AN039 Primary-Side–Control, TRIAC-Dimmable Offline LED Controller The Future of Analog IC Technology MP4020 Primary-Side–Control, TRIAC-Dimmable, Offline LED Controller Application Note Prepared by Vicky Yu Apr 28th, 2011 AN039 Rev. 1.0 12/30/2013 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. 1 AN039 –PRIMARY-SIDE–CONTROL AND TRIAC DIMMABLE LED CONTROLLER 1. INTRODUCTION ............................................................................................................................ 3 2. PRIMARY-SIDE–CONTROL, BOUNDARY-CONDUCTION–MODE OPERATION AND TRIAC DIMMING............................................................................................................................................... 4 2.1. Primary Side Control .......................................................................................................... 4 2.2. Boundary Conduction Mode Operation............................................................................. 4 2.3. TRIAC Dimming................................................................................................................... 6 3. PIN FUNCTION AND OPERATION INFORMATION .................................................................... 10 3.1. Pin1 (MULT)....................................................................................................................... 10 3.2. Pin2 (ZCD) ......................................................................................................................... 11 3.3. Pin3 (VCC) ......................................................................................................................... 13 3.4. Pin4 (GATE)....................................................................................................................... 13 3.5. Pin5 (CS)............................................................................................................................ 14 3.6. Pin6 (GND)......................................................................................................................... 15 3.7. Pin7 (FB/NC)...................................................................................................................... 15 3.8. Pin8 (COMP) ...................................................................................................................... 15 3.9. Auto Restart ...................................................................................................................... 16 3.10. Output Short Circuit Protection ....................................................................................... 16 4. DESIGN EXAMPLE ...................................................................................................................... 17 A. Specifications ................................................................................................................... 17 B. Schematic.......................................................................................................................... 17 C. Transformer Design Spreadsheet (The software is MPS design tool for MP4020 transformer design)....................................................................................................................... 18 C.1. Input and Output Spec ................................................................................................. 18 C.2. Transformer Turns Ratio .............................................................................................. 18 C.3. The Frequency and Primary Inductance of the Transformer......................................... 19 C.4. Transformer Core and Turns ........................................................................................ 19 D. Transformer Manufacture Instructions ........................................................................... 22 E. Input EMI Filter (L1, L2, CX1, CX2, CY1) .......................................................................... 24 F. Input Bridge (BD1) ............................................................................................................ 24 G. Input Capacitor (C4).......................................................................................................... 24 H. Damping and Bleeding Circuit ......................................................................................... 24 I. ZCD and OVP Detector (R1, R2, C11, D5) ........................................................................ 25 J. MULT PIN Resistor Divider (R7, R3, R4, C5) ................................................................... 25 K. Current Sensing Resistor (R8, R9, R14) .......................................................................... 25 L. Layout Guideline............................................................................................................... 25 M. BOM ................................................................................................................................... 26 5. EXPERIMENTAL RESULT........................................................................................................... 28 5.1. Efficiency vs. Line Voltage............................................................................................... 28 5.2. Output LED Current Dimming Curve ............................................................................... 28 5.3. PF, THD vs. Line Voltage.................................................................................................. 29 5.4. Conducted EMI (VIN=120V) ............................................................................................... 29 5.5. Steady State: VIN =120V .................................................................................................... 31 5.6. Input Current and MULT Voltage: VIN=120V .................................................................... 31 5.7. Start Up and Shut Down: VIN =120V ................................................................................. 