INTEGRATED CIRCUITS
DATA SHEET
UBA2000T
Electronic TL-lamp starter
Product specification
File under Integrated Circuits, IC11
1996 Jan 03
Philips Semiconductors
Product specification
Electronic TL-lamp starter
FEATURES
•
Electronic starter, fully compatible with conventional
glow-switch starters
•
Reliable and instant ignition
•
Accurate defined preheat time derived from the mains
frequency
•
Increased starter life since no mechanical parts are
used
•
No radio-interference (according to
“IEC926 10.5”)
•
Automatic reset after interruption of supply voltage
•
Large operating temperature range:
−40
to +85
°C
•
Maximum current protection of the preheat current
•
Ignition shut-off at end of lamp life; no overheating of
load.
ORDERING INFORMATION
PACKAGE
TYPE NUMBER
NAME
UBA2000T
SO8
DESCRIPTION
plastic small outline package; 8 leads; body width 3.9 mm
GENERAL DESCRIPTION
UBA2000T
The UBA2000T is an integrated circuit for electronic
TL-lamp starters and is fully compatible with conventional
glow switch starters. The circuit controls the preheating
and ignition of the lamp. The preheat time is well defined
without spread, since it is derived from the mains
frequency. When the lamp fails, ignition is shut-off after 7
ignition attempts. The circuit has an automatic reset when
the supply voltage is interrupted.
VERSION
SOT96-1
1996 Jan 03
2
Philips Semiconductors
Product specification
Electronic TL-lamp starter
BLOCK DIAGRAM
UBA2000T
handbook, full pagewidth
VCC
6
4
Vin
IC-SUPPLY
Vsupply
UBA2000T
THS
Vign
LATCH
VOLTAGE
DETECTORS
NUMBER
OF STARTS
COUNTER
OUTPUT
DRIVER
3
Vout
RES
VCC(rst)
TIME
SELECT
EDGE
DETECTOR
DECODER 1
DECODER 2
COUNTER
TEST
Vsense
8
1
Rsense
1 kΩ
CURRENT
PROTECTION
2
GND
MGE002
CURRENT
DETECTOR
Fig.1 Block diagram.
1996 Jan 03
3
Philips Semiconductors
Product specification
Electronic TL-lamp starter
PINNING
SYMBOL
V
sense
GND
V
out
V
in
n.c.
V
CC
n.c.
TEST
PIN
1
2
3
4
5
6
7
8
DESCRIPTION
sense voltage
ground (0 V)
output voltage
input voltage
not connected
supply voltage
not connected
test pin
handbook, halfpage
UBA2000T
Vsense
GND
Vout
Vin
1
2
8
7
TEST
n.c.
VCC
n.c.
UBA2000T
3
4
MGE001
6
5
Fig.2 Pin configuration.
FUNCTIONAL DESCRIPTION
The UBA2000T is an Integrated Circuit that performs all
functions necessary to ignite a TL-lamp. The circuit is
connected to the lamp circuit according to Figs. 7 or 8.
The mains voltage is rectified and divided over resistors
R1 and R2 to a lower level. When the mains power is
switched on, the buffer capacitor C1 is charged through
the resistive divider and internal switch S1. As long as the
supply voltage at the buffer capacitor (V
CC
, see
“Characteristics”) is below the reset level (V
CC(rst)
),
the UBA2000T initializes its internal circuitry.
When V
CC
has reached the start level (V
CC(sl)
) and the
peak value of V
in
> V
ign
(indicating that the mains supply is
near its peak value), the external switching device TH1 will
be turned on. This results in a current through the
electrodes of the TL-lamp, the switching device and an
integrated sense resistor. Because the current starts to
flow when the mains voltage is near its peak value,
transient currents are limited.
When the switching device is turned on, the circuit draws
its supply current from buffer capacitor C1. A typical wave
shape of the voltage at pin 6 (V
CC
) is given in Fig.3. During
the preheat periods the buffer capacitor is discharged.
