uba20261 NXP Semiconductors, uba20261 Datasheet - Page 12

• Manufacturer Part Number: uba20261
• Description: 600 V And 350 V Power Ic For Step Dimmable Cfls
• Manufacturer: NXP Semiconductors

NXP Semiconductors
UBA20261_UBA20262
Preliminary data sheet
Fig 9.
Timing diagram for preheat, ignition and overcurrent
V
V
th(CP)max
th(CP)min
5 V
0 V
7.3 Step dimming
voltage
(V)
4.5 V
3.8 V
startup
time
starts operating after the start-up state when the V
and the voltage on the CP pin passes V
saw-tooth pulses on the CP pin as shown in
The maximum ignition enabling time after the preheat phase is two complete saw-tooth
pulses. During the boost and burn state, part of the timer is used to generate the
maximum overcurrent time (more than one half of the saw-tooth pulse). If a continuous
overcurrent is detected, the timer starts.
The UBA20261/2 uses the step dimming method of dimming a lamp load. This method
enables the lamp to operate in four different light output level modes including full power.
The four different dim level modes can be selected by toggling the supply voltage which is
made possible by toggling the mains voltage switch.
To change the dim step, the low supply voltage must be above V
voltage must drop below V
boost or burn states (see
The discharge time of capacitor C
retention time. When the voltage on the CP pin drops below V
step memory is lost. The next time the supply is powered on, the lamp turns on at full
brightness. Using the default components, the retention time is  3 s. The retention time
calculation can be found in
V
CP
All information provided in this document is subject to legal disclaimers.
preheat time
Rev. 1 — 9 September 2011
Figure
DD(rst)
Section 11 on page
, irrespective of whether the IC is in the preheat, ignition,
10).
CP
600 V and 350 V power IC for step dimmable CFLs
(while the V
th(CP)max
Figure
ignition
time
23.
enabling time
. The preheat time consists of eight
DD
DD
ignition
power supply is off) sets step memory
9.
CFL ignition
supply voltage has reached V
boost-burn
overcurrent
ret(dim)CP
fault time
UBA20261/2
DD(start)
power down
(2 V typical), the
© NXP B.V. 2011. All rights reserved.
001aam768
. In addition, the
time (s)
DD(start)
12 of 32