32 5.8. OVP (open load at normal operation and OVP recovery): VIN =120V............................. 32 5.9. SCP (Short LED+ to LED- at Normal Operation and SCP Recovery): VIN =120V........... 33 5.10. TRIAC Dimmer Compatibility Test ................................................................................... 33 AN039 Rev. 1.0 12/30/2013 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. 2 AN039 –PRIMARY-SIDE–CONTROL AND TRIAC DIMMABLE LED CONTROLLER 1. INTRODUCTION The MP4020 is a primary-side–control LED lighting controller with TRIAC dimming. Primary-side control can significantly simplify the LED lighting driving system by eliminating the opto-coupler and the secondary feedback components in an isolated single stage converter. Its proprietary real-current– control method can accurately control the LED current from the primary-side information. The MP4020 also integrates active power factor correction (PFC) with boundary-conduction mode operation. This application note will introduce the basic function of MP4020, and then gives design examples that describe how to configure MP4020 for a TRIAC-dimmable LED driver with a single-stage power-factor– corrected flyback solution. Figure 1 shows the MP4020 block diagram and simple application circuit. Detail design specification will be described in the next sections. N:1 EMI filter GATE MULT PWM / PFC Control Gate driver TRIAC Phase Detector Multiplier Current control Current sense CS Current Sense COMP Current LImit Short Circuit Latch off or Restart OTP Power supply Protection UVLO FB/NC VCC Real Current Control Power Supply Zero current detection GND OVP ZCD Zero Current Detection Figure 1—MP4020 Function Block Diagram and Typical Circuit AN039 Rev. 1.0 12/30/2013 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. 3 AN039 –PRIMARY-SIDE–CONTROL AND TRIAC DIMMABLE LED CONTROLLER 2. PRIMARY-SIDE–CONTROL, BOUNDARY-CONDUCTION–MODE OPERATION AND TRIAC DIMMING 2.1. Primary-Side–Control The conventional off-line LED lighting driver usually uses secondary side control. The LED current is directly sensed from the transformer secondary side and comparared to a reference from a TL431. The EA output is compensated and fed to the primary side by an opto-coupler to determine the duty cycle that regulates the LED current. This control method has the advantage of directly and accurately controlling the LED current, but a substantial number of external components and circuits that significantly increase cost and system complexity. As shown in Figure 1, the MP4020 uses primary-side–control, which eliminates the secondary feedback components. Given that the LED current is the average current of the secondary side during a half-line cycle ( Io = Is _ avg ), the MP4020 can calculate the average current of the transformer secondary side from the primary side current and control it with an internal reference voltage, this is the MP4020 primaryside-control principle. With the addition of a dimmer to the driver, MP4020 will detect the dimming phase and change the internal reference accordingly. So the average current of the LED will be proportional to the dimming phase and realize dimming function. 2.2. Boundary-Conduction Mode Operation The MP4020 works in boundary-conduction mode (also canlled quasi-resonant mode), where the transformer works at the boundary between the continuous and discontinuous modes. Figure 2 shows the drain-source voltage waveform of the primary switch in a conventional current-mode flyback converter operating in discontinuous conduction mode (DCM). During the first time interval, the drain current ramps up to the desired current level, then the power MOSFET turns off. The leakage inductance in the flyback transformer rings with the MOSFET parasitic capacitance and causes a high voltage spike, which is limited by a clamp circuit. After the inductive spike has been damped, the drain voltage stabilizes to the input voltage plus the reflected output voltage. When the current in the output diode drops to zero, the drain voltage immediately drops to the bus voltage plus any ringing caused by the primary parasitic inductance and total parasitic capacitance. For example, if the inductance is 1mH and the parasitic capacitance is 100pF, then the resonant frequency is ~500 kHz. The resonant circuit is lightly damped and the resonant frequency given below is independent of the input voltage and load currents: fresonant = 1 2π ⋅ Lm ⋅ Ceqp Where Lm is the primary inductance; and Ceqp is the equivalent primary-side parasitic capacitance. Ceqp includes the parasitic capacitance of the primary winding, the parasitic capacitance of the MOSFET, and the parasitic capacitance of the secondary side (including the secondary winding and output rectifier diode) reflecting to the primary side. AN039 Rev. 1.0 12/30/2013 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. 4 AN039 –PRIMARY-SIDE–CONTROL AND TRIAC DIMMABLE LED CONTROLLER N: 1 + Is + VOUT - VB U S ID VD V B U S +N VO U T VBUS ID 1 /N *Is Figure 2—Single-Pulse of DCM Flyback Converter In a conventional fixed-frequency flyback converter at DCM operation, the primary MOSFET turns on at a fixed frequency and turns off when the current reaches the desired level. The device may turn on at any point during the parasitic ringing. In some cases the device may turn on when the drain voltage is lower than the bus voltage (meaning low switching losses and high efficiency), and in some cases the switch will turn on when the drain voltage is higher above the bus voltage (meaning high switching loss). This characteristic is often observed in the efficiency curves of discontinuous flyback converters with a constant load, where the efficiency fluctuates with the input voltage and the turn-on switching loss changes due to the variation of the drain voltage at the turn-on point. For the boundary conduction operation, the rectified input voltage is applied across the primary side inductor (Lm) and the primary current increases linearly from zero to its peak value (Ipk) during the external MOSFET on time (TON). When the external MOSFET turns off, the energy stored in the inductor forces the secondary side diode to turn-on, and the inductor current decreases linearly from Ipk to zero. When the current reaches zero, the resonance of the inductor with parasitic capacitance makes the MOSFET drain-source voltage decrease (see Figure 3). This decrease is also reflected on the auxiliary winding. A zero-current detector generates turn-on gate driver for the external MOSFET when the ZCD pin voltage is less than 0.35V. This ensures that the MOSFET will turn-on at a valley voltage (see Figure 3). As a result, there are virtually no primary switch turn-on losses and no secondary diode reverserecovery losses. This technique ensures high efficiency, lower temperature rise, and low electromagnetic interference (EMI) noise. . AN039 Rev. 1.0 12/30/2013 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. 