MP4026 Primary-Side-Control, Offline LED Controller with Active PFC The Future of Analog IC Technology DESCRIPTION FEATURES The MP4026 is a primary-side-control, offline LED controller that achieves high-power factor and accurate LED current for isolated, singlepower-stage lighting applications in a tiny TSOT23-6 package. It is the next generation of the successful MP4021A. The proprietary realcurrent-control method accurately controls LED current from primary-side information with good line and load regulation. The primary-side-control eliminates the secondary-side feedback components and the opto-coupler to significantly simplify LED-lighting-system design. • The MP4026 integrates power-factor correction and works in valley switching mode to reduce MOSFET switching losses. The MP4026’s multiple protection features greatly enhance system reliability and safety. These features include over-voltage protection, short-circuit protection, primary-side over-current protection, brown out protection, cycle-by-cycle current limiting, VCC under-voltage lockout, and auto-restart over-temperature protection. • • • • • • • • • • • Real-Current Control without SecondaryFeedback Circuit Good Line/Load Regulation High Power Factor (≥0.9) over Universal Input Voltage Valley Switching Mode for Improved Efficiency Brown-Out Protection Over-Voltage Protection Short-Circuit Protection Over-Temperature Protection Primary-Side Over-Current Protection Cycle-by-Cycle Current Limit Input UVLO Available in TSOT23-6 APPLICATIONS • • Industrial and Commercial Lighting Residential Lighting All MPS parts are lead-free, halogen free, and adhere to the RoHS directive. For MPS green status, please visit MPS website under Quality Assurance. “MPS” and “The Future of Analog IC Technology” are Registered Trademarks of Monolithic Power Systems, Inc. TYPICAL APPLICATION CIRCUIT Mult GATE COMP CS/ZCD GND VCC MP4026 Rev. 1.1 9/9/2015 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 1 MP4026 – PRIMARY SIDE CONTROL, OFFLINE LED CONTROLLER WITH ACTIVE PFC ORDERING INFORMATION Part Number MP4026GJ* Package TSOT23-6 Top Marking See Below * For Tape & Reel, add suffix –Z (e.g. MP4026GJ–Z); TOP MARKING AFS: product code of MP4026GJ; Y: year code. PACKAGE REFERENCE TOP VIEW VCC 1 6 GATE MULT 2 5 CS/ZCD 3 4 GND COMP TSOT23-6 MP4026 Rev. 1.1 9/9/2015 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 2 MP4026 – PRIMARY SIDE CONTROL, OFFLINE LED CONTROLLER WITH ACTIVE PFC ABSOLUTE MAXIMUM RATINGS (1) Thermal Resistance Input Voltage VCC ..........................-0.3V to +30V Gate Drive Voltage .......................-0.3V to +17V ZCD Pin .........................................-0.3V to 6.5V Other Analog Inputs and Outputs ..-0.3V to 6.5V Max. Gate Source Current ......................... 0.8A Max. Gate Sink Current ................................ -1A (2) Continuous Power Dissipation (TA = +25°C) TSOT23-6 ................................................ 1.25W Junction Temperature ...............................150°C Lead Temperature ....................................260°C Storage Temperature............... -65°C to +150°C TSOT23-6………………... Recommended Operating Conditions (3) (4) θJA θJC 100.... 55.. °C/W Notes: 1) Exceeding these ratings may damage the device. 2) The maximum allowable power dissipation is a function of the maximum junction temperature TJ (MAX), the junction-toambient thermal resistance θJA, and the ambient temperature TA. The maximum allowable continuous power dissipation at any ambient temperature is calculated by PD (MAX) = (TJ (MAX)-TA)/θJA. Exceeding the maximum allowable power dissipation will cause excessive die temperature, and the regulator will go into thermal shutdown. Internal thermal shutdown circuitry protects the device from permanent damage. 