NCL30186 Analog/Digital Dimmable Power Factor Corrected Quasi-Resonant Primary Side Current-Mode Controller for LED Lighting The NCL30186 is a controller targeting isolated and non−isolated “smart−dimmable” constant−current LED drivers. Designed to support flyback, buck−boost, and SEPIC topologies, its proprietary current− control algorithm provides near−unity power factor and tightly regulates a constant LED current from the primary side, thus eliminating the need for a secondary−side feedback circuitry or an optocoupler. Housed in the SOIC10 which has the same body size as a standard SOIC8, the NCL30186 is specifically intended for very compact space−efficient designs. The device is highly integrated with a minimum number of external components. A robust suite of safety protections is built in to simplify the design. To ensure reliable operation at elevated temperatures, a user configurable current foldback circuit is also provided. In addition, it supports analog and PWM dimming with a dedicated dimming input intended to control the average LED current. Pin−to−pin compatible to the NCL30086, the NCL30186 provides the same benefits with in addition, an increased resolution of the digital current−control algorithm for a 75% reduction in the LED current quantization ripple. • SOIC−10 CASE 751BQ MARKING DIAGRAM L30186x ALYW G L30186x = Specific Device Code x = A, B, C, D A = Assembly Location L = Wafer Lot Y = Year W = Work Week G = Pb-Free Package PIN CONNECTIONS DIM Features • • • • • • • • • • www.onsemi.com 1 NC ZCD VCC Quasi−resonant Peak Current−mode Control Operation DRV VS Valley Lockout Optimizes Efficiency over the Line/Load Range COMP GND Constant Current Control with Primary Side Feedback SD CS Tight LED Constant Current Regulation of ±2% Typical (Top View) Power Factor Correction Analog or PWM dimming ORDERING INFORMATION Line Feedforward for Enhanced Regulation Accuracy See detailed ordering and shipping information in the package dimensions section on page 27 of this data sheet. Low Start−up Current (10 mA typ.) Wide Vcc Range ♦ User programmable NTC Based Thermal Foldback 300 mA / 500 mA Totem Pole Driver with 12 V Gate ♦ Thermal Shutdown Clamp • −40 to 125°C Operating Junction Temperature Robust Protection Features • Pb−Free, Halide−Free Product ♦ Brown−Out Detection ♦ OVP on VCC • Four Versions: NCL30186A, B, C and D (See Table 1) ♦ Programmable Over Voltage / LED Open Circuit Typical Applications Protection • Integral LED Bulbs ♦ Cycle−by−cycle Peak Current Limit ♦ Winding Short Circuit Protection • LED Light Engines ♦ Secondary Diode Short Protection • LED Driver Power Supplies ♦ Output Short Circuit Protection • Smart LED Lighting Applications ♦ Current Sense (CS) Short Detection © Semiconductor Components Industries, LLC, 2016 May, 2016 − Rev. 1 1 Publication Order Number: NCL30186/D NCL30186 . Aux . . NCL30186 VDIM 1 10 2 9 3 8 4 7 5 6 Rsense Figure 1. Typical Application Schematic in a Flyback Converter . Aux . VDIM NCL30186 1 10 2 9 3 8 4 7 5 6 Rsense Figure 2. Typical Application Schematic in a Buck−Boost Converter www.onsemi.com 2 NCL30186 Table 1. FOUR NCL30186 VERSIONS Part Number Protection Mode Current Regulation Reference Voltage (VREF) Recommended for (*): Isolated converters. Non−isolated converters with NCL30186A Latching−off 250 mV V out v Ǹ2 @ (V in,rms) LL Isolated converters. Non−isolated converters with NCL30186B Auto−recovery 250 mV V out v Ǹ2 @ (V in,rms) LL Non−isolated converters with NCL30186C Latching−off 200 mV V out u Ǹ2 @ (V in,rms) LL Non−isolated converters with NCL30186D Auto−recovery 200 mV V out u Ǹ2 @ (V in,rms) LL *(Vin,rms)LL designates the lowest line rms voltage. Refer to ANDxxxx/D for more details. (http://www.onsemi.com/pub_link/Collateral/ANDxxxx−D.PDF). Table 2. PIN FUNCTION DESCRIPTION Pin No Pin Name Function Pin Description 1 DIM Analog / PWM Dimming This pin is used for analog or PWM dimming control. An analog signal that can be varied between VDIM0 and VDIM100 or a PWM signal can be used to adjust the LED current. 2 ZCD Zero Crossing Detection Connected to the auxiliary winding, this pin detects the core reset event. 3 VS Input Voltage Sensing 4 COMP Filtering Capacitor 5 SD Thermal Foldback and Shutdown 6 CS Current Sense 7 GND − 8 DRV Driver Output The driver’s output to an external MOSFET 9 VCC IC Supply Pin This pin is the positive supply of the IC. The circuit starts to operate when VCC exceeds 18 V and turns off when VCC goes below 8.8 V (typical values). After start−up, the operating range is 9.4 V up to 26 V (VCC (OVP ) minimum level). 10 NC − This pin monitors the input voltage rail for: Power Factor Correction Valley lockout Brownout Detection This pin receives a filtering capacitor for power factor correction. Typical values ranges from 1 − 4.7 mF. Connecting an NTC to this pin allows the user to program thermal current foldback threshold and slope. A Zener diode can also be used to pull−up the pin and stop the controller for adjustable OVP protection. This pin monitors the primary peak current. Controller ground pin. − www.onsemi.com 3 NCL30186 Internal Circuit Architecture Enable Over Voltage Protection (Auto−recovery or Latched) Aux_SCP OFF Thermal Foldback VCC Management Latch Internal Thermal Shutdown V TF VCC UVLO Fault Management Over Temp. Protection (Auto−recovery or Latched) SD V REF V DD STOP VCC_max VCC Over Voltage Protection WOD_SCP BO_NOK DRV FF_mode V VS VCC ZCD Zero Crossing Detection Logic (ZCD Blanking, Time−Out, ...) FF_mode Aux_SCP Clamp Circuit Valley Selection Frequency Foldback Aux. Winding Short Circuit Prot. DRV S Q CS_ok Q V VS Line feed−forward STOP VVS R DIM_disable V REFX GND CS Power Factor and Constant−Current Control Leading Edge Blanking CS_reset Ipkmax DIM_disable Maximum on time STOP t on,max COMP Ipkmax Max. Peak Current Limit VVS BO_NOK VS Brown−Out CS_ok CS Short Protection UVLO V REF t on,max DIM_disable V Winding and Output diode Short Circuit Protection WOD_SCP REFX DIM Dimming control VTF Figure 3. Internal Circuit Architecture www.onsemi.com 4 NCL30186 Table 3. MAXIMUM RATINGS TABLE(S) Symbol Rating VCC(MAX) ICC(MAX) Maximum Power Supply voltage, VCC pin, continuous voltage Maximum current for VCC pin VDRV(MAX) IDRV(MAX) Maximum driver pin voltage, DRV pin, continuous voltage Maximum current for DRV pin Value Unit −0.3 to 30 Internally limited V mA −0.3, VDRV (Note 1) −300, +500 V mA −0.3, 5.5 (Notes 2 and 5) −2, +5 V mA VMAX IMAX Maximum voltage on low power pins (except DRV and VCC pins) Current range for low power pins (except DRV and VCC pins) RθJ−A Thermal Resistance Junction−to−Air 180 °C/W Maximum Junction Temperature 150 °C Operating Temperature Range −40 to +125 °C Storage Temperature Range −60 to +150 °C ESD Capability, HBM model (Note 3) 3.5 kV ESD Capability, MM model (Note 3) 250 V 2 kV TJ(MAX) ESD Capability, CDM model (Note 3) Stresses exceeding those listed in the Maximum Ratings table may damage the device. If any of these limits are exceeded, device functionality should not be assumed, damage may occur and reliability may be affected. 