5 AN039 –PRIMARY-SIDE–CONTROL AND TRIAC DIMMABLE LED CONTROLLER N:1 + VO U T + Is VB U S ID ZC D VD V B U S+N VO U T VBUS v a lle y T1 ID 1/N*I s T0 T zcd _d elay V ZC D 0 Figure 3—Boundary Conduction Mode 2.3. TRIAC Dimming There are two kinds of phase-cut dimmers: leading-edge (TRIAC based, shown in Figure 4), and trailing-edge (transistor based, shown in Figure 5). Energy delivered Phase cut Figure 4—Leading-edge Phase Cut Mode AN039 Rev. 1.0 12/30/2013 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. 6 AN039 –PRIMARY-SIDE–CONTROL AND TRIAC DIMMABLE LED CONTROLLER Energy delivered Phase cut Figure 5—Trailing-Edge Phase-Cut Mode In leading-edge phase cut mode，the dimmer is always TRIAC-based as shown in Figure 6. The TRIAC turns on after an RC delay, and the input voltage goes to the driver every half line-cycle. The high-input skipping voltage on the input capacitors causes a large input current: This current may cause the lamp to flicker and high power loss. For applications, the input capacitance—including the EMI filter capacitor and the input buffer capacitor—must be as small as possible. Use an additional damping circuit to avoid flicker from current oscillations. Figure 6—TRIAC Based Leading-Edge Dimmer AN039 Rev. 1.0 12/30/2013 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. 7 AN039 –PRIMARY-SIDE–CONTROL AND TRIAC DIMMABLE LED CONTROLLER Figure 7(a) shows the input current without a damping circuit. In this situation, the inrush current when triac on rushes to zero and the triac is turned off abnormally. After a short time, the TRIAC turns on again. The driver input voltage (the same as MULT Pin voltage) also turns on and off repeatedly, which causes the LED to flicker. Input current Input current Mult Mult Comp Comp Gate a. Input Current without Damping Circuit Gate b. Input Current with Damping Circuit Figure 7—Input Current without and with Damping Circuit Figure 8(a) shows the damping circuit. R19 is the damping resistor used to damp the input current when TRIAC turns on. Figure 7(b) shows the input current with damping circuit. The current is damped when the TRIAC turns on and the current will gradually reach zero to avoid flicker. But if R19 is always connected in the circuit, the energy consumed by R19 will be large and the efficiency will be low. Instead, an active damping circuit composed of R15 to R18, C13, D7, D8, Q2, Q3 in figure 8(a) selectively connects R19 to the rest of the circuit. When TRIAC turns on, Q3 is off and R19 is in series to damp the input current. The base of Q2 is high so it’s off, and C13 can be charged by input voltage through R15, R16 and D7. When the voltage on C13 is enough, Q3 is turned on and R19 is shorted, so it can save the energy and increase the efficiency. When TRIAC is off, the base of Q2 is low and Q2 is on, so C13 discharges through Q2, Q3 will then turn off for the next cycle. The waveforms are shown in figure 8(b), and the re. GND is the part’s GND. AN039 Rev. 1.0 12/30/2013 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. 8 AN039 –PRIMARY-SIDE–CONTROL AND TRIAC DIMMABLE LED CONTROLLER BD1 DF06S Input current R15 750K Mult R16 750K V_R19 D7 15 Q2 3906 200K R17 Gate of Q3 R18 B1100 SMK0260 Q3 C13 12nF D8 R19 200 BZT52C15 b. Active Damping circuit working waveform Figure 8—Damping Circuit a. Active Damping Circuit The TRIAC-based leading-edge dimmer needs a holding current (usually 20 to 30mA) to maintain TRIAC on. the TRIAC will turn off unpredictably with a smaller holding current. If the holding current reduced too early, the flicker will be seen in the lamp. An extra bleeding circuit can resolve the flicker as a preload to increase the minimum holding current. Figure 9 shows the bleeding circuit used to preload the TRIAC dimmer. The bleeding circuit is a capacitor in series with a resistor. It can block the line frequency power but provide a path for the resonant frequency current, so this can help keeping the line current above the holding current and avoid flicker caused by current resonance. BD1 R24 510/1W R23 510/1W DF06S C12 0.22uF/400V Figure 9—Damping Circuit For a trailing-edge dimmer, the dimmer turns on when the input line voltage near zero, so there is no inrush current to the capacitor, and no flicker caused by the inrush current. The dimmer turns off after a manual adjusting time, and not turned off by current zero-crossing like the TRIAC dimmer. Therefore, a trailing-edge dimmer doesn’t need either bleeding or damping circuits, but the line voltage will not decrease to zero immediately after dimmer turns off as the input voltage is cut off at a high point. In addition, if the input capacitance is too large, the dimmer output voltage may decrease more slowly AN039 Rev. 1.0 12/30/2013 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. 9 AN039 –PRIMARY-SIDE–CONTROL AND TRIAC DIMMABLE LED CONTROLLER than the dimmer input voltage, the dimmer may turn on randomly and cause flicker. Therefore, chose small values for the EMI filter capacitor and buffer capacitor. 