S-8550AA-M5T1X Datasheet, PDF (2/31 Pages) Seiko Instruments Inc – RECTIFICATION, PWM CONTROL SWITCHING REGULATORS

STEP-DOWN, BUILT-IN FET, SYNCHRONOUS RECTIFICATION, PWM CONTROL SWITCHING REGULATORS
S-8550 Series
Rev.5.0_01
 Block Diagram
1. SOT-23-5
FB
V_IN C_IN
Error amplifier
Current limit
circuit
IC internal
power supply
−
+
Reference
voltage
+
PWM control
−
circuit
PWM comparator
Triangular wave
generation
circuit
ON/OFF
UVLO
circuit
circuit
VIN
*1
CONT
L
*1
C_FB
V_OUT
R_FB1
C_OUT
R_FB2
*1. Parasitic diode
ON/OFF
VSS
Figure 1
2. SNT-8A
FB
VIN CIN
Error amplifier
Current limit
circuit
IC internal
power supply
−
+
Reference
voltage
+
PWM control
−
circuit
PWM comparator
Triangular wave
generation
circuit
ON/OFF
UVLO
circuit
circuit
VIN
*1
CONT
L
*1
CFB
VOUT
RFB1
COUT
RFB2
*1. Parasitic diode
ON/OFF
VSS
PVSS
Figure 2
2