1. VDRV is the DRV clamp voltage VDRV(high) when VCC is higher than VDRV(high). VDRV is VCC otherwise. 2. This level is low enough to guarantee not to exceed the internal ESD diode and 5.5−V Zener diode. More positive and negative voltages can be applied if the pin current stays within the −2 mA / 5 mA range. 3. This device contains ESD protection and exceeds the following tests: Human Body Model 3500 V per JEDEC Standard JESD22−A114E, Machine Model Method 250 V per JEDEC Standard JESD22−A115B, Charged Device Model 2000 V per JEDEC Standard JESD22−C101E. 4. This device contains latch−up protection and has been tested per JEDEC Standard JESD78D, Class I and exceeds ±100 mA. 5. Recommended maximum VS voltage for optimal operation is 4 V. −0.3 V to +4.0 V is hence, the VS pin recommended range. Table 4. ELECTRICAL CHARACTERISTICS (Unless otherwise noted: For typical values TJ = 25°C, VCC = 12 V, VZCD = 0 V, VCS = 0 V, VSD = 1.5 V) For min/max values TJ = −40°C to +125°C, VCC = 12 V) Test Condition Symbol Min Typ Max VCC rising VCC rising VCC falling VCC(on) VCC(off) VCC(HYS) VCC(reset) 16.0 8.2 8 4 18.0 8.8 − 5 20.0 9.4 − 6 VCC Over Voltage Protection Threshold VCC(OVP) 25.5 26.8 28.5 V VCC(off) noise filter VCC(reset) noise filter tVCC(off) tVCC(reset) − − 5 20 − − ms Startup current ICC(start) − 13 30 mA Startup current in fault mode ICC(Fault) 58 75 mA Description Unit STARTUP AND SUPPLY CIRCUITS Supply Voltage Startup Threshold Minimum Operating Voltage Hysteresis VCC(on) – VCC(off) Internal logic reset Supply Current Device Disabled/Fault Device Enabled/No output load on DRV pin Device Switching V mA VCC > VCC(off) Fsw = 65 kHz CDRV = 470 pF, Fsw = 65 kHz ICC1 ICC2 ICC3 0.8 – − 1.0 2.6 3.0 1.2 4.0 4.5 Maximum Internal current limit VILIM 0.95 1.00 1.05 V Leading Edge Blanking Duration for VILIM tLEB 240 300 360 ns Propagation delay from current detection to gate off−state tILIM − 100 150 ns CURRENT SENSE 6. Guaranteed by Design 7. A NTC is generally placed between the SD and GND pins. Parameters RTF(start), RTF(stop), ROTP(off) and ROTP(on) give the resistance the NTC must exhibit to respectively, enter thermal foldback, stop thermal foldback, trigger the OTP limit and allow the circuit recovery after an OTP situation. 8. At startup, when VCC reaches VCC(on), the controller blanks OTP for more than 250 ms to avoid detecting an OTP fault by allowing the SD pin voltage to reach its nominal value if a filtering capacitor is connected to the SD pin. www.onsemi.com 5 NCL30186 Table 4. ELECTRICAL CHARACTERISTICS (Unless otherwise noted: For typical values TJ = 25°C, VCC = 12 V, VZCD = 0 V, VCS = 0 V, VSD = 1.5 V) For min/max values TJ = −40°C to +125°C, VCC = 12 V) Description Test Condition Symbol Min Typ Max Unit Maximum on−time ton(MAX) 26 36 46 ms Threshold for immediate fault protection activation VCS(stop) 1.35 1.50 1.65 V Leading Edge Blanking Duration for VCS(stop) tBCS − 150 − ns Current source for CS to GND short detection ICS(short) 400 500 600 mA VCS(low) 30 65 100 mV Drive Resistance DRV Sink DRV Source RSNK RSRC − − 13 30 − − Drive current capability DRV Sink (Note 6) DRV Source (Note 6) ISNK ISRC − − 500 300 − − CURRENT SENSE Current sense threshold for CS to GND short detection VCS rising GATE DRIVE W mA Rise Time (10% to 90%) CDRV = 470 pF tr – 40 − ns Fall Time (90% to 10%) CDRV = 470 pF tf – 30 − ns DRV Low Voltage VCC = VCC(off)+0.2 V CDRV = 470 pF, RDRV = 33 kW VDRV(low) 8 – − V DRV High Voltage VCC = VCC(MAX) CDRV = 470 pF, RDRV = 33 kW VDRV(high) 10 12 14 V Upper ZCD threshold voltage VZCD rising VZCD(rising) − 90 150 mV Lower ZCD threshold voltage VZCD falling VZCD(falling) 35 55 − mV ZERO VOLTAGE DETECTION CIRCUIT ZCD hysteresis VZCD(HYS) 15 − − mV VZCD falling TDEM − 100 300 ns Blanking delay after on−time VREFX > 30% VREF TZCD(blank1) 1.12 1.50 1.88 ms Blanking delay at light load VREFX < 25% VREF TZCD(blank2) 0.56 0.75 0.94 ms TTIMO 5.0 6.5 8.0 ms RZCD(PD) − 200 − kW Propagation Delay from valley detection to DRV high Timeout after last DEMAG transition Pulling−down resistor VZCD = VZCD(falling) CONSTANT CURRENT AND POWER FACTOR CONTROL Reference Voltage at TJ = 25°C A and B versions C and D versions VREF 245 195 250 200 255 205 mV Reference Voltage TJ = 25°C to 100°C A and B versions C and D versions VREF 242.5 192.5 250.0 200.0 257.5 207.5 mV Reference Voltage TJ = −40°C to 125°C A and B versions C and D versions VREF 240 190 250 200 260 210 mV VCS falling VCS(low) 20 50 100 mV Vratio − 4 − − GEA 40 50 60 mS Current sense lower threshold Vcontrol to current setpoint division ratio Error amplifier gain VREFX = VREF 6. Guaranteed by Design 7. A NTC is generally placed between the SD and GND pins. Parameters RTF(start), RTF(stop), ROTP(off) and ROTP(on) give the resistance the NTC must exhibit to respectively, enter thermal foldback, stop thermal foldback, trigger the OTP limit and allow the circuit recovery after an OTP situation. 8. At startup, when VCC reaches VCC(on), the controller blanks OTP for more than 250 ms to avoid detecting an OTP fault by allowing the SD pin voltage to reach its nominal value if a filtering capacitor is connected to the SD pin. www.onsemi.com 6 NCL30186 Table 4. ELECTRICAL CHARACTERISTICS (Unless otherwise noted: For typical values TJ = 25°C, VCC = 12 V, VZCD = 0 V, VCS = 0 V, VSD = 1.5 V) For min/max values TJ = −40°C to +125°C, VCC = 12 V) Description Test Condition Symbol Min Typ Max Unit VREFX = VREF (no dimming) VREFX = 25%* VREF IEA ±60 ±240 mA COMP pin grounded IEA_STUP 140 mA CONSTANT CURRENT AND POWER FACTOR CONTROL Error amplifier current capability COMP Pin Start−up Current Source LINE FEED FORWARD VVS to ICS(offset) conversion ratio Line feed−forward current on CS pin DRV high, VVS = 2 V Offset current maximum value KLFF 18 20 22 mS IFF 35 40 45 mA Ioffset(MAX) 80 100 120 mA VALLEY LOCKOUT SECTION Threshold for high− line range (HL) detection VVS rising VHL 2.28 2.40 2.52 V Threshold for low−line range (LL) detection VVS falling VLL 2.18 2.30 2.42 V tHL(blank) 15 25 35 ms tFF1LL 1.4 2.0 2.6 ms 40 − ms − ms