TDTTP4000W065AN-KIT

User Guide TDTTP4000W065AN_0V1: 4kW Analog Bridge-less Totem-pole PFC Evaluation Board Overview This user guide describes the TDTTP4000W065AN_0v1 4kW Analog Bridge-less totem-pole power factor correction (PFC) evaluation board. Very high efficiency single-phase AC-DC conversion is achieved with the TP65H035G4WS, a diode-free Gallium Nitride (GaN) FET bridge with low reverse-recovery charge. Using Transphorm GaN FETs in the fast-switching leg of the circuit and low-resistance MOSFETs in the slow-switching leg of the circuit results in improved performance and efficiency. For more information and complete design files, please visit transphormusa.com/TDTTP4000W065AN. The TDTTP4000W065AN_0v1-KIT is for evaluation purposes only. The evaluation board is shown in Fig. 1. Figure 1. TDTTP4000W065AN_0v1 4kW analog totem-pole PFC evaluation board Warning This EV demo board is intended to validate GaN FET technology and is for demonstration purposes only and no guarantees are made for standards compliance. There are areas of this evaluation board that have exposed access to hazardous high voltage levels. Implement caution to avoid contact with those voltages. Also note that the evaluation board may retain high voltage temporarily after input power has been removed. Exercise caution when handling. When testing converters on an evaluation board, ensure adequate cooling. Apply cooling air with a fan blowing across the converter or across a heat sink attached to the converter. Monitor the converter temperature to ensure it does not exceed the maximum rated per the datasheet specification. May 25, 2021 evk0011.3 © 2021 Transphorm Inc. Subject to change without notice. 1 ` TDTTP4000W065AN_0V1 User Guide TDTTP4000W065AN_0V1 input/output specifications Input Voltage: 90 Vac to 265 Vac, 47 Hz to 63 Hz Max Input Current: 18 A (rms) : (2000W at 115 Vac, 4000W at 230 Vac) Ambient temperature: < 65 C at high power operation Output Voltage: 387 Vdc +/- 5 Vdc PWM Frequency: 65 kHz Power dissipation in the GaN FET is limited by the maximum junction temperature. Refer to the TP65H035G4WS datasheet Figure 2 shows the input and output connections. To reduce EMI noise, adding a ferrite core at the input and output cable is recommended. Figure 2. Input and output cable connections May 25, 2021 evk0011.3 © 2021 Transphorm Inc. Subject to change without notice. 2 TDTTP4000W065AN_0V1 User Guide ` Circuit description for Bridge-Less Totem-Pole PFC based on GaN FET The Bridge-less totem-pole topology is shown in Fig 3 below. As shown in Fig 3(a), two GaN FETs and two diodes are used for the line rectification, while in Fig 3(b), the circuit is modified and the diodes are replaced by two low resistance silicon MOSFETs to eliminate diode drops and improve the efficiency. Further information and discussion on the performance and the characteristics of Bridge-less PFC circuit is provided in [1]. The large recovery charge (Qrr) of existing silicon MOSFETs makes CCM operation of a silicone totem-pole Bridge-less PFC impractical and reduces the total efficiency.. Figure 4(a) is a simplified schematic of a totem-pole PFC in continuous conduction mode (CCM) mode, focused on minimizing conduction losses. It comprises two fast-switching GaN FETs (Q1 and Q2) operating at a high pulse-width-modulation (PWM) frequency and two very low-resistance MOSFETs (S1 and S2) operating at a much slower line frequency (50Hz/60Hz). The primary current path includes one fast switch and one slow switch only, with no diode drop. The function of S1 and S2 is that of a synchronized rectifier as illustrated in Figures 4(b) and 4(c). During the positive AC cycle, S1 is on and S2 is off, forcing the AC neutral line tied to the negative terminal to the DC output. The opposite applies for the negative cycle. In either AC polarity, the two GaN FETs form a synchronized boost converter with one transistor acting as a master switch to allow energy intake by the boost inductor (LB), and another transistor as a slave switch to release energy to the DC output. The roles of the two GaN devices interchange when the polarity of the AC input changes; therefore, each transistor must be able to perform both master and slave functions. To avoid shoot-through a dead time is built in between two switching events, during May 25, 2021 evk0011.3 © 2021 Transphorm Inc. Subject to change without notice. 