UM10525
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© NXP B.V. 2012. All rights reserved.
User manual
Rev. 1 — 19 April 2012
10 of 21
NXP Semiconductors
UM10525
120 V 20 W CFL demo board using the UBA2212
The boost feature provides a fast run-up time. However when a hot lamp is powered, the
lamp does not need boost or only a short boost time. The UBA2212 sets a boost
overtemperature (T
j(end)bst
) to allow for the reduced boost time. The IC detects its die
temperature and ends the boost state when the temperature trigger point is reached. The
lamp then enters the burn transition.
When a lamp burns for a long time, is switched off and then after a short delay switched
on again. The end of boost is reached after only 6 s of boost. In
Figure 5
, SW counted
only 5 cycles. Normally SW sweeps through 25 cycles when OTP is not triggered.
Table 2.
Electrical parameters 12 W boost lamp (UBA2212BT N1B)
Boost ratio = 1.49; boost time = 38.5 s (25 cycles); transition time = 2 s.
State
V
IN
(V)
P
in
(W)
PF
V
lamp
(V)
I
Iamp
(mA)
I
hb
(mA)
P
lamp
(W)
f
osc
(kHz)
T
ph
(s)
I
ph
(mA)
Normal
120
21.3
0.589
107
169
366
18.1
44.3
0.76
150
Boost
-
23.1
-
80.5
252
470
20.3
39.7
-
-
(1) I
lamp
signal.
(2) SW signal timing for preheat.
(3) Half-bridge voltage.
(4) CB signal timing for boost and transition.
Fig 8.
Boost with OTP triggered
