SCY99080CDWR2G datasheet(21/27 Pages) ONSEMI

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DDA002C

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5us 10us 15us 20us

25us 30us 35us 40us

Time

400

300

200

100

11V

10V

Figure 46. Simulation Results for 350/250

ON/OFF Brown Out Levels

Vbulk = 250 V

Vbulk = 350 V

Note that the brown−out input will disable the controller

operation anytime its voltage goes below 1 V threshold. A

ms filter is used to improve the noise immunity of this

input. The full start−up sequence (i.e. PFC delay, preheat and

soft start) is provided by the controller in case the BO input

is re−enabled.

The IBO current sink is turned ON for 50 ms after any

controller restart to let the BO input voltage stabilize (big

capacitor can be connected to the BO input and the IBO is

only 20

mA so it will take some time to discharge). Once the

50 ms one shoot pulse ends the BO comparator is supposed

to either hold the IBO sink turned ON (if the bulk voltage

level is not sufficient) or turn it OFF (if the bulk voltage is

higher than Vbulk1).

See Figures 47 − 50 for better understanding on how the

BO input works.

Figure 47. BO Input Functionality −

Vbulk2 < Vbulk < Vbulk1

Figure 48. BO Input Functionality −

Vbulk2 < Vbulk < Vbulk1, PFC Start Follows

Figure 49. BO Input Functionality − Vbulk > Vbulk1

Figure 50. BO Input Functionality −

Vbulk < Vbulk2, PFC Start Follows

SCY99080CDWR2G 데이터시트(PDF) 21 Page - ON Semiconductor