3) The device is not guaranteed to function outside of its operating conditions. 4) Measured on JESD51-7, 4-layer PCB. Supply Voltage VCC ...........................12V to 28V Operating Junction Temp. (TJ)..-40°C to +125°C MP4026 Rev. 1.1 9/9/2015 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 3 MP4026 – PRIMARY SIDE CONTROL, OFFLINE LED CONTROLLER WITH ACTIVE PFC ELECTRICAL CHARACTERISTICS Typical values are at VCC = 20V, TJ = +25°C, unless otherwise noted. Minimum and maximum values are at VCC = 20V, TJ = -40°C to +125°C, unless otherwise noted, guaranteed by characterization. Parameter Supply Voltage Operating Range Turn-On Threshold Turn-Off Threshold Hysteretic Voltage Supply Current Start-up Current Quiescent Current Operating Current Under Fault Condition Operating Current Multiplier Linear Operation Range Gain Brown-Out Protection Threshold Brown-Out Detection Time Brown-Out-Protection-Hysteretic Voltage Symbol Condition Min Typ Max Units VCC VCC_ON VCC_OFF VCC_HYS After turn on VCC rising edge VCC falling edge 12 23 8.2 14.2 24.9 9.3 15.6 28 28 10.8 17.3 V V V V ISTARTUP IQ VCC= VCC_ON -1V No switching 20 0.6 50 0.82 µA mA ICC No switching 2 fs =70kHz, CGATE=1nF 2 VMULT K(5) 0 mA 3 mA 3 280 25 1.3 300 42 316 60 V 1/V mV ms 90 100 110 mV 0.401 0.413 0.425 V Error Amplifier Feedback Voltage VFB Transconductance (6) GEA 125 µA/V Upper Clamp Voltage VCOMP_H 4.5 4.75 5.1 V Lower Clamp Voltage VCOMP_L 1.42 1.5 1.58 V Max. Source Current Max. Sink Current (6) (6) ICOMP 50 µA ICOMP -200 µA Current Sense Comparator and Zero Current Detector CS/ZCD Bias Current IBIAS_CS/ZCD 500 nA Leading-Edge-Blanking Time tLEB_CS 200 320 550 ns Current-Sense-Clamp Voltage Over-Current-Protection, Leading-Edge-Blanking Time Over-Current-Protection Threshold Zero-Current-Detection Threshold Zero-Current-Detect Hysteresis VCS_CLAMP 1.9 2.0 2.1 V tLEB_CSOCP 130 200 380 ns VCS_OCP 2.4 2.5 2.6 V 0.270 0.295 0.318 V 562 595 628 mV MP4026 Rev. 1.1 9/9/2015 VZCD_T VZCD_HYS VZCD falling edge www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 4 MP4026 – PRIMARY SIDE CONTROL, OFFLINE LED CONTROLLER WITH ACTIVE PFC ELECTRICAL CHARACTERISTICS (continued) Typical values are at VCC = 20V, TJ = +25°C, unless otherwise noted. Minimum and maximum values are at VCC = 20V, TJ = -40°C to +125°C, unless otherwise noted, guaranteed by characterization. Parameter Symbol tLEB_ZCD ZCD Blanking Time tLEB_ZCD Over-Voltage Blanking Time tLEB_OVP tLEB_OVP Over-Voltage Threshold Minimum Off Time Starter Start-Timer Period Gate Driver Output-Clamp Voltage Minimum-Output Voltage Max. Source Current(6) Max. Sink Current(6) Thermal Shutdown Thermal Shutdown Threshold(7) Thermal Shutdown Recovery Hysteresis(7) VZCD_OVP tOFF_MIN Condition After turn-off, VMULT_O >0.3V After turn-off, VMULT_O ≤0.3V After turn-off, VMULT_O >0.3V After turn-off, VMULT_O ≤0.3V 1.6μs delay after turn-off Min Typ Max Units 1.2 1.6 2.1 μs 0.6 0.8 1.1 μs 1.2 1.6 2.1 μs 0.6 0.8 1.1 μs 4.9 4 5.1 5.5 5.4 8 V µs tSTART VGATE_CLAMP VCC=28V VGATE_MIN VCC=VCC_OFF + 50mV IGATE_SOURCE IGATE_SINK 190 13 6.7 14.5 µs 17 0.8 -1 V V A A TSD 150 ℃ THYS 25 ℃ Notes: 5) The multiplier output is given by: Vcs=k*VMULT*(VCOMP-1.5) 6). Guaranteed by design. 