PF C bo os t con verter d esi gn gu i d e 1200 W design example Sam Abdel-Rahman Franz Stückler Ken Siu Application Note About this document Scope and purpose This document introduces a design methodology for a Power Factor Correction (PFC) Continuous Conduction Mode (CCM) boost converter, including: Equations for design and power losses Selection guide of semiconductor devices and passive components Charts for CoolMOS™ optimum RDS(ON) selection 1200 W design example with calculated and experimental results. Schematics, layout and bill of material Intended audience This document is intended for design engineers who want to design CCM PFC boost converter. Table of contents 1 Introduction ................................................................................................................................... 2 2 Power stage design ........................................................................................................................ 4 3 ICE3PCS01G PFC boost controller ................................................................................................ 17 4 Efficiency and power losses modeling ......................................................................................... 19 5 Experimental results .................................................................................................................... 20 6 Board design ................................................................................................................................ 23 7 References ................................................................................................................................... 27 8 Symbols used in formulas ............................................................................................................ 28 Application Note 1 Revision1.1, 2016-02-22 Design Note DN 2013 -01 V1.0 January 2013 PFC boost converter design guide 1 Introduction Power Factor Correction (PFC) shapes the input current of the power supply to be in synchronization with the mains voltage, in order to maximize the real power drawn from the mains. In a perfect PFC circuit, the input current follows the input voltage as a pure resistor, without any input current harmonics. This document is to introduce a design methodology for the CCM PFC Boost converter, including equations for power losses estimation, selection guide of semiconductor devices and passive components, and a design example with experimental results. 1.1 Boost topology Although active PFC can be achieved by several topologies, the boost converter (Figure 1) is the most popular topology used in PFC applications, for the following reasons: The line voltage varies from zero to some peak value typically 375 V; hence a step up converter is needed to output a DC bus voltage of 380 V or more. For that reason the buck converter is eliminated, and the buck-boost converter has high switch voltage stress (Vin+Vo), therefore it is also not the popular one. The boost converter has the filter inductor on the input side, which provides a smooth continuous input current waveform as opposed to the discontinuous input current of the buck or buck-boost topology. The continuous input current is much easier to filter, which is a major advantage of this design because any additional filtering needed on the converter input will increase the cost and reduces the power factor due to capacitive loading of the line. Boost Key Waveforms T=1/f DC Bus AC Vac PFC Converter DC/DC Converter S Load DT Vin V_L I_Lmax Vin-Vo I_Lmin I_L L VacAC D S DC Bus Co Ro + Vo - I_Lmax I_S I_Lmax I_Lmin I_D 𝑉𝑜 1 = 𝑉in 1 − D Figure 1 Structure and key waveforms of a boost converter 1.2 PFC modes of operation (CCM operation) The boost converter can operate in three modes: continuous conduction mode (CCM), discontinuous conduction mode (DCM), and critical conduction mode (CrCM). Figure 2 shows modeled waveforms to illustrate the inductor and input currents in the three operating modes, for the same exact voltage and power conditions. By comparing DCM among the others, DCM operation seems simpler than CrCM, since it may operate in constant frequency operation; however DCM has the disadvantage that it has the highest peak current compared to CrCM and also to CCM, without any performance advantage compared to CrCM. For that reason, CrCM is a more common practice design than DCM, therefore, this document will exclude the DCM design. Application Note 2 Revision1.1, 2016-02-22 Design Note DN 2013 -01 V1.0 January 2013 PFC boost converter design guide CrCM may be considered a special case of CCM, where the operation is controlled to stay at the boundary between CCM and DCM. CrCM usually uses constant on-time control; the line voltage is changing across the 60 Hz line cycle, the reset time for the boost inductor is varying, and the operating frequency will change as well in order to maintain the boundary mode operation. CrCM dictates the controller to sense the inductor current zero crossing in order to trigger the start of the next switching cycle. The inductor current ripple (or the peak current) in CrCM is twice of the average value, which greatly increases the MOSFET RMS currents and turn-off current. But since every switching cycle starts at zero current, and usually with ZVS operation, turn-on loss of MOSFET is usually eliminated. Also, since the boost rectifier diode turns off at zero current as well, reverse recovery losses and noise in the boost diode are eliminated too, another major advantage of CrCM mode. Still, on the balance, the high input ripple current and its impact on the input EMI filter tends to eliminate CrCM mode for high power designs unless interleaved stages are used to reduce the input HF current ripple. A high efficiency design can be realized that way, but at substantially higher cost. That discussion is beyond the scope of this application note. The power stage equations and transfer functions for CrCM are the same as CCM. The main differences relate to the current ripple profile and switching frequency, which affects RMS current and switching power losses and filter design. CCM operation requires a larger filter inductor compared to CrCM. While the main design concerns for a CrCM inductor are low