NCP1392B_09 ONSEMI [ON Semiconductor], NCP1392B_09 Datasheet - Page 14

• Manufacturer Part Number: NCP1392B_09
• Description: High-Voltage Half-Bridge Driver with Inbuiltc Oscillator
• Manufacturer: ONSEMI [ON Semiconductor]

portion of the HV rail on Pin 3. Below the turn−on level,
the 18.2 mA current sink (IBO) is on. Therefore, the turn−on
level is higher than the level given by the division ratio
brought by the resistive divider. To the contrary, when the
IBO is on
IBO is off
We can extract R
and Vref
R
R
result confirms our calculations.
upper
lower
A resistive divider made of R
If we decide to turn−on our converter for V
The bridge power dissipation is 400
= 5.494 MW
= 22.066 kW
BO
= 1.0 V we obtain:
lower
Figure 30. The internal Brown−Out Configuration with an Offset Current Sink
from Equation 2 and plug it into Equation 1, then solve for R
V
bulk
R
R
upper
lower
Vref
upper
BO
BO
2
and R
+ V
/ 5.517 MW = 29 mW when front−end PFC stage delivers 400 V. Figure 31 simulation
R
lower
bulk1
lower
Vref
R
bulk1
I
BO
upper
SW
+ Vref
@
BO
, brings a
R
equals 350 V and turn it off for V
lower
+ R
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+ V
R
BO
) R
lower
lower
bulk2
@
High Level for BOdisch time after V
I
BO
upper
14
@
+
−
@
V
R
@ V
V
V
bulk2
internal BO_OK signal is high (PFC timer runs or Mlower
and Mupper pulse), the I
it becomes possible to select the turn−on and turn−off levels
via a few lines of algebra:
lower
bulk1
refBO
* I
+
−
Vref
bulk2
R
BO
* Vref
) R
lower
* V
BO
@
* Vref
upper
bulk2
R
20ms
Filter
R
BO
lower
lower
BO
) R
CC
@ R
bulk2
ON
upper
upper
upper
equals 250 V, then for I
BO_OK to and gates
:
BO
To PFC Delay
sink is deactivated. As a result,
BO
= 18.2 mA
(eq. 1)
(eq. 2)
(eq. 3)
(eq. 4)