UBA2021 NXP Semiconductors, UBA2021 Datasheet - Page 7

• Manufacturer Part Number: UBA2021
• Description: 630 V Driver Ic For Cfl And Tl Lamps
• Manufacturer: NXP Semiconductors

Philips Semiconductors
IC supply
Initially, the IC is supplied from V
R
an internal diode. As soon as V
circuit starts oscillating. After the preheat phase is finished,
pin RHV is connected to an internal resistor R
to this, pin RHV is internally connected to pin VS. The
voltage level at pin RHV thus drops from V
I
charged via the snubber capacitor CS7. Excess charge is
drained by an internal clamp that turns on at voltage
V
Minimum gate-source voltage of T1 and T2
The high side driver is supplied via capacitor C
Capacitor C
the on-periods of T2. The IC stops oscillating at a voltage
level V
the load at pin G1 of 1 nC/V, this safeguards the minimum
drive voltages V
Table 1.
Table 1 Minimum gate-source voltages
The drive voltage at G2 will exceed the drive voltage of the
high side driver.
Frequency and change in frequency
At any point in time during oscillation, the circuit will
operate between f
be gradual, no steps in frequency will occur. Changes in
frequency caused by a change in voltage at pin CI show a
rather-constant
following rates are realised (at a frequency of 85 kHz and
with a 100 nF capacitor connected to pin CI):
2002 Aug 02
RHV
VS(clamp)
RHV
For any increase in frequency:
15 and 37.5 kHz/ms
During preheat and normal operation:
decrease in frequency is between 6 and 15 kHz/ms
During the ignition phase:
frequency is between 150 and 375 Hz/ms.
630 V driver IC for CFL and TL lamps
. This current charges the supply capacitor CS9 via
75 kHz to 85 kHz
R
VS(stop)
FREQUENCY
i(RHV)
.
<75 kHz
85 kHz
boot
. Given a maximum charge consumption on
. The capacitor CS9 at pin VS will now be
is charged via the bootstrap switch during
df
(G1 S1)
/
B
dt
and f
over the entire frequency range. The
for the high side driver; see
start
. Any change in frequency will
df
/
dt
VS
for a decrease in
in
df
exceeds V
by the current through
/
dt
is between
VOLTAGE
8 V (min.)
6 V (min.)
7 V (min.)
df
/
VS
dt
for a
VS(start)
+ V
i(RHV)
boot
diode
.
; prior
, the
to
7
Ground pins
Pin PGND is the ground reference of the IC with respect to
the application. As an exception, pin SGND provides a
local ground reference for the components connected to
pins CP, CI, RREF and CF. For this purpose pins PGND
and SGND are short-circuited internally. External
connection of pins PGND and SGND is not preferred. The
sum of currents flowing out of the pins CP, CI, RREF, CF
and SGND must remain zero at any time.
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 in Fig.7, pins RREF
and CF are sensitive to this charge injection. For the rating
Q
independent of the current level. Charge coupling at
current levels below 50 A will not interfere with the
accuracy of the V
coupling at current levels below 20 A will not interfere
with the accuracy of any parameter.
couple
a safe functional operation of the IC is guaranteed,
RS(cap)
and V
RS(ctrl)
levels. Charge
Product specification
UBA2021