uba20270 NXP Semiconductors, uba20270 Datasheet - Page 8

• Manufacturer Part Number: uba20270
• Description: 600 V Driver Ic For Dimmable Compact Fluorescent Lamps
• Manufacturer: NXP Semiconductors

NXP Semiconductors
UBA20270
Product data sheet
Fig 5.
Retry cycle
V
V
th(CP)max
V
th(CP)min
th(rel)CP
7.1.5 Boost state and transition to burn state
5 V
0 V
voltage
(V)
startup
time
When ignition is detected by measuring lamp current on the CSI pin, the circuit enters the
boost state.
nominal burn state lamp current can be increased with a fixed boost ratio of 1.5:1. This
boosts up the slow luminescence increase of a cold amalgam CFL lamp, provided
V
burn state is bypassed.
A boost timing circuit is included to determine the boost time and transition to burn time.
The circuit consists of a clock generator comprising C
When the timer is not operating, C
1.1 V. This voltage, about 0.6 V, is still higher than the level at which the comparator on
C
The boost time consists of 63 saw-toothed pulses at the CB pin and automatically
followed by the transition time at the CP pin. The 32 saw-tooth pulses form the transition
time from boost to burn enabling a smooth transition between the current controlled boost
and burn state. The total transition time is approximately four times the preheat time as
shown in
DCI
CB
1
st
detects if the CB pin is shorted to ground.
> V
preheat
time
t
ph
V
CP
th(bst)DCI
enabling time
Figure
1
st
t
en(ign)
Figure 7
ignition
All information provided in this document is subject to legal disclaimers.
. If the IC is at a temperature (T
6.
1
ignition
attempt
st
shows the boost and burn state in more detail. In the boost state, the
Rev. 2 — 8 September 2011
failed
HOLD STATE
delay time
t
d(restart)
restart
600 V Driver IC for dimmable compact fluorescent lamps
CB
startup
is discharged to lower than the V
2
nd
2
nd
time
preheat
t
ph
j(bp)bst
enabling time
2
nd
t
en(ign)
ignition
) before entering the boost state, the
CB
, R
ext(RREF)
POWER DOWN STATE
2
ignition
attempt
nd
failed
and a 64-step counter.
UBA20270
th(CB)min
© NXP B.V. 2011. All rights reserved.
discharge
001aan537
to 0 V
time (s)
level of
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