Datasheet L6567, L6567D Datasheet (SGS Thomson Microelectronics)

HIGH VOLTAGE DRIVER FOR CFL

n

BCD-OFF LINE TECHNOLOGY

n FLOATING SUPPLY VOLTAGE UP TO 570V

n

GND REFERRED SUPPLY VOLTAGE UP TO
18V

n UNDER VOLTAGE LOCK OUT

n

CLAMPING ON Vs

n

DRIVER CURRENT CAPABILITY:
30mA SOURCE
70mA SINK

n

PREHEAT AND FREQUENCY SHIFT TIMING

DESCRIPTION

The device is amonolithic high voltage integrated cir­cuit designed to drive CFL and small TL lamps with a
minimum part count.

It provides all the necessary functions for proper pre­heat, ignition andsteady state operation of the lamp:

♦ variable frequency oscillator;

L6567

MULTIPOWER BCD TECHNOLOGY

SO14 DIP14

ORDERING NUMBERS:

L6567D L6567

♦

settable preheating and ignition time;

♦

capacitive mode protection;

♦

lamp power independentfrom mains voltage variation.

Besides the control functions, theIC provides the lev­el shift anddrive function for twoexternal power MOS
FETs in a half-bridge topology.

BLOCK DIAGRAM

V

5

S

CF

12

CI

14

C

SCfCi

RHV

FEED FORWARD

VCO +

FREQ. SHIFTING

VOLTAGE

REFERENCE

Rhv

13

comp.

to

Vhv

BIAS

CURRENT

GENERATOR

Ref

Cp/Cav

CP
8

F

1

V

S

PREHEATING

TIMING

LOGIC

10
R

REF

LEVEL

SHIFTING

C

HIGH
SIDE

DRIVER

LOW
SIDE

DRIVER

S

Cboot

G1

2

S1

3

6

G2

7

PGND

SGND

11

9

R

S

T1

L

T2

Rshunt

D96IN441B

Vhv

Lamp

CL

Chv

Chv

MAINS

January 2000

This ispreliminary information on a new product now in development. Details are subject to change without notice.

1/15

L6567

PIN FUNCTION

N° Pin Description

1F
2 G1 Gate of high side switch
3 S1 Source of high side switch
4 NC High Voltage Spacer. (Should be not connected)
5V
6 G2 Gate of low side switch
7 PGND Power Ground
8 CP First timing (TPRETIGN), then averaging the ripple in the representation of the HVB (derived

9R
10 R
11 SGND Signal Ground. Internally Connected to PGND
12 CF Frequency setting capacitor
13 RHV Start-up supply resistor, then supply voltage sensing.
14 CI Timing capacitor for frequency shift

Floating Supply of high side driver

S

Supply Voltage for GND level control and drive

S

through RHV).
R

S

Reference resistor for current setting

REF

: current monitoring input

SHUNT

PIN CONNECTION (Top view)

2/15

FS

G1

S1

N.C.

V

G2

PGND

14
2
3
4

S

5
6
7

D96IN440

13

12

11

10

9
8

CI1
RHV
CF
SGND
RREF
RS
CP

ABSOLUTEMAXIMUM RATINGS

Symbol Parameter Value Unit

L6567

Low Voltage Supply 18 (1) V

S

Mains Voltage Sensing VS +2VBE (2)
Preheat/Averaging 5 V
Oscillator Capacitor Voltage 5 V
Frequency Shift Capacitor Voltage 5 V
Reference Resistor Voltage 5 V
Current Sense Input Voltage -5 to 5 V

V

V
V

V

V

V

RHV

CP

CF

V

CI

RREF

RS

transient 50ns -15 V

V

G2

V

S1

Low Side Switch Gate Output 18 V
High Side Switch Source Output: normal operation -1 to 373 V

0.5sec mains transient -1 to 550 V

VG1 High Side Switch Gate Output: normal operation -1 to 391 V

0.5sec mains transient -1 to 568 V
with respect to pin S1 V

V

FS

Floating Supply Voltage: normal operation 391 V

be

to V

S

0.5sec mains transient 568 V

V

V

FS/S1

∆V

FS/∆T

∆V

S1/∆T

I

RHV

I

Vs

T

stg

T

NOTES: (1) Do not exceed package thermal dissipation limits

Note: ESD immunity for pins 1, 2 and 3 is guaranteed up to 900 V (Human Body Model)