HF core loss, low HF winding loss, and the stable value over the operating range (the inductor is essentially part of the timing circuit), the CCM mode inductor takes a different approach. For the CCM PFC, the full load inductor current ripple is typically designed to be 20-40% of the average input current. This has several advantages: Peak current is lower, and the RMS current factor with a trapezoidal waveform is reduced compared to a triangular waveform, reducing device conduction losses. Turn-off losses are lower due to switch off at much lower maximum current. The HF ripple current to be smoothed by the EMI filter is much lower in amplitude. On the other side, CCM encounters the turn-on losses in the MOSFET, which can be exacerbated by the boost rectifier reverse recovery loss due to reverse recovery charge, Qrr. For this reason, ultra-fast recovery diodes or silicon carbide Schottky Diodes with extreme low Qrr are needed for CCM mode. In conclusion, we can say that for low power applications, the CrCM boost has the advantages in power saving and improving power density. This advantage may extend to medium power ranges, however at some medium power level the low filtering ability and the high peak current starts to become severe disadvantages. At this point the CCM boost starts being a better choice for high power applications. Since this document is intended to support high power PFC applications, therefore a CCM PFC boost converter has been chosen in the application note with detailed design discussions and design examples for demonstration. 15 15 10 15 10 Iin ( t) Iin( t) IL ( t) I L ( t) 5 Iin( t) IL ( t) 5 0 5 0 0 -4 -4 -4 -4 Continuous Conduction Mode (CCM) 1 10 2 3 10 t Figure 2 10 4 10 10 0 -4 1 10 -4 -4 2 10 3 10 -4 4 10 Critical Conduction Mode (CrCM) t 0 0 -4 110 -4 210 -4 310 -4 410 Discontinuous Conduction Mode (DCM) t PFC Inductor and input line current waveforms in the three different operating modes Application Note 3 Revision1.1, 2016-02-22 Design Note DN 2013 -01 V1.0 January 2013 PFC boost converter design guide 2 Power stage design The following are the converter design and power losses equations for the CCM operated boost. The design example specifications listed in Table 1 will be used for all of the equations calculations. Also the boost converter encounters the maximum current stress and power losses at the minimum line voltage condition (𝑉𝑎𝑐.𝑚𝑖𝑛 ); hence, all design equations and power losses will be calculated using the low-line voltage condition as an extreme case. Table 1 Specifications of the power stage Input voltage 85-265 VAC 60 Hz Output voltage 400 V Maximum power steady state 1200 W Switching frequency 100 kHz Inductor current ripple 25% @ low line/full load Output voltage 120Hz ripple 10 Vp-p Hold-up time 16.6 ms @ VO,min=340 V Figure 3 Block schematic for boost power stage with input rectifier 2.1 Main PFC inductor Off-the-shelf inductors are available and usable for a first pass design, typically with single layer windings and a permeability drop of 30% or less. In some circumstances it may be desirable to further optimize the inductor configuration in order to meet the requirements for high power factor over a wide input line current range. Many popular PFC controllers use single cycle current loop control, which can provide good performance provided that the inductor remains in CCM operation. At low-line this is no problem, but for the operation in the high-line band (176 VAC to 265 VAC), the operating current will be much lower. If an inductor is used with a nominal “stable” value of inductance, it works well at low-line but results in DCM mode operation for a significant part of the load range at high-line, with poorer power factor, THDi and higher EMI. A swinging choke (also called powder core), such as Arnold/Micrometals Sendust or Magnetics Inc Kool Mu, can address this if designed with the Application Note 4 Revision1.1, 2016-02-22 Design Note DN 2013 -01 V1.0 January 2013 PFC boost converter design guide right energy capability and with full load permeability drop by 75-80%, so that at lighter load the inductance swings up. The filter inductor value and its maximum current are determined based on the specified maximum inductor current ripple as shown below: 𝐿= (85 𝑉)2 1 𝑉𝑎𝑐.𝑚𝑖𝑛 2 1 1 √2 ∙ 𝑉𝑎𝑐 .𝑚𝑖𝑛 √2 ∙ 85 𝑉 ∙ (1 − )∙𝑇 = ∙ (1 − )∙ = 168.5 𝜇𝐻 %𝑅𝑖𝑝𝑝𝑙𝑒 𝑃𝑜 𝑉𝑜 0.25 1200 𝑊 400 𝑉 100 ∙ 103 𝐻𝑧 𝐼𝐿.𝑚𝑎𝑥 = %𝑅𝑖𝑝𝑝𝑙𝑒 0.25 √2 ∙ 𝑃𝑜 √2 ∙ 1200 𝑊 ∙ (1 + )= ∙ (1 + ) = 22.5 𝐴 𝑉𝑎𝑐.𝑚𝑖𝑛 2 85 𝑉 2 Eq. 1 Eq. 2 Note: Inductor saturation current must be rated at > 22.5 A. In this evaluation board design, a 60 μ permeability Kool Mu core from Magnetics Inc. is used. It consists of two stacked of “Kool Mμ” 77083A7 toroids cores from Magnetics Inc., with 64 turns of 1.15 mm copper wire, the DC resistance is about 70 mΩ, and the inductance ranges from 680 µH at no load dropping to about 165 µH at low-line full load, which is very close to the desired value calculated above. Figure 4 Main PFC inductor Since the inductance value is varying across the line and load range, and also across the line cycle, it would be more accurate to model the inductance value as a function of Vin, Po and t. in order to obtain better estimation of the switching currents and losses. This specific inductor value was modeled as shown in Figure 5. 230Vac @ L (Henry) 85Vac @ 230Vac @ 85Vac @ Po (W) Figure 5 Swinging inductance accros load/line range Application Note 5 Revision1.1, 2016-02-22 Design Note DN 2013 -01 V1.0 January 2013 PFC boost converter design guide Inductor copper loss: The inductor RMS current and the corresponding copper loss are: 𝐼𝐿.𝑟𝑚𝑠 ≅ 𝐼𝑖𝑛.𝑟𝑚𝑠 = 𝑃𝑜 𝑉𝑎𝑐.𝑚𝑖𝑛 = 1200 𝑊 = 14.12 𝐴 85 𝑉 Eq. 3 𝑃𝐿.𝑐𝑜𝑛𝑑 = 𝐼𝐿.