L6598 High voltage resonant controller Features ■ High voltage rail up to 600 V ■ dV/dt immunity ±50 V/ns in full temperature range ■ Driver current capability: 250 mA source 450 mA sink ■ Switching times 80/40 ns rise/fall with 1 nF load ■ CMOS shutdown input ■ Undervoltage lock-out ■ Soft-start frequency shifting timing ■ Sense op amp for closed loop control or protection features ■ High accuracy current controlled oscillator ■ Integrated bootstrap diode ■ Clamping on Vs ■ SO16, DIP16 packages Figure 1. 3/. $)0 Description The device is manufactured with the BCD OFF LINE technology, able to ensure voltage ratings up to 600 V, making it perfectly suited for AC/DC Adapters and wherever a resonant topology can be beneficial. The device is intended to drive two power MOSFET, in the classical half bridge topology. A dedicated timing section allows the designer to set soft start time, soft start and minimum frequency. An error amplifier, together with the two enable inputs, are made available. In addition, the integrated bootstrap diode and the zener clamping on low voltage supply, reduces to a minimum the external parts needed in the applications. Block diagram 63 /0/54 /0). /0). /0!-0 (6 "//4342!0 $2)6%2 56 $%4%#4)/. (6' $2)6%2 6"//4 (6' /54 )FMIN 62%& $%!$ 4)-% $2)6).' ,/')# ,%6%, 3()&4%2 ,6'$2)6%2 2FMIN )FSTART 62%& #/.42/, ,/')# ,6' '.$ 6THE 2FSTART ,/!$ 6S #"//4 %. 6THE %. )SS #F 6#/ #SS !-V October 2009 Doc ID 6554 Rev 7 1/24 www.st.com 24 Contents L6598 Contents 1 Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3 Pin connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 4 Timing diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 5 Block diagram description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 5.1 High/low side driving section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 5.2 Timing and oscillator section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 5.3 Bootstrap section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 5.4 Op amp section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 5.5 Comparators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 6 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 7 Ordering codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 8 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 2/24 Doc ID 6554 Rev 7 L6598 1 Maximum ratings Maximum ratings Table 1. Absolute maximum ratings Symbol Parameter Value Unit 25 mA 14.6 V -1 to VBOOT -18 V -1 to VBOOT V Supply current at Vcl (1) IS VLVG Low side output VOUT High side reference VHVG High side output VBOOT Floating supply voltage 618 V VBOOT pin slew rate (repetitive) ±50 V/ns OUT pin slew rate (repetitive) ±50 V/ns dVBOOT/dt dVOUT/dt Vir Forced input voltage (pins Rfmin, Rfstart) -0.3 to 5 V Vic Forced input voltage (pins Css, Cf) -0.3 to 5 V VEN1, VEN2 Enable input voltage -0.3 to 5 V IEN1, IEN2 Enable input current ±3 mA -0.3 to 5 V Vopc Sense op amp common mode range Vopd Sense op amp differential mode range -5 to 5 V Vopo Sense op amp output voltage (forced) 4.6 V Tstg Storage temperature -40 to +150 °C Tj Junction temperature -40 to +150 °C Tamb Ambient temperature -40 to +125 °C 1. The device is provided of an internal clamping zener between GND and the Vs pin, It must not be supplied by a low impedance voltage source. Note: ESD immunity for pins 14, 15 and 16 is guaranteed up to 900 (human body model). Table 2. Thermal data Symbol RthJA Table 3. Parameter Thermal resistance junction to ambient DIP16 Unit 120 80 °C/W Recommended operating conditions Symbol Parameter Supply voltage VS Vout SO16N Value Unit 10 to Vcl V (1) High side reference -1 to Vboot-Vcl V (1) Floating supply rail 500 V Maximum switching frequency 400 kHz Vboot fmax 1. If the condition Vboot - Vout < 18 is guaranteed, Vout can range from -3 to 580 V. Doc ID 6554 Rev 7 3/24 Electrical characteristics 2 L6598 Electrical characteristics VS = 12 V; VBOOT - VOUT = 12 V; TA = 25 °C Table 4. Symbol