BD9540EFV ROHM Electronics, BD9540EFV Datasheet - Page 12

• Manufacturer Part Number: BD9540EFV
• Description: 2ch Switching Regulators for Desktop PC
• Manufacturer: ROHM Electronics

© 2009 ROHM Co., Ltd. All rights reserved.
BD9540EFV
www.rohm.com
FB
6. Output Voltage Setting
REF
The IC will try to maintain output voltage such that REF≒VFB.
However, the actual output voltage will also reflect the average ripple voltage value.
The output voltage is set via a resistive voltage divider between the output and the FB pin. The formula for output voltage
is given in (13) below:
It is recommended that R1 and C1 be connected in parallel to the FB pin.
In low output ripple applications (ΔV < 20 mV), add Radd and Cadd as shown in the above application circuit.
For value settings, refer to the tool provided separately.
REF voltage (for 2ch) is fixed at 0.750 V; however, REF voltage (for 1ch) can be adjusted via the CTL input conditions.
REF1 voltage setting table
Output voltage=
CONTROLLA
CTL1
H
3
H
H
L
L
Reg
TM
R1+R2
R2
CTL2
R
S
×
H
H
L
L
12/17
REF +
Q
Radd (for Low Ripple)
1
2
×ΔI
Circuit
Driver
0.781V
0.814V
0.851V
0.750V
REF1
L
×ESR・・・(13)
V
IN
R2
R1
Technical Note
2009.04 - Rev.B
Cadd (for Low Ripple)
Output voltage
C1
ESR