XC9106_1 TOREX [Torex Semiconductor], XC9106_1 Datasheet - Page 7

• Manufacturer Part Number: XC9106_1
• Description: PWM Control,PWM/PFM Switching Control, Step-Up DC/DC Converters, Externally Applied Vref
• Manufacturer: TOREX [Torex Semiconductor]

■OPERATIONAL EXPLANATION (Continued)
■RECOMMENDED EXTERNAL COMPONENTS
<Output Voltage Setting>
Output voltage can be set by adding external split resistors. Output voltage is determined by the following equation, based on
the values of R
the series can be varied externally from 0.8V to 2.5V.
The value of CFB1, speed-up capacitor for phase compensation, should result in fzfb = 1/(2π×C
30kHz. Adjustments are required depending on the application, value of inductance (L), and value of load capacity (CL).
<The Use of Ceramic Capacitor CL>
The circuit of the XC9106/9107 series is organized by a specialized circuit, which reenacts negative feedback of both voltage
and current. Also by insertion of approximately 100mΩ of a low and inexpensive sense resistor as current sense, a high
degree of stability is possible even using a ceramic capacitor, a condition, which used to be difficult to achieve. Compared to a
tantalum condenser, because the series can be operated in a very small capacity, it is suited to use of the ceramic capacitor,
which is cheap and small.
Tr:
SD:
L, C
L
:
*When a MOSFET is used:
2SK2159 (N-ch Power MOSFET, NEC)
Note* : With direct voltages over 4.5V, use the
XP161A11A1PR.
MA2Q737 (Schottky Diode type, MATSUSHITA)
Adjust as below according to the condition and peripheral components
When Ceramic capacitor is used:
L :
C
R
When Tantalum capacitor is used:
L:
C
R
When AL Electrolytic capacitor is used:
L:
C
R
C
fzfb = 30kHz (L=10μH)
fzfb = 20kHz (L=22μH)
fzfb = 10kHz (L=47μH)
L
SENSE
L
SENSE
L
SENSE
FB
V
:
:
FB1
:
OUT
:
and R
:
:
= Vref applied voltage
:
FB2
22μH (CDRH5D28, SUMIDA, FOSC = 100kHz)
10μH (CDRH5D28, SUMIDA, FOSC = 300kHz)
10V, 10μF (Ceramic capacitor, LMK325BJ106ML, TAIYOYUDEN)
Use the formula below when step-up ratio and output current is large.
C
100mΩ
50mΩ
22μH (CDRH5D28, SUMIDA, FOSC = 300kHz)
47μH (CDRH5D28, SUMIDA, FOSC = 100kHz)
16V, 47μF (Tantalum type 16MCE476MD2, NIPPONCHEMI)
Not required, but short out the wire.
22μH (CDRH5D28, SUMIDA, FOSC = 300kHz)
47μH (CDRH5D28, SUMIDA, FOSC = 100kHz)
16V, 100μF (AL electrolytic type)＋10V, 2.2μF (ceramic type)
Not required, but short out the wire.
Set up so that fzfb = 100kHz.
. The sum of R
L
= (C
Except when I
Use the formula below when step-up ratio and output current is large.
C
Except when I
Strengthen appropriately when step-up ratio and output current is large.
L
L
= (C
standard value)
L
standard value)
×
(FOSC = 300kHz)
(FOSC = 100kHz)
(R
FB1
FB1
OUT
OUT
and R
(mA) / 100mA
(mA) / 100mA
+ R
×
R
C
FB1
FB
(I
FB2
FB2
OUT
:
×
) / R
:
should normally be 2MΩ or less. The range of reference voltage of
(mA) / 300mA
(I
OUT
270kΩ
20pF
27pF
56pF
FB2
×
×
(mA) / 300mA
V
V
OUT
OUT
*When a NPN Tr. is used :
2SD1628 (SANYO)
Rb
Cb
/ V
/ V
×
(fzfb = 30kHz, L = 10μH)
(fzfb = 20kHz, L = 22μH)
(fzfb = 10kHz, L = 47μH)
V
IN
IN
OUT
＞
＞
: 500Ω (adjust with Tr's HFE or load)
: 2200pF (ceramic type)
×
2
2
R
V
/ V
FB2
→
→
OUT
Cb
IN
22
22
: 30kΩ
)
≦
/ V
μ
μ
H
H
IN
1 / (2
)
π×
Rb
FB
XC9106/XC9107
×
×R
FOSC
FB1
) equal to 5 to
×
0.7)
Series
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