ISL6263 Datasheet, PDF (15/19 Pages) Intersil Corporation – 5-Bit VID Single-Phase Voltage Regulator for IMVP-6+ Santa Rosa GPU Core

ISL6263
The gain of the droop amplifier circuit is Equation 14:
k_droopamp
=
1
+
-^R----^D----^R----^P----²--
R_DRP1
(EQ. 14)
After determining R_S and R_NTCEQ networks, use
Equation 15 to calculate the droop resistances R_DRP1 and
R_DRP2.
R_DRP2
=
⎛⎛
⎜⎜
⎝⎝
D^-----C^-----R^--R----⋅^-d--G^-r--o--₁^--o-₍^--p2---₅^----_°^--_C^----_{)⎠⎟⎞}
⎞
– 1⎟
⎠
⋅ R_DRP1
(EQ. 15)
VDD
R_droop is 8mΩ per Intel IMVP-6+ specification and R_DRP1 is
typically 1kΩ.
The effectiveness of the R_NTCEQ network is sensitive to the
coupling coefficient between the NTC thermistor and the
inductor. The NTC thermistor should be placed in the closet
proximity of the inductor.
−
OCP
+
+
−
10µA _↓
OCSET
+
DROOP
−
VSUM
DFB
DROOP
VO
R_OCSET
R_S
V_DCR
FIGURE 8. EQUIVALENT MODEL FOR DROOP CIRCUIT USING INDUCTOR DCR CURRENT SENSING
VDD
−
OCP
+
+
−
10µA _↓
OCSET
+
DROOP
−
VSUM
DFB
DROOP
VO
R_OCSET
R_S
V_RSNS
FIGURE 9. EQUIVALENT MODEL FOR DROOP CIRCUIT USING DISCRETE RESISTOR CURRENT SENSING
15
FN9213.2
June 10, 2010