AN_UBA2024T_15 Datasheet, PDF (7/18 Pages) NXP Semiconductors – CFL applications

Philips Semiconductors
CFL applications with the UBA2024T
APPLICATION NOTE
5 SELECTING COMPONENT VALUES
5.1 Selecting input configuration, buffer capacitor and fuse-resistor
Use of a voltage doubler (figure 2) or standard bridge rectifier (figure 3), values for the buffer capacitor (C BUF) and the
fusible inrush-current limiting resistor are given in table 2:
Table 2: Adviced input configuration, buffer capacitor en fusible inrush-current limiting resistor
Input Voltage Lamp Power^# Input configuration CBUF
CBUF1, CBUF2 (each) RFUS
100-127Vac
100-127Vac
≤4W
5–6W
Standard (fig. 4)
10µF/200V
15µF/200V
(n.a.)
18Ω (0.25W/23W)*
(n.a.)
12Ω (0.5W/35W)*
100-127Vac
100-127Vac
100-127Vac
7–8W
9 –11 W
12 – 14 W
Voltage Doubler
(fig.3)
(n.a.)
(n.a.)
(n.a.)
10µF/200V
15µF/200V
22µF/200V
10Ω (0.5W/47W)*
8.2Ω (0.75W/70W)*
6.8Ω (1W/103W)*
220-240Vac
≤5W
2.2µF/400V
(n.a.)
47Ω (0.25W/23W)*
220-240Vac
220-240Vac
6–8W
9 – 11 W
Standard (fig. 4)
3.3µF/400V
4.7µF/385V
(n.a.)
39Ω (0.25W/23W)*
(n.a.)
33Ω (0.5W/32W)*
220-240Vac
12 – 15 W
6.8µF/385V
(n.a.)
27Ω (0.5W/47W)*
(^# Overall lamp power including driver circuit)
(* Minimum continuous power rating / minimum peak power rating (≤20ms))
5.2 Choosing frequency, lamp inductor and lamp capacitor
Given a certain netto ¹ lamp power Plamp and lamp current Ilamp, then Vlamp=Plamp/Ilamp. If buffer capacitors are
according to table 2, an approximation of the effective lamp inductor voltage VLla_eff is given² in table 3:
Table 3: Approximated effective lamp inductor voltage
Input frequency Input
V_lamp
Voltage
configuration
≤20V
≈30V
≈40V
≈50V
≈60V
≈80V
≈100V
100 Vac
115 Vac
127 Vac
60 Hz
Standard
(fig. 4)
58
71
80
53
46
n.a.
n.a.
n.a.
n.a.
66
62
53
n.a.
n.a.
n.a.
76
70
65
n.a.
n.a.
n.a.
100 Vac
115 Vac
127 Vac
60 Hz
Voltage
Doubler
(fig.3)
123
120
117
113
108
94
n.a.
145
143
140
137
133
122
107
164
162
160
157
154
144
131
220 Vac
230 Vac
240 Vac
50 Hz
Standard
(fig. 4)
138
136
133
130
125
112
95
145
143
140
138
134
122
106
153
151
148
146
143
131
116
n.a.= not applicable (these combinations of lamp voltage and input voltage/configuration are not allowed)
The lamp inductor LLA and the lamp frequency fout have to comply to:
2πfout LLA = ^VLla_eff
Ilamp
1 _{of burner only, usually about 85% of overall lamp power.}
2 _{use linear interpolation to find values inbetween.}
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