Application Note, V1.1, October 2011 EVALPFC-300W-ICE3PCS01G 300W PFC Evaluation Board with CCM PFC controller ICE3PCS01G Power Management & Supply N e v e r s t o p t h i n k i n g . Edition 2011-10-19 Published by Infineon Technologies Asia Pacific, 168 Kallang Way, 349253 Singapore, Singapore © Infineon Technologies AP 2010. All Rights Reserved. Attention please! The information herein is given to describe certain components and shall not be considered as a guarantee of characteristics. Terms of delivery and rights to technical change reserved. We hereby disclaim any and all warranties, including but not limited to warranties of non-infringement, regarding circuits, descriptions and charts stated herein. Information For further information on technology, delivery terms and conditions and prices please contact your nearest Infineon Technologies Office (www.infineon.com). Warnings Due to technical requirements components may contain dangerous substances. For information on the types in question please contact your nearest Infineon Technologies Office. Infineon Technologies Components may only be used in life-support devices or systems with the express written approval of Infineon Technologies, if a failure of such components can reasonably be expected to cause the failure of that life-support device or system, or to affect the safety or effectiveness of that device or system. Life support devices or systems are intended to be implanted in the human body, or to support and/or maintain and sustain and/or protect human life. If they fail, it is reasonable to assume that the health of the user or other persons may be endangered. EVALPFC-300W-ICE3PCS01G Revision History: Previous Version: Page 12 2011-10 1.0 BOM list update for R3 from 390KΩ to 3.9MΩ V1.1 300W PFC Evaluation Board with CCM PFC controller ICE3PCS01G License to Infineon Technologies Asia Pacific Pte Ltd AN-PS0047 Lim Teik Eng Liu Jianwei Li Dong 3 Table of Content 1 Content ........................................................................................................................................................ 5 2 Evaluation Board........................................................................................................................................ 5 3 Technical Specifications ............................................................................................................................. 6 4 Circuit Description ..................................................................................................................................... 6 Line Input .......................................................................................................................................................... 6 Power Stage Boost Type PFC Converter ....................................................................................................... 6 PWM Control of Boost Converter ..................................................................................................................... 6 5 Circuit Operation ....................................................................................................................................... 7 5.1 Soft Startup ............................................................................................................................................. 7 5.2 Boost Follower ........................................................................................................................................ 7 5.3 Gate Switching Frequency ...................................................................................................................... 7 5.4 Protection Features .................................................................................................................................. 8 5.4.1 Input brown-out protection (BOP) ................................................................................................ 8 5.4.2 Open loop protection (OLP) ......................................................................................................... 