SI9136_11 Datasheet, PDF (9/16 Pages) Vishay Siliconix – Multi-Output Power-Supply Controller

TIMING DIAGRAMS
Si9136
Vishay Siliconix
ON/OFF
V_IN
V_L
V_REF
OSC EN
(Sysmon EN)
OSC
f_max (SS)
DH
D_L
2.4 V
t_BBM
The converter is enabled
V_IN is applied
LDO is activated
after V_IN is applied
REF circuit is activated
after V_L becomes
available
After V_REF goes above
2.4 V, the converter is
turned on
Oscillator is activated
4 ms
Slow soft-start gradually
increases the maximum
inductor current
High-side gate drive duty
ratio gradually increases
to maximum
Low-side gate drive
Figure 2. Converter is Enabled Before V_IN is Applied
ON/OFF
V_IN
V_L
V_REF
OSC EN
(Sysmon EN)
OSC
f_max (SS)
DH
DL
2.4 V
4 ms
The converter is
enabled
V_IN is applied
LDO is activated
after V_IN is applied
REF circuit is activated
after V_L becomes
available
After V_REF goes above
2.4 V, the converter is
turned on
Oscillator is activated
Slow soft-start gradually
increases the maximum
inductor current
Figure 3. Converter is Enabled After V_IN is Applied
Document Number: 70818
www.vishay.com
S11-0975-Rev. D, 16-May-11
9
This document is subject to change without notice.
THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc?91000