7). Guaranteed by characterization. MP4026 Rev. 1.1 9/9/2015 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 5 MP4026 – PRIMARY SIDE CONTROL, OFFLINE LED CONTROLLER WITH ACTIVE PFC TYPICAL PERFORMANCE CHARACTERISTICS VIN = 90V-265V, VOUT = 10-20V, ILED=350mA, TA = 25°C, unless otherwise noted. Line/Load Regulation VFB Temperature Tendency 0.416 0.359 IOUT (A) 0.413 0.412 6LEDs 0.85 0.355 0.414 VFB (V) 0.87 3LEDs 0.357 0.415 0.83 4LEDs 0.353 0.351 -10 20 50 80 110 140 0.79 6LEDs 0.345 90 120 150 180 210 240 270 VIN (VAC) PF @Full Load 5LEDs 5LEDs 0.347 0.41 -40 3LEDs 0.81 0.349 0.411 Efficiency 4LEDs 0.77 0.75 90 120 150 180 210 240 270 VIN (VAC) Steady State Steady State VIN =110V VIN =110V 1 0.99 0.98 ILED 200mA/div. 0.97 PF 0.96 0.95 0.94 0.93 VDRAIN 100V/div. VCOMP 1V/div. VCS/ZCD 2V/div. VCS/ZCD 2V/div. VGATE 10V/div. VGATE 10V/div. 0.92 0.91 0.9 90 120 150 180 210 240 270 VIN (VAC) Steady State VIN =110V IIN 100mA/div. VIN 100V/div. MP4026 Rev. 1.1 9/9/2015 Steady State Steady State VIN =230V VIN =230V ILED 200mA/div. VDRAIN 200V/div. VCOMP 1V/div. VCS/ZCD 2V/div. VCS/ZCD 2V/div. VGATE 10V/div. VGATE 10V/div. www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 6 MP4026 – PRIMARY SIDE CONTROL, OFFLINE LED CONTROLLER WITH ACTIVE PFC TYPICAL PERFORMANCE CHARACTERISTICS (continued) VIN = 90V-265V, VOUT = 10-20V, ILED=350mA, TA = 25°C, unless otherwise noted. Steady State VIN Start up VIN Start up VIN =230V VIN = 110V VIN = 230V IIN 50mA/div. VIN 200V/div. ILED 200mA/div. ILED 200mA/div. VVCC 10V/div. VVCC 10V/div. VCOMP 1V/div. VGATE 10V/div. VCOMP 1V/div. VGATE 10V/div. Open LED Protection VIN = 110V, Open LED @ Working Open LED Protection Short Circuit Protection VIN =230V, Open LED @ Working VIN =110V Short LED+ to LED- @ Working ILED 200mA/div. ILED 200mA/div. ILED 200mA/div. VVCC 10V/div. VCOMP 2V/div. VVCC 10V/div. VCOMP 2V/div. VVCC 10V/div. VCOMP 2V/div. VGATE 10V/div. VGATE 10V/div. VGATE 10V/div. Short Circuit Protection Primary-Side OCP Protection Primary-Side OCP Protection VIN =230V Short LED+ to LED- @ Working VIN =110V Short primary winding @ Working VIN =230V Short primary winding @ Working ILED 200mA/div. ILED 200mA/div. ILED 200mA/div. VVCC 10V/div. VCOMP 2V/div. VVCC 10V/div. VCOMP 2V/div. VVCC 10V/div. VCOMP 2V/div. VGATE 10V/div. VGATE 10V/div. VGATE 10V/div. MP4026 Rev. 1.1 9/9/2015 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 7 MP4026 – PRIMARY SIDE CONTROL, OFFLINE LED CONTROLLER WITH ACTIVE PFC PIN FUNCTIONS Pin Name 1 VCC Power Supply. Supplies power for the control signals and the high-current MOSFET. Bypass to ground with an external bulk capacitor (typically 4.7µF). 2 MULT Input Voltage Sense. Connect to the tap of resistor divider between the rectified AC line and GND. The half-wave sinusoid provides a reference signal for the internalcurrent-control loop. The MULT pin is also used for brown-out protection detection. 3 COMP Loop Compensation. Connect a compensation network to stabilize the LED driver and maintain an accurate LED current. 4 GND 5 CS/ZCD 6 GATE MP4026 Rev. 1.1 9/9/2015 Description Ground. Current return for the control signal and the gate-drive signal. Current Sense or Zero-Current Detection. When the gate driver turns on, a sensing resistor senses the MOSFET current. The comparison between the sensed voltage and the internal sinusoidal-current reference determines when the MOSFET turns off. If the pin voltage exceeds the current limit (2.0V, after turn-on blanking) the gate drive turns off. When the gate driver turns off, the negative falling-edge (after the blanking time) triggers the external MOSFET’s turn-on signal. Connect this pin to a resistor divider though a diode between the auxiliary winding and GND. Over-voltage condition is detected through