𝑟𝑚𝑠 2 ∙ 𝐷𝐶𝑅 = (14.12 𝐴)2 ∙ 0.07 Ω = 13.95 𝑊 Eq. 4 Inductor core losses: At low-line, core loss across the line cycle is found to be close to a sinusoidal shape (Figure 6, left). Therefore a simple and accurate enough method to estimate the average core loss is to calculate the peak core loss at the peak of the line cycle point, then multiply by 2/π. However, at high line, core losses are far from the sinusoidal shape (Figure 6, right), so the aforementioned method is not valid anymore, so it is necessary to model the core loss across the line cycle as a function of time, and then integrate it to obtain the average loss. Figure 6 Inductor core loss across the line cycle: low-line (left) , high-line (right) Since in this document we are calculating losses at the minimum line voltage, as the worst case scenario, thus we will use the first method discussed above to obtain the average core loss in the low-line, as detailed below: In order to calculate the core loss, we must calculate the minimum and maximum inductor current and the associated minimum and maximum magnetic force (H), then we can use the fitted equation of that magnetic material to calculate the minimum and maximum magnetic flux (B). Then the AC flux swing can be used to calculate the core loss by using another fitted equation. For 2 stacked Kool Mμ 77083A7 toroids, we get: 𝑃𝑎𝑡ℎ 𝑙𝑒𝑛𝑔𝑡ℎ 𝑙𝑒 = 98.4 𝑚𝑚 𝐶𝑟𝑜𝑠𝑠 𝑠𝑒𝑐𝑡𝑖𝑜𝑛 𝑎𝑟𝑒𝑎 𝐴𝑒 = 2 ∙ 107 𝑚𝑚2 𝑉𝑜𝑙𝑢𝑚𝑒 𝑉𝑒 = 2 ∙ 10600 𝑚𝑚3 Using the maximum inductor current calculated in Eq. 2, the magnetic force at the peak of the line cycle can be found as: 𝐻𝑚𝑎𝑥 = 0.4 ∙ 𝜋 ∙ 𝑁 ∙ 𝐼𝐿.𝑚𝑎𝑥 0.4 ∙ 𝜋 ∙ 64 𝑡𝑢𝑟𝑛𝑠 ∙ 22.51𝐴 = = 184 𝑂𝑒𝑟𝑠𝑡𝑒𝑑𝑠 𝑙𝑒 (𝑖𝑛 𝑐𝑚) 98.4 𝑚𝑚/10 Eq. 5 The minimum inductor current and magnetic force at the peak of the line cycle are: 𝐼𝐿.𝑚𝑖𝑛 = 𝑃𝑜 ∙ √2 %𝑅𝑖𝑝𝑝𝑙𝑒 1200 𝑊 ∙ √2 25% (1 − )= (1 − ) = 17.42 𝐴 𝑉𝑎𝑐.𝑚𝑖𝑛 2 85 𝑉 2 Eq. 6 𝐻𝑚𝑖𝑛 = 0.4 ∙ 𝜋 ∙ 𝑁 ∙ 𝐼𝐿.𝑚𝑖𝑛 0.4 ∙ 𝜋 ∙ 64𝑡𝑢𝑟𝑛𝑠 ∙ 17.42 𝐴 = = 142.37 𝑂𝑒𝑟𝑠𝑡𝑒𝑑𝑠 𝑙𝑒 (𝑖𝑛 𝑐𝑚) 98.4𝑚𝑚/10 Eq. 7 Application Note 6 Revision1.1, 2016-02-22 Design Note DN 2013 -01 V1.0 January 2013 PFC boost converter design guide Flux density for 60 Koolu material is: 𝑎 + 𝑏 ∙ 𝐻 + 𝑐 ∙ 𝐻2 𝐵=( ) 𝑎 + 𝑑 ∙ 𝐻 + 𝑒 ∙ 𝐻2 𝑥 Eq. 8 where a = 1.658e-2 b = 1.831e-3 c = 4.621e-3 d = 4.7e-3 e = 3.833e-5 x = 0.5 The minimum and maximum flux densities at the peak of the line cycle are: 𝐵𝑚𝑎𝑥 = ( 𝐵𝑚𝑖𝑛 = ( 𝑥 𝑎 + 𝑏 ∙ 𝐻𝑚𝑎𝑥 + 𝑐 ∙ 𝐻𝑚𝑎𝑥 2 𝑎 + 𝑑 ∙ 𝐻𝑚𝑎𝑥 + 𝑒 ∙ 𝐻𝑚𝑎𝑥 2) 𝑎 + 𝑏 ∙ 𝐻𝑚𝑖𝑛 + 𝑐 ∙ 𝐻𝑚𝑖𝑛 2 𝑎 + 𝑑 ∙ 𝐻𝑚𝑖𝑛 + 𝑒 ∙ 𝐻𝑚𝑖𝑛 2) Eq. 9 = 8.483 𝑘𝐺𝑎𝑢𝑠𝑠 𝑥 Eq. 10 = 8.014 𝑘𝐺𝑎𝑢𝑠𝑠 The AC flux swing at the peak of the line cycle is: ∆𝐵 = 𝐵𝑚𝑎𝑥 − 𝐵𝑚𝑖𝑛 = 0.234 𝑘𝐺𝑎𝑢𝑠 2 Eq. 11 Peak core loss at the peak of the line cycle is: 1.46 𝑓 1.46 100 ∙ 103 𝑃𝑐𝑜𝑟𝑒.𝑝𝑘 = ∆𝐵2 ∙ ( 3 ) ∙ 𝑉𝑒 ∙ 10−6 = 0.2342 ∙ ( ) 10 103 ∙ 2 ∙ 10600 ∙ 10−6 = 0.97 𝑊 Eq. 12 Average core loss across the line cycle is: 𝑃𝑐𝑜𝑟𝑒.𝑎𝑣 = 𝑃𝑐𝑜𝑟𝑒.𝑝𝑘 ∙ 2.2 2 2 = 0.968 𝑊 ∙ = 0.62 𝑊 𝜋 𝜋 Eq. 13 Rectifier bridge Using a higher rated current bridge can reduce the forward voltage drop Vf, which reduces the total power dissipation at a small incremental cost. Also using two parallel bridges is another approach to distribute the thermal dissipation. This is often a sound strategy, as with modern components, the bridge rectifier usually has the highest semiconductor loss for the PFC stage. In this evaluation board design, 2 parallel GSIB2580 are used. The bridge total power loss is calculated using the average input current flowing through two of the bridge rectifying diodes and is shown as: 𝐼𝑎𝑣𝑒𝑟𝑎𝑔𝑒 = Eq. 14 2 √2 ∙ 𝑃𝑜 2 √2 ∙ 1200 𝑊 ∙ = ∙ = 12.71 𝐴 𝜋 𝑉𝑎𝑐.𝑚𝑖𝑛 𝜋 85 𝑉 𝑃𝑏𝑟𝑖𝑑𝑔𝑒 = 2 ∙ 𝐼𝑎𝑣𝑒𝑟𝑎𝑔𝑒 ∙ 𝑉𝑓.𝑏𝑟𝑖𝑑𝑔𝑒 = 2 ∙ 12.71 𝐴 ∙ 1 𝑉 = 25.4 𝑊 Eq. 15 The selection on the heat sink is based on the process discussed in chapter 2.6 Heat sink design. 2.3 MOSFET In order to select the optimum MOSFET, one must understand the MOSFET requirements in a CCM boost converter. High voltage MOSFETS have several families based on different technologies. For a boost converter, the following are some major MOSFET selection considerations for high efficiency application design: Low figure-of merits - RDS(ON)*Qg and RDS(ON)*Eoss Application Note 7 Revision1.1, 2016-02-22 Design Note DN 2013 -01 V1.0 January 2013 PFC boost converter design guide Fast turn-on/off switching to reduce the device switching losses Gate plateau near middle of gate drive range to balance turn-on/off losses Low output capacitance Coss for low switching energy and to increase light load efficiency Drain-source breakdown voltage VBR(DSS) to handle spikes/overshoots Low thermal resistance RthJC. Package selection must consider the resulting total thermal resistance from junction to ambient, and the worst case surge dissipation, typically under low-line cycle skipping and recovery into highline while ramping the bulk voltage back up. The body diode commutation speed and reverse recovery charge are not important, since body diode never conducts in the CCM boost converter. Several CoolMOS™ series can be used for boost applications. C7 followed by CP provides the fastest switching (Figure 7) and best performance, but require careful design in terms of gate driving circuit and PCB layout. The P6/C6/E6 series provides a cost advantage, with easier design. The P6 series approaches CP performance closely at a better price point, and is recommended for new designs that are cost sensitive. In this Evaluation board C7 is used to reach the best efficiency. Figure 7 shows that CoolMOS™ C7 total gate charge Qg is less than one third of the C6 charge, and less than two thirds of the CP charge. Moreover, it shows gate-drain charge Qgd reduction in the much shorter length of the Miller Plateau compared to previous generations. These improvements in the gate charge profile are an indication of the improvement of the gate driving related losses as well as of the MOSFET switching times and losses. Figure 7 Gate charge and Eoss comparision for 41-45 mΩ CoolMOS™ C6, CP, C7 2.3.1 CoolMOS™ optimum RDS(ON) selection charts Selection of the optimum on-state resistance of a specific CoolMOS™ series is based on the balancing between switching losses and conduction losses of the device at a targeted load point. This can be done by modeling all losses in software tool such as Mathcad® by evaluating different technologies and different values of the on-state resistance. This requires few iterations and entry of several parameters from the datasheet of each part. An alternative way is using the CoolMOS™ selection charts shown in Figure 9 to Figure 12, specific charts exist for each CoolMOS™ family, optimized at half load or full load. The following is a guide on how to use these CoolMOS™ RDS(ON) selection charts. Let’s use the specifications in Table 1 as our design example: Po= 1200 W, f=100 kHz; full load efficiency is critical; CoolMOS™ C7 is preferred for best performance. Application Note 8 Revision1.1, 2016-02-22 Design Note DN 2013 -01 V1.0 January 2013 