3. PIN FUNCTION AND OPERATION INFORMATION 3.1. Pin1 (MULT) The MULT pin is one of the input pins of the internal multiplier, and it is used for PFC function and dimming phase detection in MP4020. The MULT pin connects to the tap of the resistor divider from the rectified instantaneous line voltage, so that the output of the multiplier will have the same shape as the rectified voltage. This voltage provides the reference for the current comparator which sets the primary peak current. For non-dimmer applications of the MP4020, the primary peak current is shaped as a sinusoid in phase with the input line voltage cycle by cycle and it can realize the PFC function. Otherwise, the MULT pin is used to detect the dimming phase. When mult voltage is higher than 0.35V, it means dimming on and the part will work in the dimming on state. When mult voltage is lower than 0.1V, it means dimming off. The internal reference will linearly change with the dimming duty and dim the output current accordingly. Triac output AC mains Triac dimmer RMULT1 Primary Current Sense dimming duty + MULT + - CMULT RMULT2 Current Comparator 0.1V Multiplier >2. 8V clamp COMP EA 0.4V*dimming duty Figure 10—MULT Pin Connection Circuitry The MULT pin linear operation voltage range is 0 to 3V. If the MULT voltage is much higher than 3V, the power factor (PF) will be lower and the total harmonic distortion (THD) will be higher. However, the MULT pin voltage can not be set too low or this will cause a high COMP voltage to regulate the same LED current: the COMP voltage may saturate when the MULT pin is set too low. In addition, if the MULT voltage, at low input voltage the MULT pin may not be able to detect the dimming on signal (0.35V). Set the MULT voltage using the model shown below: RMult2 2 × VIN _ MIN(rms) × > 0.5 ~ 1 RMult1 + RMult2 2 × VIN _ MAX(rms) × RMult2 < 2.5 ~ 3 RMult1 + RMult2 Considering the power loss, the RMULT1 should be large enough, usually 1M for high-input voltage use. AN039 Rev. 1.0 12/30/2013 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. 10 AN039 –PRIMARY-SIDE–CONTROL AND TRIAC DIMMABLE LED CONTROLLER 3.2. Pin2 (ZCD) Auxiliary Winding + Vcc RZCD1 Valley signal ZCD 0.35V Driver Q RZCD2 CZCD OVP signal S R RS Latch 5.5V Flip Flop 1.5uS Blanking Figure 11—ZCD Pin Connection Circuitry The ZCD pin connection circuitry is shown in Figure 11. It connects to the auxiliary winding through a resistor divider. The ZCD pin is used for two functions: one is to detect the valley voltage of the MOSFET, which occurs when the secondary side current decreases to ensure the boundary conduction mode operation; the other is to implement the output over-voltage protection (OVP) when compared to the internal 5.5V reference. Figure 12 shows the ZCD voltage. The internal valley signal triggers when the falling edge of the ZCD pin voltage drops below 0.35V. A ceramic bypass capacitor absorbs the high frequency oscillation caused by the leakage inductance and the parasitic capacitance after the primary switch turns off. Without the bypass capacitor, this oscillation may cause the false-positives in ZCD valley detection. VZCD Sampling Here 0V TOVPS TZCD_delay Figure 12—The ZCD Voltage AN039 Rev. 1.0 12/30/2013 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. 11 AN039 –PRIMARY-SIDE–CONTROL AND TRIAC DIMMABLE LED CONTROLLER The switching frequency of MP4020 changes with the input instantaneous line voltage. To limit the maximum frequency and attain good EMI and efficiency performance, MP4020 employs an internal minimum off time limiter—3.5μs, shown in Figure 13. The ZCD signal is external in Figure 13, after gate off, there will be a min off time even the part has detect the gate on signal from ZCD pin. . ZCD GATE Toff >3.5µs 1µs/div Figure 13—Minimum Off Time The output over voltage protection is achieved by detecting the positive plateau of auxiliary winding voltage which is proportion to the output voltage (see Figure 12). Once the ZCD pin voltage is higher than 5.5V after a blanking time, the OVP signal will be triggered, the gate driver will be turned off and the VCC voltage dropped below the UVLO which will make the IC reset and the system restarts again. The part will work in hiccup mode. The output OVP setting point can be calculated as: Vout − ovp ⋅ Naux R ZCD2 ⋅ = 5.5V Nsec R ZCD1 + R ZCD2 Where: VOUT_OVP—Output over voltage protection point NAUX—The auxiliary winding turns NSEC—The secondary winding turns To avoid the OVP mistriggering caused by ringing after the switch turns off, the MP4020 integrates an internal TOVPS blanking time of 1.5μs for the OVP detection (see Figure 12). AN039 Rev. 1.0 12/30/2013 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. 12 AN039 –PRIMARY-SIDE–CONTROL AND TRIAC DIMMABLE LED CONTROLLER 3.3. Pin3 (VCC) The VCC pin provides the power supply to both the internal logic circuitry and the gate driver signal. Figure 14 shows the VCC pin connection circuit and the power supply flow-chart. The bulk capacitor CVCC1 (typically 22μF) initially charges from the AC line through RVCC1 when AC power initially turns on. Once the VCC voltage reaches UVLO_H (12V), the IC will turn on and begin switching. The power consumption of the IC increases, then the auxiliary winding starts working and mainly takes in charge of the power supply for VCC. Since the auxiliary winding voltage is proportional to the secondary winding voltage, the VCC voltage stabilizes to a constant value. If VCC drops below the UVLO_L threshold (7.6V) before the auxiliary winding can provide power, the IC will shut down and VCC will begin to charge from the Bus voltage again. If OVP or other hiccup signal happens at normal operation, the switching signal will stop and the IC works in quiescent mode. When the VCC voltage drops below 7.6V the system restarts.RVCC1 must be large enough to limit the charging current which ensures the VCC voltage can drop below 7.6V (typically 1mA consumption current in quiescent mode). However, an extremely large RVCC1 will delay start-up. Also, a small ceramic capacitor CVCC2 (typically 100pF) is needed to reduce the noise. 85~265VAC RVC C 1 VCC R VC C 2 * Vcc D VC C C VC C 1 Auxiliary winding takes charge and regulates the VCC 7. 