DN05046/D 120 VAC, Low‐Cost, Dimmable, Linear, Parallel‐to‐Series LED Driving Circuit http://onsemi.com DESIGN NOTE Table 1. DEVICE DETAILS Device Application Topology Input Voltage Input Power Power Factor THD NSIC2030B LED Lighting Linear 100 to 130 VAC 6.7 W 0.97 24% Overview Key Circuit Features This design is a low-cost, off-line, dimmable, linear LED driver solution suitable for general illumination applications in the commercial, industrial, and consumer market sectors. The circuit uses the ON Semiconductor Constant Current Regulator to control the current through the LEDs and to protect against voltage surges. It is comprised of two sets of LEDs that are switched between parallel and series configurations when a threshold voltage is passed to provide improved efficiency (tunable from 72% to 94%), power factor, and total harmonic distortion attributes. The circuit is completely functional with standard phase-cut dimmers for incandescent lights. It is designed to function consistently over a wide range of temperatures and has been proven from −40 to +60°C. • • • • • • • • • • • • F1 D1 D3 D2 D4 Fully Functional with Standard Phase-cut Dimmers High Light Output Very Low-Cost No Inductors Power Factor = 0.97 Input Current THD = 24% Efficiency = 72% (94% with Four LEDs per String) Tested and Proven from −40 to +60°C Wide Input Voltage Range Constant Current and Protection for LEDs Suitable for Small Form Factor Applications Adaptable to Drive more LEDs Vin MOV1 LED1 R3 Q2 LED2 LED3 C1 R1 R4 Q3 D5 CCR2 CCR1 R5 M1 Q1 Z1 R2 C2 R6 D6 LED4 LED5 LED6 Figure 1. 2-stage Parallel-to-Series CCR Lighting Circuit © Semiconductor Components Industries, LLC, 2014 May, 2014 − Rev. 5 1 Publication Order Number: DN05046/D DN05046/D Circuit Description Circuit Data The circuit consists of a full-wave bridge rectifier (D1−D4), a threshold detection and switching circuit (D5−D6, Q1−Q3, and M1), two LED strings (LED1−LED3 and LED4−LED6), and two ON Semiconductor Constant Current Regulators (CCR1 and CCR2). Table 3. ELECTRICAL CHARACTERISTICS FOR THE CIRCUIT SHOWN IN FIGURE 1 Criteria Circuit Operation Input Frequency (Hz) The bridge rectifies the 60 Hz, 120 Vrms input providing a 120 Hz half-sin waveform with a peak voltage of 170 V. The bridge output is referenced from the cathodes of D3 and D4 to the anodes of D1 and D2. The bridge output voltage is applied across R1 and R2 creating a voltage divider. The voltage at the junction of R1 and R2 is used to turn on Q1, triggering the switching between the parallel and series configurations. The voltage at which the circuit switches is referenced as VSWITCH. It is recommended that VSWITCH be set just above the forward voltage of the two LED strings in series configuration, which is about 110 V in the provided circuit. Referring to Figure 1, VSWITCH depends on R1, R2, and the VBE(sat) of Q1. This relationship is expressed by the following equation: Power (W) ǒ 110 VAC 120 VAC 130 VAC Result Result Result 60 60 60 6.11 6.72 7.28 Input Current (mArms) 57.1 57.4 57.3 Power Factor 0.970 0.972 0.974 THD (%, Input Irms) 25.0 24.1 23.3 Efficiency (%) 75.6 72.4 69.0 Product parametric performance is indicated in the Electrical Characteristics for the listed test conditions, unless otherwise noted. Product performance may not be indicated by the Electrical Characteristics if operated under different