Blanking time for line range detection FREQUENCY FOLDBACK Minimum additional dead time in frequency foldback mode Additional dead time VREFX = 5% VREF tFF2HL − Additional dead time VREFX = 0% VREF tFF3HL 90 FSW = 65 kHz TSHDN 130 150 170 °C Thermal Shutdown Hysteresis TSHDN(HYS) − 50 – °C Threshold voltage for output short circuit or aux. winding short circuit detection VZCD(short) 0.8 1.0 1.2 V tOVLD 70 90 110 ms Auto−recovery timer duration trecovery 3 4 5 s SD pin Clamp series resistor RSD(clamp) FAULT PROTECTION Thermal Shutdown (Note 6) Short circuit detection Timer Clamped voltage VZCD < VZCD(short) 1.6 kW SD pin open VSD(clamp) 1.13 1.35 1.57 V VSD rising VOVP 2.35 2.50 2.65 V Delay before OVP or OTP confirmation TSD(delay) 22.5 30.0 37.5 ms Reference current for direct connection of an NTC (Note 8) IOTP(REF) 80 85 90 mA SD pin detection level for OVP Fault detection level for OTP (Note 7) VSD falling VOTP(off) 0.47 0.50 0.53 V SD pin level for operation recovery after an OTP detection VSD rising VOTP(on) 0.66 0.70 0.74 V OTP blanking time when circuit starts operating (Note 8) tOTP(start) 250 370 ms SD pin voltage where thermal fold−back starts (VREF is decreased) VTF(start) 0.94 1.00 1.06 V SD pin voltage at which thermal fold−back stops (VREF is clamped to VREF50) VTF(stop) 0.64 0.69 0.74 V RTF(start) 10.8 11.7 12.6 kW VTF(start) over IOTP(REF) ratio (Note 7) TJ = +25°C to +125°C 6. Guaranteed by Design 7. A NTC is generally placed between the SD and GND pins. Parameters RTF(start), RTF(stop), ROTP(off) and ROTP(on) give the resistance the NTC must exhibit to respectively, enter thermal foldback, stop thermal foldback, trigger the OTP limit and allow the circuit recovery after an OTP situation. 8. At startup, when VCC reaches VCC(on), the controller blanks OTP for more than 250 ms to avoid detecting an OTP fault by allowing the SD pin voltage to reach its nominal value if a filtering capacitor is connected to the SD pin. www.onsemi.com 7 NCL30186 Table 4. ELECTRICAL CHARACTERISTICS (Unless otherwise noted: For typical values TJ = 25°C, VCC = 12 V, VZCD = 0 V, VCS = 0 V, VSD = 1.5 V) For min/max values TJ = −40°C to +125°C, VCC = 12 V) Description Test Condition Symbol Min Typ Max Unit VTF(stop) over IOTP(REF) ratio (Note 7) TJ = +25°C to +125°C RTF(stop) 7.4 8.1 8.8 kW VOTP(off) over IOTP(REF) ratio (Note 7) TJ = +25°C to +125°C ROTP(off) 5.4 5.9 6.4 kW VOTP(on) over IOTP(REF) ratio (Note 7) TJ = +25°C to +125°C ROTP(on) 7.5 8.1 8.7 kW VREFX @ VSD = 600 mV (as percentage of VREF) SD pin falling (no OTP detection) VREF(50) 40 50 60 % Brown−Out ON level (IC start pulsing) VS rising VBO(on) 0.95 1.00 1.05 V Brown−Out OFF level (IC shuts down) VS falling VBO(off) 0.85 0.90 0.95 V FAULT PROTECTION BROWN−OUT ms BO comparators delay tBO(delay) Brown−Out blanking time tBO(blank) 15 25 35 ms VS = VBO(on) IBO(bias) 50 250 450 nA DIM pin voltage for zero output current (OFF voltage) VDIM falling VDIM0 0.66 0.70 0.74 V DIM pin voltage for maximum output current (VREFX = VREF) TJ = −40°C to +125°C TJ = +25°C to +85°C (NCL30186D only) TJ = +25°C (NCL30186D only) VDIM rising VDIM100 VS pin Pulling−down Current 30 DIMMING SECTION DIM pin voltage for 50% output current (VREFX = 50% VREF) Output Current Internal Reference (VREFX) @ VDIM = 0.8225 V) (NCL30186D only) TJ = +25°C to +50°C VDIM rising or falling VDIM50 VDIM = 0.8225 V VREF7 V − 2.32 2.335 2.45 2.45 2.450 2.60 2.57 2.555 1.35 1.57 1.75 mV 9.4 Dimming range VDIM(range) Dimming pin pull−up current source IDIM(pullup) V 14 18.6 1.75 7.5 9.6 V 12 mA 6. Guaranteed by Design 7. A NTC is generally placed between the SD and GND pins. Parameters RTF(start), RTF(stop), ROTP(off) and ROTP(on) give the resistance the NTC must exhibit to respectively, enter thermal foldback, stop thermal foldback, trigger the OTP limit and allow the circuit recovery after an OTP situation. 8. At startup, when VCC reaches VCC(on), the controller blanks OTP for more than 250 ms to avoid detecting an OTP fault by allowing the SD pin voltage to reach its nominal value if a filtering capacitor is connected to the SD pin. www.onsemi.com 8 NCL30186 TYPICAL CHARACTERISTICS 20.0 9.4 9.3 19.5 9.2 9.1 18.5 VCC(off) (V) VCC(on) (V) 19.0 18.0 17.5 17.0 −25 0 25 50 75 100 125 150 0 25 50 75 100 125 150 TJ, JUNCTION TEMPERATURE (°C) Figure 4. VCC Start−up Threshold vs. Temperature Figure 5. VCC Minimum Operating Voltage vs. Temperature 11.5 6.0 11.0 5.8 5.6 VCC(reset) (V) 5.4 10.0 9.5 9.0 5.2 5.0 4.8 4.6 8.5 4.4 8.0 7.5 −50 −25 TJ, JUNCTION TEMPERATURE (°C) 10.5 VCC(hys) (V) 8.7 8.6 8.5 8.4 8.3 8.2 −50 16.5 16.0 −50 9.0 8.9 8.8 −25 0 25 50 75 100 125 4.2 4.0 −50 150 −25 0 25 50 75 100 125 150 TJ, JUNCTION TEMPERATURE (°C) TJ, JUNCTION TEMPERATURE (°C) Figure 6. Hysteresis (VCC(on) − VCC(off)) vs. Temperature Figure 7. VCC(reset) vs. Temperature www.onsemi.com 9 NCL30186 TYPICAL CHARACTERISTICS 40 28.0 27.8 35 30 27.2 27.0 ICC(start) (mA) VCC(ovp) (V) 27.6 27.4 26.8 26.6 26.4 25 20 15 10 26.2 26.0 25.8 25.6 −50 5 −25 0 25 50 75 100 125 0 −50 150 −25 0 25 50 75 100 125 150 TJ, JUNCTION TEMPERATURE (°C) TJ, JUNCTION TEMPERATURE (°C) Figure 8. VCC Over Voltage Protection Threshold vs. Temperature Figure 9. Start−up Current vs. Temperature 2.0 150 1.8 125 ICC1 (mA) ICC(sfault) (mA) 1.6 100 75 50 1.4 1.2 1.0 0.8 25 0.6 −25 0 25 50 75 100 125 0.4 −50 150 −25 0 25 50 75 100 TJ, JUNCTION TEMPERATURE (°C) TJ, JUNCTION TEMPERATURE (°C) Figure 10. Start−up Current in Fault Mode vs. Temperature Figure 11. ICC1 vs. Temperature 3.8 3.6 3.4 3.2 3.0 2.8 2.6 2.4 2.2 2.0 1.8 1.6 1.4 1.2 −50 125 150 5.0 4.5 4.0 ICC3 (mA) ICC2 (mA) 0 −50 3.5 3.0 2.5 2.0 1.5 −25 0 25 50 75 100 125 150 1.0 −50 −25 0 25 50 75 100 TJ, JUNCTION TEMPERATURE (°C) TJ, JUNCTION TEMPERATURE (°C) Figure 12. ICC2 vs. Temperature Figure 13. ICC3 vs. Temperature www.onsemi.com 10 125 150 NCL30186 1.05 400 1.04 380 360 1.02 340 1.01 320 TLEB (ns) 1.03 1.00 0.99 280 260 0.97 240 0.96 0.95 −50 220 −25 0 25 50 75 100 125 200 −50 150 −25 0 25 50 75 100 125 150 TJ, JUNCTION TEMPERATURE (°C) TJ, JUNCTION TEMPERATURE (°C) Figure 14. Maximum Internal Current Limit vs. Temperature Figure 15. Leading Edge Blanking vs. Temperature 150 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0 −50 50 48 46 44 42 40 38 36 34 −25 0 25 50 75 100 125 32 30 −50 150 −25 0 25 50 75 100 125 150 TJ, JUNCTION TEMPERATURE (°C) TJ, JUNCTION TEMPERATURE (°C) Figure 16. Current Limit Propagation Delay vs. Temperature Figure 17. Maximum On−time vs. Temperature 1.60 220 210 1.58 200 190 1.56 1.54 1.52 TBCS (ns) VCS(stop) (V) 300 0.98 TON(max) (ms) TILIM (ns) VILIM (V) TYPICAL CHARACTERISTICS 1.50 1.48 1.46 1.44 1.42 1.40 1.38 −50 −25 0 25 50 75 100 125 150 180 170 160 150 140 130 120 110 100 −50 −25 0 25 50 75 100 125 150 TJ, JUNCTION TEMPERATURE (°C) TJ, JUNCTION TEMPERATURE (°C) Figure 18. VCS(stop) vs. Temperature Figure 19. Leading Edge Blanking Duration for VCS(stop) vs. Temperature www.onsemi.com 11 NCL30186 TYPICAL CHARACTERISTICS 600 100 580 90 560 80 VCS(low) (mV) ICS(short) (mA) 540 520 500 480 460 −25 0 25 50 75 100 125 20 −50 150 25 50 75 100 125 150 Figure 20. ICS(short) vs. Temperature Figure 21. VCS(low), VCS Rising vs. Temperature 14 12 RSRC (W) RSNK (W) 0 TJ, JUNCTION TEMPERATURE (°C) 16 10 8 6 4 −25 0 25 50 75 100 125 150 40 38 36 34 32 30 28 26 24 22 20 18 16 14 12 10 −50 −25 0 25 50 75 100 125 150 TJ, JUNCTION TEMPERATURE (°C) TJ, JUNCTION TEMPERATURE (°C) Figure 22. Sink Gate Drive Resistance vs. Temperature Figure 23. Source Gate Drive Resistance vs. Temperature 50 45 45 40 40 35 35 30 30 tF (ns) 50 25 25 20 20 15 15 10 10 5 0 −50 −25 TJ, JUNCTION TEMPERATURE (°C) 18 tr (ns) 50 30 20 2 0 −50 60 40 440 420 400 −50 70 −25 0 25 50 75 100 125 150 5 0 −50 −25 0 25 50 75 100 TJ, JUNCTION TEMPERATURE (°C) TJ, JUNCTION TEMPERATURE (°C) Figure 24. Gate Drive Rise Time vs. Temperature Figure 25. Gate Drive Fall Time (CDRV = 470 pF) vs. Temperature www.onsemi.com 12 125 150 NCL30186 TYPICAL CHARACTERISTICS 9.8 15.0 9.6 14.5 14.0 VDRV(high) (V) VDRV(low) (V) 9.4 9.2 9.0 8.8 12.0 11.0 8.4 8.2 −50 −25 0 25 50 75 100 125 10.5 10.0 −50 150 −25 0 25 50 75 100 125 150 TJ, JUNCTION TEMPERATURE (°C) TJ, JUNCTION TEMPERATURE (°C) Figure 26. DRV Low Voltage vs. Temperature Figure 27. DRV High Voltage vs. Temperature 150 80 140 130 75 120 110 65 VZCD(falling) (mV) 70 100 90 80 70 60 55 50 45 60 50 40 40 30 −50 35 30 −50 −25 0 25 50 75 100 125 150 0 25 50 75 100 125 150 TJ, JUNCTION TEMPERATURE (°C) Figure 28. Upper ZCD Threshold Voltage vs. Temperature Figure 29. Lower ZCD Threshold vs. Temperature 50 2.0 45 1.9 40 1.8 35 1.7 30 25 20 15 10 5 0 −50 −25 TJ, JUNCTION TEMPERATURE (°C) tZCD(blank1) (ms) VZCD(rising) (mV) 13.0 12.5 11.5 8.6 VZCD(HYS) (mV) 13.5 1.6 1.5 1.4 1.3 1.2 −25 0 25 50 75 100 125 150 1.1 1.0 −50 −25 0 25 50 75 100 125 150 TJ, JUNCTION TEMPERATURE (°C) TJ, JUNCTION TEMPERATURE (°C) Figure 30. ZCD Hysteresis vs. Temperature Figure 31. ZCD Blanking Delay vs. Temperature www.onsemi.com 13 NCL30186 TYPICAL CHARACTERISTICS 7.8 256 255 254 253 7.6 7.4 252 VREF (mV) TTIMO (ms) 7.2 7.0 6.8 6.6 6.4 246 −25 0 25 50 75 100 125 245 244 −50 150 25 50 75 100 125 150 Figure 32. ZCD Time−out vs. Temperature Figure 33. Reference Voltage vs. Temperature (A and B versions) 110 60 58 90 56 54 70 GEA (mS) VCS(low) (mV) 0 TJ, JUNCTION TEMPERATURE (°C) 100 60 50 52 50 48 40 30 46 20 10 −50 44 −25 0 25 50 75 100 125 42 −50 150 −25 0 25 50 75 100 125 150 TJ, JUNCTION TEMPERATURE (°C) TJ, JUNCTION TEMPERATURE (°C) Figure 34. Current Sense Lower Threshold (VCS Falling) vs. Temperature Figure 35. Error Amplifier Trans−conductance Gain vs. Temperature 44 21.5 43 21.0 42 20.5 41 IFF (mA) 22.0 20.0 40 19.5 39 19.0 38 18.5 37 18.0 −50 −25 TJ, JUNCTION TEMPERATURE (°C) 80 KLFF (mS) 249 248 247 6.2 6.0 5.8 −50 251 250 −25 0 25 50 75 100 125 150 36 −50 −25 0 25 50 75 100 125 150 TJ, JUNCTION TEMPERATURE (°C) TJ, JUNCTION TEMPERATURE (°C) Figure 36. Feedforward VVS to ICS(offset) Conversion Ratio vs. Temperature Figure 37. Line Feedforward Current on CS Pin (@ VVS = 2 V) vs. Temperature www.onsemi.com 14 NCL30186 TYPICAL CHARACTERISTICS 120 2.55 115 2.50 2.45 105 VHL (V) Ioffset(MAX) (mA) 110 100 95 2.40 2.35 90 2.30 85 80 −50 −25 0 25 50 75 100 125 2.25 −50 150 0 25 50 75 100 125 150 TJ, JUNCTION TEMPERATURE (°C) TJ, JUNCTION TEMPERATURE (°C) Figure 38. Ioffset(MAX) vs. Temperature Figure 39. Threshold for High−line Range Detection vs. Temperature 2.60 40 2.55 38 36 THL(blank) (ms) 2.50 2.45 VLL (V) −25 2.40 2.35 34 32 30 28 26 2.30 24 2.25 −25 0 25 50 75 100 125 22 20 −50 150 0 25 50 75 100 125 150 TJ, JUNCTION TEMPERATURE (°C) Figure 40. Threshold for Low−line Range Detection vs. Temperature Figure 41. Blanking Time for Low−line Range Detection vs. Temperature 1.20 115 1.15 110 1.10 105 1.05 100 1.00 0.95 95 90 0.90 85 0.85 80 0.80 −50 −25 TJ, JUNCTION TEMPERATURE (°C) tOVLD (ms) VZCD(short) (V) 2.20 −50 −25 0 25 50 75 100 125 150 75 −50 −25 0 25 50 75 100 125 150 TJ, JUNCTION TEMPERATURE (°C) TJ, JUNCTION TEMPERATURE (°C) Figure 42. Threshold Voltage for Output Short Circuit Detection vs. Temperature Figure 43. Short Circuit Detection Timer vs. Temperature www.onsemi.com 15 NCL30186 TYPICAL CHARACTERISTICS 5.00 2.20 2.10 4.75 RSD(clamp) (kW) Trecovery (s) 4.50 4.25 4.00 3.75 3.50 3.00 −50 1.50 1.40 1.20 1.10 1.00 −50 −25 0 25 50 75 100 125 150 −25 0 25 50 75 100 125 150 TJ, JUNCTION TEMPERATURE (°C) TJ, JUNCTION TEMPERATURE (°C) Figure 44. Auto−recovery Timer Duration vs. Temperature Figure 45. SD Pin Clamp Series Resistor vs. Temperature 1.60 2.58 1.55 2.56 1.50 2.54 1.45 2.52 1.40 VOVP (V) VSD(clamp) (V) 1.70 1.60 1.30 3.25 1.35 1.30 2.50 2.48 2.46 1.25 1.20 2.44 1.15 1.10 −50 2.42 −25 0 25 50 75 100 125 2.40 −50 150 0 25 50 75 100 125 150 TJ, JUNCTION TEMPERATURE (°C) Figure 46. SD Pin Clamp Voltage vs. Temperature Figure 47. SD Pin OVP Threshold Voltage vs. Temperature 91 90 36 89 88 IOTP(REF) (mA) 34 32 30 28 26 24 22 −50 −25 TJ, JUNCTION TEMPERATURE (°C) 38 TSD(delay) (ms) 2.00 1.90 1.80 −25 0 25 50 75 100 125 150 87 86 85 84 83 82 81 80 79 −50 −25 0 25 50 75 100 125 150 TJ, JUNCTION TEMPERATURE (°C) TJ, JUNCTION TEMPERATURE (°C) Figure 48. TSD(delay) vs. Temperature Figure 49. IOTP(REF) vs. Temperature www.onsemi.com 16 NCL30186 12.5 12.4 12.3 12.2 12.1 12.0 11.9 11.8 11.7 11.6 11.5 11.4 11.3 11.2 11.1 11.0 −50 8.8 8.7 RTF(stop) (kW) RTF(start) (kW) TYPICAL CHARACTERISTICS −25 0 25 50 75 100 125 8.2 8.1 8.0 7.9 7.8 7.7 7.6 −50 150 −25 0 25 50 75 100 125 150 TJ, JUNCTION TEMPERATURE (°C) TJ, JUNCTION TEMPERATURE (°C) Figure 50. RTF(start) vs. Temperature Figure 51. RTF(stop) vs. Temperature 8.8 8.7 8.6 6.4 6.3 6.2 ROTP(on) (kW) 6.1 ROTP(off) (kW) 8.6 8.5 8.4 8.3 6.0 5.9 5.8 5.7 8.5 8.4 8.3 8.2 8.1 8.0 7.9 5.6 −25 0 25 50 75 100 125 7.8 7.7 7.6 −50 150 −25 0 25 50 75 100 125 150 TJ, JUNCTION TEMPERATURE (°C) TJ, JUNCTION TEMPERATURE (°C) Figure 52. ROTP(off) vs. Temperature Figure 53. ROTP(on) vs. Temperature 55 1.05 54 1.04 53 1.03 52 1.02 VBO(on) (V) VREF(50) (%) 5.5 5.4 −50 51 50 49 1.01 1.00 0.99 48 0.98 47 0.97 46 45 −50 0.96 0.95 −50 −25 0 25 50 75 100 125 150 −25 0 25 50 75 100 125 150 TJ, JUNCTION TEMPERATURE (°C) TJ, JUNCTION