Advanced Turn Off Delay; Off Delay; Delay Pin; A Review Of The Control Scheme - Infineon ICE2HS01G Application Note

2.4.3

Advanced Turn off delay

Advanced turn-off delay time of the SR MOSFET
delay and transition time in the actual converter system. The value of
pin. For example, if the delay time required is 220ns, a
according to the curve below.
Figure 11 Turn-off delay time versus Rdelay
2.4.4

A review of the control scheme

After all the SR related parameters have been set, such as maximum on-time
delay , advanced turn-off delay
T
_
on delay
for the two conditions when
From the waveforms on the left, the switch-on of the SR MOSFET is
primary side switch; while switch-off of the SR MOSFET is in advance with
primary side switch. Under this operation condition, the SR MOSFET's on-time changes with the primary
side MOSFET gate switching.
From the waveforms on the right, the SR MOSFET on-time is almost constant and equal to
which is independent of the primary side MOSFET turn-off.
In actual operation, the
signal comes first – the turning-off of the primary gate, or the falling edge of
Application Note
T
off
T
_
off delay
> and <
f f f
sw r sw
doesn't have to be monitored. SR MOSFET will be turned off by whichever
f
sw

- Delay pin

_
delay
, normally is determined by the propagate
T
_
off delay
=
33
R k
delay
, simplified typical waveforms can be drawn in Figure 12
.
f
r
21
can be set by the Delay
T
_
off delay
Ω
need to connect at Delay pin
T
_ max
on
after the switch-on of the
T
_
on delay
to the switch-off of
T
_
off delay
.
T
_ max
on
, turn-on
,
T
_ max
on
2011-07-06