ZCD. For every turn-off interval, if the ZCD voltage exceeds the over-voltage-protection threshold after the 1.6µs (Vmult_o >0.3V) or 0.8µs (Vmult_o ≤0.3V) blanking time, over-voltage protection triggers and the system stops switching until auto-restart. CS/ZCD is also used for primary-side over-current-protection, if the sensing voltage reaches to 2.5V after a blanking time at gate turn-on interval, the primary-side overcurrent-protection triggers and the system stops switching until auto-restart. A 10pF ceramic cap is recommended to connect from CS/ZCD to GND to bypass the high frequency noise. In order to reduce the RC delay influence to the sample accuracy of the current sensing signal, the CS/ZCD down side resistance (RZCD2 in figure 7) is suggested to be selected as small as 1kΩ. Gate Drive Output. This totem-pole output stage can drive a high-power MOSFET with a peak current of 0.8A source and 1A sink. The high-voltage limit is clamped to 14.5V to avoid excessive gate-drive voltage. The low-voltage is higher than 6.7V to guarantee a sufficient drive capacity. www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 8 MP4026 – PRIMARY SIDE CONTROL, OFFLINE LED CONTROLLER WITH ACTIVE PFC FUNCTION DIAGRAM N:1 EMI Filter MULT UVLO GND Internal Power supply Peak detector Brown out VCC Multiplier PWM generator Driver Gate Q1 Brown out OTP Current Sense COMP CS/ZCD Current Limit OCP Real Current Control OVP OCP ZCD_OVP detection Zero Crossing detecti on Figure 1—MP4026 Function Block Diagram MP4026 Rev. 1.1 9/9/2015 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 9 MP4026 – PRIMARY SIDE CONTROL, OFFLINE LED CONTROLLER WITH ACTIVE PFC OPERATION The MP4026 is a primary-side-controlled, offline LED controller for high-performance LED lighting. It has primary-side real-current control for accurate LED current regulation. It also has active power factor correction (PFC) to eliminate harmonic noise on the AC line. The rich protections can achieve a high safety and reliability in real application. VDRAIN VBUS+NVOUT VBUS Turn On Start Up IPRI Initially, AC line charges up VCC through the start-up resistor. When VCC reaches 24.9V, the control logic starts. Then the power supply is taken over by the auxiliary winding when the voltage of auxiliary winding builds up. ISEC/N Magnetizing Current tON tOFF VCS/ZCD The MP4026 will shut down when VCC drops below 9.3V. 0 The high hysteretic voltage allows for a small VCC capacitor (typically 4.7μF) to shorten the start-up time. Figure 2: Valley Switching Mode Valley Switching Mode During the external MOSFET ON-time (tON), the rectified-input voltage (VBUS) charges the primary-side inductor (LP) causing the primaryside current (IPRI) to increase linearly from zero to peak value (IPK). When the MOSFET turns off, the energy stored in the inductor is transferred to the secondary-side, which activates the secondary-side diode to power the load. The secondary current (ISEC) decreases linearly from its peak value to zero. When the secondary current decreases to zero, the MOSFET drainsource voltage starts oscillating, which is caused by the primary-side magnetizing inductance and parasitic capacitances—the voltage ring also is reflected on the auxiliary winding (see Figure 2). To improve primarycontrol precision, the chip monitors when ZCD voltage falls to zero twice before the next switching period. The zero-current detector from CS/ZCD generates GATE turn-on signal when the ZCD voltage falls below 0.295V the second time (see Figure 3). This virtually eliminates switch turn-on loss and diode reverse-recovery