8 5.4.3 First over-voltage protection (OVP1) ........................................................................................... 9 5.4.4 Second over-voltage protection (OVP2) ....................................................................................... 9 5.4.5 Peak current limit .......................................................................................................................... 9 5.4.6 IC supply under voltage lockout ................................................................................................... 9 5.4.7 Bulk Voltage Monitor and Enable Function (VBTHL_EN) ......................................................... 9 6 Circuit Diagram........................................................................................................................................ 10 7 PCB Layout............................................................................................................................................... 11 7.1 Top layer view ...................................................................................................................................... 11 7.2 Bottom layer view ................................................................................................................................. 11 8 Component List ........................................................................................................................................ 12 9 Boost Choke Layout ................................................................................................................................. 13 10 Test report................................................................................................................................................. 14 10.1 Load and Line Test .......................................................................................................................... 14 10.2 Load and Line Test in Boost Follower Mode .................................................................................. 15 10.3 Harmonic test according to EN61000-3-2 Class D requirement ...................................................... 17 11 Test Waveforms ........................................................................................................................................ 18 12 References: ................................................................................................................................................ 19 4 1 Content The evaluation board presented here is a 300W power factor correction (PFC) circuit with 85~265VAC universal input and output of 395VDC rated voltage or 333VDC in boost follower mode. The continuous conduction mode (CCM) PFC controller ICE3PCS01G is employed in this board to achieve the unity power factor. This ICE3PCS01G is specially designed for applications of power supplies used in PC, server, LCD/PDP TV and Telecom, requesting high efficiency and power factor. The voltage loop compensation is integrated digitally for better dynamic response and less design effort. Appreciated for its high integrated design, ICE3PCS01G can achieve full requirements of the PFC application implemented in the 14-pin in DSO14 package. At the same time the number of peripheral components is minimized. The gate switching frequency is adjustable from 21kHz to 250kHz and able to synchronize with external switching frequency from 50kHz to 150kHz. In order to improve the power conversion efficiency further, the CoolMOSTM CP series and high voltage silicon carbide (SiC) schottky diode thinQ!TM are used into this boost type PFC circuit. 