S-8520A20MC-AVFT2X Datasheet, PDF (21/44 Pages) Seiko Instruments Inc – SWITCHING REGULATOR CONTROLLER

STEP-DOWN, PWM CONTROL or PWM / PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
Rev.9.0_01
S-8520/8521 Series
 Standard Circuits
1. Using a bipolar transistor
Tr
VIN
R_b
C_b
EXT
V_IN
+
C_IN
SD
______
ON/OFF
2. Using a Pch MOS FET transistor
L
Oscillation
circuit
Reference voltage
source with soft start
VOUT
PWM control or
+
PWM / PFM switching
control circuit
−
V ______
ON/OFF
VSS
Figure 12
+
C_OUT
Tr
VIN
EXT
V_IN
+
SD
C_IN
______
ON/OFF
L
Oscillation
circuit
Reference voltage
source with soft start
VOUT
PWM control or
+
PWM / PFM switching
control circuit
−
VSS
V ______
ON/OFF
+
C_OUT
Figure 13
Caution The above connection diagram and constant will not guarantee successful operation. Perform
through evaluation using the actual application to set the constant.
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