6V /12V 32.5V + C VC C 2 EN Internal bias OVP or other hiccup signal 12V 7.6V Gate Switching Pulses Figure 14—VCC Pin Connection Circuitry and the Power Supply Flow-Chart 3.4. Pin4 (GATE) Pin 4 is the gate driver output to drive an external MOSFET. The internal totem-pole output stage can drive an external high-power MOSFET with 1A source and 1.2A sink capability. The pin voltage is clamped to 13V to avoid excessive gate driver voltage. Connect this pin to the MOSFET gate in series with a driving resistor. A smaller driving resistor provides faster MOSFET switching, reduces switching loss, and improves MOSFET thermal performance. However, larger driving resistors usually provide better EMI performance. For this reason, the driving resistors should be tuned for different applications. Typically, the value of the driving resistor ranges from 5Ω to 20Ω. AN039 Rev. 1.0 12/30/2013 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. 13 AN039 –PRIMARY-SIDE–CONTROL AND TRIAC DIMMABLE LED CONTROLLER 3.5. Pin5 (CS) The CS pin senses the primary side current using a sensing resistor. The resulting voltage is fed to both the current comparator to determine the MOSFET turn off time and the average current calculation block to calculate the primary current average value. The output LED mean current can be calculated approximately as: N × VFB IO ≈ 2 × RS Where: N is the turn ratio between the primary winding and the secondary winding VFB is the feedback reference voltage (typically 0.4) Rs is the sensing resistor connected between the MOSFET source and GND. The maximum voltage on CS pin is clamped at 2.8V to get a cycle-by-cycle current limit. In order to avoid premature termination of the switching pulse due to parasitic capacitance discharge when the MOSFET turns on, the MP4020 uses an internal leading-edge blanking (LEB) unit between the CS Pin and internal feedback. During the blanking time, the internal fed path is blocked. Figure 15 shows the LEB VCS TLEB =280nS t Figure 15—Leading-Edge Blanking AN039 Rev. 1.0 12/30/2013 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. 14 AN039 –PRIMARY-SIDE–CONTROL AND TRIAC DIMMABLE LED CONTROLLER 3.6. Pin6 (GND) The ground pin is the current return for the control signal and the gate driver signal. Connect this pin to both power and analog GND on the PCB layout. Otherwise, keep power and analog GNDs on separate planes on the PCB. 3.7. Pin7 (FB/NC) Pin 7 is the feedback signal pin. As shown in Figure 16, the FB signal connects to the negative input of the error amplifier (EA) and compared against the 0.4V reference when dimming on, so at steady state, the average value of FB will be regulated to 0.4V*Ddimming . The average current calculation block output is internally connected to the FB with high input impedance. If there is no other external feedback signal is applied on FB pin, the average current from CS pin will be regulated, if there is external FB signal with low input impedance apply in this pin, the external FB signal will be regulated. This structure makes the MP4020 suitable for both primary side control application without other feedback signals and direct control application with an applied external feedback signal. Average current calculation COMP CCOMP FB ICOMP EA 0.4V*D dimming Figure 16—FB Pin Structure 3.8. Pin8 (COMP) Pin 8 is the loop compensation pin. Connect a low-ESR ceramic compensation capacitor—such as an X7R capacitor—from this pin to AGND. The COMP pin is the internal current-source error amplifier output with maximum 75uA source current and 200uA sink current. Select a capacitor value between 2.2uF and 10uF in order to get a limit loop bandwidth of <20Hz. A small cap will result in low PF, because the comp voltage will change to compensate the mult voltage, and the multiplier output voltage could not follow the line voltage and the PF is low. A large capacitor results in small input and output current ripple and better thermal, EMI, and steady-state performance. However, a large capacitor also results in a longer soft-start time which will cause a bigger voltage drop for VCC at start up (see figure 17)—if VCC drops below UVLO, start-up may fail.. AN039 Rev. 1.0 12/30/2013 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. 15 AN039 –PRIMARY-SIDE–CONTROL AND TRIAC DIMMABLE LED CONTROLLER VCC Io COMP GATE 400ms/div Figure 17—COMP and VCC Waveform at Start Up 3.9. Auto Restart The MP4020 integrates an auto starter that begins when the MOSFET turns on. If ZCD fails to send out another turn-on signal after 130us, the starter will automatically send a turn-on signal that can avoid unnecessary IC shutdown by ZCD missing detection. 3.10. Output Short-Circuit Protection In the event of an output short circuit, the positive plateau of the auxiliary winding voltage is also near zero. so the gate signal is 130us auto starter, the VCC can not be held on and it will drop below VCC UVLO. The IC will run at hiccup mode. AN039 Rev. 1.0 12/30/2013 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. 16 AN039 –PRIMARY-SIDE–CONTROL AND TRIAC DIMMABLE LED CONTROLLER 4. DESIGN EXAMPLE Example 1: 8W, 120V, TRIAC-Dimmable LED Bulb Driver A. Specifications Parameter Input voltage Output voltage Output current Symbol Vac Vo Io_max Value 95 to 135 16 500 Unit V V mA B. Schematic Figure 18—Schematic of Example 1 AN039 Rev. 1.0 12/30/2013 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. 17 AN039 –PRIMARY-SIDE–CONTROL AND TRIAC DIMMABLE LED CONTROLLER C. Transformer Design Spreadsheet (THE SOFTWARE IS MPS DESIGN TOOL FOR MP4020 TRANSFORMER DESIGN) C.1. Input and Output Spec The underlined red data is user input. This tool can calculate the cyan data. C.2. Transformer Turn Ratio The primary voltage spike occurs at the MOSFET Q1. It usually results from energy dissipation from the leakage inductance of the transformer and the RCD snubber circuit as shown in Figure 19. R6 and C8 can regulate the primary voltage spike. Larger values of C8 and smaller values of R6 result in a smaller spike, but very small spikes result in low efficiency. For optimal results, select voltage spike amplitudes between 100 and 150V. Reflected output voltage is the voltage reflecting from the secondary side of the transformer to the primary side when the MOSFET is off. It determines the Q1 MOSFET voltage rating, the D2 diode voltage rating, and the transformer turn ratio. A larger reflected output voltage means a higher Q1 voltage rating, and a smaller reflected output voltage means a higher D2 voltage rating. Selected a reflect output between 100 and 150V. AN039 Rev. 1.0 12/30/2013 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. 