FEATURE DESCRIPTIONS (CON.)
Sequential Start-up
Ratio-Metric
Sequential start-up (Figure 27) is implemented by placing
an On/Off control circuit between VoPS1 and the On/Off pin
of PS2.
Ratio–metric (Figure 29) is implemented by placing the
voltage divider on the TRACK pin that comprises R1 and
R2, to create a proportional voltage with VoPS1 to the
Track pin of PS2.
PS2
PS1
Vin
Vin
For Ratio-Metric applications that need the outputs of
PS1 and PS2 reach the regulation set point at the same
time
VoPS1
VoPS2
R3
On/Off
R1
Q1
C1
On/Off
The following equation can be used to calculate the value
of R1 and R2.
R2
The suggested value of R2 is 10kΩ.
Vo,PS 2
R2
=
Vo,PS1 R + R2
1
Simultaneous
Simultaneous tracking (Figure 28) is implemented by
using the TRACK pin. The objective is to minimize the
voltage difference between the power supply outputs
during power up and down.
PS1
PS2
Vin
Vin
VoPS1
VoPS2
R1
TRACK
On/Off
R2
The simultaneous tracking can be accomplished by
connecting VoPS1 to the TRACK pin of PS2. Please note
the voltage apply to TRACK pin needs to always higher
than the VoPS2 set point voltage.
On/Off
The high for positive logic
The low for negative logic
PS2
PS1
Vin
Vin
VoPS1
VoPS
TRACK
On/Off
On/Off
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DELTA [ DELTA ELECTRONICS, INC. ]