TEMPERATURE (°C) Figure 54. Ratio VREF(50) over VREF vs. Temperature Figure 55. Brown−out ON Level vs. Temperature www.onsemi.com 17 NCL30186 TYPICAL CHARACTERISTICS 0.95 0.94 0.93 tBO(blank) (ms) 0.91 0.90 0.89 0.88 0.87 0.86 0.85 −50 −25 0 25 50 75 100 125 150 −25 0 25 50 75 100 125 150 TJ, JUNCTION TEMPERATURE (°C) TJ, JUNCTION TEMPERATURE (°C) Figure 56. Brown−out OFF Level vs. Temperature Figure 57. Brown−out Blanking Time vs. Temperature 500 450 400 350 IBO(bias) (nA) VBO(off) (V) 0.92 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 −50 300 250 200 150 100 50 0 −50 −25 0 25 50 75 100 125 TJ, JUNCTION TEMPERATURE (°C) Figure 58. VS Pin Pulling−down Current vs. Temperature www.onsemi.com 18 150 NCL30186 Application Information The NCL30186 is a driver for power−factor corrected flyback and non−isolated buck−boost/ SEPIC converters. It implements a current−mode, quasi−resonant architecture including valley lockout and frequency fold−back capabilities for maintaining high−efficiency performance over a wide load range. A proprietary circuitry ensures both accurate regulation of the output current (without the need for a secondary−side feedback) and near−unity power factor correction. The circuit contains a suite of powerful protections to ensure a robust LED driver design without the need of extra external components or overdesign • Quasi−Resonance Current−Mode Operation: implementing quasi−resonance operation in peak current−mode control, the NCL30186 optimizes the efficiency by turning on the MOSFET when its drain−source voltage is minimal (valley). In light−load conditions, the circuit changes valleys to reduce the switching losses. For a stable operation, the valley at which the MOSFET switches on remains locked until the input voltage or the output current set−point significantly changes. • Primary−Side Constant−Current Control with Power Factor Correction: a proprietary circuitry allows the LED driver to achieve both near−unity power factor correction and accurate regulation of the output current without requiring any secondary−side feedback (no optocoupler needed). A power factor as high as 0.99 and an output current deviation below ±2% are typically obtained. • Linear or PWM dimming: the DIM pin allows implementing both analog and PWM dimming. • Main protection features: ♦ Over Temperature Thermal Fold−back/ Shutdown/Over Voltage Protection: the NCL30186 features a gradual current foldback to protect the driver from excessive temperature down to 50% of the programmed current. If the temperature continues to rise after this point to a second level, the controller stops operating. This mode would only be expected to be reached under normal conditions if there is a severe fault. The first and second temperature thresholds depend on the ZCD VCS STOP VVS ♦ ♦ ♦ ♦ ♦ NTC connected to the circuit SD pin. The SD pin can also be used to shutdown the device by pulling this pin below the VOTP(off) min level. A Zener diode can also be used to pull−up the pin and stop the controller for adjustable OVP protection. Both protections are latching−off (A and C versions) or auto−recovery (the circuit can recover operation after 4−s delay has elapsed − B and D versions). Cycle−by−cycle peak current limit: when the current sense voltage exceeds the internal threshold VILIM, the MOSFET is immediately turned off. Winding or Output Diode Short−Circuit Protection: an additional comparator senses the CS signal and stops the controller if it exceeds 150% x VILIM for 4 consecutive cycles. This feature can protect the converter if a winding is shorted or if the output diode is shorted or simply if the transformer saturates. This protection is latching−off (A and C versions) or auto−recovery (B and D versions). Output Short−circuit protection: if the ZCD pin voltage remains low for a 90−ms time interval, the controller detects that the output or the ZCD pin is grounded and hence, stops operation. This protection is latching−off (A and C versions) or auto−recovery (B and D versions). Open LED protection: if the VCC pin voltage exceeds the OVP threshold, the controller shuts down and waits 4 seconds before restarting switching operation. Floating or Short Pin Detection: NCL30186 protections aid in pass safety tests. For instance, the circuit stops operating when the CS pin is grounded or open. Power Factor and Constant Current Control The NCL30186 embeds an analog/digital block to control the power factor and regulate the output current by monitoring the ZCD, VS and CS pin voltages (signals ZCD, VS and VCS of Figure 59). This circuitry generates the current setpoint (VCONTROL/4) and compares it to the current sense signal (VCS) to dictate the MOSFET turning off event when VCS exceeds VCONTROL/4. VREF PWM Latch reset Power Factor and Constant−Current Control COMP DIM_disable C1 Figure 59. Power Factor and Constant−Current Control www.onsemi.com 19 NCL30186 the time to charge the VCC capacitor, initiate startup and begin switching and the time to charge the output capacitor until sufficient current flows into the LED string. To speed−up this phase, the following defines the start−up sequence: • The COMP pin is grounded when the circuit is off. The average COMP voltage needs to exceed the VS pin peak value to have the LED current properly regulated (whatever the current target is). To speed−up the COMP capacitance charge and shorten the start−up phase, an internal 80−mA current source adds to the OTA sourced current (60 mA max typically) to charge up the COMP capacitance. The 80−mA current source remains on until the OTA starts to sink current as a result of the COMP pin voltage sufficient rise. At that moment, the COMP pin being near its steady−state value, it is only driven by the OTA. • If VCC drops below the VCC(off) threshold because the circuit fails to start−up properly on the first attempt, a new attempt takes place as soon as VCC is recharged to VCC(on). The COMP voltage is not reset at that moment. Instead, the new attempt starts with the COMP level obtained at the end of the previous operating phase. • If the load is shorted, the circuit will operate in hiccup mode with VCC oscillating between VCC(off) and VCC(on) until the AUX_SCP protection trips (AUX_SCP is triggered if the ZCD pin voltage does not exceed 1 V within a 90−ms operation period of time thus indicating a short to ground of the ZCD pin or an excessive load preventing the output voltage from rising). The NCL30186A and NCL3006C latch off in this case. With the B and D versions, the AUX_SCP protection forces the 4−s