rt9245b Richtek Technology Corporation, rt9245b Datasheet - Page 18

• Manufacturer Part Number: rt9245b
• Description: Multi-phase Controller Core Power Supply
• Manufacturer: Richtek Technology Corporation

RT9245B
Design Procedure Suggestion
a.Output filter pole and zero (Inductor, output capacitor
b.Error amplifier compensation & sawtooth wave amp-
c.Kelvin sense for V
Current Loop Setting
a.GM amplifier S/H current (current sense component
b.Over-current protection trip point (R
VRM Load Line Setting
a.Droop amplitude (ADJ pin resistor).
b.No load offset (R
c.DAC offset voltage setting (VOSS pin & compen- sation
Power Sequence & SS
DVD pin external resistor and SS pin capacitor.
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18
value & ESR).
litude (compensation network).
DCR, CSN pin external resistor value).
network resistor RB1).
Figure 27. EA Frequency Response with closed loop gain set at 0db to observe gain-bandwidth product; -3dB at
CSN2
180
CORE
0dB
)
.
IMAX
resistor).
10.86MHz
PCB Layout
a.Kelvin sense for current sense GM amplifier input.
b.Refer to layout guide for other items.
Voltage Loop Setting
Design Example
Given:
Apply for four phase converter
V
V
I
V
OCP trip point set at 40A for each channel (S/H)
DCR = 0.6m of inductor at 25 C
L = 0.3 H
C
LOAD
IN
CORE
DROOP
OUT
= 12V
= 30A to 125A
= 5600 F with 1m equivalent ESR.
= 1.4V
= 95mV with load (1m Load Line)
DS9245B-02 March 2007