Floating Supply vs S1 Voltage 18 V
VFS Slew Rate (Repetitive) -4 to 4 V/ns
VS1 Slew Rate (Repetitive) -4 to 4 V/ns
Current Into R
Clamped Current into V

HV

S

Storage Temperature -40 to 150 °C
Junction Temperature -40 to 150 °C

j

(2) For VS ≤ VShigh 1
(3) For VS > VS high 1
(4) Internally Limited

3 (3) mA

200 (4) mA

3/15

L6567

ELECTRICAL CHARACTERISTCS

(VS=12V;R

Symbol Parameter Test Condition Min. Typ. Max. Unit

- SUPPLYVOLTAGE SECTION

V

S

=30KΩ;CF= 100pF; Tj=25°C; unless otherwise specified.)

REF

V

S high 1

V

S high2

V

S low 2

V

S HYST

V

S low 1

I

SSP

I

SOP

VSTurn On Threshold 10.7 11.7 12.7 V
VSClamping Voltage VS = 20mA 12 13 14 V
VSTurn Off Threshold 9 10 11 V
Supply Voltage Hysteresis 1.5 1.65 1.8 V
VSVoltage to Guarantee

=”0”and VG2=”1

V

G1

16V

VSSupply Current at Start Up VS= 10.6V Before turn on 50 250 mA
VSSupply Operative Current VS= VShigh 1 1.2 mA

OSCILLATOR SECTION

f

osc min

f

osc 600

f

osc 1mA

Minimum Oscillator frequency I
Feed Forward Frequency I

m

Feed Forward Frequency I

= 0mA; CI = 5V 41.7 43 44.29 kHz

RHV

= 600mA 47.88 50.4 52.92 kHz

RHV

= 1mA 79.8 84 88.2 kHz

RHV

fosc max Maximum Oscillator Frequency CI = 0V 96.75 107.5 118.25 KHz

∆ICF/∆V

Oscillator Transconductance 9 17.5 µA/V

CI

PREHEAT/IGNITION SECTION

P.H.T. Preheat Time Cp = 150nF 0.88 1 1.12 sec

P.H.clocks Number of Preheat Clocks 16

IGN.clocks Number of Ignition Clocks 15

RATE OF FREQUENCY CHANGE SECTION

ICIP charge CI Charging Current During

106 118 130 mA

Preheat

ICII charge CI Charging Current During

1 1.2 1.4 mA

Ignition

ICI disch CI Discharge Current -52 -47 -42 mA

V

TH CI

CI Low Voltage Threshold 10 100 mV

RS - THRESHOLD SECTION

V

CMTH

Capacitive Mode Voltage

02040mV

Threshold

V

PH

Preheat Voltage Threshold -0.64 -0.6 -0.56 V

G1 - G2DELAY TIMES SECTION

G1

DON

On Delay of G1 Output 1.05 1.4 1.75

4/15

s

µ

L6567

ELECTRICAL CHARACTERISTCS

(Continued)

Symbol Parameter Test Condition Min. Typ. Max. Unit

G2

DON

G1

+

DONG1ON

------- ------ -------- ------- -------- --- -- --

G2

+

DONG2ON

On Delay of G2 Output 1.05 1.4 1.75
Ratio between Delay Time +

Conduction Time of G1 and G2

I

= 1mA; Cl = 5V

RHV

Cl = 0V

0.87

0.77

1.15

1.30

LOW SIDE DRIVER SECTION

Ron G2 so G2 Source Output Resistance V

Ron G2 si G2 Sink OutputResistance V

Ron G1 so G1 Source Output Resistance V

Ron G1 si G1 Sink OutputResistance V

= 12V,V = 3V 80 190

S

= 12V,V = 3V 65 125 Ω

S

= 10V,V = 3V 80 190 Ω

S

= 10V,V = 3V 65 125 Ω

S

HIGH SIDE DRIVER SECTION

I

FSLK

I

S1 LK

Leakage Current of FS PIN to
GND

Leakage Current of S1 PIN to
GND

VFS= 568V; G1 = L

= 568V; G1 = H

V

FS

VS1= 568V; G1 = L

= 568V; G1 = H

V

S1

5
5

5
5

BOOTSTRAP SECTION

Boot Th BOOTSTRAP Threshold V

= 10.6V before turnon 5 (*) V

S

µ

Ω

µA
µA

µA
µA

s

AVERAGE RESISTOR

R

AVERAGE

(*) Beforestartingthe first commutation; when switching 6V is guaranteed.

