UBA2028 データシートの表示（PDF） - NXP Semiconductors.
部品番号
コンポーネント説明
メーカー
UBA2028 Datasheet PDF : 23 Pages
| |||
NXP Semiconductors
UBA2028
600 V dimmable power IC for compact fluorescent lamps
lamp. If during restart the lamp still fails, the voltage remains high until the end of the
ignition time. At the end of the ignition time the circuit stops oscillating and the circuit will
enter the Power-down mode.
8.9 Power-down mode
The Power-down mode will be entered if, at the end of the ignition time, the voltage at pin
LVS is above Vlamp(fail). In the Power-down mode the oscillator will be stopped and both
TR1 and TR2 will be non-conductive. The VDD supply is internally clamped. The circuit is
released from the Power-down mode by lowering the low voltage supply below VDD(rst).
8.10 Capacitive mode protection
The signal across R15 see Figure 8 (R6 in Figure 9) also gives information about the
switching behavior of the half-bridge. If, after the preheat state, the voltage across the
ACM resistor (R15 or R6) does not exceed the Vdet(capm) level during the non-overlap
time, the Capacitive Mode Detection circuit (CMD) assumes that the circuit is in the
capacitive mode of operation. As a consequence the frequency will directly be increased
to fmax. The frequency behavior is de coupled from the voltage at pin CSW until CCSW has
been discharged to zero.
8.11 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 the pins IREF and CF are
sensitive to this charge injection. For charge coupling of approximately 8 pC, a safe
functional operation of the IC is guaranteed, independent of the current level.
Charge coupling at current levels below 50 μA will not interfere with the accuracy of the
VCS, Vi(PCS) and Vi(ACM) levels.
Charge coupling at current levels below 20 μA will not interfere with the accuracy of any
parameter.
8.12 Design equations
The following design equations are used to calculate the desired preheat time, the
maximum ignition time, and the minimum and the maximum switching frequency.
tph
=
1.8 × ---------C----C---T--------- × ----R---I--R---E---F-----
330 × 10–9 33 × 103
(1)
tign
=
0.26
×
---------C----C---T---------
330 × 10–9
×
----R---I--R---E----F----
33 × 103
(2)
fmin
=
40.5 × 103 × -1---0---0----×-----1---0---–--1---2 × -3---3----×-----1---0---3-
CCF
RIREF
(3)
fmax = 2.5 × fmin
(4)
Start of ignition is defined as the moment at which the measured lamp voltage crosses the
Vlamp(fail) level; see Section 8.8.
UBA2028
Product data sheet
All information provided in this document is subject to legal disclaimers.
Rev. 02 — 19 July 2010
© NXP B.V. 2010. All rights reserved.
8 of 23
Share Link: 