Electrical characteristics Pin Parameter Test condition Min. Typ. Max. Unit Supply voltage Vsuvp VS turn on threshold 10 10.7 11.4 V Vsuvn VS turn off threshold 7.3 8 8.7 V Vsuvh Supply voltage under voltage hysteresis 2.7 V 12 Vcl Supply voltage clamping 14.6 Isu Start up current VS < Vsuvn Iq Quiescent current, fout = 60 kHz, no load VS > Vsuvp 15.6 2 16.6 V 250 µA 3 mA High voltage section Ibootleak 16 BOOT pin leakage current VBOOT = 580 V 5 µA Ioutleak 14 OUT pin leakage current VOUT = 562 V 5 µA RDSon 16 Bootstrap driver on resistance 300 Ω 100 150 High/low side drivers High side driver source current VHVG-VOUT = 0 170 250 mA Ihvgsi High side driver sink current VHVG-VBOOT = 0 300 450 mA Ilvgso Low side driver source current VLVG-GND = 0 170 250 mA Low side driver sink current VLVG -VS = 0 300 450 mA Ihvgso 15 11 Ilvgsi trise Low/high side output rise 15,11 time tfall Cload = 1nF 80 120 ns Cload = 1nF 40 80 ns 48 50 52 % Oscillator DC fmin fstart 4/24 Output duty cycle 14 Minimum output oscillation frequency Cf = 470pF; Rfmin = 50kΩ 58.2 60 61.8 kHz Soft start output oscillation frequency Cf = 470pF; Rfmin = 50kΩ; Rfstart = 47kΩ 114 120 126 kHz Doc ID 6554 Rev 7 L6598 Electrical characteristics Table 4. Electrical characteristics (continued) Symbol Pin Vref 2, 4 td IVref Parameter Test condition Min. Typ. Max. Unit Voltage to current converters threshold 1.9 2 2.1 V 14 Dead time between low and high side conduction 0.2 0.27 0.35 µs 2, 4 Reference current 120 μA Timing section kss 1 Soft start timing constant Css = 330nF 0.115 0.15 0.185 s/µF 0.1 µA Sense op amp lIB Input bias current 6, 7 Vio Input offset voltage -10 10 mV Rout Output resistance 200 300 ? Iout- 5 Iout+ Vic 6,7 GBW Gdc Source output current Vout = 4.5V 1 mA Sink output current Vout = 0.2V 1 mA Op amp input common mode range -0.2 Sense op amp gain band width product (1) 0.5 1 MHz DC open loop gain 60 80 dB 3 V Comparators Vthe1 8 Enabling comparator threshold 0.56 0.6 0.64 V Vthe2 9 Enabling comparator threshold 1.05 1.2 1.35 V tpulse 8,9 Minimum pulse length 200 ns 1. Guaranteed by design Doc ID 6554 Rev 7 5/24 Pin connections 3 L6598 Pin connections Figure 2. Pin connections #SS 6"//4 2FSTART (6' #F /54 2FMIN .# /0/54 63 /0). ,6' /0). '.$ %. %. !-V Table 5. 6/24 Pin description Pin n° Name Function 1 CSS Soft start timing capacitor 2 Rfstart Soft start frequency setting - low impedance voltage source -see also Cf 3 Cf 4 Rfmin Minimum oscillation frequency setting - low impedance voltage source - see also Cf 5 OPout Sense op amp output - low impedance 6 OPon- Sense op amp inverting input -high impedance 7 OPon+ Sense op amp non inverting input - high impedance 8 EN1 Half bridge latched enable 9 EN2 Half bridge unlatched enable 10 GND Ground 11 LVG Low side driver output 12 Vs 13 N.C. Not connected 14 OUT High side driver reference 15 HVG High side driver output 16 Vboot Bootstrapped supply voltage Oscillator frequency setting - see also Rfmin, Rfstart Supply voltage with internal zener clamp Doc ID 6554 Rev 7 L6598 4 Timing diagram Timing diagram Figure 3. EN2 timing diagrams 96 I287 IVWDUW IPLQ (1 9&VV 766 766 !-V Figure 4. EN1 timing diagrams +9* /9* (1 (1 !-V Doc ID 6554 Rev 7 7/24 Timing diagram Figure 5. L6598 Oscillator/output timing diagram &I +9* /9* !-V 8/24 Doc ID 6554 Rev 7 L6598 Block diagram description 5 Block diagram description 5.1 High/low side driving section An high and low side driving section provide the proper driving to the external power MOS or IGBT. An high sink/source driving current (450/250 mA typ) ensure fast switching times also when size for power MOS are used. The internal logic ensures a minimum dead time to avoid cross-conduction of the power devices. 5.2 Timing and oscillator section The device is provided of a soft start function. It consists in a period of time, TSS, in which the switching frequency shifts from fstart to fmin. This feature is explained in the following description (ref. fig.7 and fig.8). Figure 6. Soft start and frequency shifting block ,VV ,IVWDUW ,IPLQ JP ,RVF 26& &VV !