18 AN039 –PRIMARY-SIDE–CONTROL AND TRIAC DIMMABLE LED CONTROLLER C8 R6 A D2 leakage inductance Figure 19—RCD Snubber Circuit on Primary Side C.3. The Frequency and Primary Inductance of the Transformer The min frequency of the transformer occurs at the peak of the min input voltage, and determines the primary side inductance and the max frequency. In the universal input case, select the min frequency somewhere between 40kHz and 45kHz. In narrow input case, select the min frequency between 60kHz and 80kHz. Lower frequency can decrease the switching loss and improve EMI performance, but increase the size of the transformer. C.4. Transformer Core and Turns Users need to determine which core to use and then input the Ae and Aw. This tool will calculate the turns and diameter of each winding using the user’s core information. This tool will also check the fill factor: if the fill factor is larger than 0.3, users need to select a larger core; if the fill factor is much lower than 0.3, users need to select a smaller core. After filling in the parameters, users can press the button and the tool will print the specs of the transformer as shown in Figure 20. AN039 Rev. 1.0 12/30/2013 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. 19 AN039 –PRIMARY-SIDE–CONTROL AND TRIAC DIMMABLE LED CONTROLLER If the user does not know which core to select, there is an auto-select core method. Users just need to select the core shape, and the tool will auto-select a suitable core for the spec and calculate the winding turns. Then users need to determine the diameter of the windings. Then the tool can check the fill factor and generate the transformer specs as the first method shows. For example, we use the same core shape in two different methods, the result are the same, just as Figure 20 shows. AN039 Rev. 1.0 12/30/2013 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. 20 AN039 –PRIMARY-SIDE–CONTROL AND TRIAC DIMMABLE LED CONTROLLER AN039 Rev. 1.0 12/30/2013 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. 21 AN039 –PRIMARY-SIDE–CONTROL AND TRIAC DIMMABLE LED CONTROLLER Figure 20—Paper Design Result of the Transformer D. Transformer Manufacture Instructions There are two main considerations for the transformer design. To minimize the effect of the leakage inductance spike, the coupling between the transformer primary side and the secondary side should be as tight as possible. This can be accomplished be interleaving the primary and secondary winding in transformer manufacture (shown in figure 21). To minimize the coupling capacitance between the primary winding and the secondary winding, the auxiliary winding can be sandwiched between them as shown in Figure 21. The Drain pin should be the starting dot of the primary side winding. And on the PCB layout, the GND of the auxiliary winding must be placed between the primary side and the auxiliary side as shown in Figure 22. AN039 Rev. 1.0 12/30/2013 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. 22 AN039 –PRIMARY-SIDE–CONTROL AND TRIAC DIMMABLE LED CONTROLLER Figure 21—The Transformer Winding Diagram 6 N4 x N1 1 5 N3 3 2 AUX+ N2 SEC.二次侧 PRI.一次侧 AUX+ is one pin of auxiliary winding WINDING START TEFLON TUBE Figure 22—Transformer Pin-Out and the Connection Diagram AN039 Rev. 1.0 12/30/2013 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. 23 AN039 –PRIMARY-SIDE–CONTROL AND TRIAC DIMMABLE LED CONTROLLER E. Input EMI Filter (L1, L2, CX1, CX2, CY1) The input EMI filter is comprised of L1, L2, CX1, CX2, and the safety rated Y class capacitor CY1. The value of the components should be selected to pass the EMI test standard EN55015 for lighting production. Usually, the interference below 1MHz is caused by differential mode (DM). Noise interefence from 1MHz to 5MHz is caused by both common mode (CM) and DM. CM causes interference above 5MHz. The interference is low enough (tested without common choke, as the results show), to only require DM capacitors (CX1 = CX2 = 22nF) and inductors (L1 = L2 = 2.2mH) in this case. Increasing the DM capacitor and inductor can improve the EMI result below 1MHz. But in the TRIAC dimming condition, a large capacitor may cause flicker, so chose a small capacitor. If the event of poor results between 1MHz and 5MHz ,add common choke to the filter: this choke can also improve results above 5MHz. The Y class capacitor can improve results from 20MHz to 30MHz. F. Input Bridge (BD1) The input bridge can use standard slow recovery, low-cost diodes. Diode selection involves consideration of 3 criteria: the maximum input RMS current, the maximum input line voltage, and the thermal performance. G. Input Capacitor (C4) Chose a relatively small value for the input decoupling capacitor to get a high power factor. The function of the capacitor is mainly to attenuate the switching current ripple of the transformer at high magnetizing frequencies. The worst case occurs at the peak of the minimum rated input voltage. The maximum high frequency voltage ripple of the capacitor should be limited to 20%, or the large voltage ripple will influence the sensing accuracy of the MULT pin which will also influence the PFC function. In real applications, the input capacitor must be as small as possible, and designed to account for the EMI filter, the power factor value, and TRIAC dimming performance H. Damping and Bleeding Circuit The principle of the Damping and Bleeding circuit is described in “2.3 TRIAC dimming”. R15, R16, R17, R18, C13, D7, D8, Q2, Q3 are used with R19 to consist an active damping circuit. In this case, as the resonance is not so strong, so R19=0, and the damping circuit can be removed from the circuit. As a reference, we put the parameters in the circuit. Larger R19 (usually from 200 Ω to 500Ω，too large will cause low efficiency) will result in strong damping, increasing the RC time of (R15+R16)*C13 can also increase the function of the damping circuit. And other components can usually use the commend parameters as the SCH shows. R23, R24 and C12 consist of the bleeding circuit. It can block the line frequency power but provide a path for resonant frequency current, so this can help keeping the line current above the holding current and avoiding flicker caused by resonant current. Larger C12 results in strong bleeding, and C12 is usually selected from 100nF to 220nF. R19, R23, R24 and C12 need to be regulated in the real circuit. AN039 Rev. 1.0 12/30/2013 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. 