HVLED815PF Offline LED driver with primary-sensing and high power factor up to 15 W Datasheet − production data Features ■ High power factor capability (> 0.9) ■ 800 V, avalanche rugged internal 6 Ω Power MOSFET ■ Internal high-voltage startup ■ Primary sensing regulation (PSR) ■ +/- 5% accuracy on constant LED output current ■ Quasi-resonant (QR) operation ■ Optocoupler not needed ■ Open or short LED string management ■ Automatic self supply SO16N Table 1.
Contents HVLED815PF Contents 1 2 3 4 Principle application circuit and block diagram . . . . . . . . . . . . . . . . . . . 4 1.1 Principle application circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.2 Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Pin description and connection diagrams . . . . . . . . . . . . . . . . . . . . . . . 7 2.1 Pin description . . . . . . . . . . . . . . . . . . . . . .
HVLED815PF List of figures List of figures Figure 1. Figure 2. Figure 3. Figure 4. Figure 5. Figure 6. Figure 7. Figure 8. Figure 9. Figure 10. Figure 11. Figure 12. Figure 13. Figure 14. Figure 15. Figure 16. Figure 17. Figure 18. Figure 19. Figure 20. Figure 21. Figure 22. Figure 23. Figure 24. Figure 25. Figure 26. Application circuit for high power factor LED driver - single range input. . . . . . . . . . . . . . . . 4 Application circuit for standard LED driver . . . . . . . . . . . . . . . . . . .
Principle application circuit and block diagram 1.1 Principle application circuit Figure 1. Application circuit for high power factor LED driver - single range input Lin 2 1 Lf CON1 9 3 4 8 J1 CON1 R12 C12 C13 Minimum Load 5 6 Cout Bulk Cout SMD J3 CON1 TRANSFORMER Lf Rf CON1 VIN D5 U1 HVLED8xxPF Rsense 1 Rsense RA SOURCE DRAIN R1 (500 - 1.
HVLED815PF Figure 2. Application circuit for standard LED driver 1 1A_DIP 2 1 Lf CON1 8 C16 C27 Minimum Load 5 6 Cf Cout Bulk Cout SMD J6 CON1 TRANSFORMER 4 Lf Rf U2 HVLED8xxPF Rsense 1 Rsense SOURCE DRAIN 2 CS DRAIN VCC 3 C_Vcc (10uF) 4 C_ILED (10uF) 5 Rf b DMG 6 Rf (8.2k-15k) Cf (330nF/680nF) 7 NA 8 Cp (1nF/10nF) VCC DRAIN GND DRAIN 16 S nubber D iode CON1 J5 CON1 R18 C23 Y 1 - SAFETY 15 14 13 ILED DMG COMP N.A.
Block diagram Figure 3. Block diagram + VIN VCC HV start-up & Supply Logic DRAIN LED Vref PROTECTION & FEEDFORWARD LOGIC Doc ID 023409 Rev 4 DEMAG LOGIC RDMG RFB DMG DRIVING LOGIC CONSTANT CURRENT REGULATION Principle application circuit and block diagram 6/36 1.2 3.
HVLED815PF 2 Pin description and connection diagrams Pin description and connection diagrams Figure 4. Pin connection (top view) SOURCE 11 16 16 DRAIN CS 22 15 15 DRAIN VCC 33 14 14 DRAIN GND 44 13 13 DRAIN ILED 55 12 12 N.C. DMG 66 11 11 N.A. COMP 77 10 10 N.A. N.A. 88 9 N.A. AM13210v1 2.1 Pin description Table 2. N. 1 2 Pin description Name Function SOURCE Source connection of the internal power section. CS Current sense input.
Pin description and connection diagrams Table 2. N. Pin description (continued) Name Function VCC Supply voltage of the device. A capacitor, connected between this pin and ground, is initially charged by the internal high-voltage startup generator; when the device is running, the same generator keeps it charged in case the voltage supplied by the auxiliary winding is not sufficient. This feature is disabled in case a protection is tripped. A small bypass capacitor (100 nF typ.
HVLED815PF Pin description and connection diagrams Table 3. Symbol Thermal data (continued) Parameter Max. value Unit 0.
Electrical specifications HVLED815PF 3 Electrical specifications 3.1 Absolute maximum ratings Table 4. Absolute maximum ratings Symbol Pin VDS 1, 13-16 Parameter Drain-to-source (ground) voltage Value Unit -1 to 800 V (1) 1 A 50 mJ ID 1, 13-16 Drain current Eav 1, 13-16 Single pulse avalanche energy (Tj = 25 °C, ID = 0.7 A) VCC 3 Supply voltage (Icc < 25 mA) Self limiting V IDMG 6 Zero current detector current ±2 mA VCS 2 Current sense analog input -0.3 to 3.
