L6567 STMICROELECTRONICS | Alldatasheet
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This is preliminary information on a new product now in development. Details are subject to change without notice. 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 a monolithic high voltage integrated cir- cuit designed to drive CFL and small TL lamps with a minimum part count. It provides all the necessary functions for proper pre- heat, ignition and steady state operation of the lamp: ♦ variable frequency oscillator; ♦ settable preheating and ignition time; ♦ capacitive mode protection; ♦ lamp power independent from mains voltage variation. Besides the control functions, the IC provides the lev- el shift and drive function for two external power MOS FETs in a half-bridge topology. SO14 DIP14 ORDERING NUMBERS: L6567D L6567 HIGH VOLTAGE DRIVER FOR CFL BLOCK DIAGRAM L FEED FORWARD VCO + FREQ. SHIFTING VOLTAGE REFERENCE BIAS CURRENT GENERATOR C S Cf Ci CI CF VS to comp. PREHEATING TIMING LOGIC RHV Rhv Vhv Cp/Cav C CP LEVEL SHIFTING HIGH SIDE DRIVER VS Cboot FS LOW SIDE DRIVER Vhv Chv Chv MAINST2 Rshunt PGND R S RREFRef D96IN441B Lamp CL SGND MULTIPOWER BCD TECHNOLOGY
PIN CONNECTION (Top view) N ° Pin Description 1F S Floating Supply of high side driver
2 G1 Gate of high side switch
3 S1 Source of high side switch
4 NC High Voltage Spacer. (Should be not connected) 5V S Supply Voltage for GND level control and drive
6 G2 Gate of low side switch
7 PGND Power Ground
8 CP First timing (TPRE TIGN), then averaging the ripple in the representation of the HVB (derived
through RHV). S R SHUNT : current monitoring input
10 R REF Reference resistor for current setting
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
N.C. VS PGND CP RREF RS SGND CF RHV CI1 D96IN440
NOTES: (1) Do not exceed package thermal dissipation limits (2) For VS≤ VS high 1 (3) For VS > VS high 1 (4) Internally Limited Note: ESD immunity for pins 1, 2 and 3 is guaranteed up to 900 V (Human Body Model) Symbol Parameter Value Unit VS Low Voltage Supply 18 (1) V VRHV Mains Voltage Sensing VS +2VBE (2) VCP Preheat/Averaging 5 V VCF Oscillator Capacitor Voltage 5 V VCI Frequency Shift Capacitor Voltage 5 V VRREF Reference Resistor Voltage 5 V VRS Current Sense Input Voltage -5 to 5 V transient 50ns -15 V VG2 Low Side Switch Gate Output 18 V V S1 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 be to VS V VFS Floating Supply Voltage: normal operation 391 V 0.5sec mains transient 568 V VFS/S1 Floating Supply vs S1 Voltage 18 V ΔVFS /ΔT VFS Slew Rate (Repetitive) -4 to 4 V/ns ΔV S1/ΔT VS1 Slew Rate (Repetitive) -4 to 4 V/ns IRHV Current Into RHV 3 (3) mA IVs Clamped Current into VS 200 (4) mA Tstg Storage Temperature -40 to 150 °C Tj Junction Temperature -40 to 150 °C
(VS =1 2 V ;RREF =3 0 KΩ ;C F = 100pF; Tj=2 5°C; unless otherwise specified.) Symbol Parameter Test Condition Min. Typ. Max. Unit VS - SUPPLY VOLTAGE SECTION VS high 1 VS Turn On Threshold 10.7 11.7 12.7 V VS high2 VS Clamping Voltage VS = 20mA 12 13 14 V V S low 2 VS Turn Off Threshold 9 10 11 V VS HYST Supply Voltage Hysteresis 1.5 1.65 1.8 V V S low 1 VS Voltage to Guarantee VG1 =”0”and VG2 =” 1 16 V ISSP VS Supply Current at Start Up VS = 10.6V Before turn on 50 250 mA ISOP VS Supply Operative Current VS = VShigh 1 1.2 mA OSCILLATOR SECTION fosc min Minimum Oscillator frequency IRHV = 0mA; CI = 5V 41.7 43 44.29 kHz fosc 600m Feed Forward Frequency I RHV = 600mA 47.88 50.4 52.92 kHz fosc 1mA Feed Forward Frequency I RHV = 1mA 79.8 84 88.2 kHz fosc max Maximum Oscillator Frequency CI = 0V 96.75 107.5 118.25 KHz ΔICF /ΔVCI Oscillator Transconductance 9 17.5 µA/V PREHEAT/IGNITION SECTION 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 Preheat 106 118 130 mA ICII charge CI Charging Current During Ignition 1 1.2 1.4 mA ICI disch CI Discharge Current -52 -47 -42 mA VTH CI CI Low Voltage Threshold 10 100 mV RS - THRESHOLD SECTION VCMTH Capacitive Mode Voltage Threshold 02 0 4 0 m V VPH Preheat Voltage Threshold -0.64 -0.6 -0.56 V G1 - G2 DELAY TIMES SECTION G1 DON On Delay of G1 Output 1.05 1.4 1.75 µs
(*) Before starting the first commutation; when switching 6V is guaranteed. 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 is achieved, 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 to turn on the upper and lower MOS transistors 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 the current to determine if the circuit is operating in capacitive mode. If capacitive switching is 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 RHV pin (pin 13) from the rectified mains. The current charges the CS capacitor connected to the VS pin (pin 5). When the VS voltage reaches the threshold VSL O W 1(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 VS HIGH1 threshold is reached the oscillator starts, and the RHV pin does not provide anymore the supply current for the IC (see fig.1). G2 DON On Delay of G2 Output 1.05 1.4 1.75 µs Ratio between Delay Time + Conduction Time of G1 and G2 IRHV = 1mA; Cl = 5V Cl = 0V 0.87 0.77 1.15 1.30 LOW SIDE DRIVER SECTION Ron G2 so G2 Source Output Resistance V S = 12V, V = 3V 80 190 Ω Ron G2 si G2 Sink Output Resistance V S = 12V, V = 3V 65 125 Ω Ron G1 so G1 Source Output Resistance V S = 10V, V = 3V 80 190 Ω Ron G1 si G1 Sink Output Resistance V S = 10V, V = 3V 65 125 Ω HIGH SIDE DRIVER SECTION IFSLK Leakage Current of FS PIN to GND VFS = 568V; G1 = L VFS = 568V; G1 = H µA µA IS1 LK Leakage Current of S1 PIN to GND VS1 = 568V; G1 = L VS1 = 568V; G1 = H µA µA BOOTSTRAP SECTION Boot Th BOOTSTRAP Threshold V S = 10.6V before turn on 5 (*) V AVERAGE RESISTOR R AVERAGE Average Resistor 27 38.5 50 k Ω Symbol Parameter Test Condition Min. Typ. Max. Unit G1 DON G1 ON+ ELECTRICAL CHARACTERISTCS (Continued)
Figure 1. Start up The IC oscillating frequency is between FMIN and FMAX = 2.5 · FMIN in all conditions. old is reached, the frequency is held constant for the programmed preheating time TPRE . current that depends on RREF , and these 16 cycles determine the TPRE . The circuit is held in the preheating mode when pin 8 (CP) is grounded. the low side MOS transistor gate on and the high side gate off. This condition is kept until VS undershoots VSL O W 1.