24 AN039 –PRIMARY-SIDE–CONTROL AND TRIAC DIMMABLE LED CONTROLLER I. ZCD and OVP Detector (R1, R2, C11, D5) Please refer to page 12 and 13 for detailed design information. The resistor divider by R1 and R2 sets the OVP threshold: Vo _ ovp ⋅ Naux R2 ⋅ = 5.5V Ns R1 + R2 (32) Where Vo _ ovp is the output OVP setting voltage; Naux is the auxiliary winding turns of the transformer and Ns is secondary winding turns of the transformer. In this case, Vo_ovp is about 20V, Naux = 22, Ns = 14, so we can select R2 = 2.4k, R1 = 11.5k. A 10pF ceramic bypass capacitor (C11) is added on ZCD pin absorbs the high frequency oscillation on ZCD voltage when the MOSFET turns off. In addition, a diode (D5) connected from ZCD pin to GND clamps the ZCD negative voltage, which can help improve the noise influence on the ZCD pin. J. MULT PIN Resistor Divider (R7, R3, R4, C5) For the MULT pin resistor divider setting information, please refer to design information on page 11. In this example, we have chosen R3 = 1MΩ, R4 = 3kΩ, and C5 = 100pF. K. Current Sensing Resistor (R8, R9, R14) The current sensing resistor can be approximately set by the following equation: Rs ≈ VFB ⋅ N 2 ⋅ Io (33) Where N is the turn ratio of primary winding to secondary winding, VFB is the feedback reference voltage (typically 0.4V), Rs is the sensing resistor connected between the MOSFET source and GND. But in real applications with primary-side control, modeling accuracy for the output current is much more difficult because there are many factors influencing the output current setting value—such as the internal logic delay of the IC, the transformer inductance, the MOSFET input and output capacitor, the ZCD detection delay time, the RCD snubber, the gate driver resistor, among them. With this in mind, determine the current sensing resistor last after fine-tuning the resistance with a bench test. L. Layout Guideline z The path of the main power flow should be as short as possible, and the trace should be as wide as possible, the cooper pour for the power devices should be as large as possible to get a good thermal performance. z Separate the power and the analog GNDs, except at a single via to the GND of C4. z In order to minimize the coupling interference between the primary winding and the auxiliary winding, the same mean dot of the two windings should be far away. It is better to be separated by the GND. z Make a loop from C4, through the primary winding of T1, through Q1, .R8, R9, and R14 as small and short as possible. Do not run the loop under the IC. z The IC pin components should be placed as close as possible to the corresponding pin, especially the ZCD bypass capacitor and the COMP pin capacitor. z The primary side and the secondary side should be well isolated, and the trace from the transformer output return pin to the return point of the output filter capacitor should be as short as possible. AN039 Rev. 1.0 12/30/2013 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. 25 AN039 –PRIMARY-SIDE–CONTROL AND TRIAC DIMMABLE LED CONTROLLER M. BOM Qty Designator Value 1 BD1 DF06S 2 C1, C2 470uF/35V 1 1 C3 C4 NC 100nF/400V 2 C5, C7 100pF 1 C6 22uF/50V 1 C8 22nF/630V 1 C9 NC 1 C10 2.2uF/10V 1 C11 10pF 1 C12 220nF/400V 1 C13 12nF 1 C14 NC 2 CX1,CX2 22nF 1 CY 2.2nF 1 1 1 D1 D2 D3 1 D4 NC US1K-E3 ES1D MBRS3100T 3G 1 D5 1N4148W 1 D6 BZT52C20 1 D7 B1100 1 D8 BZT52C15 1 F1 250V/2A 2 L1,L2 1 Q1 1 Q2 AN039 Rev. 1.0 12/30/2013 Inductor,2.2 mH IPP50R350C P MMBT3906L T1 Description DIODE/BRIDGE /DF06S/B Electrolytic Capacitor;35V Package Manufacturer Manufacture_PN SMD Qianlongxin DF06S DIP Rubycon 470uF/35V CBB,400V Ceramic Cap,50V,NPO Electrolytic Capacitor;50V Ceramic Cap, 630V，X7R DIP Panasonic CBB 0.1uF/400V 0603 LION 0603B10K500T DIP Jianghai CD281L-50V22 1210 muRata GRM32QR72J223KW 01 0805 LION C1608X7R1H102K 0603 LION 0603N100J500T DIP Panasonic 0603 muRata ECQE4224KF GRM188R71H123KA 01D DIP carli DIP Hongke JN09F222ML72N Diode, 1A,800V Diode, 1A,200V SMA SMA US1K-E3/61T ES1D Diode,3A,100V SMC Vishay Premier ON Semiconductor Ceramic Capacitor;10V;X 7R;0805 Ceramic Cap,50V,X7R CBB,400V Ceramic Cap,50V,X7R Film Capacitor, X2,275V Y Capacitor,2600 V DIODES/SOD123 DIODES/SOD123 schottky diode DIODES/SOD123 MBRS3100T3G SOD-123 Diodes 1N4148W SOD-123 Diodes BZT52C20 SMA Diodes B1100-13-F SOD-123 Diodes BZT52C15 SS-5-2A DIP COOPER BUSSMAN SS-5-2A Inductor,2.2mH DIP MOSFET, 550V TO-220 PNP,transistor SOT-23 IPP50R350CP ON Semiconductor MMBT3906LT1 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. 26 AN039 –PRIMARY-SIDE–CONTROL AND TRIAC DIMMABLE LED CONTROLLER Qty Designator Value Description Package Manufacturer Manufacture_PN 1 Q3 MOSFET, 600V TO-252 Q4 NPN, transistor SOT-23 1 1 1 1 1 1 1 2 1 1 1 1 1 2 1 1 1 1 2 R1 R2 R3 R4 R5 R6 R7 R8,R14 R9 R10 R11 R12 R13 R15,R16 R17 R18 R19 R20 R21,R22 Film RES, 1% Film RES, 1% Film RES, 1% Film RES, 1% Film RES, 1% Film RES, 5% Film RES, 1% Film RES,1% 0603 0603 1206 0603 1206 1206 0603 1206 AUK ON Semiconductor Yageo LIZ Panasonic Yageo Panasonic Yageo Yageo Royalohm SMK0260D 1 SMK0260D MMBT3904L T1 11.5k 2.4k 1M 3k 499k 100K 20 1 NC 10M 30k 100 357 750k 200k 15 200 0 1K RC0603FR-0711K5L CR0603JA0242G RC1206FR-071ML RC0603FR-073KL ERJ8EF4993V RM12JTN104 RC0603FR-07560KL 1206F100KT5E 1206 1206 0603 1206 0603 0603 0603 DIP 0603 1206 Royalohm Royalohm Yageo Yageo Yageo Yageo Yageo 12061005T5E 12063002T6E RC0603FR-07100RL RC1206FR-07357RL RC0603FR-07750KL RC0603FR-07200KL RC0603FR-0715RL Royalohm Royalohm RR0603L0R0JT 1206F1001T5E 2 R23,R24 510 Film RES,1% Film RES,1% Film RES,1% Film RES,1% Film RES,1% Film RES,1% Film RES,1% DIP, 2W Film RES, 1% Film RES,1% DIP,1W RESISTOR 1 2 1 R25 JR1 RV1 NC 0 NC Film RES, 1% 0805 1 T1 RM6 1 U1 MP4020GS AN039 Rev. 1.0 12/30/2013 Np:Ns:Naux=11 2:14:22 Lp=2.4mH MP4020GS MMBT3904LT1 DIP 0805S8J0000T5E RM6 SOIC8 MPS www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. 