Average Resistor 27 38.5 50 kΩ

General operation

The L6567 uses a small amount of current from a supply resistor(s) to start the operation of the IC. Once start
up condition isachieved, the IC turns on the lower MOS transistor of the half bridge which allows the bootstrap
capacitor to charge. Once this is achieved, the oscillator begins toturn on the upper and lower MOStransistors
at high frequency, and immediately ramps down to a preheat frequency. During this stage, the IC preheats the
lamp and after a predetermined time ramps down again until it reaches the final operating frequency. The IC
monitors thecurrentto determine if the circuitisoperating in capacitivemode.If capacitive switchingis detected,
the IC increases the output frequency until zero-voltage switching is resumed.

Startup and supply in normal operation

At start up the L6567 is powered via a resistor connected to the RHVpin (pin 13) from the rectified mains. The
current charges the C
V

SLOW1

(max 6V), the low side MOS transistor is turned on while the high side one is kept off. This condition
assures that the bootstrap capacitor is charged. When V
the R

pin does not provide anymore the supply current for the IC (seefig.1).

HV

capacitor connected to the VSpin (pin 5). When the VSvoltage reaches the threshold

S

SHIGH1

threshold is reached the oscillator starts, and

5/15

L6567

Figure 1. Start up

VSHIGH1

VSLOW1

TDT

G

V

lowside mosfet

VS

0

0

VG-VS

high side mosfet

0

CF

0

TIME

Oscillator

The circuit starts oscillating when the voltage supply VShas reached the V
condition theoscillatorcapacitor C
ly by the external resistor R
and resistor R

. This fixed value is called F

REF

REF

(at pin12) ischarged and discharged symmetrically with a current setmain-

F

connected to pin 10. The value of the frequency is determined by capacitor C

. A dead time TDTbetween the ON phases of the transistors

MIN

S HIGH1

threshold. In steady state

is provided for avoiding cross conduction, so the duty cycle for each is less than 50%. The dead time depends
on R

The IC oscillating frequency is between F

value (fig. 7).

REF

MIN

and F

MAX

= 2.5 · F

in all conditions.

MIN

F

Preheatingmode

The oscillator starts switching at the maximum frequency F

. Then the frequency decreases at once to reach

MAX

the programmed preheating frequency (fig.2). The rate of decreasing (df/dt) is determined by the external ca­pacitor C
current is adjusted by sense resistance R
sense resistor R

(pin 14). The preheat time T

I

(connected between pin 9-RS- and pin 7-PGND-). At pin 9 the voltage drop on R

SHUNT

is adjustable with external components (R

PRE

. During the preheating time the load current is sensed withthe

SHUNT

and CP). The preheat

REF

SHUNT

is sensed at the moment the lowside MOS FET is turned off. There is an internal comparator with afixed thresh­old V
old is reached, the frequency is held constant for the programmed preheating time T

T
current that depends on R

So the preheat mode is programmable with external components as far as T
as far as the preheating current is concerned (choosing properly R
Land C

The circuit is held in the preheating mode when pin 8 (C
In case F

the low side MOS transistor gate on and the high side gate off. This condition is kept until VSundershoots V

6/15

:ifVRS>VPHthe frequency is decreased and ifVRS<VPHthefrequency is increased. Ifthe VPHthresh-

PH

is determined by the external capacitor CP(pin8) and by the resistor R

PRE

).

L

is reached during preheat, the IC assumes an open load. Consequently the oscillation stops with

MIN

, and these 16 cycles determine the T

REF

) is grounded.

P

REF:CP

.

PRE

is concerned (R

PRE

and the resonant load components:

SHUNT

.

PRE

is charged 16 times with a

REF&CP

SLOW1

) and

.

L6567

Figure 2. Preheating and ignition state.