losses, ensuring high efficiency and low EMI noise. MP4026 Rev. 1.1 9/9/2015 Figure 3: Zero-Current Detector Real-Current Control The proprietary real-current-control method allows the MP4026 to control the secondaryside LED current using primary-side information. The mean output LED current is approximately: Io ≈ N ⋅ VFB 2 ⋅ Rs Where: • N is the primary-side-to-secondary-side turn ratio, • VFB is the feedback reference voltage (typically 0.413V), and • Rs is the sensing resistor connected between the MOSFET source and GND. www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 10 MP4026 – PRIMARY SIDE CONTROL, OFFLINE LED CONTROLLER WITH ACTIVE PFC Power-Factor Correction Minimum Off Time The MULT pin is connected to a pull up resistor from the rectified-instantaneous-line voltage and fed as one input of the Multiplier. The multiplier output is sinusoidal.. This signal provides the reference for the current comparator and comparing with the primary-side-inductor current, which sets the sinusoidal primary-peak current. This helps to achieve a high-power factor. The MP4026 operates with a variable switching frequency; the frequency changes with the instantaneous-input-line voltage. To limit the maximum frequency and get a good EMI performance, the MP4026 employs an internal, minimum-off-time limiter—5.5µs. Multiplier output Inductor current Figure 4: Power-Factor Correction The maximum voltage of the multiplier output to the current comparator is clamped at 2V for a cycle-by-cycle current limit. Leading-Edge Blanking To avoid premature switching-pulse termination due to the parasitic capacitances discharging when the MOSFET turns on at normal operation, the MP4026 uses an internal-leading edge blanking (LEB) unit between the CS/ZCD pin and the current-comparator input. During the blanking time, the path from the CS/ZCD pin to the current comparator input is blocked. Figure 6 shows the leading-edge blanking. The LEB time of primaryside OCP detection is relatively short, 200ns. VCS tLEB =320ns VCC Under-Voltage Lockout When VCC drops below the UVLO threshold (9.3V), the MP4026 stops switching and shuts down. The operating current is very low under this condition, the VCC will be charged up again by the external start up resistor from AC line. Figure 5 shows the typical VCC under-voltage lockout waveform. Vcc Auxiliary Winding Takes Charge And Regulates the VCC Protection happens 24.9V 9.3V Gate Switching Pu lses Figure 5: VCC Start-Up Waveform Auto Starter The MP4026 has an integrated auto starter. The starter times when the MOSFET is OFF: If ZCD fails to send out another turn-on signal after 190µs, the starter will automatically send out the turn-on signal to avoid unnecessary shutdowns due to missing ZCD detections. MP4026 Rev. 1.1 9/9/2015 t Figure 6: Leading-Edge Blanking Output Over-Voltage Protection Output over-voltage protection prevents component damage during an over-voltage condition. The auxiliary-winding voltage’s positive plateau is proportional to the output voltage: the OVP uses the auxiliary winding voltage instead of directly monitoring the output voltage. Figure 7 shows the OVP sampling unit. Once the ZCD voltage exceeds 5.1V at gate turn off interval, the OVP signal will be triggered and latched, the gate driver will be turned off and the IC works at quiescent mode, the VCC voltage dropped below the UVLO which will make the IC shut down, and the system restarts again. www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 11 MP4026 – PRIMARY SIDE CONTROL, OFFLINE LED CONTROLLER WITH ACTIVE PFC voltage drops to follow the