-V During the soft start time the current ISS charges the capacitor CSS, generating a voltage ramp which is delivered to a transconductance amplifier, as shown in fig. 7. Thus this voltage signal is converted in a growing current which is subtracted to Ifstart. Therefore the current which drives the oscillator to set the frequency during the soft start is equal to: Equation 1 g m I ss⎞ I osc = I fmin + ( I fstart – g m V Css ( t ) ) = I fmin + ⎛⎝ I fstart – ------------C ss ⎠ Equation 2 where V REF V REF I fmin = --------------, I fstart = ---------------- ,V REF = 2V R fmin R fstart Doc ID 6554 Rev 7 9/24 Block diagram description L6598 At the start-up (t = 0) the oscillator frequency is set by: Equation 3 1 - + --------------1 -⎞ I OSC ( 0 ) = I fmin + I fstart = V REF ⎛⎝ ------------R fmin R fstart⎠ At the end of soft start (t = TSS) the second term of eq.1 decreases to zero and the switching frequency is set only by Imin (i.e. Rfmin): Equation 4 V REF I OSC ( T SS ) = I fmin = ------------R fmin Since the second term of eq.1 is equal to zero, we have: Equation 5 g m I ss C ss I fstart I fstart – -------------- T SS = 0 → T SS = ----------------------C ss g m I ss Note that there is not a fixed threshold of the voltage across CSS in which the soft start finishes (i.e. the end of the frequency shifting), and TSS depends on CSS, Ifstart, gm, and ISS (eq. 5). Making TSS independent of Ifstart, the ISS current has been designed to be a fraction of Ifstart, so: Equation 6 I fstart C ss I fstart C ss I SS = -------------- → T SS = -------------------------- → T SS = ----------- → T SS – k SS C SS K g m I fstart K gm K In this way the soft start time depends only on the capacitor CSS. The typical value of the kSS constant (Soft start timing constant) is 0.15 s/μF. The current Iosc is fed to the oscillator as shown in fig. 7. It is twice mirrored (x4 and x8) generating the triangular wave on the oscillator capacitor Cf. Referring to the internal structure of the oscillator (fig.7), a good relationship to compute an approximate value of the oscillator frequency in normal operation is: Equation 7 1.41 f min = ------------------R fmin C f 10/24 Doc ID 6554 Rev 7 L6598 Block diagram description The degree of approximation depends on the frequency value, but it remains very good in the range from 30 kHz to 100 kHz (figg.9-13) Figure 7. Oscillator block ,RVF 9WK ; 6 &I 5 9WK ; !-V Doc ID 6554 Rev 7 11/24 Block diagram description Figure 8. Typ. fmin vs. Rfmin @ Cf = 470 pF Figure 10. Typ. (fstart-fmin) vs. Rfstar @ Cf = 470 pF 12/24 L6598 Figure 9. Typ. (fstart-fmin) vs. Rfstar @ Cf = 470 pF Figure 11. fmin @ different Rf vs Cf Doc ID 6554 Rev 7 L6598 Block diagram description Figure 12. Typ. (fstart-fmin) vs. Rfstar @ Cf = 470 pF 5.3 Bootstrap section The supply of the high voltage section is obtained by means of a bootstrap circuitry. This solution normally requires an high voltage fast recovery diode for charging the bootstrap capacitor (fig. 14a). In the device a patented integrated structure, replaces this external diode. It is released by means of a high voltage DMOS, driven synchronously with the low side driver (LVG), with in series a diode, as shown in fig. 14b. Figure 13. Bootstrap driver To drive the synchronized DMOS it is necessary a voltage higher than the supply voltage Vs. This voltage is obtained by means of an internal charge pump (fig. 14b). The diode connected in series to the DMOS has been added to avoid undesirable turn on of it. The introduction of the diode prevents any current can flow from the Vboot pin to the VS one in case that the supply is quickly turned off when the internal capacitor of the pump is not fully discharged. Doc ID 6554 Rev 7 13/24 Block diagram description L6598 The bootstrap driver introduces a voltage drop during the recharging of the capacitor Cboot (i.e. when the low side driver is on), which increases with