FREQUENCY

FMAX

MIN

F

preheating
state

ignition
state

burning state

TIME

Ignitionmode

At the end of the preheat phasethe frequency decreses tothe minimumfrequency (F
coil current and a high voltage appearing across the lamp. That is because the circuit works near resonance.
This high voltage normally ignites the lamp. There is no protection to avoid high ignition currents through the
MOS transistors when thelampdoesn’t ignite. This only occurs inan end of lamp life situation in which the circuit
may break. Now the lowest frequency is the resonance frequency of L and C

The ignition phase finishes when the frequency reaches F
elapsed. The ignition timeis related toT
the same current used to charge it during T

PRE:TIGN

PRE

The frequency shiftingslope is determined by C
During the ignition time the V

monitoring function changes inthe capacitive mode protection.

RS

= (15/16) · T

.

.

I

or (at maximum) when the ignition time has

MIN

. The CPcapacitor is charged 15times with

PRE

(the capacitor across the lamp).

L

), causing anincreased

MIN

Steady state operation: feed forwardfrequency

The lamp starts operating at F

, determined by R

MIN

and CFdirectly after the ignition phase. To prevent too

REF

high lamp power at high mains voltages, a feed forward correction is implemented. At the end of the preheat
phase the R
increases and overcomes a value set by R

pinisconnected to an internal resistortosensethe HighVoltage Bus.Ifthe current in this resistor

HV

, the current that charges the oscillator capacitor CFincreases

REF

too. The effect is an increase in frequency limiting the power in the lamp. In order toprevent feed forward of the
ripple of the V

voltage, the ripple is filtered with capacitor CPon pin 8 and an integrated resistor R

HV

AVERAGE

Figure 3. Burn state

FREQUENCY

feed forward mode

MIN

F

Irhv

.

7/15

L6567

Capacitivemode protection

During ignition and steady state the operating frequency is higher than the resonance frequency of the load
(L,C

L,RLAMP

order to maintain Zero Voltage Switching.
If the operating frequency undershoots the resonance frequency ZVS doesn’t occur and causes hard switching

of theMOStransistors. The L6567 detects this situation by measuring V

on. At pin 9 there is an internal comparatorwith thresholdV

assumed and the frequency is increased as long as this situation is present. The shift is determined by CI.

Steady state frequency

At anytime during steadystate thefrequency isdetermined by the maximumon the following three frequencies:

and R

FILAMENT

), so the transistors are turned on during the conduction time of the body diode in

when the low side MOS FET is turned

RS

(typ~20mV): if VRS<V

CMTH

capacitive mode is

CMTH

f

STEADYSTATE

=MAX{F

MIN,fFEEDFORWARD,fCAPACI T IV EMODEPROT ECTIO N

}.

IC supply

At start up the IC is supplied with a current that flows through RHVand an internal diode to the VSpin which­charges theexternal capacitor C
provide anymore the supply current. The easiest way to charge the C

. In steady state condition RHVis used as a mainsvoltage sensor, so it doesn’t

S

capacitor (and tosupply theIC)is to use

S

a charge pump from the middle point of the half bridge.
To guarantee a minimum gate power MOS drive, the IC stops oscillating when V

restart once the V
starts operating atf = F

will become higher than V

S

,then the frequency shifts towards F

MAX

. A minimum voltage hysteresis isguaranteed. The IC re-

SHIGH1

. The timing ofthis frequency shifting is T

MIN

is lower than V

S

SHIGH2

. It will

IGN

(that is: CPcapacitor is charged and discharged 15 times).Now the oscillator frequency is controlled as in stan­dard burning condition (feedforward and capacitive mode control). Excess charge on C
nal clamp that turns on at voltage V

SCL

.

is drained by an inter-

S

Groundpins

Pin 7(PGND) is the ground reference of the IC with respect to the application. Pin 11( SGND) provides a local
signal ground reference for the components connected to the pins C

P,CI,RREF

and CF.

Relationship betweenexternal components and sistemworking condition

L6567 is designed todriveCFL and TLlamps with a minimumpartcount topology. This feature implies that each
external component isrelated to one or more circuit operating state.

