uba2213 NXP Semiconductors, uba2213 Datasheet - Page 9

• Manufacturer Part Number: uba2213
• Description: Half-bridge Power Ic Family For Cfl Lamps
• Manufacturer: NXP Semiconductors

NXP Semiconductors
UBA2213
Product data sheet
7.12 Saturation Current Protection (SCP)
7.11 Minimum glow time control
During boost state, the threshold of temperature is T
When the die temperature has reached T
steady state and OTP is enabled.
If the preheat time is set too short or omitted, the lamp electrodes do not have the correct
temperature in the ignition state. This results in instant light but also in a reduced
switching lifetime because when the electrode temperature is too low electrode sputtering
and damage occur. The minimum glow time control limits electrode damage by ensuring
maximum power use during the glow phase to heat the electrodes quickly (see
Remark: The glow time control is active as t
A critical parameter in the design of the lamp inductor is its saturation current. When the
momentary inductor exceeds its saturation current, the inductance drops significantly. If
the inductance drops significantly, the inductor current and the current flowing through the
LSPT and HSPT power switches increases rapidly. This action can cause the current to
exceed the half-bridge power transistors maximum ratings.
Saturation of the lamp inductor is likely to occur in cost-effective and miniaturized CFLs.
The UBA2213 family internally monitors the power transistor current. When this current
exceeds the momentary rating of the internal power transistors, the conduction time is
reduced and the frequency is slowly increased (by discharging C
the system to balance at the edge of the current rating of the power switches.
Fig 6.
V
2.5 × f
SWinter
0.6 × V
V
V
V
SW
SW
f
SW
osc(boost)
f
osc(nom)
osc(nom)
boostH
boostL
HIGH
boost
H(RC)
V
lamp
, f
All information provided in this document is subject to legal disclaimers.
osc(int)
V
preheat
SW(ph)
Rev. 2 — 21 November 2011
, V
SW
ignition
, and V
glow
SW(ph)
plotted against time
j(end)bst
ph
Half-bridge power IC family for CFL lamps
boost
is too short to preheat the electrodes.
, the boost state ends, the IC enters
... ...
j(end)bst
which is lower than T
SW
). This function causes
UBA2213
transition
© NXP B.V. 2011. All rights reserved.
Figure
001aan140
RMS
th(otp)
f
osc(int)
V
V
lamp
SW
9 of 21
.
6).