conditions. Dimmers Tested Table 4. THE CIRCUIT WAS FULLY FUNCTIONAL WITH EACH DIMMER TESTED Dimmer Cooper Aspire 9530 Ǔ V SWITCH + V BE(sat) @ R1 ) R2 R2 GE DI 61 Kuei Lin AC 110 V, 500 W Q1 is an ON Semiconductor MMBT3904L. A VBE(sat) value of Q1 at 25°C is 0.68 V. With R1 = 1 MW and R2 = 6.2 kW, VSWITCH is about 110 V. When the bridge output voltage is less than 110 V, the two LED strings are in parallel. As shown in Table 2, Q1 & Q2 are off and M1 & Q3 are on. D5 and D6 do not conduct because they are reverse-biased. Z1 protects the gate of M1. When the bridge output voltage is greater than 110 V, the two LED strings are in series. Q1 & Q2 are on and M1 & Q3 are off. D5 and D6 conduct and join the two LED strings. The circuit achieves an efficiency of 72%. Improved efficiency of 94% is achievable by inserting an additional LED in each string. However, with four LEDs per string, power factor falls from 0.97 to 0.90, THD rises from 24% to 47%, and dimming performance is degraded. Leviton 6615−POW Leviton 6633−PLW Leviton 6674 Universal Leviton Illumatech IPI06 Leviton OC58L1 Lightolier CT600WC Lutron CT−603PGH Lutron CTCL−153PD Lutron MAW−600H Lutron TG−10PR Lutron TG−600P−AC Lutron TG−600PH Lutron S−600PR Table 2. STATES OF THE TRANSISTORS AND CONNECTING DIODES IN PARALLEL AND SERIAL OPERATION Pass & Seymour D703PLAV Pass & Seymour DCL453PTC Pass & Seymour LS603PLAV LED Configuration Pass & Seymour LSLV603PWV Parallel Series D5 Reverse-Biased Forward-Biased D6 Reverse-Biased Forward-Biased M1 On Off Q1 Off On Q2 Off On Q3 On Off Pass & Seymour WS703PW SCT YM2508A WattStopper DCD267 Universal http://onsemi.com 2 DN05046/D Representational Circuit Diagrams Parallel Operation: Bridge Output Voltage < 110 V Series Operation: Bridge Output Voltage > 110 V LED1 LED1 LED2 LED2 LED3 LED3 Q3 D5 CCR1 CCR1 CCR2 CCR2 D6 M1 LED4 LED4 LED5 LED5 LED6 LED6 Figure 2. The Circuit Switches between Parallel and Series LED Configurations as the Bridge Output Voltage Passes 110 Volts. Total Input Current is the Same in both Configurations. http://onsemi.com 3 DN05046/D Waveforms Figure 3. The Voltage across each CCR Changes as the Circuit Switches between Parallel and Series. Figure 4. The LEDs are On for almost the Entire Cycle. Each LED String Consists of Fhree Cree MX-S LEDs. http://onsemi.com 4 DN05046/D Figure 5. Q1 Switches as the Bridge Output Voltage Passes 110 V, Triggering the Switching of M1 and Q2. Figure 6. Q2 Switches as the Bridge Output Voltage Passes 110 V in Order to Cause Q3 to Switch. http://onsemi.com 5 DN05046/D Figure 7. Q3 is Off when Q2 is On. Figure 8. M1 is Pulled Low as Q1 Turns On. http://onsemi.com 6 DN05046/D Figure 9. The LED Current in each String is 30 mA in Parallel Configuration and 60 mA in Series Configuration. Figure 10. The Circuit is Fully Functional with Standard Phase-cut Incandescent Dimmers. http://onsemi.com 7 DN05046/D Figure 11. The Current Waveforms Closely Track the Bridge Output Voltage as the Circuit is Dimmed. Figure 12. At the Least Bright Setting, the Lights are Barely On. Total Input Current was 7.1 mArms. http://onsemi.com 8 DN05046/D Bill of Materials Table 5. BILL OF MATERIALS FOR CIRCUIT SHOWN IN FIGURE 1 Designator Qty Description Value Tolerance Manufacturer Part Number C1 1 Capacitor 2.2 nF, 250 V − Any − C2 1 Capacitor 1 nF, 10 V − Any − CCR1−CCR2 2 Constant Current