
ML4871
VIN
100µF
20µH
(Sumida CD75)
ML4871
VL1 PWR GND
VIN
RESET
GND
VL2
DETECT VOUT
IOUT
200µF
Figure 1. Application Test Circuit.
IL
1
VL1
VIN
2
RSENSE
START-UP
6
VL2
SYNCHRONOUS
RECTIFIER
CONTROL
Q2
A2
VOUT
5
VOUT
+
–
BOOST
CONTROL
Q1
A1
A3
1.25V
PWR GND
ISET
8
GND
3
Figure 2. PFM Regulator Block Diagram.
IL(MAX)
IL
ISET
0
VOUT
VL2
0
Q1 ON
Q2 OFF
Q1 OFF
Q2 ON
Figure 3. Inductor Current and Voltage Waveforms.
4