Philips UBA2021T, UBA2021P Datasheet

INTEGRATED CIRCUITS

DATA SH EET

UBA2021

630 V driver IC for CFL and TL lamps

Product speciﬁcation Supersedes data of 2000 Jul 24 File under Integrated Circuits, IC11

2001 Jan 30

Philips Semiconductors Product speciﬁcation

630 V driver IC for CFL and TL lamps UBA2021

FEATURES

• Adjustable preheat and ignition time

• Adjustable preheat current

• Adjustable lamp power

• Lamp temperature stress protection at higher mains

GENERAL DESCRIPTION

The UBA2021 is a high-voltage IC intended to drive and control Compact Fluorescent Lamps (CFL) or fluorescent TL-lamps. It contains a driver circuit for an external half-bridge, an oscillator and a control circuit for starting up, preheating, ignition, lamp burning and protection.

voltages

• Capacitive mode protection

• Protection against a too-lowdrive voltage for the power

MOSFETs.

QUICK REFERENCE DATA

SYMBOL PARAMETER CONDITIONS MIN. TYP. MAX. UNIT

High voltage supply

high side supply voltage IFS<15µA; t < 0.5 s −−630 V

Start-up state

VS(start)

VS(stop)

VS(standby)

oscillator start voltage − 11.95 − V oscillator stop voltage − 10.15 − V standby current VVS=11V − 200 −µA

Preheat mode

start

RS(ctrl)

start frequency − 108 − kHz preheat time CCP= 100 nF − 666 − ms control voltage at pin RS −−600 − mV

Frequency sweep to ignition

ign

bottom frequency − 42.9 − kHz ignition time − 625 − ms

Normal operation

tot

, R

G1(on)

, R

G1(off)

bottom frequency − 42.9 − kHz non-overlap time − 1.4 −µs total supply current fB= 43 kHz − 1 − mA high and low side on resistance − 126 −Ω

G2(on)

high and low side off resistance − 75 −Ω

G2(off)

Feed-forward

i(RHV)

feed-forward frequency I

= 0.75 mA − 63.6 − kHz

RHV

= 1.0 mA − 84.5 − kHz

RHV

operating range of input current at pin RHV 0 − 1000 µA

2001 Jan 30 2

Philips Semiconductors Product speciﬁcation

630 V driver IC for CFL and TL lamps UBA2021

ORDERING INFORMATION

TYPE NUMBER

PACKAGE

NAME DESCRIPTION VERSION

UBA2021T SO14 plastic small outline package; 14 leads; body width 3.9 mm SOT108-1 UBA2021P DIP14 plastic dual in-line package; 14 leads (300 mil) SOT27-1

BLOCK DIAGRAM

handbook, full pagewidth

n.c.

RHV

SUPPLY

BAND GAP

REFERENCE

RREF

OSCILLATOR

LEVEL

SHIFTER

bootstrap charging circuit

HIGH SIDE

DRIVER

MONITOR

TIMING

CONTROL

NON

OVERLAP

UBA2021

LOW SIDE

DRIVER

SGND

MGS988

PGND

Fig.1 Block diagram.

2001 Jan 30 3

Philips Semiconductors Product speciﬁcation

630 V driver IC for CFL and TL lamps UBA2021

PINNING

SYMBOL PIN DESCRIPTION

FS G1 S1 n.c. VS G2 PGND CP RS RREF SGND CF RHV CI

1 2 3 4 5 6 7 8

9 10 11 12 13 14

high side ﬂoating supply voltage gate high transistor (T1) source high transistor (T1) high-voltage spacer, not to be connected low voltage supply gate low transistor (T2) power ground timing/averaging capacitor current monitoring input reference resistor signal ground oscillator capacitor start-up resistor/feed-forward resistor integrating capacitor

handbook, halfpage

FS G1 S1

n.c.

VS G2

PGND

1 2 3 4

UBA2021T

5 6 7

MGS989

RHV

SGND

RREF

Fig.2 Pin configuration (SO14).

2001 Jan 30 4

handbook, halfpage

n.c.

VS G2

PGND

1 2 3 4

UBA2021P

5 6 7

MGS990

RHV

SGND

RREF

Fig.3 Pin configuration (DIP14).

Philips Semiconductors Product speciﬁcation

630 V driver IC for CFL and TL lamps UBA2021

FUNCTIONAL DESCRIPTION Introduction

The UBA2021 is an integrated circuit for electronically ballasted compact fluorescent lamps and their derivatives operating with mains voltages up to 240 V (RMS). It provides all the necessary functions for preheat, ignition and on-state operation of the lamp. In addition to the control function, the IC provides level shift and drive functions for the two discrete power MOSFETs, T1 and T2 (see Fig.7).

