UBA2211

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© NXP B.V. 2011. All rights reserved.

Objective data sheet

Rev. 2 — 3 January 2011

8 of 19

NXP Semiconductors

UBA2211

Half-bridge power IC family for CFL lamps

(3)

Taking the square root of both sides results in Equation 4:

(4)

or

(5)

A constant current flows through the power switches and the lamp which is defined by the

this ratio can be adjusted. This is described in more detail in the UBA2211 user manual.

7.8 Non-overlap time

The non-overlap time is defined as the time when both MOSFETs are not conducting. The

non-overlap time is fixed internally.

7.9 OverTemperature Protection (OTP)

OTP is active in all states. When the die temperature reaches the OTP activation

set to the startup state. When the oscillator is stopped, the DVDT supply no longer

state is entered as described in Section 7.2 on page 5. OTP is reset when the

7.10 Minimum glow time control

If the preheat time is set too short or omitted, the lamp electrodes do not have the correct

temperature in the ignition state. This results in instant light but also in a reduced

switching lifetime because when the electrode temperature is too low electrode sputtering

and damage occur. The minimum glow time control minimizes electrode damage by

ensuring maximum power use during the glow phase to heat the electrodes heat as

quickly as possible (see Figure 6).

1

T

osc

----------

V

SENSE

2

t

()DT

1

T

osc

----------

V

Oref

()RMS

2

DT

0

T

osc

∫

×

=

0

T

osc

∫

×

1

T

osc

----------

V

SENSE

2

t

()DT

0

T

osc

∫

×

1

T

osc

----------

V

Oref

()RMS

2

DT

0

T

osc

∫

×

=

RMS V

SENSE

V

Oref

()RMS

R

SENSE

I

LSPT

×

==