auto−recovery delay to reduce the operation duty−ratio. Figure 60 illustrates a start−up sequence with the output shorted to ground, in this second case. The VS pin provides the sinusoidal reference necessary for shaping the input current. The obtained current reference is further modulated so that when averaged over a half−line period, it is equal to the output current reference (VREFX). This averaging process is made by an internal Operational Trans−conductance Amplifier (OTA) and the capacitor connected to the COMP pin (C1 in Figure 59). Typical COMP capacitance is 2.2 mF and should not be less than 1 mF to ensure stability. The COMP ripple does not affect the power factor performance as the circuit digitally eliminates it when generating the current setpoint. If the VS pin properly conveys the sinusoidal shape, power factor will be close to 1. Also, the Total Harmonic Distortion (THD) will be low, especially if the output voltage ripple is small. In any case, the output current will be well regulated following the equation below: I out + V REFX 2N PSR sense (eq. 1) Where: • NPS is the secondary to primary transformer turns NPS = NS / NP • Rsense is the current sense resistor (see Figure 1). • VREFX is the output current internal reference. VREFX = VREF (250 mV in A and B versions and 200 mV in C and D versions, typically) at full load. The output current reference (VREFX) is VREF unless thermal fold−back is activated by the SD pin voltage being reduced below 1 V typical (see “protections” section) or unless the DIM pin voltage is below VDIM100 (see analog dimming section). If a major fault is detected, the circuit enters the latched−off or auto−recovery mode and the COMP pin is grounded (except in an UVLO condition). This ensures a clean start−up when the circuit resumes operation. Start−up Sequence Generally an LED lamp is expected to emit light in < 1 sec and typically within 300 ms. The start−up phase consists of www.onsemi.com 20 NCL30186 VCC(on) VCC VCC(off) (‧‧‧ ) (‧‧‧ ) time AUX_SCPtrips as t 1 + t2 + t3 = tOVLD (tOVLD ^90 ms) DRV t1 t3 t1 t2 t3 time t2 trecovery (^4 s ) trecovery (^4 s ) Figure 60. Start−up Sequence in a Load Short−circuit Situation (auto−recovery versions) Zero Crossing Detection Block situation, the NCL30186 features a time−out circuit that generates pulses if the voltage on ZCD pin stays below the 55−mV threshold for 6.5 ms nominal. The time−out also acts as a substitute clock for the valley detection and simulates a missing valley in case the free oscillations are too damped. The ZCD pin detects when the drain−source voltage of the power MOSFET reaches a valley by crossing below the 55−mV internal threshold (VZCD(TH)). At startup or in case of extremely damped free oscillations, the ZCD comparator may not be able to detect the valleys. To avoid such a t ZCD(blank1) t ZCD(blank) FF_mode t ZCD(blank2) ZCD + V ZCD(TH) − Clock Time−Out V ZCD(short) + + − − S Q Q 90−ms Timer R 4−s Timer (auto−recovery version) Vcc<Vcc(reset) (latching−off version) Figure 61. Zero Current Detection Block www.onsemi.com 21 Aux_SCP NCL30186 • After the appropriate number of “clock” pulses in If the ZCD pin or the auxiliary winding happen to be shorted, the time−out function would normally make the controller keep switching and hence lead to improper LED current value. The “AUX_SCP” protection prevents such a stressful operation: a secondary timer starts counting that is only reset when the ZCD voltage exceeds the VZCD(short) threshold (1 V typically). If this timer reaches 90 ms (no ZCD voltage pulse having exceeded VZCD(short) for this time period), the controller detects a fault and stops operation for 4 seconds (B and D versions) or latches off (A and C versions). The “clock” shown in Figure 61 is used by the “valley selection frequency foldback” circuitry of the block diagram (Figure 3), to generate the next DRV pulse (if no fault prevents it): • Immediately when the clock occurs in QR mode at low line or valley 2 at high line (full load) thermal foldback mode For an optimal operation, the maximum ZCD level should be maintained below 5 V to stay safely below the built in clamping voltage of the pin. Line Range Detection As sketched in Figure 62, this circuit detects the low−line range if the VS pin remains below the VLL threshold (2.3 V typical) for more than the 25−ms blanking time. High−line is detected as soon as the VS pin voltage exceeds VHL (2.4 V typical). These levels roughly correspond to 184−V rms and 192−V rms line voltages if the external resistors divider applied to the VS pin is designed to provide a 1−V peak value at 80 V rms. Figure 62. Line Range Detection efficiency over the line range by turning on the MOSFET at the first valley in low−line conditions and at the second valley in the high−line case. This is illustrated by Figure 63 that sketches the MOSFET Drain−Source voltage in both cases. In the event that thermal foldback is activated, additional valleys can be skipped as the power is reduced. In the low−line range, conduction losses are generally dominant. Adding a dead−time would further increase these losses. Hence, only a short dead−time is necessary to reach the MOSFET valley. In high−line conditions, switching losses generally are the most critical. It is thus efficient to skip one valley to lower the switching frequency. Hence, under normal operation, the NCL30186 optimizes the Figure 63. Full−load Operation − Quasi−resonant Mode in low line (left), turn on at valley 2 when in high line (right) Line Feedforward current. By adding an external resistor in series between the sense resistor and the CS pin, a voltage offset proportional to the input voltage is added to the CS signal for the MOSFET on−time. To compensate for current regulation errors due to AC line variation, the NCL30186 includes a method to add line feedforward adjustment. As illustrated by Figure 64, the input voltage is sensed by the VS pin and converted into a www.onsemi.com 22 NCL30186 Bulk rail vDD VS CS I CS(offset) RCS Rsense Q_drv Figure 64. Line Feed−Forward Schematic In Figure 64, Q_drv designates the output of the PWM latch which is high for the on−time and low otherwise. PWM or Linear Dimming Detection The DIM pin of the NCL30186 is provided to implement linear and/or PWM dimming of the LED current. Applying a voltage on the DIM pin voltage (VDIM) forces the output current internal reference to operate in one of three regions: V REFX + 0 if V DIM v V DIM0 V REFX + V REF if V DIM w V DIM100 V REFX + V DIM * V DIM0 V V DIM100 * V DIM0 REF Where: • NPS is the