2 Evaluation Board Figure 1 ICE3PCS01G Demoboard 5 3 Technical Specifications Input voltage 85VAC~265VAC Input frequency 47~63Hz Output voltage and current 395VDC, 0.75A Output power ~ 300W Average efficiency >96% at 115VAC Switching Frequency 21kHz~250kHz 4 Circuit Description Line Input The AC line input side comprises the input fuse F1 as over-current protection. The choke L1, X2capacitors CX1/CX2 and Y1-capacitor CY1/CY2 are used to suppress common mode noise as well as differential mode noise. RT1 is placed in series to limit inrush current during each power on. A relay is mounted across the RT1 to short the resistor when VOUT is higher than 95% rated voltage. Power Stage Boost Type PFC Converter After the bridge rectifier BR1, there is a boost type PFC converter consisting of L2, Q2, D3 and C3. The third generation CoolMOS™ IPP60R199P is used as the power switch Q2. BR1, Q2 and SiC Diode D3 share the same heat sink so that the system heat can be equably spread. Output capacitor C3 provides energy buffering to reduce the output voltage ripple (100Hz) to the acceptable level and meet the holdup time requirement. PWM Control of Boost Converter The ICE3PCS01G is a 14-pins control IC for power factor correction converters. It is suitable for wide range line input applications from 85 to 265 VAC with overall efficiency above 96%. The IC supports converters in boost topology and it 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 controls the output bulk voltage, 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 condition for both the system and device. 6 5 Circuit Operation 5.1 Soft Startup During power up when the VOUT is less than 95% 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 0A thus reducing the current stress in the power components. Once VOUT has reached 95% of the rated level, the soft-start control is released to achieve good regulation and dynamic response and VB_OK pin outputs 5V indicating PFC output voltage in normal range. 5.2 Boost Follower The IC provides adjustable lower step of bulk voltage in case of low line input and light output power. The low line condition is determined when pin BOP voltage is less than 2.3V. Pin BOFO is connected to PWM feedback voltage through a voltage divider, representing the output power. The light load condition is determined when pin BOFO voltage is less than 0.5V. Once these two conditions are met in the same time, a 20uA current source is flowing out of pin VSENSE so that the bulk voltage should be reduced to a lower level in order to keep the VSENSE voltage same as the internal reference 2.5V. The reduced bulk voltage can be designed by upper side resistance of voltage divider from pin VSENSE. Thus the low side resistance is designed by the voltage divider ratio from the reference 2.5V to the rated bulk voltage. An internal 300kΩ resistor will be paralleled with external low side resistor of BOFO pin to provide the adjustable hysteresis for entry/exit power when boost follower is activated. The boost follower feature will be disabled internally during PFC soft-start in order to prevent bulk voltage oscillation due to the unstable PWM feedback voltage. This feature can also be disabled externally by pulling up pin BOFO higher than 0.5V continuously. 5.3 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 2. The recommended operating frequency range is from 21 kHz to 250 kHz. As an example, a RFREQ of 68kΩ at pin FREQ will set a switching frequency FSW of 65 kHz typically. 7 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 2 Frequency setting The switching frequency can be synchronized to the external pulse signal after 6 external pulses delay once the voltage at the FREQ pin is higher than 2.5V. The synchronization means two points. Firstly, the PFC switching frequency is tracking the external pulse signal frequency. Secondly, the falling edge of the PFC signal is triggered by the rising edge of the external pulse signal. The external R20 combined with R21 and the external diode, D6 can ensure FREQ pin voltage to be kept between 1.0V (clamped internally) and 5V (maximum pin voltage). If the external pulse signal has disappeared longer than 108us (typical) the switching frequency will be synchronized to internal clock set by the external resistor R20. 