secondary-winding voltage, VCC drops to less than the UV threshold, and the system restarts. This sequence limits the output power and IC temperature rise if an output short occurs. The output-OVP-set point is then: VOUT _ OVP ⋅ NAUX R ZCD2 ⋅ = 5.1V NSEC R ZCD1 + R ZCD2 Where: • VOUT_OVP is the protection point, output-over-voltage- • NAUX is the number of auxiliary-winding turns, and • NSEC is the number of secondary-winding turns. Gate Gate_OFF CS/ZCD + - Latch 5.1V OVP Blanking time RZCD 2 R1 RZCD 1 Primary-Side Over-Current Protection The primary-side over-current protection prevents device damage caused by extremely excessive current, like primary winding short. If the CS/ZCD pin voltage rising to 2.5V at gate turn on interval, as shown in Figure 9, the primary-side over-current protection signal will be triggered and latched, the gate driver will be turned off and the IC works at quiescent mode, the VCC voltage dropped below the UVLO which will make the IC shut down, and the system restarts again. To avoid mis-trigger by the parasitic capacitances discharging when the MOSFET turns on, a LEB time is needed, this LEB time is relatively smaller than current regulation sensing LEB time, typical 200ns. Gate Figure 7: OVP Sampling Unit To prevent a voltage spike from mis-triggering OVP after the switch turns off, OVP sampling has a tLEB_OVP blanking period (typically 1.6µs when VMULT_O > 0.3V and 0.8µs when VMULT_O ≤ 0.3V) as shown in Figure 8. VCS/ZCD Gate_ON CS/ZCD Latch + - 2.5V OCP Blanking time RZCD 2 R1 RZCD 1 Sampling Here Figure 9: Primary-side OCP Sampling Unit 0V t LE B _OV P Figure 8: ZCD Voltage and OVP Sampler Output Short-Circuit Protection If an output short occurs, the ZCD can not detect the transformer’s zero-current-crossing point, so the 190μs auto-restart timer triggers the power MOSFET’s turn-on signal. Then the switching frequency of the power circuit drops to about 5kHz, and the output current is limited to its nominal current. The auxiliary-winding MP4026 Rev. 1.1 9/9/2015 Brown-Out Protection The MP4026 has brown-out protection: the internal peak detector detects the peak value of the rectified sinusoid waveform in MULT pin. If the peak value is less than the brown-outprotection threshold 0.3V for 42ms, the IC recognizes this condition as a brown-out, quickly drops the COMP voltage to zero, and disables the power circuit. If the peak value exceeds 0.4V, the IC restarts and the COMP voltage rises softly again. This feature prevents both the transformer and LED currents from saturating during fast ON/OFF switching. Figure 10 shows the brown-out waveforms. www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 12 MP4026 – PRIMARY SIDE CONTROL, OFFLINE LED CONTROLLER WITH ACTIVE PFC IC Thermal Shut Down VCC Brown out happen Vbus Brown out detected Brown out recover To prevent from any lethal thermal damage, when the inner temperature exceeds the OTP threshold, the MP4026 shuts down switching cycle and latched until VCC drop below UVLO and restart again. Design Example For the design example, please refer to MPS application note AN076 for the detailed design procedure. V peak_ Mult Vcomp Vgate Figure 10: Brown-Out Protection Waveforms MP4026 Rev. 1.1 9/9/2015 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 13 MP4026 – PRIMARY SIDE CONTROL, OFFLINE LED CONTROLLER WITH ACTIVE PFC NON-ISOLATED APPLICATIONS The isolated solution can prevent human body from an electric shock by grid when touching the load. But the power loss and the cost are increased. Recur to safety enclosure frame of the lamp, compared with isolated solution, the