the frequency and with the size of the external power MOS. It is the sum of the drop across the RDSON and of the diode threshold voltage. At low frequency this drop is very small and can be neglected. Anyway increasing the frequency it must be taken in to account. In fact the drop, reducing the amplitude of the driving signal, can significantly increase the RDSON of the external power MOS (and so the dissipation). To be considered that in resonant power supplies the current which flows in the power MOS decreases increasing the switching frequency and generally the increases of RDSON is not a problem because power dissipation is negligible. The following equation is useful to compute the drop on the bootstrap driver: Equation 8 Qg V drop = I ch arg e R dson + V diode → V drop = ------------------- R dson + V diode T ch arg e where Qg is the gate charge of the external power MOS, Rdson is the on resistance of the bootstrap DMOS, and Tcharge is the time in which the bootstrap driver remains on (about the semi-period of the switching frequency minus the dead time). The typical resistance value of the bootstrap DMOS is 150 Ω. For example using a power MOS with a total gate charge of 30 nC the drop on the bootstrap driver is about 3 V, at a switching frequency of 200 kHz. In fact: Equation 9 30nC V drop = ------------------ 150Ω + 0.6V ∼ 2.6V 2.23μs To summaries, if a significant drop on the bootstrap driver (at high switching frequency when large power MOS are used) represents a problem, an external diode can be used, avoiding the drop on the RDSON of the DMOS. 5.4 Op amp section The integrated op amp is designed to offer low output impedance, wide band, high input impedance and wide common mode range. It can be readily used to implement protection features or a closed loop control. For this purpose the op amp output can be properly connected to Rfmin pin to adjust the oscillation frequency. 14/24 Doc ID 6554 Rev 7 L6598 5.5 Block diagram description Comparators Two CMOS comparators are available to perform protection schemes. Short pulses (≥ 200 ns) on comparators input are recognized. The EN1 input (active high), has a threshold of 0.6 V (typical value) forces the device in a latched shut down state (e.g. LVG low, HVG low, oscillator stopped), as in the under voltage conditions. Normal operating conditions are resumed after a power-off power-on sequence. The EN2 input (active high), with a threshold of 1.2 V (typical value) restarts a Soft Start sequence (see timing diagrams). In addition the EN2 comparator, when activated, removes a latched shutdown caused by EN1. Figure 14. Switching time waveform definitions Figure 15. Dead time and duty cycle waveform definition Doc ID 6554 Rev 7 15/24 Block diagram description L6598 Figure 16. Typ. fmin vs. temperature Figure 17. Start-up current vs temperature Figure 18. Typ. fstart vs. temperature Figure 19. Quiescent current vs temperature 16/24 Doc ID 6554 Rev 7 L6598 Block diagram description Figure 20. Vs thresholds and clamp vs temp. Figure 21. HVG source and sink current vs. temperature Figure 22. LVG source and sink current vs. temperature Figure 23. Soft-start timing constant vs. temperature Doc ID 6554 Rev 7 17/24 Block diagram description L6598 Figure 24. Wide range AC/DC adapter application 18/24 Doc ID 6554 Rev 7 L6598 6 Package mechanical data Package mechanical data In order to meet environmental requirements, ST offers these devices in different grades of ECOPACK® packages, depending on their level of environmental compliance. ECOPACK® specifications, grade definitions and product status are available at: www.st.com. ECOPACK is an ST trademark. Doc ID 6554 Rev 7 19/24 Package mechanical data L6598 Plastic DIP-16 (0.25) MECHANICAL DATA mm. inch DIM. MIN. a1 0.51 B 0.77 TYP MAX. MIN. TYP. MAX. 0.020 1.65 0.030 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 17.78 0.700 F 7.1 0.280 I 5.1 0.201 L Z 3.3 0.130 1.27 0.050 P001C 20/24 Doc ID 6554 Rev 7 L6598 Package