secondary to primary transformer turns N PS + N SńN P • Rsense is the current sense resistor (see Figure 1). • VREF is the output current internal reference (250 mV (eq. 2) typically) • Iout,nom is the full−load output current. The DRV output is disabled whenever the DIM pin voltage is lower than VDIM0 and the output current setpoint is maximal when VDIM exceeds VDIM100. Thus, for PWM dimming, a PWM signal with a low−state value below VDIM0 and a high−state value above VDIM100 should be applied. In this case, the output current will be: otherwise VDIM0 and VDIM100 respectively, are 0.7 V and 2.45 V typically. The output current can then be controlled by the DIM pin as follows: I out + 0 if V DIM v V DIM0 (eq. 3) V REF if V DIM w V DIM100 I out + I out,nom + 2 N PSR sense I out + V DIM * V DIM0 I V DIM100 * V DIM0 out,nom I out ^ I out,nom @ d (eq. 4) Where d is the duty ratio of the DIM pin signal. otherwise VDIM VDIM100 VDIM0 time Iout Iout,nom 0A time Figure 65. Pin DIM Chronograms www.onsemi.com 23 NCL30186 Notes: • The current does not immediately reach its new target • If either the high−state (VDIM(high)) or low−state level (VDIM(low)) of the input or both are between VDIM0 and VDIM100, the output current will be proportionally reduced as both analog and PWM dimming are simultaneous active, thus the output current will be: value when the PWM dimming signal state changes due to system time constants like the time necessary to charge or discharge the output capacitor to the required level. The output current settling time can hence affect the obtained output current, particularly if the PWM signal frequency is high. I out ^ I out ^ I out ^ ǒ V DIM(high) * V DIM0 V DIM100 * V DIM0 V DIM(high) * V DIM0 V DIM100 * V DIM0 ǒ d) d) V DIM(low) * V DIM0 V DIM100 * V DIM0 Ǔ (1 * d) I out,nom if V DIM0 v V DIM(low) v V DIM(high) v V DIM100 d @ I out,nom V DIM(low) * V DIM0 V DIM100 * V DIM0 (1 * d) if V DIM0 v V DIM(high) v V DIM100 and V DIM(low) v V DIM0 Ǔ if V DIM(high) w V DIM100 and V DIM0 v V DIM(low) v V DIM100 I out,nom • If thermal foldback is activated as well, the current Protections The circuit incorporates a full suite of protection features listed below to make the LED driver very rugged. reduction is cumulative. For instance, if the DIM pin voltage and the thermal foldback respectively, reduces the output current setpoint by 50% and 20% respectively, the output current will be 80%*50% that is 40% of its nominal level. Output Short Circuit Situation An overload fault is detected if the ZCD pin voltage remains below VZCD(short) for 90 ms. In such a situation, the circuit stops generating pulses until the 4−s delay auto−recovery time has elapsed (B and D versions) or latches off (A and C versions). The DIM pin is pulled up internally by a 10−mA current source. Thus, if the pin is let open, the controller is able to start. For any power factor corrected single stage architecture there will be a component of line ripple (100 / 120 Hz) on the output. If PWM dimming is used, it is recommended to select the dimming frequency to be sufficiently high not to generating beat frequencies that could create optical artifacts. >> As a general rule, the minimum PWM frequency should be at least 2.5x the line ripple frequency and not be set near multiples of the line frequency. Winding or Output Diode Short Circuit Protection If a transformer winding happens to be shorted, the primary inductance will collapse leading the current to ramp up in a very abrupt manner. The VILIM comparator (current limitation threshold) will trip to open the MOSFET and eventually stop the current rise. However, because of the abnormally steep slope of the current, internal propagation delays and the MOSFET turn−off time, a current rise > 50% of the nominal maximum value set by VILIM is possible. As illustrated in Figure 66, an additional circuit monitors for this current overshoot to detect a winding short circuit. The leading edge blanking (LEB) time for short circuit protection (LEB2) is significantly faster than the LEB time for cycle−by−cycle protection (LEB1). Practically, if four consecutive switching periods lead the CS pin voltage to exceed (VCS(stop) = 150% * VILIM), the controller enters the auto−recovery mode (4−s operation interruption between active bursts with versions B and D) or latches off (versions A and C). www.onsemi.com 24 NCL30186 S DRV Q Vdd aux UVLO Q TSD CS LEB1 + Vcontrol / 4 PWMreset VCC Vcc management BONOK UVLO R − 4−s timer + STOP Ipkmax − V ILIMIT AUX_SCP SD Pin OVP (OVP2) LEB2 + WOD_SCP latch VCCreset (grand reset) VCC(ovp) 4−pulse counter − OTP V CS(stop) S S OFF Q Q R 4−s timer latch Q Q AUTORECOVERY (B and D versions) R LATCHING−OFF (A and C versions) VCCreset Figure 66. Winding Short Circuit Protection, Max. Peak Current Limit Circuits VCC Over Voltage Protection Programmable Over Voltage Protection (OVP2) The circuit stops generating pulses if VCC exceeds VCC(OVP) and enters auto−recovery mode. This feature protects the circuit in the event that the output LED string is disconnected or an individual LED in the string happens to fail open. In addition to the VCC OVP protection, it is possible to connect a Zener diode between VCC and the SD pin to implement programmable VCC OVP monitoring (DZ of Figure 67). The triggering level is (VZ+VOVP) where VOVP is the 2.5−V internal threshold. If this protection trips, the NCL30186A and NCL30186C latch off while the NCL30186B and NCL30186D enter the auto−recovery mode. Vdd IOTP(REF) NCL30186B / NCL30186D (autorecovery versions) SD PIN OVP (OVP2) DETECTION S + Q VCC − OFF Q VOVP T SD(delay) DZ R SD 4−s Timer OTP DETECTION − NTC NCL30186A / NCL30186C (latching off versions) + TOTP(start) VOTP(off) / VOTP(on) S Q Q Thermal Foldback R VTF grand reset Clamp Rclamp Vclamp Figure 67. Thermal Foldback and OVP/OTP Circuitry www.onsemi.com 25 Latch NCL30186 The SD pin is clamped to about 1.35 V (Vclamp ) through a 1.6−kW resistor (Rclamp ). It is then necessary to inject about ǒ Ǔ V OVP * V clamp R clamp that is ǒ2.501.6* k1.35 ^ 700 mAǓ typically, to trigger the OVP protection. This current helps ensure an accurate detection by using the Zener diode far from its knee region. Programmable Over Temperature Foldback Protection (OTP) Figure 68. Output Current Reduction versus SD Pin Voltage Connect an NTC between the SD pin and ground to detect an over−temperature condition. In response to a high temperature (detected if VSD drops below VTF(start)), the circuit gradually reduces the LED current down to 50% (> 50% reduction in output power) of