HVLED815PF Electrical specifications Table 5. Electrical characteristics(1) (2) (continued) Symbol Parameter Test condition Min. Typ. Max. Unit Supply voltage VCC VCC_ON VCC_OFF VZ Operating range After turn-on Turn-on threshold (4) 11.5 23 12 13 14 V Turn-off threshold (4) 9 10 11 V Internal Zener voltage Icc = 20 mA 23 25 27 V See Figure 7 200 300 µA Supply current ICC_START-UP Startup current Iq Quiescent current See Figure 8 1 1.
Electrical specifications Table 5. HVLED815PF Electrical characteristics(1) (2) (continued) Symbol Parameter Test condition Min. Typ. Max. Unit Source current VDMG = 2.3 V, VCOMP = 1.65 V 70 100 µA Sink current VDMG = 2.7 V, VCOMP = 1.65 V 400 750 µA VCOMPH Upper COMP voltage VDMG = 2.3 V 2.7 V VCOMPL Lower COMP voltage VDMG = 2.7 V 0.
HVLED815PF Figure 6. Electrical specifications COSS output capacitance variation 600 Coss [pF] 500 400 300 200 100 0 0 25 50 75 100 125 150 Vds [ V] AM13212v1 Figure 7. Startup current test circuit Iccstart-up 11.8 V A VDD 2.5V DRAIN + CURRENT CONTROL - DMG ILED COMP GND CS SOURCE AM13213v1 Figure 8. Quiescent current test circuit Iq_meas A 14V VDD 2.5V DMG 33k 3V DRAIN + CURRENT CONTROL ILED COMP 0.8V GND CS SOURCE 10k 0.
Electrical specifications Figure 9. HVLED815PF Operating supply current test circuit Icc A 27k VDD 220k 2.5V DMG 10k DRAIN + CURRENT CONTROL ILED COMP 10k 1.5K 2W 15V GND CS 150V SOURCE 10 2.8V 5.6 -5V 50 kHz AM13215v1 Note: The circuit across the DMG pin is used for switch-on synchronization. Figure 10. Quiescent current during fault test circuit Iq(fault) 14V A VDD 2.
HVLED815PF 4 Device description Device description The HVLED815PF is a high-voltage primary switcher intended for operating directly from the rectified mains with minimum external parts to provide high power factor (> 0.90) and an efficient, compact and cost effective solution for LED driving. It combines a highperformance low-voltage PWM controller chip and an 800 V, avalanche-rugged Power MOSFET, in the same package.
Device description HVLED815PF 1. QR mode at heavy load. Quasi-resonant operation lies in synchronizing MOSFET's turn-on to the transformer's demagnetization by detecting the resulting negative-going edge of the voltage across any winding of the transformer. Then the system works close to the boundary between discontinuous (DCM) and continuous conduction (CCM) of the transformer.
HVLED815PF 4.3 Device description High voltage startup generator Figure 12 shows the internal schematic of the high-voltage start-up generator (HV generator). It includes an 800 V-rated N-channel MOSFET, whose gate is biased through the series of a 12 MΩ resistor and a 14 V Zener diode, with a controlled, temperature compensated current generator connected to its source. The HV generator input is in common with the DRAIN pins, while its output is the supply pin of the device (VCC pin).
Device description HVLED815PF Figure 13. Timing diagram: normal power-up and power-down sequences VIN VStart t VCC VccON Vccrestart t DRAIN t ICHARGE 5.5 mA Normal operation CV mode Power-on Normal operation CC mode Power-off t AM13563v1 4.4 Secondary side demagnetization detection and triggering block The demagnetization detection (DMG) and Triggering blocks switch on the power MOSFET if a negative-going edge falling below 50 mV is applied to the DMG pin.
HVLED815PF Device description The triggering block is blanked after MOSFET's turn-off to prevent any negative-going edge that follows leakage inductance demagnetization from triggering the DMG circuit erroneously. This TBLANK blanking time is dependent on the voltage on COMP pin: it is TBLANK=30 µs for VCOMP=0.9 V, and decreases almost linearly down to TBLANK=6 µs for VCOMP=1.3 V.
Device description 4.5 HVLED815PF Constant current operation Figure 16 presents the principle used for controlling the average output current of the flyback converter. The voltage of the auxiliary winding is used by the demagnetization block to generate the control signal for the internal MOSFET switch Q. A resistor R in series with it absorbs a current equal to VILED/R, where VILED is the voltage developed across the capacitor CLED capacitor.