27 AN039 –PRIMARY-SIDE–CONTROL AND TRIAC DIMMABLE LED CONTROLLER 5. EXPERIMENTAL RESULT All measurements performed at room temperature 5.1. Efficiency vs. Line Voltage Vin(V) 95 100 110 120 135 Pin(W) 7.13 7.67 8.84 8.96 9.21 Vo(V) 15.26 15.3 15.44 15.44 15.47 Io(mA) 379 410 469 478 493 Efficiency 81.12% 81.79% 81.92% 82.37% 82.81% Efficiency vs Vin 100.00% Efficiency(%) 90.00% 80.00% 70.00% 60.00% 50.00% 40.00% 30.00% 20.00% 10.00% 0.00% 90 100 110 120 130 140 Vin(V) Figure 23— Efficiency vs. Input Line Voltage 5.2. Output LED Current Dimming Curve 180 478 Dimming on Phase(°) IO (mA) 134 444 114 386 94 318 73 245 63 190 50 132 35 67 27 43 Dimming curve (Dimmer：LEVITON 1G40O5) 500 450 400 Io(mA) 350 300 250 200 150 100 50 0 0 50 100 Dimming on Phase(°) 150 200 Figure 24— Output Current Accuracy vs. Input Line Voltage AN039 Rev. 1.0 12/30/2013 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. 28 AN039 –PRIMARY-SIDE–CONTROL AND TRIAC DIMMABLE LED CONTROLLER 5.3. PF, THD vs. Line Voltage Vin(V) PF THD 3rd harmonics IEC610003-2 95 100 110 120 135 98.80% 98.70% 98.50% 98.00% 97.20% 9.10% 9.30% 9.50% 9.60% 9.80% 8.40% 8.60% 9.00% 9.20% 9.40% 29.64% 29.61% 29.55% 29.40% 29.16% PF & THD vs Vin 120.00% PF & THD(%) 100.00% 80.00% PF THD 3rd harmonics IEC61000-3-2 60.00% 40.00% 20.00% 0.00% 90 100 110 120 Vin(V) 130 140 Figure 25—Output Current Accuracy vs. Input Line Voltage 5.4. Conducted EMI (VIN=120V) EMI test condition: Figure 26 shows the test conditon Figure 26—EMI Test Condition AN039 Rev. 1.0 12/30/2013 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. 29 AN039 –PRIMARY-SIDE–CONTROL AND TRIAC DIMMABLE LED CONTROLLER Test Result: as Figure 27 shows, the result meets the standard EN55015, and the margin is enough. Att 10 dB AUTO dBµV 100 kHz 120 RBW 200 Hz MT 1 s PREAMP OFF 1 MHz 10 MHz EN55015Q 110 SGL 1 PK MAXH 100 90 2 AV MAXH TDS 80 70 60 EN55015A 50 6DB 40 30 20 10 0 -10 9 kHz 30 MHz EDIT PEAK LIST (Final Measurement Results) EN55015Q Trace1: Trace2: EN55015A Trace3: --- TRACE FREQUENCY LEVEL dBµV DELTA LIMIT dB 1 Quasi Peak 9.24 kHz 56.59 2 CISPR Average9.48 kHz 51.50 1 Quasi Peak 39.8 kHz 53.30 2 CISPR Average54.6 kHz 61.72 1 Quasi Peak 250 kHz 43.85 -17.90 2 CISPR Average298 kHz 35.04 -15.25 2 CISPR Average566 kHz 31.93 -14.06 1 Quasi Peak 41.20 -14.79 2 CISPR Average2.15 MHz 31.23 -14.76 1 Quasi Peak 2.182 MHz 37.73 -18.26 2 CISPR Average8.858 MHz 25.45 -24.54 1 Quasi Peak 21.83 -38.16 938 kHz 27.226 MHz -53.41 -56.69 Figure 27—Conducted EMI Performance at 220V AC Input AN039 Rev. 1.0 12/30/2013 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. 30 AN039 –PRIMARY-SIDE–CONTROL AND TRIAC DIMMABLE LED CONTROLLER 5.5. Steady State: VIN =120V Figure 28—Max Dimming Phase Figure 29—220 VAC, Full Load Channel 4 : ILED, 200mA/div Channel 3 : VCS, 1V/div Channel 2 : VZCD, 5V/div Channel 1 : Gate, 10V/div, 4ms/div 5.6. Input Current and MULT Voltage: VIN=120V Figure 30—Max Dimming Phase Figure 31—Min Dimming Phase Channel 4 : ILED, 200mA/div Channel 1 : VMULT, 500mV/div, 4ms/div AN039 Rev. 1.0 12/30/2013 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. 31 AN039 –PRIMARY-SIDE–CONTROL AND TRIAC DIMMABLE LED CONTROLLER 5.7. Start Up and Shut Down: VIN =120V Figure 32—Start up, Full Load Figure 33—Shut Down, Full Load Channel 4 : ILED, 200mA/div Channel 3 : VCC, 10V/div Channel 2 : VCOMP 2V/div Channel 1 : Gate, 10V/div, 4ms/div 5.8. OVP (open load at normal operation and OVP recovery): VIN =120V Figure 34—OVP at Normal Operation Figure 35—OVP Recovery Channel 4 : ILED, 200mA/div Channel 3 : VCC, 10V/div Channel 2 : VCOMP, 2V/div Channel 1 : Gate, 10V/div, 4ms/div AN039 Rev. 1.0 12/30/2013 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. 32 AN039 –PRIMARY-SIDE–CONTROL AND TRIAC DIMMABLE LED CONTROLLER 5.9. SCP (Short LED+ to LED- at Normal Operation and SCP Recovery): VIN =120V Figure 36—SCP at Normal Operation Figure 37—SCP Recovery Channel 4 : ILED, 200mA/div Channel 3 : VCC, 10V/div Channel 2 : VCOMP, 2V/div Channel 1 : Gate, 10V/div, 4ms/div 5.10. TRIAC Dimmer Compatibility Test This spec and board is compatible with the following dimmers and the list will be updated after more test. AN039 Rev. 1.0 12/30/2013 Manufacturer Part No. Power Stage Imax (mA) Imin (mA) LUTRON 6B38-DV-600P 600W 433 110 LUTRON 6B38-DVLV-600P 600W 434 126 LUTRON 6B38-DV-603PG 600W 384 116 LUTRON 6B38-S-600P 600W 435 107 LUTRON 6B38-S-603PG 600W 387 105 LUTRON 6B38-S-600 600W 456 109 LUTRON 6B38-SLV-600P 600W 439 118 LUTRON 6B38-GL-600-IV 600W 457 135 LUTRON 6B38-GL-600-WH 600W 455 109 LUTRON NTLV-600-AL 600W 455 112 LUTRON LG-600PH-AL 600W 439 114 LUTRON AY-600P-AL 600W 437 136 LUTRON DNG-603PH-WH 600W 425 28 LUTRON TG-603GH-WH 600W 374 135 LUTRON TG-600PH-WH 600W 433 137 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. 33 AN039 –PRIMARY-SIDE–CONTROL AND TRIAC DIMMABLE LED CONTROLLER Manufacturer Part No. Power Stage Imax (mA) Imin (mA) LUTRON CN-600P 600W 432 125 LUTRON 6B38-Q-600P 600W 438 147 LUTRON TT300 300W 460 87 LEVITON 6633-P 600W 467 87 LEVITON 6633-P 600W 467 99 LEVITON 6633-P 600W 463 96 LEVITON 6631 600W 440 69 LEVITON IG40O5 600W 441 39 LEVITON TBI03 300W 470 25 NOTICE: The information in this document is subject to change without notice. Please contact MPS for current specifications. Users should warrant and guarantee that third party Intellectual Property rights are not infringed upon when integrating MPS products into any application. MPS will not assume any legal responsibility for any said applications. AN039 Rev. 1.0 12/30/2013 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. 34