The rectified current through the sense resistor is detected
and the output signal of the detector is used as a clock
signal for the counter. The preheat time is defined to 1.52 s
(at 50 Hz mains supply) using this counter. The preheat
time is very accurate, since it only depends on the
frequency of the mains supply.
After preheating, the switching device is turned off when
the current through the internal sense resistor equals at
least 285 mA. As a result of the current interruption and the
presence of an inductive load, a voltage peak is generated
that will normally ignite the TL-lamp. After ignition, the
lamp voltage is lower than the mains voltage. An ignited
TL-lamp prevents the voltage at pin 6 (V
CC
) to exceed start
level. In Fig.3 the TL-lamp is ignited after two ignition
attempts.
handbook, full pagewidth
MGE006
VCC(sl)
VCC
first
ignition
first preheat
second
ignition
second
preheat
time
tini
tprf
tprn
Fig.3 Typical wave shape of supply voltage.
1996 Jan 03
4
Philips Semiconductors
Product specification
Electronic TL-lamp starter
During preheating, the integrated circuit draws its supply
current from the buffer capacitor. As a result, the voltage
over the buffer capacitor decreases. When the ignition has
failed after the ignition pulse, the voltage on the buffer
capacitor increases to start level and the external
switching device will be turned on again. This time the
preheat time is reduced to 0.64 seconds because the lamp
electrodes are still warm. An internal counter limits the
number of ignitions attempts to 7. This prevents the lamp
from flickering at end of lamp life.
The UBA2000T has an integrated current protection.
When the current through the sense resistor exceeds the
protection level (I
prot
), the switching device is turned off
and the circuit will enter a standby state. Switching the
mains voltage off and on again will reset the circuit.
The flow chart of the starting process is given in Fig.5.
In the following subsections the several blocks of the block
diagram are described in more detail.
IC supply
When the mains power is switched on, the buffer capacitor
is charged and the internal current source is started.
The internal voltage is stabilized, making it independent of
the voltage at the buffer capacitor. An internal zener diode
limits the voltage at pin 6 (V
CC
) to start level (V
CC(sl)
).
Voltage detectors
The voltage detectors measure the voltage on the buffer
capacitor and activate the switching device when the start
value (V
CC(sl)
) is reached. The time required to charge the
capacitor is the initial time (t
ini
, see also Fig.3).
UBA2000T
This time depends on the value of C1, the IC current and
the source resistance at pin V
in
(R1//R2). When the mains
voltage is near its peak value, the switching device is
actually turned on. When the voltage decreases to a value
indicating that the mains supply is interrupted, the starter
is ready to start preheating and igniting the TL-lamp at the
moment the mains supply returns.
Latch
The internal state of the latch represents the state of the
switching device. The setting of the latch depends on the
outputs of the voltage detectors, the number of starts
counter and the standby state. Resetting the latch is
controlled by the timer, the current detector and the current
protection circuit.
Current detector
The current detector detects when the switching device
must be turned off. The current detector also generates the
clock pulses to activate the counter (see Fig.4). For proper
functioning, the preheat current should be within the range
indicated by I
pr
. By including an hysteresis, unwanted
current peaks on the preheat current have no effect on the
counter. Because the current detector has a low-pass
transfer function, it is not influenced by spikes. This
circuitry eliminates the effect of spikes on the preheat time.
Edge detector
The edge detector ensures that the switching device will
be turned off when the rectified preheat current is on the
negative-going edge.
handbook, full pagewidth
Iso level
hysteresis
current through
sense resistor
clock signal
(fed to counter)
MGE007
clock generation during preheat
switch off level at end of preheat
Fig.4 Current detection.
1996 Jan 03
5
LED专区
京公网安备 11010802033920号
Copyright © 2005-2026 EEWORLD.com.cn, Inc. All rights reserved
电子工程世界
