UBA2211APN1 NXP [NXP Semiconductors], UBA2211APN1 Datasheet - Page 7

• Manufacturer Part Number: UBA2211APN1
• Description: Half-bridge power IC family for CFL lamps
• Manufacturer: NXP [NXP Semiconductors]

NXP Semiconductors
UBA2211
Objective data sheet
7.6 Ignition state
7.7 Steady state
The ignition state is entered after the preheat state has finished. The capacitor on pin SW
(C
During this frequency sweep, the resonance frequency is reached resulting in the ignition
of the lamp (see
and lamp capacitor (C
reaches 0.6 × 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
During the other oscillator clock cycle, the input of the squarer is connected to the internal
reference voltage V
current. This charge current is also added to capacitor C
equal, then
Fig 5.
SW
) is charged by I
2.5 × f
0.6 × V
V
SW
f
f
osc(nom)
osc(nom)
osc(nom)
HIGH
H(RC)
Equation 3
0
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H(RC)
Figure
, V
SW
O(ref)RMS
.
SW
, V
lamp
Rev. 2 — 3 January 2011
is true:
4). The resonance frequency is set by the lamp inductor (L
SW(ph)
up to 0.6 × V
). The ignition state ends when the voltage on pin SW (V
. This voltage is squared and converted into a negative
and V
preheat time
V
SW(ph)
lamp
H(RC)
plotted against time
which corresponds to the frequency f
Half-bridge power IC family for CFL lamps
SENSE
ignition
) is equal to V
SW
. When both currents are
SENSE
) is squared and
O(ref)RMS
UBA2211
© NXP B.V. 2011. All rights reserved.
RMS control
001aal992
. This
time (s)
f
osc(int)
osc(nom)
V
V
lamp
SW
SW
lamp
SW
7 of 19
)
.
)
.