PFC boost converter design guide Step 1: Find the correct chart, Figure 8 shows the chart for CoolMOS™ C7 optimized at full load. Step 2: Find the 100 kHz curves (blue curves in this example) Step3: Mark the 1200 W on the x-axis Step 3: Find the 1200 W intersection with the solid blue line for the 100 kHz, read the left side y-axis, we find that 0.055 Ohm is the optimum for CoolMOS™ C7, then we may choose 045C7. Step 4: Find the 1200 W intersection with the dashed blue line for the 100 kHz, read the right side y-axis, we find that the 0.055 Ω will result in 13.9 W power loss at full load and low line 115 VAC. Ron optimized at full load Best thermal performance 100 400kHz 200kHz 150kHz 100kHz 65kHz 45kHz 225C7 190C7 Max Power Loss (W) for Optimum FET @ 115 Vac Optimum FET On-Resistance (ohm) 1 13.9W 125C7 095C7 0.1 065C7 10 400kHz 0.055ohm 200kHz 150kHz 100kHz 65kHz 45kHz 045C7 019C7 1 0.01 100 1200W 10,000 Output Power (W) Figure 8 Example on how to use the CoolMOS™ optimum RDS(on) selection charts. Application Note 9 Revision1.1, 2016-02-22 Design Note DN 2013 -01 V1.0 January 2013 PFC boost converter design guide Ron optimized at full load Best thermal performance 225C7 190C7 125C7 095C7 0.1 10 065C7 400kHz 045C7 200kHz 150kHz 100kHz 65kHz 45kHz 019C7 1 0.01 100 125C7 095C7 0.1 400kHz 10 200kHz 150kHz 100kHz 65kHz 45kHz 065C7 045C7 019C7 1 0.01 100 1000 Output Power (W) 10,000 CoolMOS™ C7 optimum RDS(on) selection charts Ron optimized at 50% load Balanced light/full load efficiency 200kHz 400kHz 150kHz 100kHz 65kHz 45kHz Ron optimized at full load Best thermal performance 600CP 520CP 385CP 299CP 250CP 199CP 165CP 125CP 099CP 0.1 075CP 10 400kHz 200kHz 150kHz 100kHz 65kHz 45kHz 045CP 1 0.01 100 Figure 10 1000 Output Power (W) 1 100 Optimum FET On-Resistance (ohm) 400kHz 200kHz 150kHz 100kHz 65kHz 45kHz Max Power Loss (W) for Optimum FET @ 115 Vac 1 Optimum FET On-Resistance (ohm) 100 225C7 190C7 10,000 1000 Output Power (W) 400kHz 200kHz 150kHz 100kHz 65kHz 45kHz 600CP 520CP 100 385CP 299CP 250CP 199CP 165CP 400kHz 125CP 099CP 0.1 075CP 200kHz 150kHz 100kHz 65kHz 45kHz 045CP 1 0.01 100 10,000 10 1000 Output Power (W) 10,000 Max Power Loss (W) for Optimum FET @ 115 Vac Figure 9 1 Max Power Loss (W) for Optimum FET @ 115 Vac 100 Optimum FET On-Resistance (ohm) 400kHz 200kHz 150kHz 100kHz 65kHz 45kHz Max Power Loss (W) for Optimum FET @ 115 Vac Optimum FET On-Resistance (ohm) 1 Ron optimized at 50% load Balanced light/full load efficiency CoolMOS™ CP optimum RDS(on) selection charts Application Note 10 Revision1.1, 2016-02-22 Design Note DN 2013 -01 V1.0 January 2013 PFC boost converter design guide 380P6 330P6 280P6 230P6 190P6 160P6 125P6 099P6 0.1 100 10 400kHz 070P6 200kHz 150kHz 100kHz 65kHz 45kHz 041P6 1 0.01 Figure 11 600P6 380P6 330P6 280P6 230P6 190P6 160P6 125P6 099P6 0.1 1 0.01 100 1000 Output Power (W) 10,000 1 Ron optimized at 50% load Balanced light/full load efficiency 100 400kHz 950C6 45kHz 280C6 190C6 160C6 125C6 099C6 0.1 070C6 45kHz 65kHz 100kHz 150kHz 200kHz 400kHz 200kHz 150kHz 100kHz 65kHz 45kHz 400kHz 041C6 10 1 0.01 100 1000 Optimum FET On-Resistance (ohm) 380C6 Max Power Loss (W) for Optimum FET @ 115 Vac Optimum FET On-Resistance (ohm) 10 CoolMOS™ P6 Optimum RDS(on) selection charts 600C6 520C6 1 100 400kHz 45kHz 600C6 520C6 380C6 280C6 190C6 160C6 125C6 099C6 0.1 400kHz 200kHz 150kHz 100kHz 65kHz 45kHz 070C6 10 041C6 1 0.01 10,000 100 Output Power (W) Figure 12 200kHz 150kHz 100kHz 65kHz 45kHz 041P6 Ron optimized at full load Best thermal performance 950C6 100 400kHz 070P6 10,000 1000 Output Power (W) 100 1 1000 Output Power (W) Max Power Loss (W) for Optimum FET @ 115 Vac Optimum FET On-Resistance (ohm) 600P6 200kHz 150kHz 100kHz 65kHz 45kHz Optimum FET On-Resistance (ohm) 400kHz Max Power Loss (W) for Optimum FET @ 115 Vac 1 Ron optimized at 50% load Balanced light/full load efficiency 200kHz 150kHz 400kHz 100kHz 65kHz 45kHz Max Power Loss (W) for Optimum FET @ 115 Vac Ron optimized at full load Best thermal performance 10,000 CoolMOS™ C6 optimum RDS(on) selection charts Since we found that 45 mΩ CoolMOS™ C7 “IPW65R045C7” is the optimum device for our design, we can base on it to calculate different power losses at the worst case of 85 Vac full load condition, as follows: The MOSFET RMS current across the 60 Hz line cycle can be calculated by the following equation, and consequently the MOSFET conduction loss can be obtained as: Application Note 11 Revision1.1, 2016-02-22 Design Note DN 2013 -01 V1.0 January 2013 PFC boost converter design guide 𝐼𝑆.𝑟𝑚𝑠 = 𝑃𝑜 𝑉𝑎𝑐.𝑚𝑖𝑛 ∙ √1 − Eq. 16 8 ∙ √2 ∙ 𝑉𝑎𝑐.𝑚𝑖𝑛 1200 𝑊 8 ∙ √2 ∙ 85 𝑉 = ∙ √1 − = 12.2 𝐴 3 ∙ 𝜋 ∙ 𝑉𝑜 85 𝑉 3 ∙ 𝜋 ∙ 400 𝑉 𝑃𝑆.𝑐𝑜𝑛𝑑 = 𝐼𝑆.𝑟𝑚𝑠 2 ∙ 𝑅𝑜𝑛(100℃) = 12.2 2 ∙ (0.045 ∙ 1.8) = 12 𝑊 Eq. 17 (𝐴𝑠𝑠𝑢𝑚𝑖𝑛𝑔 𝑅𝑜𝑛(100℃) = 1.8 ∙ 𝑅𝑜𝑛(25℃) ) For switching losses calculation, the average input current is used to estimate the losses over the line cycle. The calculation is based on the switching time consideration, where the triangular area between current and voltage changing references to the switching losses. Figure 13 Simplified turn-on and turn-off waveforms The average input current is given as: 𝐼𝐿.𝑎𝑣𝑔 = 𝑃𝑜 𝑉𝑎𝑐.𝑚𝑖𝑛 ∙ Eq. 18 2 ∙ √2 1200 𝑊 2 ∙ √2 = = ∙ = 12.71 𝐴 𝜋 85 𝑉 𝜋 Turn-on time and loss are: 𝑡𝑜𝑛 = 𝐶𝑖𝑠𝑠 ∗ 𝑅𝑔 ∙ 𝑙𝑛 ( 𝑉𝑔 − 𝑉𝑡ℎ 𝑉𝑔 − 𝑉𝑝𝑙 ) + 𝐶𝑟𝑠𝑠 ∙ 𝑅𝑔 ∙ ( 𝑉𝑑𝑠 − 𝑉𝑝𝑙 𝑉𝑔 − 𝑉𝑝𝑙 Eq. 19 ) 12 𝑉 − 3.5 𝑉 400 𝑉 − 5.4 𝑉 = 4340 ∙ 10−12 𝐹 ∙ 1.8 Ω ∙ 𝑙𝑛 ( ) + 75 ∙ 10−12 𝐹 ∙ 1.8Ω ∙ ( ) 12 𝑉 − 5.4 𝑉 12 𝑉 − 5.4 𝑉 = 10 ∙ 10−9 𝑠 (𝑉𝑑𝑠 = 𝑉𝑜 = 400 𝑉 , 𝐶𝑟𝑠𝑠 = 𝑄𝑔𝑑 93 ∙ 10−9 𝑛𝐶 = = 75 ∙ 10−12 𝐹) 𝑉𝑑𝑠 400 𝑉 𝑃𝑆.𝑜𝑛 = 0.5 ∙ 𝐼𝐿.𝑎𝑣𝑔 ∙ 𝑉𝑜 ∙ 𝑡𝑜𝑛 ∙ 𝑓 = 0.5 ∙ 12.71𝐴 ∙ 400 𝑉 ∙ 10 ∙ 10−9 𝑠 ∙ 100 ∙ 103 𝐻𝑧 = 2.5 𝑊 Eq. 20 Turn-off time and loss are: 𝑡𝑜𝑓𝑓 = 𝐶𝑟𝑠𝑠 ∗ 𝑅𝑔 ∙ ( 𝑉𝑑𝑠 − 𝑉𝑝𝑙 𝑉𝑝𝑙 = 75 ∙ 10−12 𝐶 ∙ 1.8Ω ∙ ( ) + 𝐶𝑖𝑠𝑠 ∙ 𝑅𝑔 ∙ 𝑙𝑛 ( 𝑉𝑝𝑙 𝑉𝑡ℎ Eq. 21 ) 400 𝑉 − 5.4 𝑉 5.4 𝑉 ) + 4340 ∙ 10−12 𝐶 ∙ 1.8Ω ∙ 𝑙𝑛 ( ) = 13.3 ∙ 10−9 𝑠 5.4 𝑉 3.5 𝑉 𝑃𝑆.𝑜𝑓𝑓 = 0.5 ∙ 𝐼𝐿.𝑎𝑣𝑔 ∙ 𝑉𝑜 ∙ 𝑡𝑜𝑓𝑓 ∙ 𝑓 = 0.5 ∙ 12.71𝐴 ∙ 400𝑉 ∙ 13.25 ∙ 10−9 𝑠 ∙ 100 ∙ 103 𝐻𝑧 = 3.4 𝑊 Eq. 22 The above is the “classic” format for calculating turn-off time and loss; due to the high Qoss of Super Junction MOSFETs, the Coss acts like a nonlinear capacitive snubber, and actual turn-off losses with fast switching can Application Note 12 Revision1.1, 2016-02-22 Design Note DN 2013 -01 V1.0 January 2013 PFC boost converter design guide be up to 50% lower than calculated. The current flow through the drain during turn-off under these conditions is non-dissipative capacitive current, and with fast drive, the channel may be completely turned off by the onset of drain voltage rise. Output capacitance Coss switching loss are: 𝑃𝑆.