SMM665B
Preliminary Information
APPLICATIONS INFORMATION (CONTINUED)
12V
12V
PUPB
C8
Rtrim
1.6K
SS1
FB1
TRIMB
SDA
R7
R9
SCL
CS
I2C BUS
VMB+
VSW1
FB1S
VOUT1
1.5V
SMM665B
PUPA
Not all components Shown
For interface purposes only
Part designators are from
the International Rectifier
iP1202 Demo board .
C7
Rtrim
3.3K
SS2
TRIMA
FB2
IR
R8
R10
iP1202
VMA+
VSW2
FB2S
VOUT2
2.5V
Figure 12 – The SMM665B can be used to sequence and control discrete DC switching regulators. The ADOC
function sets the output voltage of the IR iP1202 Regulator through the FBX feedback pins. Accuracy is
improved even under full load, essentially acting as a “SENSE” pin. The sequence function is applied
through the iP1202 SSX soft start pins.
Figure 13 – Ch1 is set to 2.5V and Ch2 is set to
1.5V on the ip1202 board. Ch1 is set to sequence
on first followed by Ch2 after 50ms. Then Ch1 is
margined high while Ch2 is margined low. Ch2 is
then sequenced off followed by Ch1 after 50ms.
Figure 14 – This is the same sequencing-on
function but with
a
shorter delay between
channels, the HEALTHY and RESET flags are also
shown.
Summit Microelectronics, Inc
2089 1.1 10/20/04
20
SUMMIT [ SUMMIT MICROELECTRONICS, INC. ]
