A
+
10000000
DRP
Comparator
+
-
PWM
(eq. 12)
(eq. 13)
(eq. 14)