mechanical data SO-16 MECHANICAL DATA DIM. mm. MIN. TYP A a1 inch MAX. MIN. TYP. 1.75 0.1 0.068 0.25 a2 0.004 0.010 1.64 0.063 b 0.35 0.46 0.013 b1 0.19 0.25 0.007 C MAX. 0.5 0.018 0.010 0.019 c1 45° (typ.) D 9.8 10 0.385 0.393 E 5.8 6.2 0.228 0.244 e 1.27 e3 8.89 0.050 0.350 F 3.8 4.0 0.149 0.157 G 4.6 5.3 0.181 0.208 L 0.5 1.27 0.019 M 0.62 S 0.050 0.024 8° (max.) 0016020D Doc ID 6554 Rev 7 21/24 Ordering codes 7 L6598 Ordering codes Table 6. Ordering information Order codes Package Packing L6598 DIP16 Tube L6598D Tube SO16N L6598D016TR 22/24 Tape and reel Doc ID 6554 Rev 7 L6598 8 Revision history Revision history Table 7. Document revision history Date Revision Changes 21-Jun-2004 5 Changed the impagination following the new release of “corporate technical pubblication design guide”. Done a few of corrections in the text. 09-Sep-2004 6 Added ordering number fot the tape and reel version, updated Table 4 on page 4 02-Oct-2009 7 Updated Table 4 on page 4 Doc ID 6554 Rev 7 23/24 L6598 Please Read Carefully: Information in this document is provided solely in connection with ST products. STMicroelectronics NV and its subsidiaries (“ST”) reserve the right to make changes, corrections, modifications or improvements, to this document, and the products and services described herein at any time, without notice. All ST products are sold pursuant to ST’s terms and conditions of sale. Purchasers are solely responsible for the choice, selection and use of the ST products and services described herein, and ST assumes no liability whatsoever relating to the choice, selection or use of the ST products and services described herein. No license, express or implied, by estoppel or otherwise, to any intellectual property rights is granted under this document. If any part of this document refers to any third party products or services it shall not be deemed a license grant by ST for the use of such third party products or services, or any intellectual property contained therein or considered as a warranty covering the use in any manner whatsoever of such third party products or services or any intellectual property contained therein. UNLESS OTHERWISE SET FORTH IN ST’S TERMS AND CONDITIONS OF SALE ST DISCLAIMS ANY EXPRESS OR IMPLIED WARRANTY WITH RESPECT TO THE USE AND/OR SALE OF ST PRODUCTS INCLUDING WITHOUT LIMITATION IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE (AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION), OR INFRINGEMENT OF ANY PATENT, COPYRIGHT OR OTHER INTELLECTUAL PROPERTY RIGHT. UNLESS EXPRESSLY APPROVED IN WRITING BY AN AUTHORIZED ST REPRESENTATIVE, ST PRODUCTS ARE NOT RECOMMENDED, AUTHORIZED OR WARRANTED FOR USE IN MILITARY, AIR CRAFT, SPACE, LIFE SAVING, OR LIFE SUSTAINING APPLICATIONS, NOR IN PRODUCTS OR SYSTEMS WHERE FAILURE OR MALFUNCTION MAY RESULT IN PERSONAL INJURY, DEATH, OR SEVERE PROPERTY OR ENVIRONMENTAL DAMAGE. ST PRODUCTS WHICH ARE NOT SPECIFIED AS "AUTOMOTIVE GRADE" MAY ONLY BE USED IN AUTOMOTIVE APPLICATIONS AT USER’S OWN RISK. Resale of ST products with provisions different from the statements and/or technical features set forth in this document shall immediately void any warranty granted by ST for the ST product or service described herein and shall not create or extend in any manner whatsoever, any liability of ST. ST and the ST logo are trademarks or registered trademarks of ST in various countries. Information in this document supersedes and replaces all information previously supplied. The ST logo is a registered trademark of STMicroelectronics. All other names are the property of their respective owners. © 2009 STMicroelectronics - All rights reserved STMicroelectronics group of companies Australia - Belgium - Brazil - Canada - China - Czech Republic - Finland - France - Germany - Hong Kong - India - Israel - Italy - Japan Malaysia - Malta - Morocco - Philippines - Singapore - Spain - Sweden - Switzerland - United Kingdom - United States of America www.st.com 24/24 Doc ID 6554 Rev 7