NCP4303AMNTWG ON Semiconductor, NCP4303AMNTWG Datasheet - Page 21

• Manufacturer Part Number: NCP4303AMNTWG
• Description: Power Switch ICs - Power Distribution SEC SIDE SYNC RECT DRV
• Manufacturer: ON Semiconductor

Specifications of NCP4303AMNTWG

• Product Category: Power Switch ICs - Power Distribution

Minimum T
time periods that ease the implementation of the
synchronous rectification system in a power supply. These
calculated as:
capacitor (Ct) charging, one can calculate the minimum
on−time duration using this equation.
OFF times are independent of the V
T
The NCP4303 offers adjustable minimum ON and OFF
Current through the Min_Ton adjust resistor can be
As the same current is used for the internal timing
As can be seen from Equation 5, the minimum ON and
on_min
6
5
4
3
2
1
0
0
+ C
+ C
Figure 49. Min T
Figure 48. Internal Connection of the Min_Ton Generator (the Min_Toff Works in the Same Way)
on
t
10
t
and T
@ R
@
I
R_Ton_min
Ton_min
I
R_Ton_min
V
off
ref
20
Adjustment
R
min_Ton
+ C
on
+
Adjust Characteristic
30
R
t
+
Ton_min
(kW)
V
ref
R
ref
Ton_min
V
V
ref
ref
40
or V
CC
50
level. The
(eq. 4)
(eq. 5)
http://onsemi.com
60
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timers avoid false triggering on the CS input after the
MOSFET is turned on or off. The adjustment is based on an
internal timing capacitance and external resistors connected
to the GND pin – refer to Figure 48 for better understanding.
internal capacitor size would be too high if we would use
directly I
the internal current mirror ratio. One can then calculate the
minimum T
equations:
accuracy of Equations 6 and 7 when T
selected near to their minimum possible values. Please refer
to Figure 49 and 50 for measured minimum on and off time
charts.
T
T
6
5
4
3
2
1
0
Note that the internal timing comparator delay affects the
on_min
off_min
0
Figure 50. Min T
R_Ton_min
+ 9.82 * 10
+ 9.56 * 10
10
on
and T
current thus this current is decreased by
20
−11
−11
off
R
* R
* R
min_Toff
off
blanking periods using below
T_on_min
T_off_min
Adjust Characteristic
30
(kW)
) 4.66 * 10
) 5.397 * 10
40
on
/T
off
50
−8
−8
times are
[ms]
[ms]
(eq. 6)
(eq. 7)
60