STEP-DOWN, SYNCHRONOUS PWM CONTROL SWITCHING REGULATOR CONTROLLER
S-8533 Series
Rev.2.3_00
Though the conditions mentioned above are required to prevent back-flow current, they are guidelines. Check the
validity by measuring the prototype or the actual device.
L
Back-flow current
VOUT
Coil
current IL
VIN PDRV
NDRV
+
+
VIN
CIN
VSS
Figure 9 Back-Flow Current
Coil current under no load
Coil current when 109 mA
flows as a load
IL
IL
ILmax.
ΔIL
ILmin.
Back-flow current = 0 mA
218 mA
109 mA
ILmax.
109 mA
IOUT
ΔIL
Back-flow
current
ILmin.
0 mA
IOUT
0 mA
−109 mA
Figure 10 Example for No Back-Flow Current
10
Seiko Instruments Inc.