Capacitive mode protection During ignition and steady state the operating frequency is higher than the resonance frequency of the load (L,CL,RLAMP and RFILAMENT), so the transistors are turned on during the conduction time of the body diode in order to maintain Zero Voltage Switching. If the operating frequency undershoots the resonance frequency ZVS doesn’t occur and causes hard switching of the MOS transistors. The L6567 detects this situation by measuring VRS when the low sideMOS FET is turned on. At pin 9 there is an internal comparator with threshold VCM TH (typ~20mV): if VRS <V CM TH capacitive mode is assumed and the frequency is increased as long as this situation is present. The shift is determined by CI. Steady state frequency At any time during steady state the frequency is determined by the maximum on the following three frequencies: fSTEADY STATE =M A X{ FMIN,fFEED FORWARD ,fCAPACITIVE MODE PROTECTION }. IC supply At start up the IC is supplied with a current that flows through RHV and an internal diode to the VS pin which- charges the external capacitor CS. In steady state condition RHV is used as a mains voltage sensor, so it doesn’t provide anymore the supply current. The easiest way to charge the CS capacitor (and to supply the IC) is to use a charge pump from the middle point of the half bridge. To guarantee a minimum gate power MOS drive, the IC stops oscillating when VS is lower than VSH I G H 2. It will restart once the VS will become higher than VSH I G H 1. A minimum voltage hysteresis is guaranteed. The IC re- starts operating at f = FMAX ,then the frequency shifts towards FMIN. The timing of this frequency shifting is TIGN (that is: CP capacitor is charged and discharged 15 times).Now the oscillator frequency is controlled as in stan- dard burning condition (feed forward and capacitive mode control). Excess charge on CS is drained by an inter- nal clamp that turns on at voltage VSC L . Ground pins 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,C I,R REF and CF. Relationship between external components and sistem working condition L6567 is designed to drive CFL and TL lamps with a minimum part count topology. This feature implies that each external component is related to one or more circuit operating state. This table is a short summary of these relationships: F MIN ---> RREF &C F FFEED FORWARD ---> CF &IRHV TPRE &T IGN ---> CP &R REF FPRE ---> RSHUNT ,L ,CL, LAMP TDT ---> RREF df/dt ---> CI Some useful formulas can well approximate the values: If IRHV is greater than: , the feed forward frequency is settled and the frequency value is fitted by the following expression: FMIN IRHV R REF FFEEDFORWARD IRHV
Other easy formulas fit rather well: TDT ≅ 46.75 · 10^-12·RREF TPRE ≅ 224 · CP ·R REF As far as df/dt is concerned, there are no easy formulas that fit the relation between CF,RF, and CI.CIis charged and discharged by three different currents that are derived from different mirroring ratios by the current flowing on RREF . The voltage variations on CI are proportional to the current that charges CF, that is to say they are proportional to df/dt. The values obtained in the testing conditions (CI= 100nF) are: during preheating and working conditions 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 HV has to be chosen looking at startup current needs and dissipation problems. Then the feed forward frequency range has to be determined, and so CF is set. Given a certain CF,R REF is set in order to fix FMIN. Now CP can be chosed to set the desired TPRE and TIGN. The other external parameters (RSHUNT and CI) can be chosen at the end because they are just related to a single circuit parameters.
Figure 4. IC Operation
DIM. mm inch 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 OUTLINE AND MECHANICAL DATA
DIM. mm inch 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 flash or protrusion s. Mold flash or potrusio ns shall not exceed 0.15mm (.006inch). OUTLINE AND MECHANICAL DATA (max.)
Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics products are not authorized for use as critical components in life support devices or systems without express written approval of STMicroelectronics. The ST logo is a registered trademark of STMicroelectronics 1999 STMicroelectronics - All Rights Reserved STMicroelectronics GROUP OF COMPANIES Australia - Brazil - China - Finland - France - Germany - Hong Kong - India - Italy - Japan - Malaysia - Malta - Morocco - Singapore - Spain - Sweden - Switzerland - United Kingdom - U.S.A. http://www.st.com L6567