uba2015t/n1 NXP Semiconductors, uba2015t/n1 Datasheet - Page 23

• Manufacturer Part Number: uba2015t/n1
• Description: 600 V Fluorescent Lamp Driver With Pfc, Linear Dimming And Boost Function
• Manufacturer: NXP Semiconductors

NXP Semiconductors
UBA2016A_15_15A
Objective data sheet
7.6.12 Brownout protection
timer is no longer detected for a period longer than the fault release delay time t
the fault timer will be reset and at any new occurance of the fault, the timer will start from
zero.
Faults which activate the fault timer are shown as SlowFault in
The fault timer uses the same pin (CPT) to set the time with an external capacitor C
as the preheat timer. The ratio between the preheat time-out time t
time-out time t
an external parallel resistor R
“CPT
The fault timer incorporates a protection that ensures safe operation conditions if the CPT
pin voltage is below V
f
Brownout protection is designed to maintain stable and safe lamp operation during dips in
mains supply. Without this protection the current demand from the bus voltage to maintain
constant lamp power would increase upon a drop in bus voltage. This creates an unstable
situation with the mains input voltage dropping and the PFC reaching its regulation range
limit.
Brownout protection reduces the lamp power when the PFC is out of regulation. This
situation is only allowed for a limited time to prevent excessive component stress.
When the PFC is outside its regulation range and the bus voltage is still too low
(V
added to the charge current at pin CF, thus increasing the f
current I
proportional to the difference between V
the fault timer will start.
The start-up bleeder resistor and the regulation range of the PFC should be dimensioned
in such a way that if the fault timer times out on brownout protection and the IC enters
Stop state, the input mains voltage is too low to support the standby current of the IC via
the bleeder resistor. The IC will then automatically reset and start-up in normal mode (and
reignite the lamps) when the mains voltage has returned to normal.
sw(high)
Fig 15. CPT connections
COMPPFC
connections”.
.
dch(bo)(CIFB)
= V
to(fault)
clamp(COMPPFC)
All information provided in this document is subject to legal disclaimers.
t
smaller ratio
to(ph)
is also drawn from pin CIFB. Both I
can be changed by adding an external series resistor R
th(scp)(CPT)
CPT
/t
to(fault)
Rev. 1 — 20 May 2011
C ext(CPT)
p(ext)(CPT)
and V
(shorted to GND) by holding the oscillation frequency at
R p(ext)(CPT)
FBPFC
to the external capacitor C
FBPFC
< V
t
to(ph)
default ratio
reg(FBPFC)
CPT
and V
/t
to(fault)
C ext(CPT)
UBA2016A/15/15A
reg(FBPFC)
), a brownout current I
bo(CF)
t
to(ph)
600 V fluorescent lamp driver
larger ratio
sw(low)
CPT
and I
/t
. If V
to(fault)
R s(ext)(CPT)
Figure 9 “State
C ext(CPT)
001aan210
. A discharge brownout
ext(CPT)
dch(bo)(CIFB)
FBPFC
to(ph)
© NXP B.V. 2011. All rights reserved.
and the fault
; see
< V
th(bo)(FBPFC)
s(ext)(CPT)
bo(CF)
are
Figure 15
diagram”.
d(rel)fault
ext(CPT)
is
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or
,