UBA2021_4 © NXP B.V. 2008. All rights reserved.
Product data sheet Rev. 04 — 25 July 2008 10 of 16
NXP Semiconductors
UBA2021
630 V driver IC for CFL and TL lamps
[1] The start-up supply current is specified in a temperature (T
vj
) range of 0 °C to 125 °C. For T
vj
<0°C and T
vj
>125 °C the start-up supply
current is < 350 µA.
[2] The clamp margin is defined as the voltage difference between turn-on of the clamp and start of oscillation. The clamp is in the off-state
at start of oscillation.
[3] Data sampling of V
RS(ctrl)
is performed at the end of conduction of T2.
[4] The total supply current is specified in a temperature (T
vj
) range of −20 °C to +125 °C. For T
vj
< −20 °C and T
vj
>125 °C the total supply
current is < 1.5 mA.
[5] Data sampling of V
RS(cap)
is performed at the start of conduction of T2.
[6] Within the allowed range of R
RREF
, defined as 30 kΩ +10 %.
[7] Typical values for the on and off resistances at T
vj
= 87.5 °C are: R
G2(on)
and R
G1(on)
= 164 Ω, R
G2(off)
and R
G1(off)
= 100 Ω.
[8] The input current at RHV pin may increase to 1600 µA during voltage transient at V
in
. Only for currents I
RHV
beyond approximately
550 µA is the oscillator frequency proportional to I
RHV
.
[9] The symmetry SYM
ff
is calculated from the quotient SYM
ff
= T1
tot
/ T2
tot
, with T1
tot
the time between turn-off of G2 and turn-off of G1,
and T2
tot
the time between turn-off of G1 and turn-off of G2.
11. Design information
11.1 Design equations
•
Bottom frequency:
(1)
• Feed-forward frequency:
(2)
• Where:
– X1 = 3.68.
– X2 = 22.28.
– τ = 0.4 µs.
– R
int
= 3 kΩ.
– C
par
= 4.7 pF
• Operating frequency is the maximum of f
B
, f
ff
or f
cm
.
f
ff
feed-forward frequency I
RHV
= 0.75 mA 60.4 63.6 66.15 kHz
I
RHV
= 1 mA 80.3 84.5 88.2 kHz
SYM
ff
symmetry I
RHV
= 1 mA
[9]
0.9 1 1.1
RR ripple rejection f
Vin
= 100 Hz - 6 - dB
R
CP(sw)
CP switch series resistance ICP = 100 µA 0.75 1.5 2.25 kΩ
R
AV
averaging resistor ICP = 10 µA 22.4 32 41.6 kΩ
Table 7. Characteristics
…continued
V
VS
= 11 V; V
FS
- V
S1
= 11 V; T
amb
= 25
°
C; all voltages referenced to ground; unless otherwise specified. See Figure 8.
Symbol Parameter Conditions Min Typ Max Unit
f
B
1
2C
CF
C
par
+()X1 R
RREF
R
int
–×()×[]τ+{}×
------------------------------------------------------------------------------------------------------------------------
=
f
ff
1
2C
CF
C
par
+()
X2 V
RREF
×
I
i RHV()
------------------------------
R
int
–
×τ+
×
--------------------------------------------------------------------------------------------------------------------------
=