non-isolated solution can achieve higher efficiency and highly cost-effective. voltage, since the higher output voltage can extend the duty cycle to improve the PF and THD and the efficiency can also be improved meanwhile. For the non-isolated solution with low output voltage, the tapped-inductor can be applied to improve the PF and THD. Generally, the Flyback converter is common for the offline isolated applications. As topology transmutation, the non-isolated low-side Buckboost converter is also popular. Besides fitting in isolated application, the MP4026 can also operate in the offline non-isolated LED lighting applications. Figure 16 is a 30W low-side Buck-boost LED driver with MP4026. Operation of Low-side Buck-boost The low-side Buck-boost can be treated as Flyback converter with 1:1 turn ratio transformer. So, the whole operation is absolutely same as the description above. Different from isolated solution, there are no separate primary- and secondary-winding, so a smaller core size is available for design. Without the impact of the leakage inductance, the snubber is unnecessary. All of these can save cost and improve the efficiency of the driver. The Selection of FET & Rectifier Diode Since it is just an inductor for non-isolated solution, compared with isolated solution, at same output voltage, the power FET can be selected with lower voltage rating. But, oppositely, the voltage rating of rectifier diodes for output and aux-winding must be increased. Improvement of RF EMI CY1 in Figure 16 is added for RF EMI improvement. The recommended value is from 10nF to 47nF with 630V rating. Improvement of PFC & THD The impact of non-turn-ratio is that the duty cycle of the converter becomes smaller at same spec. Based on MP4026 PFC principle, the PF and THD of the converter drops compared with isolated solution. So, generally, the non-isolated solution is especially suitable for high output MP4026 Rev. 1.1 9/9/2015 Figure 11: Tapped-inductor for Low-side Buckboost Solution Shown in Figure 11, the tapped-inductor includes two windings (N1 & N2) and a tap to connect the rectifier diode. When the power FET is turned on, the current goes thru both of the windings. But when the power FET is off, just N1 conducts the current thru the rectifier diode. The stored energy of N2 is released by flux couple. So, the tapped-inductor features a similar turn-ratio like the transformer in isolated solution. The nominal turn-ratio is n= N1 + N2 >1 N1 The duty cycle of the converter is obviously extended by tapped-inductor, and then the better PF and THD are available. But, like transformer, the snubber is necessary to clamp the voltage spike caused by leakage inductance. www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 14 MP4026 – PRIMARY SIDE CONTROL, OFFLINE LED CONTROLLER WITH ACTIVE PFC On the other hand, the non-dimmable solution usually needs to cover universal input range. The input range is very wide, from 85VAC to 264VAC. The MULT pin is used to detect the input voltage signal, but the resistor divider of MULT is fixed. So, at high line input, the signal for MULT input is very low, which results in adverse effect for internal multiplier sampling, then affect the PFC performance. Figure 12 shows an improved circuitry on MULT resistor divider to adjust the ratio of the divider to achieve better THD. BUS ZD1 RMULT1 Figure 13: The MULT Signal with THD Improved Circuitry As Figure 13 shown, after adding the THD improved circuitry, the top part of the MULT voltage rises up as the dashed line. Then the input current at top of BUS is increased while