𝑜𝑠𝑠 = 𝐸𝑜𝑠𝑠 ∙ 𝑓 = 11.7 ∙ 10−6 𝐽𝑜𝑢𝑙𝑒 ∙ 100 ∙ 103 𝐻𝑧 = 1.17 𝑊 Eq. 23 Gate drive loss is defined as: 𝑃𝑆.𝑔𝑎𝑡𝑒 = 𝑉𝑔 ∙ 𝑄𝑔 ∙ 𝑓 = 12 𝑉 ∙ 93 ∙ 10−9 𝑛𝐶 ∙ 100 ∙ 103 𝐻𝑧 = 0.11 𝑊 Eq. 24 Total MOSFET loss is defined as: 𝑃𝑆.𝑡𝑜𝑡𝑎𝑙 = 𝑃𝑆.𝑐𝑜𝑛𝑑 + 𝑃𝑆.𝑜𝑛 + 𝑃𝑆.𝑜𝑓𝑓 + 𝑃𝑆.𝑜𝑠𝑠 = 19.2 𝑊 2.3.2 Eq. 25 TO-247 4-pin package with Kelvin source connection In common gate drive arrangements, the fast current transient causes a voltage drop VLS across the parasitic inductance of the source of the MOSFET that can counteracts the driving voltage. The induced source voltage, VLS = L*di/dt, can reduce the gate current (Figure 14), therefore lead to slowing down the switching transient and increasing the associated energy loss. On the other hand, the kelvin-source package concept is to exclude the package source inductance and layout inductance from the driving loop, so that the L*di/dt induced voltage is outside the gate drive loop and not affecting the gate current and switching losses. The 4pin MOSFET recommended for this design would be IPZ65R045C7. Figure 14 2.4 a) Conventional package b) TO-247 4pin package Boost diode Selection of the boost diode is a major design decision in CCM boost converter. Since the diode is hard commutated at a high current, and the reverse recovery can cause significant power loss, noise and current spikes. Reverse recovery can be a bottle neck for high switching frequency and high power density power supplies. Additionally, at low line, the available diode conduction duty cycle is quite low, and the forward current quite high in proportion to the average current. For that reason, the first criteria for selecting a diode in CCM boost are fast recovery with low reverse recovery charge, followed by Vf operating at high forward current. Since Silicon Carbide (SiC) Schottky Diodes have capacitive charge ,Qc, rather than reverse recovery charge, Qrr. Their switching loss and recovery time are much lower compared to silicon ultrafast diode, and will show an enhanced performance. Moreover, SiC diodes allow higher switching frequency designs, hence, higher power density converters is achieved. Application Note 13 Revision1.1, 2016-02-22 Design Note DN 2013 -01 V1.0 January 2013 PFC boost converter design guide The capacitive charge for SiC diodes are not only low, but also independent on di/dt, current level, and temperature; which is different from Si diodes that have strong dependency on these conditions, as shown in Figure 15. Figure 15 Capacitive charge as a function of di/dt for Si pin double diode and SiC diode The newer generations of SiC diodes are not just Schottky devices, but are merged structure diodes known as MPS diodes - Merged PN/Schottky (Figure 16). They combine the relatively low Vf and capacitive charge characteristics of Schottky Diodes with the high peak current capability of PN diodes, while avoiding the high junction voltage penalty (typically 2.5-3 V at room temperature) of a pure PN wide bandgap diode. Figure 16 Schottky and Merged PN/Schottky compared The recommended diode for CCM boost applications is the 650 V CoolSiC™ Schottky Diode Generation 5, which include Infineon’s leading edge technologies, such as diffusion soldering process and wafer thinning technology. The result is a new family of products showing improved efficiency over all load conditions, coming from both the improved thermal characteristics and an improved figure-of-merit (Qc x Vf). With the high surge current capability of the MPS diode, there is some latitude for the selection of the boost diode. A simple rule of thumb that works well for a wide input range PFC is 1 A diode rating for each 150 W of output power for good cost/performance tradeoffs, or 1 A diode rating for each 75 W for a premium performance. For example, a 600 W application will only need a 4 A rated diode, but an 8 A diode would perform better at full load. Especially at low-line operation, where the input current is quite high with a Application Note 14 Revision1.1, 2016-02-22 Design Note DN 2013 -01 V1.0 January 2013 PFC boost converter design guide short duty cycle, the higher rated diode will have a much lower Vf at the actual operating current, reducing the conduction losses. Note that even when using the MPS type SiC diode, it is still preferred to use a bulk pre-charge diode as shown earlier in Figure 3. This is a low frequency standard diode with high I2t rating to support pre-charging the bulk capacitor to the peak of the AC line voltage; this is a high initial surge current stress (which should be limited by a series NTC) that is best avoided for the HF boost rectifier diode. In this design example, we are using the 1 A/75 W rule, so for a 1200 W we require a 16 A diode, therefore SiC diode IDH16G65C5 is selected. The boost diode average current and conduction loss are: 𝐼𝐷.𝑎𝑣𝑔 = 𝑃𝑜 1200 𝑊 = =3𝐴 𝑉𝑜 400 𝑉 Eq. 26 𝑃𝐷.𝑐𝑜𝑛𝑑 = 𝐼𝐷.𝑎𝑣𝑔 ∙ 𝑉𝑓.𝑑𝑖𝑜𝑑𝑒 = 3 𝐴 ∙ 1.5 𝑉 = 4.5 𝑊 Eq. 27 Diode switching loss, which is carried by the boost MOSFET is: 𝑃𝐷.𝑠𝑤𝑖𝑡 = 0.5 ∙ 𝑉𝑜 ∙ 𝑄𝐶 ∙ 𝑓 = 0.5 ∙ 400𝑉 ∙ 23 ∙ 10−9 𝑛𝐶 ∙ 100 ∙ 103 𝐻𝑧 = 0.46 𝑊 Eq. 28 Diode total loss is: Eq. 29 𝑃𝐷.𝑡𝑜𝑡𝑎𝑙 = 𝑃𝐷.𝑐𝑜𝑛𝑑 + 𝑃𝐷.𝑠𝑤𝑖𝑡 = 4.5 𝑊 + 0.46 𝑊 = 4.96 𝑊 2.5 Output capacitor The output capacitor is sized to meet both of the hold-up time (16.6 ms) and the low frequency voltage ripple (10 V) requirements. The capacitor value is selected to have the larger value among the two equations in below: 𝐶𝑜 ≥ 𝐶𝑜 ≥ 2 ∙ 𝑃𝑜 ∙ 𝑡ℎ𝑜𝑙𝑑 2 𝑉𝑜 − 𝑉𝑜.𝑚𝑖𝑛 2 = 2 ∙ 1200 𝑊 ∙ 16.6 ∙ 10−3 𝑠𝑒𝑐 = 900.9 𝜇𝐹 (400 𝑉)2 − (340 𝑉)2 𝑃𝑜 2 ∙ 𝜋 ∙ 𝑓𝑙𝑖𝑛𝑒 ∙ ∆𝑉𝑜 ∙ 𝑉𝑜 = Eq. 30 1200 𝑊 = 795.8 𝜇𝐹 2 ∙ 𝜋 ∙ 60 𝐻𝑧 ∙ 10 𝑉 ∙ 400 𝑉 Eq. 31 → 𝐶𝑜 = 𝑚𝑎𝑥 (900.9 𝜇𝐹 , 795.8 𝜇𝐹) = 900.9 𝜇𝐹 In this design we use two parallel 560 μF , 450 V, with dissipation factor DF=0.2, consequently the capacitor ESR loss is obtained as below: 𝐸𝑆𝑅 = 𝐷𝐹 0.2 = = 0.237 Ω 2 ∙ 𝜋 ∙ 𝑓 ∙ 𝐶𝑜 2 ∙ 𝜋 ∙ 120𝐻𝑧 ∙ (2 ∙ 560 𝜇𝐹) Eq. 32 The capacitor RMS current across the 60Hz line cycle can be calculated by the following equation. 8 ∙ √2 ∙ 𝑃𝑜 2 𝑃𝑜 2 8 ∙ √2 ∙ (1200 𝑊)2 (1200 𝑊)2 𝐼𝐶𝑜.