S-8541 Seiko Instruments, S-8541 Datasheet - Page 2

• Manufacturer Part Number: S-8541
• Description: (S-8540 / S-8541) 600 kHz PWM CONTROL or PWM/PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
• Manufacturer: Seiko Instruments

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STEP-DOWN, 600 kHz PWM CONTROL or PWM/PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
S-8540/8541 Series
Block Diagrams
1. A, C types (fixed output voltage)
2. B, D types (feed back)
V
V
I N
I N
Pch Power
MOS FET
Pch Pow er
MOS FET
SD
SD
C
C
IN
EXT
IN
VIN
EXT
VIN
Power for IC
Po we r for IC
ON/OFF
O N/O FF
Sh utdown soft start
circ uit
Sh utdo wn soft start
circuit
Seiko Instruments Inc.
C
Trian gula r wave
oscill ation circuit
C
PWM com parato
S S
T riangu lar wave
o scillatio n circu it
PWM comp arato r
S S
R
R
S S
PWM or
PWM / PF M
switchin g
S S
Figure 1
Figure 2
PWM or
PWM / PFM
switch ing
L
V
L
V
ON/ OFF
ON/ OFF
Voltage/current
reference
Vo ltage/c urrent
referen ce
Phase
com pensation
circuit
Phase
com pen satio n
circuit
Error amplifier
C
Erro r a mplifier
V
C
V L
V
RE F
V L
RE F
=1.0 V
=1.0 V
SENSE
SENSE
CVREF
CVREF
125 mV
R
125 mV
R
S ENS E
S ENS E
VOUT
C
VSS
FB
VO UT
VSS
FB
C
OUT
R
R
A
B
C
V
OUT
OUT
Rev.3.2
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