the input current at the zero-crossing is reduced, which results in the input current more like sinusoid and then the THD is improved. RMULT3 MULT Multiplier RMULT2 COMP CCOMP Figure 12: THD Improved Circuitry The ZD1 is a HV Zener diode. The common voltage rating is from 80V to 130V. At low line input, the BUS can not breaks down ZD1, the MULT pin signal is VMULT = VBUS × RMULT2 RMULT1 + RMULT 2 When the input voltage rises up, once the BUS breaks down ZD1, RMULT3 is paralleled with RMULT1 to increase the ratio of the divider to raise the MULT signal. MP4026 Rev. 1.1 9/9/2015 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 15 MP4026 – PRIMARY SIDE CONTROL, OFFLINE LED CONTROLLER WITH ACTIVE PFC TYPICAL APPLICATION CIRCUITS R3 5.1k/1206 L3 1.5mH/0.25A BD1 MB6S RM6 Lp=2.18mH Np:Ns:Naux=115:23:26 R14 100k/1206 C6 22nF/630V C2 100nF/400V 1 CX1 22nF/275VAC W R4 470k/0.5W R7 C7 LED- R10 U1 MP4026J 1 VCC GATE 6 R8 20 D4 BAV21W 200V/0.2A 1 3 2 F1 250V/2A B R15 C3 R9 1 2 N LED+ 20V/350mA Aux+ RV1 TVR10431 L C8 R13 30k/1206 6 D2 BAV21W 200V/0.2A R2 5.1k/1206 D1 MBRS320T3 200V/3A 2 2 L1 1.5mH/0.25A L2 1.5mH/0.25A R1 5.1k/1206 T1 D3 S1ML 1000V/1A R6 R5 C4 2.2nF/50V MULT CS/ZCD CY1 2.2nF/4kV Q1 ISU04N65A 650V/4A 5 C1 10pF/50V 3 90VAC-265VAC C5 COMP GND 4 R11 R12 Figure 14: A19 Bulb Driver, 90-265VAC Input, Isolated Flyback Converter, VO =20V, IO=350mA EVB Model: EV4026-J-00A Figure 15: PAR38 Driver, 90-265VAC Input, Isolated Flyback Converter, VO =40V, IO=500mA EVB Model: EV4026-J-00B MP4026 Rev. 1.1 9/9/2015 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 16 MP4026 – PRIMARY SIDE CONTROL, OFFLINE LED CONTROLLER WITH ACTIVE PFC R3 5.1k/1%/1206 LED- L3 1mH/0.5A BD1 KBP206 600V/2A T1 EE25 Lm=460uH C2 CX1 47nF/275VAC 470nF/450V R4 300k/1W R1 5.1k/1% 1206 L1 1mH 0.5A L2 1mH 0.5A 90Ts R6 499k/1%/1206 R18 20/1%/1206 R2 5.1k/1% 1206 R7 4.3M/1% R17 499k/1%/1206 L4 10mH/0.7A U1 MP4026 1 2 1 2 2 F1 250V/3.15A 1 RV1 TVR14431 D4 BZT52C27 VCC 2 R5 6.2k/1% 90VAC-264VAC 6 MULT CS/ZCD COMP GND 5 R9 2.2k/1% 1 3 2 87V/350mA L5 600uH D1 STTH3R06S 600V/3A C8 C7 100uF/160V 100uF/160V 26Ts LED+ CY1 47nF/630V 1206 R15 0/1%/1206 Q1 AP3990I 600V/10A C1 10pF/50V C4 2.2nF/50V 1 N R8 20/0805 GATE C3 6.8uF/50V 3 L R10 10.2k/1% D2 BAV23A/SOT-23 200V/0.2A R13 100k/1206 4 R11 0.3/1%/1206 R16 1.5/1%/1206 C5 2.2uF/6.3V/0805 R12 0.3/1%/1206 Figure 16: 90-264VAC Input, Non-isolated Low-side Buck-boost Converter, VO =87V, IO=350mA MP4026 Rev. 1.1 9/9/2015 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 17 MP4026 – PRIMARY SIDE CONTROL, OFFLINE LED CONTROLLER WITH ACTIVE PFC PACKAGE INFORMATION TSOT23-6 0.95 BSC 0.60 TYP 2.80 3.00 6 4 1.20 TYP See Note 7 EXAMPLE TOP MARK PIN 1 AAAA 1 1.50 1.70 2.60 3.00 2.60 TYP 3 TOP VIEW R EC OMMEN DED LA ND PA TTERN 0.84 0.90 1.00 MAX 0.09 0.20 SEATING PLANE 0.30 0.50 0.95 BSC 0.00 0.10 SEE DETAIL "A" FRONT VIEW SIDE VIEW NOTE: GAUGE PLANE 0.25 BSC o 0 -8 o 0.30 0.50 D ETA IL “A” 1) ALL DIMENSIONS ARE IN MILLIMETERS. 2) PACKAGE LENGTH DOES NOT INCLUDE MOLD FLASH , PROTRUSION OR GATE BURR. 3) PACKAGE WIDTH DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSION. 4) LEAD COPLANARITY(BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.10 MILLIMETERS MAX. 5) DRAWING CONFORMS TO JEDEC MO-193, VARIATION AB. 6) DRAWING IS NOT TO SCALE. 7) PIN 1 IS LOWER LEFT PIN WHEN READING TOP MARK FROM LEFT TO RIGHT, (SEE EXAMPLE TOP MARK) NOTICE: The information in this document is subject to change without notice. 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. MP4026 Rev. 1.1 9/9/2015 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 18