HVLED815PF Device description The capacitor CLED has to be chosen so that its voltage VILED can be considered as a constant. Since it is charged and discharged by currents in the range of some ten µA (IREF=20 µA typ.) at the switching frequency rate, a capacitance value in the range 4.7-10 nF is suited for switching frequencies in the ten kHz. When high power factor schematic is implemented, a higher capacitor value should be used (i.e. 1 µF-10 µF).
Device description HVLED815PF Equation 6 This formula shows that the average output current IOUT does not depend anymore on the input voltage VIN or the output voltage VOUT, neither on transformer inductance values. The external parameters defining the output current are the transformer ratio n and the sense resistor RSENSE. The previous formula (Equation 6) is valid for both standard and high power factor implementation. 4.
HVLED815PF Device description Figure 18. Voltage control principle: internal schematic DMG + Aux EA + S/H - Rdmg 2.5V Rf b DEMAG LOGIC To PWM Logic CV From CS pin COMP R C AM13568v1 4.7 Voltage feed-forward block The current control structure uses the VCLED voltage to define the output current, according to equation 6 on Section 4.5.
Device description HVLED815PF Figure 19. Feed-forward compensation: internal schematic DRAIN DMG Feedforward Logic . Rfb Aux IFF CC Block - Rdmg PWM LOGIC CC + Rff CS SOURCE Rsense AM13569v1 During MOSFET's ON-time the current sourced from DMG pin is mirrored inside the "Feedforward Logic" block in order to provide a feed-forward current, IFF.
HVLED815PF Device description Equation 13 Finally, the Rdmg resistor can be calculated as follows: Equation 14 In this case the peak drain current does not depend on input voltage anymore, and as a consequence the average output current IOUT do not depend from the VIN input voltage. When high power factor is implemented (see Section 4.
Device description HVLED815PF Figure 20. Load-dependent operating modes: timing diagrams COMP 50 mV hysteresis (Hys) VCOMPL IDS t Normal-mode Burst-mode Normal-mode t AM13570v1 4.9 Soft-start and starter block The soft start feature is automatically implemented by the constant current block, as the primary peak current will be limited from the voltage on the CLED capacitor.
HVLED815PF Device description Ultimately, this will result in a low-frequency intermittent operation (hiccup-mode operation), with very low stress on the power circuit. This special condition is illustrated in the timing diagram of Figure 21. Figure 21. Hiccup-mode OCP: timing diagram VCC Secondary diode is shorted here VccON VccOFF Vccrest t VCS Vcsdis 1V VDS t Two switching cycles t AM13571v1 4.
Device description HVLED815PF Figure 22. High power factor implementation connection - single range input DRAIN DMG Feedf orward Logic1 . Rf b Aux IFF CC Block1 - Rdmg PWM LOGIC2 CC + Rf f CS SOURCE RPF R1 ROS VIN (after bridge diode) RA Rsense RB COS AM13572v1 The components selection flow starts from Rdmg resistor: this resistor has to be selected in order to minimize the internal feed-forward effect.
HVLED815PF Device description Equation 18 Where VOS_TYP is the desired voltage across COS capacitor applying the VIN_TYP typical input voltage (i.e. VIN_TYP=220 V for 176/264 Vac input range); Fsw is the switching frequency and can be estimated using the following formula, where fT and fR are the transition and resonant frequency respectively: Equation 19 Equation 20 Equation 21 π where CD is the total equivalent capacitor afferent at the drain node.
Device description HVLED815PF Equation 24 where VCLED is internally defined (0.2 V typical - see Table 5: Electrical characteristics). System design tips Starting from the estimated value using the previous formulas, further fine-tuning on the real led driver board could be necessary and it can be easily done considering that: 4.
HVLED815PF Device description Figure 23.
Package information 5 HVLED815PF Package information 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. Figure 24. SO16N mechanical data mm Dim. Min. Typ. A 1.75 A1 0.10 0.25 A2 1.25 b 0.31 0.51 c 0.17 0.25 D 9.80 9.90 10.00 E 5.80 6.00 6.20 E1 3.
HVLED815PF Package information Figure 25.
Package information HVLED815PF Figure 26.
HVLED815PF 6 Revision history Revision history 22-Oct Table 6. Document revision history Date Revision 26-Jul-2012 1 Initial release. 29-Aug-2012 2 Added Table 2: Pin description on page 7. 3 Modified TJ value on Table 3: Thermal data. Updated TJ value in note 2 (below Table 5: Electrical characteristics). Minor text changes. 4 Added sections from 4.1 to 4.12.
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