S-8340A25AFT-T2-X Datasheet, PDF (2/55 Pages) Seiko Instruments Inc – SWITCHABLE SWITCHING REGULATOR CONTROLLER

STEP-UP, 600 kHz, PWM CONTROL OR PWM/PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
S-8340/8341 Series
Rev.4.0_01
 Block Diagrams
(1) S-8340/8341 Series A and C Types (Output Voltage Fixed Output Type)
L
SD
VDD
VOUT
VIN
Nch Power
MOS FET
EXT
SENSE
RSENSE
Triangular wave
oscillation circuit
PWM comparator
Phase
compensation
circuit
IC internal power
supply
VOUT
RS
CS
120 mV
Shutdown
circuit
PWM, PWM/PFM
switching control
circuit
Soft-start
circuit
CC
R1
Error amplifier
R2
VREF =1.0 V
Voltage/current
reference
+
CL
VSS
ON/OFF
CSS
CVREF
CSS
CVREF
Figure 1
(2) S-8340/8341 Series B and D Types (Output Voltage External Setting Type)
L
SD
VDD
VOUT
VIN
Nch Power
MOS FET
EXT
SENSE
RSENSE
Triangular wave
oscillation circuit
PWM comparator
Phase
compensation
circuit
IC internal power
supply
RS
CS
120 mV
Shutdown
circuit
PWM, PW M/PFM
switching control
circuit
Soft-start
circuit
Error amplifier
VREF =1.0 V
Voltage/current
reference
FB
CFB
RFB1
+
CL
RFB2
VSS
ON/OFF
CSS
CVREF
CSS
CVREF
Figure 2
2