uba2213 NXP Semiconductors, uba2213 Datasheet - Page 6

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

NXP Semiconductors
UBA2213
Product data sheet
7.5 Preheat state
The output voltage of the bridge changes with the falling edge of the signal on pin RC. The
nominal half-bridge frequency is shown in
The maximum frequency is 2.5  f
internal LSPT and HSPT drive signals and the output is shown in
As described in
V
capacitor on pin SW (C
enabled and the half-bridge circuit starts oscillating.
The preheat current is monitored using the external R
frequency using output voltage V
internal reference voltage (V
conduction time. The preheat peak current through the lamp filament is calculated as
shown in
The external capacitor (C
calculated as shown in
voltage equals V
Fig 4.
I
DD
ph peak

f
is above V
osc nom


Oscillator, HSPT/LSPT drivers and output signals
Equation
=
HSPT driver

LSPT driver
half-bridge
V
----------------- -
R
=
ref ph
SENSE
DD(start)
All information provided in this document is subject to legal disclaimers.
------------------------------------------ -
k
V
Section

SW(ph)
osc
V
OUT
RC
2:

0
0
0
0

Rev. 2 — 21 November 2011
R
; see
and OTP is not active. The sweep current (I
SW
osc
Equation
1
7.2, the IC enters the preheat state when the voltage on pin
SW
). The preheat Operational Transconductance Amplifier (OTA) is

Figure
C
ref(ph)
) defines the preheat time. Typically, the external capacitor is
osc
SW(ph)
3.The preheat state ends when the down-going C
). The peak voltage is the voltage at the end of the LSPT
osc(nom)
4.
so that the peak voltage across R
and is set at V
Equation
Half-bridge power IC family for CFL lamps
1:
SENSE
SW
. An overview of the oscillator,
resistor. The OTA controls the
Figure
SW
) charges the
UBA2213
001aam035
© NXP B.V. 2011. All rights reserved.
SENSE
4.
time (s)
time (s)
time (s)
time (s)
equals the
SW
6 of 21
(1)
(2)