𝑟𝑚𝑠 = √ − 2=√ − = 6.47 𝐴 3 ∙ 𝜋 ∙ 𝑉𝑎𝑐.𝑚𝑖𝑛 ∙ 𝑉𝑜 𝑉𝑜 3 ∙ 𝜋 ∙ 85 𝑉 ∙ 400 𝑉 (400 𝑉)2 Eq. 33 𝑃𝐶𝑜 = 𝐼𝐶𝑜.𝑟𝑚𝑠 2 ∙ 𝐸𝑆𝑅 = (6.47𝐴)2 ∙ 0.237 Ω = 9.91 𝑊 Eq. 34 Application Note 15 Revision1.1, 2016-02-22 Design Note DN 2013 -01 V1.0 January 2013 PFC boost converter design guide 2.6 Heat sink design The MOSFET and boost diode share the same heat sink, thermal resistors are modeled as in Figure 17. In this evaluation board the maximum heat sink temperature 𝑇𝑆 is regulated to 60°C, so we can calculate the average junction temperature for the MOSFET and diode as follows: 𝑇𝐽.𝑑𝑖𝑜𝑑𝑒 = 𝑇𝑆 + 𝑃𝑑𝑖𝑜𝑑𝑒 ∙ (𝑅𝑡ℎ𝐶𝑆.𝑑𝑖𝑜𝑑𝑒 + 𝑅𝑡ℎ𝐽𝐶.𝑑𝑖𝑜𝑑𝑒 ) Eq. 35 𝑇𝐽.𝐹𝐸𝑇 = 𝑇𝑆 + 𝑃𝐹𝐸𝑇 ∙ (𝑅𝑡ℎ𝐶𝑆.𝐹𝐸𝑇 + 𝑅𝑡ℎ𝐽𝐶.𝐹𝐸𝑇 ) Eq. 36 The 𝑇𝑆 can be regulated by choosing a heatsink that with certain airflow can reach the thermal resistance (𝑅𝑡ℎ𝑆𝐴 ) calculated below: 𝑅𝑡ℎ𝑆𝐴 = 𝑇𝑆 − 𝑇𝐴 𝑃𝐹𝐸𝑇 + 𝑃𝑑𝑖𝑜𝑑𝑒 Eq. 37 Where: 𝑅𝑡ℎ𝐽𝐶 : Thermal resistance from junction to case, this is specified in the MOSFET and Diode datasheets. 𝑅𝑡ℎ𝐶𝑆 : Thermal resistace from case to heatsink, typically low compared to the overall thermal resistance, its value depends on the the interface material, for example, thermal grease and thermal pad. 𝑅𝑡ℎ𝑆𝐴 : Thermal resistance from heatsink to ambient, this is specified in the heatsink datasheets, it depends on the heatsink size and design, and is a function of the surroundings, for example, a heat sink could have difference values for R thSA for different airflow conditions. 𝑇𝑆 : Heatsink temperature. 𝑇𝐶 : Case temperature. 𝑇𝐴 : Ambient temperature. 𝑃𝐹𝐸𝑇 : FET total power loss. 𝑃𝑑𝑖𝑜𝑑𝑒 : Diode total power loss. PFET TJ.FET RthJC.FET TC.FET RthCS.FET TS Pdiode Figure 17 TJ.diode RthJC.diode TC.diode RthCS.diode RthSA TA PFET+Pdiode Schematic of thermal network Application Note 16 Revision1.1, 2016-02-22 Design Note DN 2013 -01 V1.0 January 2013 PFC boost converter design guide 3 ICE3PCS01G PFC boost controller The ICE3PCS01G is a 14pins controller IC for power factor correction converters. It is suitable for wide range line input applications from 85 to 265 VAC and with overall efficiency above 97%. The IC supports the converters in boost topology and operates in continuous conduction mode (CCM) with average current control. The IC operates with a cascaded control; the inner current loop and the outer voltage loop. The inner current loop of the IC controls the sinusoidal profile for the average input current. It uses the dependency of the PWM duty cycle on the line input voltage to determine the corresponding input current. This means the average input current follows the input voltage as long as the device operates in CCM. Under light load condition, depending on the choke inductance, the system may enter into discontinuous conduction mode (DCM) resulting in a higher harmonics but still meeting the Class D requirement of IEC 1000-3-2. The outer voltage loop of the IC controls the output bulk voltage and is integrated digitally within the IC. Depending on the load condition, internal PI compensation output is converted to an appropriate DC voltage which controls the amplitude of the average input current. The IC is equipped with various protection features to ensure safe operating for the system and the device. 3.1 Soft startup During power up when the VOUT is less than 96% of the rated level, internal voltage loop output increases from initial voltage under the soft-start control. This results in a controlled linear increase of the input current from 0 A as can be seen in Figure 17. This helps to reduce the current stress in power components. Once VOUT has reached 96% of the rated level, the soft-start control is released to achieve good regulation and dynamic response and VB_OK pin outputs 5 V indicating PFC output voltage in normal range. 3.2 Gate switching frequency The switching frequency of the PFC converter can be set with an external resistor RFREQ at pin FREQ with reference to pin SGND. The voltage at pin FREQ is typical 1V. The corresponding capacitor for the oscillator is integrated in the device and the RFREQ/frequency is given in Figure 18. The recommended operating frequency range is from 21 kHz to 250 kHz. As an example, a RFREQ of 43 kΩ at pin FREQ will set a switching frequency fSW of 100 kHz typically. Frequency vs Resistance 260 240 Resistance /kohm Frequency /kHz Resistance /kohm Frequency /kHz 220 15 278 110 40 17 249 120 36 20 211 130 34 30 141 140 31.5 160 40 106 150 29.5 140 50 86 169 26.2 120 60 74 191 25 70 62 200 23 80 55 210 21.2 80 90 49 221 20.2 60 100 43 232 19.2 200 Frequency/kHz 180 100 40 20 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 Resistance/kohm Figure 18 Frequency setting Application Note 17 Revision1.1, 2016-02-22 Design Note DN 2013 -01 V1.0 January 2013 PFC boost converter design guide 3.3 Protection features 3.3.1 Open loop protection (OLP) The open loop protection is available for this IC to safe-guard the output. Whenever voltage at pin VSENSE falls below 0.5 V, or equivalently VOUT falls below 20% of its rated value, it indicates an open loop condition (i.e. VSENSE pin not connected). In this case, most of the blocks within the IC will be shutdown. It is implemented using a comparator with a threshold of 0.5 V. 3.3.2 First over-voltage protection (OVP1) Whenever VOUT exceeds the rated value by 8%, the first over-voltage protection OVP1 is active. This is implemented by sensing the voltage at pin VSENSE with respect to a reference voltage of 2.7 V. A VSENSE voltage higher than 2.7 V will immediately block the gate signal. After bulk voltage falls below the rated value, gate drive resumes switching again. 3.3.3 Peak current limit The IC provides a cycle by cycle peak current limitation (PCL). It is active when the voltage at pin ISENSE reaches -0.2 V. This voltage is amplified by a factor of -5 and connected to comparator with a reference voltage of 1.0 V. A deglitcher with 200 ns after the comparator improves noise immunity to the activation of this protection. In other words, the current sense resistor should be designed lower than -0.2 V PCL for normal operation. 