5.4 Protection Features 5.4.1 Input brown-out protection (BOP) ICE3PCS01G provides a new BOP feature whereby it senses directly the input voltage for Input Brown-Out condition via an external resistor/capacitor/diode network. This network provides a filtered value of VIN which turns the IC on when the voltage at pin 9 (BOP) is more than 1.25V. The IC enters into the fault mode when BOP goes below 1.0V. The hysteresis prevents the system to oscillate between normal and fault mode. Note also that the peak of VIN needs to be at least 20% of the rated VOUT in order to overcome open loop protection and power up system. 5.4.2 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 0.5V, 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 0.5V. 8 5.4.3 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 2.7V. A VSENSE voltage higher than 2.7V will immediately block the gate signal. After bulk voltage falls below the rated value, gate drive resumes switching again. 5.4.4 Second over-voltage protection (OVP2) The second OVP (OVP2) is provided in case that the first one fails due to the aging or incorrect resistors connected to the VSENSE pin. This is implemented by sensing the voltage at pin OVP with respect to a reference voltage of 2.5V. When voltage at OVP pin is higher than 2.5V, the IC will immediately turn off the gate, thereby preventing damage to bus capacitor. When the bulk voltage drops out of the hysteresis, which is below 2.3V the IC can be latched further or begin auto soft-start. These two protection modes are distinguished through detecting the external equivalent resistance connecting to VBTHL_EN pin after VCC is higher than UVLO threshold. If the equivalent resistance is higher than 100kΩ the IC selects latch mode for second OVP, otherwise auto soft-start mode. In normal operation the trigger level of OVP2 should be designed higher than OVP1. However in the condition of mains transient overshoot the bulk voltage may be pulled up to the peak value of mains that is higher than the threshold of OVP1 and OVP2. In this case the OVP1 and OVP2 are triggered in the same time the IC will shut down the gate drive until bulk voltage falls out of the two protection hysteresis, then resume the gate drive again 5.4.5 Peak current limit The IC provides a cycle by cycle peak current limitation (PCL). It is active when the voltage at pin ISENSE reaches -0.2V. This voltage is amplified by a factor of -5 and connected to comparator with a reference voltage of 1.0V. A deglitcher with 200ns after the comparator improves noise immunity to the activation of this protection. In other words, the current sense resistor should be designed lower than -0.2V PCL for normal operation. 5.4.6 IC supply under voltage lockout When VCC voltage is below the under voltage lockout threshold VCCUVLO, typical 11V, IC is off and the gate drive is internally pull low to maintain the off state. The current consumption is down to 1.4mA only. 5.4.7 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 0.5V 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. 9 6 Circuit Diagram Figure 3 Schematic of 300W PFC demo board 10 7 PCB Layout 7.1 Top layer view 7.2 Bottom layer view 11 8 Component List Designator Part Type Description BR1 C1 C2 C3 C4 C5 C6 C7 C8 C9 C10 C11 C13 CX1 CX2 CY1 CY2 D1 D2 D3 D4 D5 D6 F1 IC1 J1 J2 J3 J4 J5 L1 L2 Q1 Q2 R1 R2 R3 R4 R5A R5 R6 R7 R8 R9 R10 R11 R12 8A, 400V 10uF/50V 0.1uF/630V 220uF/450V 1.5 uF/50V 1.5 uF/50V 100pF/50V 100uF/25V 1uF/25V 4.7nF/50V 10nF/50V 10pF/50V 4.7nF/50V 0.68uF, X1, 275V 0.68uF, X1, 275V 2.2nF, Y2, 250V 2.2nF, Y2, 250V 1N4148 1N5408 IDH04S60C 1N4007 1N4007 1N4148 5A ICE3PCS01G Jumper Jumper Jumper Jumper Jumper 2*3.9mH 750uH BC517 IPP60R199CP 100R/0.25W, 5% 10k/0.25W, 1% 3.9M/0.25W, 1% 68/0.25W, 1% 0.33/0.5W, 5% 0.1/0.5W, 5% 0.1/0.5W, 5% 0.1/0.5W, 5% 3.3/0.25W, 1% 10k/0.25W, 5% 1.5M/0.25W, 1% 2M/0.25W, 1% 130k/0.25W, 1% Bridge Rectifier Electrolytic Cap Ceramic Cap Electrolytic Cap Ceramic Cap Ceramic Cap Ceramic Cap Electrolytic Cap Ceramic Cap Ceramic Cap Ceramic Cap Ceramic Cap Ceramic Cap Ceramic Cap Ceramic Cap Ceramic Cap Ceramic Cap Diode Diode Diode Diode Diode Diode Fuse DSO-14 Connector (BOFO) Connector (SYNC) Connector (VCC) Connector (VIN) Connector (VOUT) CM Choke PFC Choke NPN Transistor Power MOSFET Carbon Film Resistor Carbon Film Resistor Carbon Film Resistor Carbon Film Resistor Metal Film Resistor Metal