Initial start-up

Initial start-up is achieved by charging capacitor CS9 with the current applied to pin RHV. At start-up, MOSFET T2 conducts and T1 is non-conducting, ensuring C

boot

becomes charged. This start-up state is reached for a supply voltage V

VS(reset)

(this is the voltage level at pin VS at which the circuit will be reset to the initial state) and maintained until the low voltage supply (VVS) reaches a value of V

. The circuit is reset in the start-up state.

VS(start)

Oscillation

When the low voltage supply (VVS) has reached the value of V

VS(start)

the circuit starts oscillating in the preheat state. The internal oscillator is a current-controlled circuit which generates a sawtooth waveform. The frequency of the sawtooth is determined by the capacitor CCF and the current out of pin CF (mainly set by R

). The sawtooth

RREF

frequency is twice the frequency of the signal across the load. The IC brings MOSFETs T1 and T2 alternately into conduction with a duty factor of approximately 50%. Figure 4 represents the timing of the IC. The circuit block 'non-overlap' generates a non-overlap time tno that ensures conduction periods of exclusively T1 or T2. Time tno is dependent on the reference current I

RREF

handbook, halfpage

internal

clock

(G1-S1)

(G2)

start-up

MGS991

time

Fig.4 Oscillator timing.

Operation in the preheat mode

The circuit starts oscillating at approximately 2.5 × f

(108 kHz). The frequency gradually decreases until a defined value of current I

is reached (see Fig.5). The

shunt

slope of the decrease in frequency is determined by capacitor CCI. The frequency during preheating is approximately 90 kHz. This frequency is well above the resonantfrequencyofthe load, which means that the lamp is off; the load consists of L2, C5 and the electrode resistance only. The preheat time is determined by capacitor CCP. The circuit can be locked in the preheat state by connecting pin CP to ground. During preheating, the circuit monitors the load current by measuring the voltage drop over external resistor R conduction of T2 with decision level V frequency is decreased as long as VRS>V frequency is increased for VRS<V

shunt

RS(ctrl)

at the end of

. The

RS(ctrl)

2001 Jan 30 5

Philips Semiconductors Product speciﬁcation

630 V driver IC for CFL and TL lamps UBA2021

Feed-forward frequency

Above a defined voltage level the oscillation frequency

handbook, halfpage

start

preheat state

For calculations refer to Chapter “Design equations”.

ignition

state

Fig.5 Operation in the preheat mode.

MGS992

burn state

time

also depends on the supply voltage of the half-bridge (see Fig.6).Thecurrentforthecurrent-controlled oscillator is in the feed-forward range derived from the current through R tothe average value of the current through R operating range of I

. The feed-forward frequency is proportional

RHV

withinthe

RHV

, given the lower limit set by fB.

i(RHV)

For currents beyond the operating range (i.e. between

1.0 and 1.6 mA)thefeed-forwardfrequencyisclamped.In order to prevent feed-forward of ripple on Vin, the ripple is filtered out. The capacitor connected to pin CP is used for this purpose. This pin is also used in the preheat state and the ignition state for timing (tphand t

ign

Ignition state

The RS monitoring function changes from V

RS(ctrl)

regulation to capacitive mode protection at the end of the preheat time. Normally this results in a further frequency decrease down to the bottom frequency fB(approximately 43 kHz). The rate of change of frequency in the ignition state is less than that in the preheat mode. During the downward frequency sweep, the circuit sweeps through the resonant frequency of the load. A high voltage then appears across the lamp. This voltage normally ignites the lamp.

Failure to ignite

Excessive current levels may occur if the lamp fails to ignite. The IC does not limit these currents in any manner.

Transition to the burn state

Assuming that the lamp has ignited during the downward frequencysweep,thefrequencynormallydecreasestothe bottom frequency. The IC can transit to the burn state in two ways:

1. In the event that the bottom frequency is not reached,

transition is made after reaching the ignition time t

ign

2. As soon as the bottom frequency is reached. The bottom frequency is determined by R

RREF

and CCF.

handbook, halfpage

(kHz)

feed-forward

range

bottom

frequency

(mA)

RHV

For calculations refer to Chapter “Design equations”.

Fig.6 Feed-forward frequency.

Capacitive mode protection

When the preheat mode is completed, the IC will protect the power circuit against losing the zero voltage switching condition and getting too close to the capacitive mode of operation. This is detected by monitoring voltage VRS at pin RS. If the voltage is below V

RS(cap)

at the time of turn-onof T2, then capacitive mode operation is assumed. Consequently the frequency increases as long as the

capacitive mode is detected. The frequency decreases down to the feed-forward frequency if no capacitive mode is detected. Frequency modulation is achieved via pin CI.

MGS993

2001 Jan 30 6

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