3.3.4 IC supply under voltage lockout When VCC voltage is below the under voltage lockout threshold VCC,UVLO, typical 11 V, IC is off and the gate drive is internally pull low to maintain the off state. The current consumption is down to 1.4 mA only. 3.3.5 Bulk voltage monitor and enable function (VBTHL_EN) The IC monitors the bulk voltage status through VSENSE pin and output a TTL signal to enable PWM IC or control inrush relay. During soft-start once the bulk voltage is higher than 95% rated value, pin VB_OK outputs a high level. The threshold to trigger the low level is decided by the pin VBTHL voltage adjustable externally. When pin VBTHL is pulled down externally lower than 0.5 V most function blocks are turned off and the IC enters into standby mode for low power consumption. When the disable signal is released the IC recovers by soft-start. Application Note 18 Revision1.1, 2016-02-22 Design Note DN 2013 -01 V1.0 January 2013 PFC boost converter design guide 4 Efficiency and power losses modeling The design example discussed in this document was modeled in Mathcad®. All of the power losses equations were written as a function of the output power in order to be able to plot an estimated efficiency curve across the output power range as shown in Figure 19. Figure 19 Calculated efficiency @ 85VAC vs experimental efficiency @ 90VAC Figure 20 shows a breakdown of main power losses at the full load of both low and high line conditions. 230Vac 100% load Total power loss = 25.3W 85Vac 100% load Total power loss = 74.1W Output capacitor loss 13% Rectifier bridge loss 34% Figure 20 Output capacitor loss 9% MOSFET losses 26% Inductor losses 20% Boost diode losses 7% Rectifier bridge loss 37% MOSFET losses 16% Inductor losses 18% Boost diode losses 20% Breakdown of main power losses Figure 21 shows the simulated and experimental inductor current at the low line full load condition. Figure 21 Simulated and experimental Inductor current waveforms at low-line full load condition Application Note 19 Revision1.1, 2016-02-22 Design Note DN 2013 -01 V1.0 January 2013 PFC boost converter design guide 5 Experimental results Figure 22 Evaluation board All test conditions are based on 60°C heat sink temperature. 5.1 Load and line measurement data The test data of the evaluation board under different test conditions are listed in Table 2. The corresponding efficiency waveforms are shown in Figure 23 and Figure 24. Table 2 Efficiency test data with IPZ65R045C7 & IDH12G65C5 @ 100kHz , Rg= 1.8 Ω VIN [V] IIN [A] PIN [W] UOUT [V] IOUT [A] 88.88 14.3962 1278.5 402.05 2.984 1200.02 93.829 0.9996 89.11 10.8743 968.8 402.09 2.282 917.68 94.719 0.9997 89.33 8.0877 722.4 402.12 1.711 688.38 95.290 0.9998 89.51 5.3667 480.2 402.15 1.141 459.05 95.597 0.9996 89.74 2.6953 241.5 402.18 0.571 229.82 95.161 0.9984 229.5 5.3365 1222.1 402.03 2.985 1200.01 98.186 0.9976 229.6 4.431 1014.9 402.06 2.479 996.66 98.198 0.9975 229.7 3.3171 758.7 402.10 1.852 744.59 98.138 0.9956 229.8 2.2298 508.8 402.12 1.239 498.18 97.910 0.9929 229.9 1.1304 253.4 402.16 0.612 246.15 97.120 0.9752 Input 90 VAC 230 VAC Application Note 20 POUT [W] Efficiency [%] Power factor Revision1.1, 2016-02-22 Design Note DN 2013 -01 V1.0 January 2013 PFC boost converter design guide Figure 23 High-line efficiency with IPZ65R045C7 & IDH12G65C5 @ 100kHz, Rg= 1.8 Ω Figure 24 Low-line efficiency with IPZ65R045C7 & IDH12G65C5 @ 100kHz, Rg= 1.8 Ω 5.2 Conductive EMI test Compliance with EN55022 standard is a very important quality factor for a power supply. The EMI has to consider the whole SMPS and is split into radiated and conductive EMI consideration. For the described evaluation PFC board it is most important to investigate on the conducted EMI-behavior since it is the input stage of any SMPS below a certain power range, as shown in Figure 25. Application Note 21 Revision1.1, 2016-02-22 Design Note DN 2013 -01 V1.0 January 2013 PFC boost converter design guide Figure 25 Conductive EMI measurement of the board with resistive load 5.3 Startup behavior During power up when the VOUT is less than 96% of the rated level, internal voltage loop output increases from initial voltage under the soft-start control. This results in a controlled linear increase of the input current from 0 A thus reducing the current stress in the power components as can be seen on the yellow waveform in Figure 26. Figure 26 Waveform capture during low-line startup Application Note 22 Revision1.1, 2016-02-22 Design Note DN 2013 -01 V1.0 January 2013 PFC boost converter design guide 6 Board design 6.1 Schematics Figure 27 Evaluation board schematic Application Note 23 Revision1.1, 2016-02-22 Design Note DN 2013 -01 V1.0 January 2013 PFC boost converter design guide 6.2 PCB layout Figure 28 PCB top layer view Figure 29 PCB bottom layer view Application Note 24 Revision1.1, 2016-02-22 Design Note DN 2013 -01 V1.0 January 2013 PFC boost converter design guide 6.3 Bill of material Table 3 Bill of material Designator Value Description B1, B2 Bias1 C1 C2 C3 C4, C5 C6 C7 C8, C30 C10, C31 C11 C12, C25, C32 C13 C14, C15 C16 C17, C18 C19, C20 C21, C24 C22 C23 C26 C27 C28 C29 D1 D2, D3 D4 D6 D10 DUT1 D_Z3 EMI_1 GL1, GL2 IC1 IC2 IC3 IC4 IC5 J1, J11 J2 J3 J6 J7, J12 J8, J10 J9 K1 K2 KL1 KL01 KL01-S KL02 KL02-S closed with 0 Ω 12 V Bias 10 µ 4n7 10 n 1µ 4.7 n 10 n 100n500 V 1n 10 µ 100 n 100 n 1µ 100 µ 1.1 n 3.3 n 560 µ 1u_400 V 1.5u_400 V 220 n 10 µ 470p 22n SS26 1N4148 1N5408 short ES1C IPZ65R045C7 ZMM15 not placed GSIB2580 TDA2030 LM4040 ICE3PCS01G 1EDI60N12AF IFX91041 Jumper_3Pin Current measure bridge Current measure bridge open close with solder open close with solder SK426 KM75-1 BNC HV in Complement Vin_sense Complement Placeholder for Ferrite Bead, 0 Ω resistor Bias adapter 25 V 25 V 25 V x-capacitor 25 V 25 V VJ1825Y104KXEAT 25 V 25 V 25 V 25 V 25 V 25 V Y-capacitor Y-capacitor EETHC2G561KA or EKMR421VSN561MR50S BFC237351105; Farnel 1215540 Application Note 25 V 25 V 25 V 25 V 0Ω 1 A 150 V fast diode 1N4734A EMI Adapter GSIB2580 Mount with M2.5x6 LM4040D20IDBZRG4 PFC_CCM_Controller 6 A_isolated_MOSdriver 1.8A Step down switching regulator SPC20486 1.25 mm isolated copper wire U-shape-Cu-wire 1.25 mm 2 cm distance Solder jumper; 4 pin as 3 pin Solder jumper; driver ground to SS, Solder jumper; isolated driver power Solder jumper; 3pin ground, Solder jumper; driver power none isolated Solder jumper; isolated driver power 100 mm long; mound with 2xM4x15 KM75-1 +4clip 4597; Fischer Oscilloscope_ Funtion generator GMSTBVA 