Film Resistor Metal Film Resistor Metal Film Resistor Carbon Film Resistor Carbon Film Resistor Carbon Film Resistor Carbon Film Resistor Carbon Film Resistor 12 Manufacturer/ Part No. Vishay / KBU8G Epcos / B32652A6104J Epcos / B43304C5227M Epcos / B32922C3474M Epcos / B32922C3474M Epcos / B81123C1222M000 Epcos / B81123C1222M000 Vishay / 1N5408 Infineon Technologies Vishay / 1N4007 Vishay /1N4007 Infineon Technologies Epcos / B82725J2602N20 Infineon Technologies R13 R14 R15 R16 R17 R18 R19 R20 R21 R22 R23 R24 R25 RT1 VAR1 9 3.9M/0.25W, 1% 330k/0.25W, 1% 1.5M/0.25W, 1% 2M/0.25W, 1% 200k/0.25W, 1% 200k/0.25W, 1% 200k/0.25W, 1% 68k/0.25W, 1% 130k/0.25W, 1% 27k/0.25W, 1% 62k/0.25W, 1% 24k/0.25W, 1% 560k/0.25W, 1% S237/5 S10K275 Carbon Film Resistor Carbon Film Resistor Carbon Film Resistor Carbon Film Resistor Carbon Film Resistor Carbon Film Resistor Carbon Film Resistor Carbon Film Resistor Carbon Film Resistor Carbon Film Resistor Carbon Film Resistor Carbon Film Resistor Carbon Film Resistor NTC Thermistor Varistor Boost Choke Layout Core: PQ-core PQ3535 (TDK) Material: PC95 Inductance: L=750uH 13 Epcos / B57237S509M Epcos / B72210S271K101 10 Test report 10.1 Load and Line Test Input 85Vac 115Vac 230Vac 265Vac VIN IIN PIN VOUT IOUT POUT Eff. PF 84.88 0.27 21.99 395.70 0.05 20.90 95.07 0.98 84.75 0.50 42.25 395.70 0.10 40.43 95.69 0.99 84.64 0.72 60.55 395.70 0.15 57.99 95.78 0.99 84.46 0.98 82.66 395.70 0.20 79.16 95.76 1.00 84.32 1.22 102.56 395.70 0.25 98.52 96.06 1.00 83.99 1.83 153.71 395.70 0.37 147.67 96.07 1.00 83.59 2.49 207.71 395.70 0.50 199.03 95.82 1.00 83.29 3.10 257.86 395.70 0.62 246.26 95.50 1.00 82.89 3.76 310.84 395.70 0.75 295.84 95.17 1.00 114.84 0.21 21.95 395.70 0.05 20.90 95.19 0.93 114.75 0.38 42.36 395.70 0.10 40.84 96.43 0.98 114.67 0.53 59.97 395.70 0.15 57.98 96.68 0.99 114.53 0.72 81.78 395.70 0.20 79.33 97.01 0.99 114.43 0.89 101.66 395.70 0.25 98.51 96.90 1.00 114.18 1.34 152.27 395.70 0.37 147.69 96.99 1.00 113.90 1.81 205.23 395.70 0.50 198.99 96.96 1.00 113.69 2.24 254.16 395.70 0.62 246.15 96.85 1.00 113.36 2.70 305.67 395.70 0.75 295.73 96.75 1.00 229.84 0.16 21.90 395.70 0.05 20.89 95.37 0.58 229.79 0.23 42.15 395.70 0.10 40.85 96.92 0.80 229.76 0.30 59.43 395.70 0.15 57.96 97.54 0.88 229.69 0.38 81.17 395.70 0.20 79.35 97.75 0.92 229.64 0.46 100.56 395.70 0.25 98.48 97.93 0.95 229.52 0.67 150.32 395.70 0.37 147.66 98.23 0.97 229.38 0.90 202.36 395.70 0.50 198.91 98.30 0.98 229.27 1.10 250.09 395.70 0.62 245.99 98.36 0.99 229.10 1.32 300.44 395.70 0.75 295.58 98.38 0.99 264.87 0.17 21.85 395.70 0.05 20.87 95.55 0.48 264.83 0.22 42.14 395.70 0.10 40.86 96.95 0.71 264.80 0.28 59.52 395.70 0.15 57.96 97.38 0.81 264.76 0.35 81.24 395.70 0.20 79.37 97.70 0.87 264.69 0.42 100.58 395.70 0.25 98.46 97.89 0.92 264.59 0.60 150.30 395.70 0.37 147.68 98.26 0.95 264.47 0.78 202.05 395.70 0.50 198.90 98.44 0.97 264.37 0.96 249.75 395.70 0.62 245.97 98.49 0.98 264.22 1.15 299.93 395.70 0.75 295.54 98.54 0.99 14 ICE3PCS01G Efficiency 100.00 85Vac 115Vac 230Vac 265Vac 99.00 Efficiency(%) 98.00 97.00 96.00 95.00 94.00 93.00 0.00 50.00 100.00 150.00 200.00 250.00 300.00 Output Power (W) Figure 4 PFC stage efficiency ICE3PCS01G PF 1.00 0.90 PF 0.80 0.70 85Vac 115Vac 230Vac 265Vac 0.60 0.50 0.40 0.00 50.00 100.00 150.00 200.00 250.00 300.00 Output Power (W) Figure 5 Power factor 10.2 Load and Line Test in Boost Follower Mode Input 85Vac Vin Iin Pin Vout Iout Pout Eff. PF 84.88 0.28 23.52 333.53 0.07 22.51 95.69 0.98 84.79 0.47 39.38 333.53 0.11 38.09 96.72 0.99 84.67 0.74 62.22 333.53 0.18 59.82 96.14 1.00 84.57 0.96 80.87 333.53 0.23 77.83 96.25 1.00 84.44 1.23 103.28 333.53 0.30 99.47 96.32 1.00 84.15 1.85 155.70 333.53 0.45 149.83 96.23 1.00 83.87 2.45 205.07 333.53 0.59 196.81 95.97 1.00 83.55 3.13 260.78 333.53 0.75 249.27 95.59 1.00 83.26 3.77 313.24 333.53 0.89 298.15 95.18 1.00 15 115Vac 114.84 0.22 23.50 333.53 0.07 22.50 95.75 0.94 114.78 0.35 39.46 333.53 0.12 38.43 97.39 0.97 114.69 0.54 61.59 333.53 0.18 59.80 97.09 0.99 114.61 0.70 80.09 333.53 0.23 77.80 97.14 0.99 114.52 0.90 102.44 333.53 0.30 99.47 97.10 1.00 114.31 