UBA2211AP PHILIPS [NXP Semiconductors], UBA2211AP Datasheet - Page 7

• Manufacturer Part Number: UBA2211AP
• Description: Half-bridge power IC family for CFL lamps
• Manufacturer: PHILIPS [NXP Semiconductors]

NXP Semiconductors
UBA2211
Product data sheet
7.6 Ignition state
7.7 Steady state
If during the preheat time, capacitive mode is sensed and the internal V
discharged. The frequency sweep restarts at f
The ignition state is entered after the preheat state has finished. The current I
the capacitor on pin SW (C
f
During this frequency sweep, the resonance frequency is reached resulting in the ignition
of the lamp (see
(C
(V
In the steady state, the RMS current control is active. This control sets the frequency so
that the RMS voltage across the sense resistor (R
ensures the current through the power switches and through the lamp is constant. This
results in constant IC dissipation and temperature at a fixed ambient temperature.
During one oscillator clock cycle, the voltage on pin SENSE (V
converted into a positive current. This discharge current is added to the capacitor C
C
osc(nom)
Fig 5.
sw
SW
lamp
=
) reaches 0.6  V
2.5 × f
) set the resonance frequency. The ignition state ends when the voltage on pin SW
0.6 × V
----------------------------------- -
1.5 s
.
V
SW
f
V
osc(nom)
osc(nom)
lamp
HIGH
H(RC)

t
ph
100 nF
, f
0
All information provided in this document is subject to legal disclaimers.
osc(int)
Figure
, V
H(RC)
Rev. 3 — 26 August 2011
4). The combination of lamp inductor (L
SW
SW
.
and V
) up to 0.6  V
preheat time
V
SW(ph)
SW(ph)
plotted against time
H(RC)
Half-bridge power IC family for CFL lamps
max
V
which corresponds to the frequency
SW
which is equal to 2.5  f
SENSE
ignition
) is equal to V
SENSE
lamp
) and lamp capacitor
) is squared and
O(ref)RMS
UBA2211
© NXP B.V. 2011. All rights reserved.
SW
RMS control
min
HIGH node is
.
SW
001aal992
. This
time (s)
f
osc(int)
V
charges
V
lamp
SW
SW
7 of 20
.
(3)