2,5 HC/ 3-G-7,62 GMSTB 2,5 HCV/ 3-ST-7,62 GMSTBVA 2,5 HC/ 2-G-7,62 GMSTB 2,5 HCV/ 2-ST-7,62 25 Revision1.1, 2016-02-22 Design Note DN 2013 -01 V1.0 January 2013 PFC boost converter design guide L1 L2 L3 L4 LED1 LED2, LED3, LED4, LED5 M1, M2 M1, M2 L_PFC 10 A 100 µH 8120-RC 33 µH red 2times 77083A7 64wind_1.15 mm Würth 744824101 BOURNS_8120-RC_2m4H_17 A 74454133 Power on LED blue Power on LED Fan 60mm finger guard for Fan 60mm PMD1206PTB1-A LZ28CP PWM-Signal R1, R3, R13, R20, R56 R2, R8, R15, R44 R4 R5 R6 R7, R11 R9, R16 R10, R25 R12, R42 R14, R19 R17 R18 R21 R22, R23 R24 R27 R28 R29 R30 R31 R35 R36 R37 R45 REL1 REL2 R_NTC1 R_NTC2 S1, S2, S3, S4, S5, S6 S1, S2, S3, S4, S5, S6 S1, S2, S3, S4, S5, S6 Vin Vout Vout_sense X1 X2 X3 X4 X5 X6 X7 X8, X9 X12 SMA 1k 10 k 5k 680 220R 10R 20R 47R 330 k 2M 27 k 36 k LTO100 4R7 500 k 0R005 np 20 k 22 k 1k 100 k 2R np np 500 k 200 k AZ762 G6D_1A_ASI 5k 3R3 SCREW_M4 M4 Screw nut washer M4 HV_in Vout Vout_sense np (Heat sink) np (MOS1) np (Diode) np (Choke) np (MOS2) Rg_4pin Rg_3pin KL_STANDARD_2 Np Oscilloscope_ Function generator 5% 5% 67WR20KLF 5% 5% 5% 3314G-1-200E 5% 5% 5% 5% 5% include two 20F2617 Bürklin connector 10% FCSL90R005FE Application Note 23AR20KLFTR 5% 10 V 67WR100KLF 5% 5% 5% 12 V 12 V B57560G502F mound in K1 under MOS R_SL22 3 cm Distance holder M4 Screw nut washer M4 GMSTBA_2.5HC_3G7.62 GMSTBA_2.5HC_2G7.62 GMSTBVA_2.5HC_2G7.62 thermocouple plug thermocouple plug thermocouple plug thermocouple plug thermocouple plug SPC20485 SPC20485 SPC20485 for adapter power supply 26 Revision1.1, 2016-02-22 Design Note DN 2013 -01 V1.0 January 2013 PFC boost converter design guide 7 References  F. Stueckler, E. Vecino, Infineon Technologies Application Note: “Coo lMOSTM C7 650V Switch in a Kelvin Source Configuration”. May 2013. http://www.infineon.com/dgdl/Infineon+-+Application+Note+-+TO-247-4pin+-+650V+CoolMOS™ +C7+Switch+in+a+Kelvin+Source+Configuration.pdf?folderId=db3a304333b8a7ca0133c6bec0956188&fi leId=db3a30433e5a5024013e6a9908a26410  J. Hancock, F. Stueckler, E. Vecino, Infineon Technologies Application Note: “CoolMOS™ C7 : Mastering the Art of Quickness”. April 2013. http://www.infineon.com/dgdl/Infineon+-+Application+Note+-+650V+CoolMOS™ +C7++Mastering+the+Art+of+Quickness.pdf?folderId=db3a304333b8a7ca0133c6bec0956188&fileId=db3a30 433e5a5024013e6a966779640b  ICE3PCS01G controller datasheet. http://www.infineon.com/dgdl/Infineon-ICE3PCS01-DS-v02_00en.pdf?folderId=5546d4694909da4801490a07012f053b&fileId=db3a304329a0f6ee0129a67ae8c02b46  Power Factor Correction (PFC) Parts Selection Guide http://www.infineon.com/dgdl/Infineon+-+Selection+Guide+-+PFC+-+Power+Factor+Correction++CoolMOS™ +-+SiC+Diodes++Controllers.pdf?folderId=db3a30433e5a5024013e6a288c8f6352&fileId=db3a30433e5a5024013e6a35c b806364 Application Note 27 Revision1.1, 2016-02-22 Design Note DN 2013 -01 V1.0 January 2013 PFC boost converter design guide 8 Symbols used in formulas Table 4 Symbols used in formulas Vac Input voltage Vac.min Minimum input voltage Vo Output voltage Po Output power f Switching frequency T Switching time period fline line frequency L Filter inductor %Ripple Inductor current ripple percentage to input current DCR Inductor DC resistance Iin.rms Input rms current IL.rms Inductor rms current IL.avg Inductor average current across the line cycle IL.pk Inductor peak current PL.cond Inductor conduction loss Vf.bridge Bridge diode forward voltage drop Pbridge Bridge power loss Ron(100C) MOSFET on-resistance at 100oC Qgs MOSFET gate-source charge Qgd MOSFET gate-drain charge Qg MOSFET total gate charge Rg MOSFET gate resistance Vpl MOSFET gate plateau voltage Vth MOSFET gate threshold voltage ton MOSFET turn-on time toff MOSFET turn-off time Eoss MOSFET output capacitance switching energy IS.rms MOSFET rms current over the line cycle PS.cond MOSFET conduction loss PS.on MOSFET turn-on power loss PS.off MOSFET turn-off power loss PS.oss MOSFET output capacitance switching loss PS.gate MOSFET gate drive loss ID.avg Boost diode average current Vf.diode Boost diode forward voltage drop Qrr Boost diode reverse recovery charge Application Note 28 Revision1.1, 2016-02-22 Design Note DN 2013 -01 V1.0 January 2013 PFC boost converter design guide Vac Input voltage PDcond Boost diode conduction loss PD.sw Boost diode switching loss Co Output capacitor ESR Output capacitor resistance thold Hold-up time Vo.mi Hold up minimum output voltage ∆Vo Output voltage ripple ICo.rms Output capacitor rms current PCo Output capacitor conduction loss Revision history Major changes since the last revision Page or reference -Figure 8-12 Application Note Description of change First release (Revision 1.0) Corrected output power on y-Axis: 10,000(Revision 1.1.) 29 Revision1.1, 2016-02-22 Trademarks of Infineon Technologies AG AURIX™, C166™, CanPAK™, CIPOS™, CoolGaN™, CoolMOS™, CoolSET™, CoolSiC™, CORECONTROL™, CROSSAVE™, DAVE™, DI-POL™, DrBlade™, EasyPIM™, EconoBRIDGE™, EconoDUAL™, EconoPACK™, EconoPIM™, EiceDRIVER™, eupec™, FCOS™, HITFET™, HybridPACK™, Infineon™, ISOFACE™, IsoPACK™, i-Wafer™, MIPAQ™, ModSTACK™, my-d™, NovalithIC™, OmniTune™, OPTIGA™, OptiMOS™, ORIGA™, POWERCODE™, PRIMARION™, PrimePACK™, PrimeSTACK™, PROFET™, PRO-SIL™, RASIC™, REAL3™, ReverSave™, SatRIC™, SIEGET™, SIPMOS™, SmartLEWIS™, SOLID FLASH™, SPOC™, TEMPFET™, thinQ!™, TRENCHSTOP™, TriCore™. Trademarks updated August 2015 Other Trademarks All referenced product or service names and trademarks are the property of their respective owners. www.infineon.com Edition 2014-11-01 Published by Infineon Technologies AG 81726 Munich, Germany © 2016 Infineon Technologies AG. All Rights Reserved. Do you have a question about any aspect of this document? Email: [email protected] Document reference AN_201409_PL52_009 Legal Disclaimer THE INFORMATION GIVEN IN THIS APPLICATION NOTE (INCLUDING BUT NOT LIMITED TO CONTENTS OF REFERENCED WEBSITES) IS GIVEN AS A HINT FOR THE IMPLEMENTATION OF THE INFINEON TECHNOLOGIES COMPONENT ONLY AND SHALL NOT BE REGARDED AS ANY DESCRIPTION OR WARRANTY OF A CERTAIN FUNCTIONALITY, CONDITION OR QUALITY OF THE INFINEON TECHNOLOGIES COMPONENT. THE RECIPIENT OF THIS APPLICATION NOTE MUST VERIFY ANY FUNCTION DESCRIBED HEREIN IN THE REAL APPLICATION. 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