1.35 154.17 333.53 0.45 149.78 97.15 1.00 114.11 1.78 202.70 333.53 0.59 196.77 97.07 1.00 113.88 2.26 257.07 333.53 0.75 249.23 96.95 1.00 113.67 2.71 307.99 333.53 0.89 297.98 96.75 1.00 ICE3PCS01G (Boost Follower Mode) Efficiency 98.00 97.50 Efficiency(%) 97.00 96.50 96.00 95.50 95.00 85Vac 115Vac 94.50 94.00 0.00 50.00 100.00 150.00 200.00 250.00 300.00 Output Power (W) Figure 6 Power stage efficiency at boost follower mode ICE3PCS01G (Boost Follower mode) PF 1.00 0.99 0.98 PF 0.97 0.96 0.95 85Vac 115Vac 0.94 0.93 0.92 0.00 50.00 100.00 150.00 Output Power (W) Figure 7 Power factor at boost follower mode 16 200.00 250.00 300.00 10.3 Harmonic test according to EN61000-3-2 Class D requirement Test condition I: 85VAC input, full load (300W output) class D measurement 1.2 1 1 0.8 0.8 current (A) current (A) measurement 1.2 0.6 class D 0.6 0.4 0.4 0.2 0.2 0 0 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 3 39 5 7 9 Figure 8 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 harmonics (Vac=85V Po=300W Kp=1, Boost Follower) harmonics (Vac=85V Po=300W Kp=1) Harmonics in normal operation Figure 9 Harmonics in boost follower Test condition II: 85VAC input, 10% of full load (30W output) class D measurement 0.12 0.1 0.1 0.08 0.08 current (A) current (A) measurement 0.12 0.06 class D 0.06 0.04 0.04 0.02 0.02 0 0 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 3 39 5 Figure 10 7 9 11 13 15 17 19 21 23 25 27 29 31 33 Harmonics in normal operation Figure 11 Harmonics in boost follower Test condition III: 265VAC input measurement class D measurement 1.2 0.12 1 0.1 class D 0.08 current (A) current (A) 0.8 0.6 0.4 0.06 0.04 0.2 0.02 0 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 0 39 harmonics (Vac=265V Po=30W Kp=1, Boost Follower) harmonics (Vac=265V Po=300W Kp=1, Boost Follower) Figure 12 35 harmonics (Vac=85V Po=30W Kp=1, Boost Follower) harmonics (Vac=85V Po=30W Kp=1) Harmonics at 300W output Figure 13 17 Harmonics at 30W output 37 39 11 Test Waveforms BOP triggered startup Figure 14 VCC triggered startup Startup test at 85VAC, 300W During startup the average current of PFC choke increases from zero to maximum limited by PCL and PFC output voltage rises gradually with very slight overshoot. Pout from 0W to 300W Figure 15 Pout from 300W to 0W Load jump test at 85VAC The under shoot of output voltage is only 60V when load jump from no load to full load at 85Vac while the overshoot is within 35V vice versa. The choke current shows no distortion during load dynamic change. Latch Mode Figure 16 Auto Restart Mode OVP2 test 18 When OVP2 happens the gate drive can be latched off continuously as shown in left picture or enter auto startup as shown in right picture depending on the equivalent resistance at VBTHL pin. Enter brown-out and leave brown-out , Pout: 300W Figure 17 Open Loop protection at 85V, Pout: 150W Brownout and OLP test The gate drive is latched off once BOP pin voltage is lower than 1V and initiates another soft-startup once BOP voltage is higher than 1.25V as shown in the left picture. The gate drive can also be latched off once Vsense pin voltage is below 0.5V indicating an inadequate output voltage and initiates another soft-startup once Vsense voltage is higher than 0.5V as shown in the right picture. Enter Boost Follower mode Figure 18 Exit Boost Follower mode Boost follower mode test During low line condition the output voltage is able to step down to 329V by pulling BOFO pin voltage below 0.5V in left picture and recovers to normal output voltage 400V vice versa in right picture. 12 References: [1] ICE3PCS01G datasheet, Infineon Technologies AG, 2010. [2] Luo Junyang, Liu Jianwei and Jeoh Meng Kiat, “Design tips for CCM PFC controller ICE2PCSxx”, Application note, Infineon Technologies, 2008. [3] Liu Jianwei, Luo Junyang and Jeoh Meng Kiat, “300W PFC evaluation board with CCM PFC controller ICE2PCS01”, Application note, Infineon Technologies, 2009. [4] Luo Junyang, Liu Jianwei and Jeoh Meng Kiat, “ICE1PCS01 based boost type CCM PFC design guide – control loop modeling”, Application note, Infineon Technologies, 2007. 19