Regulator 120 V, 30 mA ±15% ON Semiconductor NSIC2030B D1−D4 4 Diode 400 V, 1 A − ON Semiconductor MRA4004 D5−D6 2 Diode 75 V, 200 mA − ON Semiconductor BAS16H F1 1 Fuse 250 Vac, 1 A − Any − LED1−LED6 6 LED 20 V, 175 mA − Cree MX−6S M1 1 N-MOSFET 100 V, 17 A − ON Semiconductor NTD6416AN MOV1 1 Varistor 150 V − Littelfuse V150LA5P Q1 1 NPN 40 V, 200 mA − ON Semiconductor MMBT3904L Q2 1 PNP 40 V, 200 mA − ON Semiconductor MMBT3906L Q3 1 PNP 150 V, 500 mA − ON Semiconductor MMBT5401L R1 1 Resistor 1 MW, 1/8 W ±1% Any − R2 1 Resistor 6.2 kW, 1/8 W ±1% Any − R3 1 Resistor 360 W, 1/8 W ±1% Any − R4 1 Resistor 62 kW, 1/8 W ±1% Any − R5 1 Resistor 10 W, 1/8 W ±10% Any − R6 1 Resistor 150 kW, 1/8 W ±10% Any − Z1 1 Zener Diode 15 Vz ±5% ON Semiconductor MMSZ15 http://onsemi.com 9 DN05046/D ADDENDUM Alternative Circuit F1 D1 D3 D2 D4 Vin MOV1 LED1 R8 LED2 LED3 Q4 R3 D5 R5 R1 C1 R6 CCR1 CCR2 R4 D6 Q2 LED4 Q1 Q3 R2 C2 LED5 LED6 R7 Figure 13. Alternative Circuit Alternative Schematic Circuit Data • With Hysteresis/EMI Suppression Resistor R4 (Table 6) • Without Hysteresis/EMI Suppression Resistor R4 (Table 7) Table 6. ELECTRICAL CHARACTERISTICS FOR ALTERNATIVE SCHEMATIC WITH R4 Input Frequency (Hz) Table 7. ELECTRICAL CHARACTERISTICS FOR ALTERNATIVE SCHEMATIC WITHOUT R4 110 VAC 120 VAC 130 VAC 60 60 60 Input Frequency (Hz) 110 VAC 120 VAC 130 VAC 60 60 60 Power (W) 5.40 6.02 6.47 Power (W) 5.54 6.08 6.59 Input Current (mArms) 50.66 50.62 51.80 Input Current (mArms) 51.88 51.83 51.74 Power Factor 0.957 0.964 0.968 Power Factor 0.963 0.967 0.970 THD (%, Input Irms) 29.38 26.69 24.94 THD (%, Input Irms) 27.33 25.66 24.48 Efficiency (%) 82.2 78.9 73.1 Efficiency (%) 80.8 76.1 72.1 Product parametric performance is indicated in the Electrical Characteristics for the listed test conditions, unless otherwise noted. Product performance may not be indicated by the Electrical Characteristics if operated under different conditions. Product parametric performance is indicated in the Electrical Characteristics for the listed test conditions, unless otherwise noted. Product performance may not be indicated by the Electrical Characteristics if operated under different conditions. http://onsemi.com 10 DN05046/D Bill of Materials Table 8. BILL OF MATERIALS FOR ALTERNATIVE CIRCUIT Designator Qty Description Value Tolerance Manufacturer Part Number C1 1 Capacitor 2.2 nF, 250 V − Any − C2 1 Capacitor 1 nF, 10 V Any − CCR1−CCR2 2 Constant Current Regulator 120 V, 30 mA ±15% ON Semiconductor NSIC2030B D1−D4 4 Diode 400 V, 1 A − ON Semiconductor MRA4004 D5−D6 2 Diode 100 V, 200 mA − ON Semiconductor MMBD914L F1 1 Fuse 250 Vac, 1 A − Any − LED1−LED6 6 LED 20 V, 175 mA − Cree MX−6S MOV1 1 Varistor 150 V − Littelfuse V150LA5P Q1 1 NPN 40 V, 200 mA − ON Semiconductor MMBT3904L Q2 1 NPN 350 V, 100 mA − ON Semiconductor MMBT6517L Q3 1 NPN 150 V, 600 mA − ON Semiconductor MMBT5550L Q4 1 PNP 150 V, 500 mA − ON Semiconductor MMBT5401L R1 1 Resistor 1 MW, 1/8 W ±1% Any − R2 1 Resistor 6.2 kW, 1/8 W ±1% Any − R3 1 Resistor 301 kW, 1/8 W ±1% Any − R4 1 Resistor 10 MW, 1/8 W ±5% Any − R5 1 Resistor 27 kW, 1/8 W ±1% Any − R6 1 Resistor 27 kW, 1/8 W ±1% Any − R7 1 Resistor 2.2 kW, 1/8 W ±1% Any − R8 1 Resistor 2.2 kW, 1/8 W ±1% Any − ON Semiconductor and are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). 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