UBA20271 データシートの表示（PDF） - NXP Semiconductors.
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UBA20271 Datasheet PDF : 33 Pages
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NXP Semiconductors
UBA20271/2
350 V and 600 V Power ICs for dimmable compact fluorescent lamps
voltage
(V)
5V
Vth(CP)max
1st failed
VCP
ignition
attempt
Vth(CP)min
Vth(rel)CP
startup
time
1st preheat
time
tph
ten(ign)
1st ignition
enabling time
HOLD STATE
td(restart)
restart
delay time
2nd failed
ignition
attempt
discharge
to 0 V
2nd preheat
time
tph
ten(ign)
POWER DOWN STATE
2nd
startup
2nd ignition
enabling time
0V
Fig 5. Retry cycle
time (s)
001aan537
7.1.5 Boost state and transition to burn state
When ignition is detected by measuring lamp current on the CSI pin, the circuit enters the
boost state. Figure 7 shows the boost and burn state in more detail. In the boost state, the
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
VDCI > Vth(bst)DCI. If the IC is at a temperature (Tj(bp)bst) before entering the boost state, the
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 CCB, Rext(RREF) and a 64-step counter.
When the timer is not operating, CCB is discharged to lower than the Vth(CB)min level of
1.1 V. This voltage, about 0.6 V, is still higher than the level at which the comparator on
CCB detects if the CB pin is shorted to ground.
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 Figure 6.
UBA20271_UBA20272
Product data sheet
All information provided in this document is subject to legal disclaimers.
Rev. 2.1 — 12 October 2011
© NXP B.V. 2011. All rights reserved.
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