This table is a short summary of these relationships:
F

---> R

MIN

F

FEEDFORWARD

T

PRE&TIGN

F

PRE

T

DT

df/dt ---> C

---> R

---> R

REF&CF

---> CF&I

---> CP&R

SHUNT

REF

I

RHV

REF

,L,CL, LAMP

Some useful formulas can wellapproximate the values:

1

MIN

≅

------------ -------- -------------

8R

⋅⋅

REFCF

F

If I

following expression:

8/15

is greater than: , the feed forward frequency is settledand the frequency value is fitted by the

RHV

I

RHV

≥

15

------------ --

R

REF

F

FE EDFO R W ARD

I

RHV

----------- --------- -≅

121 CF⋅

L6567

Other easy formulas fit rather well:
T
T

DT
PRE

≅

46.75 · 10

≅ 224 · C

^-12

·R

P·RREF

REF

As far asdf/dt isconcerned, there are no easyformulas that fitthe relation between CF,RF, and CI.CIis charged
and discharged by three different currents that are derived from different mirroringratios by thecurrent flowing
on R

. The voltage variations on CIare proportional to the current that charges CF, that is to say they are

REF

proportional to df/dt.
The values obtained in the testing conditions (C

= 100nF) are:

I

during preheating and workingconditions the typical frequency increase is ~ 20KHz/ms, the typical decrease is
~-10Khz/ms;

During ignition the frequency variation is ~ -200Hz/ms.
If slower variations are needed, CI has to be increased.
Due to these tight relationships, it is recommended to follow a precise procedure: first R

has to be chosen

HV

looking at startup current needs and dissipation problems. Then the feed forward frequency range has to be
determined, and so C

Given a certain C
The other external parameters (R

is set.

F

F,RREF

is set in order to fix F

SHUNT

and CI) can be chosen at the end because they are just related to a

. Now CPcan be chosed to set the desired T

MIN

PRE

and T

IGN

.

single circuit parameters.

9/15

L6567

Figure 4. IC Operation

START

PREHEATING MODE

N

OPEN LOADDETECTION:STOP
LOW SIDE MOSON
AND HIGH SIDEMOS OFF

F>F

MIN

Y

DECREASE
FREQUENCY

Y

Y

SHIGH2

PRE

PH

INCREASE
FREQUENCY

N

N

Y

V

S>VSLOW1

NO OSCILLATION
LOW SIDE MOS ON
HIGH SIDE MOS OFF

V

S>VSHIGH1

STARTOSCILLATION
F=F

MAX

T=T

0

N

V

>V

S

Y

T=T0+T

N

NY

VRS>V

STOP OSCILLATION
LOW SIDE MOS ON
HIGH SIDE MOS OFF

BURNING MODE

VS>V

N

IGNITION MODE

DECREASE
FREQUENCY

FEED FORWARDMODE
ACTIVATED

N

S>VSHIGH2

V

Y

VRS<VCMTH

N

Y

F>FFEEDFORWARD

SHIGH2

Y

T>T0+T

PRE+TIGN

Y

N

VRS<V

NY

F>F

MIN

Y

Y

N

CMTH

INCREASE
FREQUENCY

10/15

V

S>VSHIGH1

Y

RESTARTWITH
F=F

MAX

FREQUENCYSHIFTS IN T=T
TOWARDSBURNINGSTATECONDITION
(F=MAX{F

MAX,FFEEDFORWARD,FCAPACITIVEMODE

N

IGN

N

DECREASE
FREQUENCY

F>F

Y

MIN

INCREASE
FREQUENCY

})

L6567

Figure 5. Working frequency vs I

@R

160.00

150.00

140.00

130.00

120.00

110.00

100.00

90.00

80.00

70.00

frequen cy [kH z]

60.00

50.00

40.00

30.00

20.00

10.00

0.00

0.20 0.40 0.60 0.80 1.00 1.20

Figure 6. Frequency vs CF@R

160.00

150.00

140.00

130.00

120.00

110.00

100.00

90.00

80.0 0

70.00

frequency[kHz]

60.00

50.00

40.0 0

30.00

20.00

10.00

0.00

60.00 100.00 140.00 180.00 220.0040.00 80.00 120.00 160.00 200.00 240.00

Figure 7. TDTvs R

2.40

= 30Kohm

REF

Rref=30Kohm

Irhv [m A]

Cf [pF]

@CF= 100pF

REF

Tdt [calculated data]

