uba2213 NXP Semiconductors, uba2213 Datasheet - Page 8

• Manufacturer Part Number: uba2213
• Description: Half-bridge Power Ic Family For Cfl Lamps
• Manufacturer: NXP Semiconductors

NXP Semiconductors
UBA2213
Product data sheet
7.10 OverTemperature Protection (OTP)
7.8 Steady state
7.9 Non-overlap time
When boost state is ended, transition control is turned on. V
reset. Capacitor C
f
0.6  V
In the steady state, the RMS current control is active. This control sets the frequency so
that the RMS voltage across the sense resistor (R
feature ensures the current through the power switches and through the lamp is constant.
This results in constant IC dissipation and temperature at a fixed ambient temperature.
During one oscillator clock cycle, the voltage on pin SENSE (V
converted into a positive current. This discharge current is added to the capacitor C
During the other oscillator clock cycle, the input of the squarer is connected to the internal
reference voltage V
current. This charge current is also added to capacitor C
equal, then
Where T
Taking the square root of both sides results in
or
The internal reference voltage (V
constant current which flows through the power switches and the lamp.
The non-overlap time is defined as the time when both MOSFETs are not conducting. The
non-overlap time is fixed internally and is fixed at the t
OTP is active in all states except boost. When the die temperature reaches the OTP
activation threshold (T
(LSPT/HSPT) are set to the start-up state. When the oscillator is stopped, the DVDT
supply no longer generates the supply current I
and the start-up state is entered as described in
the temperature < T
--------- -
T
RMS V
min
1
osc
--------- -
T
1
osc
to f


T
nom
H(RC)
SENSE
osc

0
T
osc
osc

0
V
. The transition state ends when the voltage on pin SW (V
SENSE
V
Equation 4
.
equals the operating frequency f
SENSE
=
All information provided in this document is subject to legal disclaimers.
V
2
t  DT
O ref
SW
2

t  DT
O(ref)RMS
th(rel)otp
Rev. 2 — 21 November 2011
is discharged by internal current, the frequency was increased from
RMS
th(act)otp
=
is true:
=
--------- -
T
1
osc
.
=
. This voltage is squared and converted into a negative
--------- -
T

), the oscillator is stopped and the power switches
R
1
osc
T
SENSE
osc

0
O(ref)RMS

V
T
O ref
osc

0


V
I
O ref
LSPT
RMS

) and the external R
RMS
osc
Half-bridge power IC family for CFL lamps
2
DT
Equation
DVDT
/ 1.
Section 7.2 on page
2
DT
SENSE
. Voltage V
no
) is equal to V
5:
SW
value (see
. When both currents are
ph
SENSE
is disconnected to V
SENSE
DD
gradually decreases
resistor define the
Table
SW
5. OTP is reset when
) is squared and
O(ref)RMS
UBA2213
) reaches
© NXP B.V. 2011. All rights reserved.
5).
. This
SW
SW
8 of 21
and
.
(4)
(5)
(6)