S-8540 Datasheet, PDF (18/36 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
„ Standard Circuits
1. Fixed output voltage (Pch MOS FET)
RSEN SE
L
SENSE
Tr
VIN ^{Power for IC Triangular wave}
oscillation circuit
+
EXT
PWM c omparator
−
Phase
compe nsation
ci rc ui t
− _125mV
VOUT
+
VIN
SD
CIN
PW M, PW M/PFM
switching control
circuit
Error amplifier
−
+
C_{O UT}
Shutdown soft start
c irc uit
VREF=1. 0 V
Voltage/ current
referenc e
VSS
One point ground
ON/OFF
VON/OFF
CVREF
Figure 13
2. Feed back type (Pch MOS FET)
R_{SEN SE}
L
SENSE
Tr
VIN ^{Power for IC Triangular wave}
oscillation circuit
+
−
EXT
PWM comparator
−
Phase
comp ensation
ci rc ui t
125m V
VOUT
VIN
SD
+
Error amplifier
RA
CFB
PW M, PW M/PFM
−
COUT
C_IN
switching control
circuit
+
FB
Shutdown s of t start
circuit
VREF=1.0 V
V o lta ge / cu rre n t
referenc e
VSS
RB
One point ground
ON/OFF
V_ON/OFF
CVREF
Figure 14
Caution The above connection diagram and constant will not guarantees successful operation.
Perform through evaluation using the actual application to set the constant.
18
Seiko Instruments Inc.