REF

RHV

=30Kohm

Rref=30Kohm

Cf=47pF

Cf=56pF

Cf=68pF

Cf=82pF

Cf=100 pF

Cf=120pF

Cf=150pF

Cf=180pF

Cf=220pF

I=1mA

I=0 .75 mA )

I=0.5mA

Figure 8. Frequency vs I

120.00

100.00

80.00

Rref=20K

frequency [kHz]

Rref=22K

Rref= 24K

60.00

Rref=27K

Rref=30K

Rref= 33K
Rref=36K

40.00

Rref=39K,43K, 47K,51K

0.20 0.40 0.60 0.80 1.00 1.20

Figure 9. Frequency vs I

100.0 0

80.00

Rref=20K

Rref=22K

60.00

Rref=24K

frequency [kHz]

Rref=27K

Rref=30K
Rref=33K

40.00

Rref=36K

Rref=39K,43K

20.00

0.20 0.40 0.60 0.80 1.00 1.20

Irhv [mA]

Figure 10. Frequency vs I

80.0 0

@CF= 82pF

RHV

Irhv [m A ]

@CF=100pF

RHV

@CF=120pF

RHV

Tdt[measureddata]

2.00

1.60

Tdt [us]

1.20

0.80

20.00 30.00 40.00 50.00 6 0.00

Rref[Kohm]

60.0 0

Rref=20K

Rref=22K

Rref=24K

frequency [kHz]

40.0 0

Rref=27K

Rref=30K
Rref=33K

Rref=36K
Rref=39K

Rref=43K, 4 7K, 51K

20.0 0

0.20 0.40 0. 60 0.80 1. 00 1.20

Irhv [mA]

11/15

L6567

Figure 11. Frequency vs I

80.00

60.00

Rref=20K

40.00

frequency [kHz]

Figure 12. F

Rref=22K
Rref=24K

Rref= 27K
Rref= 30K

Rref= 33K

Rref=36K
Rref= 39K

20.00

Rref=43 K, 47K , 51 K

0.20 0.40 0.60 0.80 1.00 1.20

: measurementsand calculations

MIN

100.00

80.00

Irhv [m A ]

@CF= 150pF

RHV

measuraments

Fmin=1/(8*Cf*Rref)

Figure 13. F

Freq . fe ed forwa rd [H z]

120000.00

110000.00

100000.00

90000.00

80000.00

70000.00

60000.00

50000.00

40000.00

30000.00

20000.00

10000.00

calculations(1/121)*Irhv/Cf

0.00

0.40 0.60 0.80 1.00 1.20

FEED FORWARD

calculations

meas u rements

Irhv [mA]

: measurements and

Cf=8 2pF

Cf=1 00p F

Cf=120pF

Cf=1 50p F

60.00

Fmin [KHz]

40.00

20.00

0.00

20.00 30.00 40.00 50.00

Rref[Kohm]

Cf=82pF

Cf=100pF

Cf=120pF

Cf=150pF

12/15

L6567

DIM.

MIN. TYP. MAX. MIN. TYP. MAX.

a1 0.51 0.020

B 1.39 1.65 0.055 0.065

b 0.5 0.020

b1 0.25 0.010

D 20 0.787

E 8.5 0.335

e 2.54 0.100

e3 15.24 0.600

F 7.1 0.280

I 5.1 0.201

L 3.3 0.130

Z 1.27 2.54 0.050 0.100

mm inch

OUTLINE AND

MECHANICAL DATA

DIP14

13/15

L6567

DIM.

MIN.. TYP. MAX.. MIN.. TYP.. MAX..

A 1.75 0.069
a1 0.1 0.25 0.004 0.009
a2 1.6 0.063

b 0.35 0.46 0.014 0.018
b1 0.19 0.25 0.007 0.010

C 0.5 0.020

c1 45° (typ.)

D (1) 8.55 8.75 0.336 0.344

E 5.8 6.2 0.228 0.244

e 1.27 0.050
e3 7.62 0.300

F (1) 3.8 4 0.150 0.157

G 4.6 5.3 0.181 0.209

L 0.4 1.27 0.016 0.050

M 0.68 0.027

S8°

(1) D and F do not include mold flashor protrusions. Mold flash or

potrusions shall not exceed0.15mm (.006inch).

mm inch

(ma x.)

OUTLINE AND

MECHANICAL DATA

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