S-8540 Datasheet, PDF (2/36 Pages) Seiko Instruments Inc – STEP-DOWN, 600 kHz PWM CONTROL or PWM/PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER

STEP-DOWN, 600 kHz PWM CONTROL or PWM/PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
S-8540/8541 Series
Rev.3.2_00
„ Block Diagrams
1. A, C types (fixed output voltage)
Pch Pow er
MOS FET
VIN
L
VIN ^{Powe r for IC}
T riangu lar wave
o scillatio n circu it
E XT
PWM comp arato r
SE NS E
Phase
com pen satio n
circuit
SD
CIN
PWM or
PWM / PFM
switch ing
Sh utdo wn soft start
circuit
Erro r a mplifier
VREF=1.0 V
Vo ltage/c urrent
referen ce
R_{S ENS E}
125 mV
VO UT
COUT
V SS
O N/O FF
RS S
CS S
V _{ON/ OFF}
CVREF
CVL
Figure 1
2. B, D types (feed back)
Pch Power
MOS FET
VIN
L
VI N
Power for IC
Trian gula r wave
oscill ation circuit
E XT
PWM com parato
SE NS E
Phase
com pensation
circuit
SD
CIN
PWM or
PWM / PF M
switchin g
Sh utdown soft start
circ uit
Error amplifier
VREF=1.0 V
Voltag e/current
reference
R_{S ENS E}
125 mV
VO UT
C_FB
FB
V SS
V _OUT
RA
COUT
RB
O N/O FF
RS S
CSS
V _{ON/ OFF}
CVREF
CV L
Figure 2
2
Seiko Instruments Inc.