UBA2014P PHILIPS [NXP Semiconductors], UBA2014P Datasheet - Page 7

• Manufacturer Part Number: UBA2014P
• Description: 600 V driver IC for HF fluorescent lamps
• Manufacturer: PHILIPS [NXP Semiconductors]

Philips Semiconductors
Lamp failure mode
D
If the lamp does not ignite, the voltage level increases.
When the lamp voltage exceeds the V
voltage will be regulated at the V
At crossing the V
already started. If the voltage at pin LVS is above the
V
stops oscillating and is forced in a Power-down mode. The
circuit will be reset only when the supply voltage is
powered-down.
D
If the lamp fails during normal operation, the voltage
across the lamp will increase and the lamp voltage will
exceed the V
ignition timer is started. If the lamp voltage increases
further it will reach the V
circuit to re-enter the ignition state and results in an
attempt to re-ignite the lamp. If during restart the lamp still
fails, the voltage remains high until the end of the ignition
time. At the end of the ignition time the circuit stops
oscillating and the circuit will enter in the Power-down
mode.
Power-down state
The Power-down state will be entered if, at the end of the
ignition time, the voltage at pin LVS is above V
In the Power-down mode the oscillator will be stopped and
both TR1 and TR2 will be non-conductive. The V
is internally clamped. The circuit is released from the
Power-down state by lowering the low voltage supply
below V
Capacitive mode protection
The signal across R16 also gives information about the
switching behaviour of the half bridge.
If, after the preheat state, the voltage across the ACM
resistor (R16) does not exceed the V
non-overlap time, the Capacitive Mode Detection circuit
(CMD) assumes that the circuit is in the capacitive mode
of operation. As a consequence the frequency will directly
be increased to f
decoupled from the voltage at pin CSW until C
been discharged to zero.
2002 May 16
lamp(fail)
URING IGNITION STATE
URING BURN STATE
600 V driver IC for HF fluorescent lamps
DD(reset)
level at the end of the ignition time the circuit
lamp(fail)
.
max
lamp(fail)
. The frequency behaviour is
level; see Fig.7. At that moment the
lamp(max)
level the ignition timer was
lamp(max)
level. This forces the
CMD
lamp(max)
level; see Fig.6.
level during the
CSW
lamp(fail)
level, the
DD
supply
has
.
7
Charge coupling
Due to parasitic capacitive coupling to the high voltage
circuitry all pins are burdened with a repetitive charge
injection. Given the typical application the pins IREF and
CF are sensitive to this charge injection. For charge
coupling of 8 pC, a safe functional operation of the IC is
guaranteed, independent of the current level.
Charge coupling at current levels below 50 A will not
interfere with the accuracy of the V
levels.
Charge coupling at current levels below 20 A will not
interfere with the accuracy of any parameter.
Design equations
The following design equations are used to calculate the
desired preheat time, the maximum ignition time, and the
minimum and the maximum switching frequency.
t
t
f
with C
is defined as the moment at which the measured lamp
voltage crosses the V
failure mode”.
f
ph
ign
max
min
= 1.7
= 3.1
= 2.5
=
CT
-------------------------------------
C
in nF, R
125 10
CF
10
10
f
min
4
5
R
(kHz)
IREF
IREF
C
C
3
CT
CT
in k , and C
lamp(fail)
in kHz
R
R
IREF
IREF
level; see Section “Lamp
(s)
(s)
CF
CS
in pF. Start of ignition
Product specification
, V
PCS
UBA2014
and V
ACM