its initial value when VSD reaches VTF(stop), in accordance with the characteristic of Figure 68 (Note 9). At this point, if the temperature continues to rise and the secondary OTP level is reached, (VSD drop below VOTP), the circuit latches off (A and C versions) or enters auto−recovery mode (B and D versions) and cannot resume operation until VSD exceeds VOTP(on) to provide some temperature hysteresis (around 10°C typically). The OTP thresholds nearly correspond to the following resistances of the NTC: • Thermal foldback starts when RNTC ≤ RTF(start) (11.7 kW, typically) • Thermal foldback stops when RNTC ≤ RTF(stop) (8.0 kW, typically) • OTP triggers when RNTC ≤ ROTP(off) (5.9 kW, typically) • OTP is removed when RNTC ≤ ROTP(on) (8.0 kW, typically) (Note 10) At startup, when VCC reaches VCC(on), the OTP comparator is blanked for at least 180 ms which allows the SD pin voltage to reach its nominal value if a filtering capacitor is connected to the SD pin. This avoids flickering of the LED light during turn on. Brown−Out Protection The NCL30186 prevents operation when the line voltage is too low for proper operation. As sketched in Figure 69, the circuit detects a brown−out situation if the VS pin remains below the VBO(off) threshold (0.9 V typical) for more than the 25−ms blanking time. In this case, the controller stops operating. Operation resumes as soon as the VS pin voltage exceeds VBO(on) (1.0 V typical) and VCC is higher than VCC(on). To ease recovery, the circuit overrides the VCC normal sequence (no need for VCC cycling down below VCC(off)). Instead, its consumption immediately reduces to ICC(start) so that VCC rapidly charges up to VCC(on) and the circuit re−starts operation. Figure 69. Brown−out Circuit 9. The above mentioned initial value is the output current before the system enters the thermal foldback, that is, its maximum level if PWM or analog dimming is not engaged or a lower one based on the dimming value. 10. This condition is sufficient for operation recovery of the B and D versions. For the A and C versions which latches off when OTP is triggered, the circuit further needs to be reset by the VCC drop below VCC(reset). www.onsemi.com 26 NCL30186 Die Over Temperature (TSD) Fault Management The circuit stops operating if the junction temperature (TJ) exceeds 150°C typically. The controller remains off until TJ goes below nearly 100°C. OFF Mode The circuit turns off in the case of an incorrect feeding of the circuit: “UVLO high”. The UVLO signal becomes high when VCC drops below VCC(off) and remains high until VCC exceeds VCC(on). The circuit also turns off whenever a major faulty condition prevents it from operating: • Severe OTP (VSD level below VOTP(off)) • VCC OVP • OVP2 (additional OVP provided by SD pin) • Output diode short circuit protection: “WOD_SCP high” • Output / Auxiliary winding Short circuit protection: “Aux_SCP high” • Die over temperature (TSD) Pin Connection Faults The circuit addresses most pin connection fault cases: • CS Pin Short to Ground The circuit senses the CS pin impedance every time it starts−up and after DRV pulses terminated by the 36−ms maximum on−time. If the measured impedance does not exceed 120 W typically, the circuit stops operating. In practice, it is recommended to place a minimum of 250 W in series between the CS pin and the current sense resistor to take into account parasitics. • Fault of the GND Connection If the GND pin is properly connected, the supply current drawn from the positive terminal of the VCC capacitor, flows out of the GND pin to return to the negative terminal of the VCC capacitor. If the GND pin is not connected, the circuit ESD diodes offer another return path. The accidental non−connection of the GND pin is monitored by detecting that one of the ESD diode is conducting. Practically, the ESD diode of CS pin is monitored. If such a fault is detected for 200 ms, the circuit stops generating DRV pulses. In this mode, the DRV pulses generation is interrupted. In the case of a latching−off fault, the circuit stops pulsing until the LED driver is unplugged and VCC drops below VCC(reset). At that moment, the circuit resumes operation. In the auto−recovery case, the circuit cannot generate DRV pulses for the auto−recovery 4−s delay. When this time has elapsed, the circuit recovers operation as soon as the VCC voltage has exceeded VCC(on). In the B and D versions, all these protections are auto−recovery. The SD pin OTP and OVP, WOD_SCP and AUX_SCP functions are latching off in the A and C versions (see Table 5). More generally, incorrect pin connection situations (open, grounded, shorted to adjacent pin) are covered by ANDxxxx. Table 5. PROTECTION MODES AUX_SCP WOD_SCP SD Pin OTP SD Pin OVP NCL30186A* Latching off Latching off Latching off Latching off NCL30186B Auto−recovery Auto−recovery Auto−recovery Auto−recovery NCL30186C* Latching off Latching off Latching off Latching off NCL30186D Auto−recovery Auto−recovery Auto−recovery Auto−recovery ORDERING INFORMATION Device Package Type Shipping SOIC−8 (Pb−Free/Halide Free) 2500 / Tape & Reel NCL30186ADR2G* NCL30186BDR2G NCL30186CDR2G* NCL30186DDR2G *Please contact local sales representative for availability www.onsemi.com 27 NCL30186 PACKAGE DIMENSIONS SOIC−10 NB CASE 751BQ ISSUE A 2X 0.10 C A-B D D A 2X 0.10 C A-B 10 F 6 H E 1 5 0.20 C 10X B 2X 5 TIPS L2 b 0.25 A3 L C SEATING PLANE DETAIL A M NOTES: 1. DIMENSIONING AND TOLERANCING PER ASME Y14.5M, 1994. 2. CONTROLLING DIMENSION: MILLIMETERS. 3. DIMENSION b DOES NOT INCLUDE DAMBAR PROTRUSION. ALLOWABLE PROTRUSION SHALL BE 0.10mm TOTAL IN EXCESS OF ’b’ AT MAXIMUM MATERIAL CONDITION. 4. DIMENSIONS D AND E DO NOT INCLUDE MOLD FLASH, PROTRUSIONS, OR GATE BURRS. MOLD FLASH, PROTRUSIONS, OR GATE BURRS SHALL NOT EXCEED 0.15mm PER SIDE. DIMENSIONS D AND E ARE DETERMINED AT DATUM F. 5. DIMENSIONS A AND B ARE TO BE DETERMINED AT DATUM F. 6. A1 IS DEFINED AS THE VERTICAL DISTANCE FROM THE SEATING PLANE TO THE LOWEST POINT ON THE PACKAGE BODY. C A-B D DIM A A1 A3 b D E e H h L L2 M TOP VIEW 10X h X 45 _ 0.10 C 0.10 C M A A1 e C DETAIL A SEATING PLANE END VIEW SIDE VIEW MILLIMETERS MIN MAX 1.25 1.75 0.10 0.25 0.17 0.25 0.31 0.51 4.80 5.00 3.80 4.00 1.00 BSC 5.80 6.20 0.37 REF 0.40 1.27 0.25 BSC 0_ 8_ RECOMMENDED SOLDERING FOOTPRINT* 1.00 PITCH 10X 0.58 6.50 10X 1.18 1 DIMENSION: MILLIMETERS *For additional information on our Pb−Free strategy and soldering details, please download the ON Semiconductor Soldering and Mounting Techniques Reference Manual, SOLDERRM/D. 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