AN727 Datasheet, PDF (1/8 Pages) Vishay Siliconix – High-Frequency, High-Efficiency Buck Converter Design For Multi-Cell Battery Configured Systems Using Si9167

AN727
Vishay Siliconix
High-Frequency, High-Efficiency Buck Converter Design For
Multi-Cell Battery Configured Systems Using Si9167
Nitin Kalje
INTRODUCTION
The Si9167 is a high-frequency synchronous dc-to-dc
switching buck regulator, with an operating range suitable for
two-cell Li+ battery-powered applications. Capable of
operation up to 2 MHz, the Si9167 can be used to supply
power amplifiers and to power up baseband circuits in satellite
phones. Its high operating frequency reduces the size of
inductor and capacitor components, while its low
on-resistance internal driver ensures maximum power
conversion efficiency. Additional features include an
integrated input undervoltage lockout, power on reset,
integrated soft start, light load pulse skipping mode selection,
synchronization, clock output for master-slave configuration of
multiple regulators, uncommitted power-good comparator,
and over temperature protection. An output power in excess of
2 W at 3.6 V_O is possible in 0.3 square inches.
TYPICAL APPLICATION CIRCUIT
+V_IN ¹
5 - 10 V
2
PGND
C1
10 mF
16 V
C1
0.1 mF
ENABLE/DISABLE
PWM/PSM
Si9167
1
SD
20
COIL
2
19
PWM/PSM COIL
R9*
51 kW
3
V_IN
4
V_IN
5
POK
18
PGND
17
COIL
16
PGND
6
SYNC
15
POKIN
1.3 V
C3
0.1 mF
7
CLK
8
GND
9
V_REF
10
FB
14
V_O
13
V_DD
12
R_OSC
11
COMP
STAR GND CON
* Optional
R3
8.2 kW
C5
1000 pF
R1*
51 W
L1
4.7 mH
IHLP2525
D1
R2
75 kW
C4
56 pF
C6
0.1 mF
R4
200 W
C7
330 pF
FIGURE 1. Typical Application Circuit—Buck
C1
10 mF
16 V
R5
22 kW
R6
12.4 kW
3.6 V @ 600 mA
7
V_OUT
C9
0.1 mF
8
PGND
R7
105 kW
R8
64 kW
Document Number: 70959
07-Jul-99
www.vishay.com S FaxBack 408-970-5600
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