HVLED007

HVLED007 Transition mode PFC controller for flyback converters Datasheet - Production data converters operated in transition mode (aka quasi-resonant operation). Targeting both indoor and outdoor solid-state lighting applications, it provides extended temperature range operation down to -40 °C with guaranteed electrical specification. The main feature of this IC is a special circuit (Input Current Shaper, ICS), that enables High-PF quasi-resonant flyback converters to draw a theoretically sinusoidal input current from the power line, unlike the traditional control. Features  Transition-mode (quasi-resonant) control of flyback PFC pre-regulators  Proprietary input current shaper for minimum THD of line current  Control input for isolated feedback and optocoupler driving  Output overvoltage protection  Overload and short-circuit protection  Low (≤ 60 μA) start-up current and low (≤ 4 ma) quiescent current  Digital leading-edge blanking on current sense  -600/+800 mA totem pole gate driver with UVLO pull-down and voltage clamp In practice, with little effort it is possible to achieve a total distortion of the input current (THD) lower than 10% at full load and lower than 20% at 30% load over the entire input voltage range. The IC is provided with a control input intended for being driven by the phototransistor of an optocoupler to close a secondary-regulated isolated control loop. However, with the addition of a simple external circuitry it can be used to close a primary-regulated voltage loop as well. The HVLED007 includes protection features to handle overload, short-circuit and overvoltage conditions. The totem-pole output stage, capable of 600 mA source and 800 mA sink current, is suitable for big MOSFET drives which, combined with the other features, makes the device an excellent low-cost solution for EN61000-3-2 compliant SMPS up to 100 W.  SO8 package Applications Flyback PFC converters for:  AC-DC LED drivers for domestic, commercial and industrial lighting  Street lighting Table 1. Device summary Order code HVLED007  EN61000-3-2 compliant SMPS HVLED007TR Package SO8 Packaging Tube Tape and Reel Description The HVLED007 is a current-mode PFC controller specific for isolated high power factor, flyback January 2019 This is information on a product in full production. DS12866 Rev 1 1/33 www.st.com Contents HVLED007 Contents 1 Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2 Pin connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 4 Application information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 4.2 Input current shaping function - operating principle . . . . . . . . . . . . . . . . . . 9 4.3 Operation of a Hi-PF QR flyback converter based on the HVLED007 . . . 13 4.4 Shaping capacitor (Ct) selection (pin CT) . . . . . . . . . . . . . . . . . . . . . . . . . 16 4.5 Control input for isolated feedback and optocoupler driving (pin COMP) 17 4.6 Multiplier input for input voltage sensing (pin MULT) . . . . . . . . . . . . . . . . 19 4.7 Current sensing input (pin CS). Sense resistor (Rs) selection . . . . . . . . . 19 4.8 Zero current detection and triggering block (pin ZCD); starter . . . . . . . . . 22 4.9 Overload and short-circuit protection (OCP function) . . . . . . . . . . . . . . . . 23 4.10 Overvoltage protection (OVP function) . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 4.11 Soft-restart function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 4.12 Suggested step-by-step design procedure of a Hi-PF QR flyback converter based on the HVLED0007 26 5 Referenced documents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 6 Package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 7 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 2/33 DS12866 Rev 1 HVLED007 1 Block diagram Block diagram Figure 1. Block diagram 08/7  9  ȝ$ N: &203 &7  9 ,1387 &855(17 6+$3(5 Dh>d/W>/Z *'B6 293  89/2 2&3  D^d d Ct  Rf Rt  VZf Q 293 Q Vcsref ș VCt RmultL S SW Vcsmax Cf Ip tș R WtD ĐŽŵƉĂƌĂƚŽƌ ^ Vcs tș Rs dDĐŽŶƚƌŽůůŽŽƉ /^ ,s>ϬϬϳ The ON/OFF mechanism of the external power switch is exactly the same as in the traditional TM method: the power switch is turned on as the secondary current zeroes (with a delay TR to achieve valley switching, see "Section 4.8: Zero current detection and triggering block (pin ZCD); starter") and turned off when the voltage Vcs (t, θ) on the current sensing input CS (proportional to the primary current Ip (t, θ)) reaches the reference value Vcsref (θ). Note that the explicit dependence on time (t) denotes cycle-by-cycle quantities. The difference between the traditional TM method and that implemented in the HVLED007 is in the way the reference Vcsref (θ) is generated. In the traditional TM method, Vcsref (θ) is generated by taking the input voltage as the template and adjusting its amplitude with feedback loop control voltage via the multiplier; in the HVLED007 the output of the multiplier is processed by the ICS circuit highlighted in the dotted box before being provided to the PWM comparator. The ICS circuit is composed of the current generator IMULT (θ), the external capacitor Ct connected between pin CT and ground and a switched resistor Rt that is connected in parallel to Ct during the ON-time TON (θ) of the power switch through the switch SW. The current generator provides the charging current for Ct, given by: Equation 3 I MULT    = k I  K p  V inpk sin  V c  where Kp = RmultL / (RmultH + RmultL) is the voltage gain of the resistor divider that senses the rectified input voltage. The key waveforms are shown in Figure 6. Assuming T(θ) Vcsmax) to prevent a too large dead zone between the external voltage generated across Ct by the shaping circuit and Vcsref (θ) internally clamped at Vcsmax. For further details about the operating principle and the effect of non-idealities please refer to Reference 1. Figure 7. Shape of the current reference Vcsref(θ) (5) at different input voltages (i.e. Kv values) 4.3 Operation of a Hi-PF QR flyback converter based on the HVLED007 The ICS circuit changes the profile of the peak current envelope along a line half-cycle (as shown in Figure 7) and this slightly changes the timing and the electrical quantities in the converter in steady-state operation as compared to those of a traditionally controlled Hi-PF QR flyback converter [Reference 2]. There are differences in the peak and rms currents but DS12866 Rev 1 13/33 33 Application information HVLED007 no difference in the voltage stresses apart from those caused by parasitics and resulting from the different peak currents. The timing, the control and electrical quantities of a Hi-PF QR flyback converter based on the HVLED007, needed for a proper design, are summarized in Table 6, 7 and 8 respectively. The symbolism used has been defined already or is obvious. Their derivation is based on some simplifying assumptions (in addition to T(θ)