3 TDTTP4000W065AN_0V1 User Guide ` which both transistors are momentarily off. To allow CCM operation, the body diode of the slave transistor must function as a flyback diode for the inductor current to flow during dead time. The diode current; however, must quickly reduce to zero and transition to the reverse blocking state once the master switch turns on. This is the critical process for a totem-pole PFC which, with the high Qrr of the body diode of high-voltage Si MOSFETs, results in abnormal spikes, instability, and associated high switching losses. The low Qrr of the GaN switches allows designers to overcome this barrier. As seen in Figure 5, inductive tests at 430V bus show healthy voltage waveforms up to inductor current exceeding 35A using either a high-side (Figure 5(a)) or low-side (Figure 5(b)) GaN transistor as a master switch. With a design goal of 4.4kW output power in CCM mode at 230VAC input, the required inductor current is 20A. This test confirms a successful totem-pole power block with enough current overhead. Fig 5. Hard-switched waveforms of a pair of GaN FET switches when setting a) high side as master and b) low side as master One issue inherent in the bridgeless totem-pole PFC is the operation mode transition at AC voltage zero-crossing. For instance, when the circuit operation mode changes from positive half-line to negative half-line at the zero-crossing, the duty ratio of the high-side GaN switch changes abruptly from almost 100% to 0% and the duty ratio of low-side GaN switch changes from 0% to 100%. Due to the slow reverse recovery of diodes (or body diode of a MOSFET), the voltage VD cannot jump from ground to VDC instantly; a current spike will be induced. To avoid the problem, a soft-start at every zero-crossing is implemented to gently reverse duty ratio (a soft-start time of a few switching cycles is enough). The TDTTP4000W065AN evaluation board is designed to run in CCM and the larger inductance alleviates the current spike issue at zero-crossing. May 25, 2021 evk0011.3 © 2021 Transphorm Inc. Subject to change without notice. 4 TDTTP4000W065AN_0V1 User Guide ` While a typical Si MOSFET has a maximum dV/dt rating of 50V/ns, the TP65H035G4WS GaN FET will switch at dV/dt of 100V/ns or higher to achieve the lowest possible switching loss. At this level of operation, even the layout becomes a significant contributor to performance. As shown in Figure 8, the recommended layout keeps a minimum gate drive loop and keeps the traces between the switching nodes very short--with the shortest practical return trace to the power bus and ground. The power ground plane provides a large cross-sectional area to achieve an even ground potential throughout the circuit. The layout carefully separates the power ground and the IC (small signal) ground, only joining them at the source pin of the FET to avoid any possible ground loop. Note that the Transphorm GaN FETs in TO-247 packages have pinout configuration of G-S-D, instead of the traditional G-D-S of a MOSFET. The G-S-D configuration is designed with thorough consideration to minimize the gate source driving loop, reducing parasitic inductance and to separate the driving loop (gate source) and power loop (drain source) to minimize noise. All PCB layers of the TDTTP4000W065AN_0V1 design are shown Figure 8(a-c) and available in the design files. Design details A detailed circuit schematic for the main board is shown in Figures 7a and 7b. A detailed circuit schematic for the controlboard is shown in figures 8a, 8b, and 8c. The PCB layers in Figure 9, and the parts list in Table 1 (also included in the design files). May 25, 2021 evk0011.3 © 2021 Transphorm Inc. Subject to change without notice. 5 ` TDTTP4000W065AN_0V1 User Guide Fig 7a May 25, 2021 evk0011.3 © 2021 Transphorm Inc. Subject to change without notice. 6 ` TDTTP4000W065AN_0V1 User Guide Fig 7b May 25, 2021 evk0011.3 © 2021 Transphorm Inc. Subject to change without notice. 7 ` TDTTP4000W065AN_0V1 User Guide Fig 8a May 25, 2021 evk0011.3 © 2021 Transphorm Inc. Subject to change without notice. 8 ` TDTTP4000W065AN_0V1 User Guide Fig 8b May 25, 2021 evk0011.3 © 2021 Transphorm Inc. Subject to change without notice. 9 ` TDTTP4000W065AN_0V1 User Guide Fig 8c May 25, 2021 evk0011.3 © 2021 Transphorm Inc. Subject to change without notice. 10 TDTTP4000W065AN_0V1 User Guide ` Table 1. TDTTP4000W065AN_0V1 main board bill of materials (BOM) TDTTP4000W065AN_MAINBOARD - BOM Qty Value Device Parts Manufacturing PN 2 JUMPER TIN SMD JUMPER TIN SMD JP1, JP2 S1621-46R 5 CONN RCPT 5POS 0.079 CONN RCPT 5POS 0.079 X1, X2, X3, X4, X5 MMS-105-01-L-SV GOLD PCB GOLD PCB TERM BLK 3P SIDE ENT TERM BLK 3P SIDE ENT CN1 OSTT7032150 9.53MM PCB 9.53MM PCB TERM BLK 2P SIDE ENT TERM BLK 2P SIDE ENT CN2 OSTT7022150 9.53MM PCB 9.53MM PCB 2 FUSE CLIP CARTRIDGE PCB F1 - Holder BK/1A1907-06-R 1 FUSE CERM 30A 250VAC 125VDC 3AB F1 - Fuse BK/ABC-30-R 1 LAM 4K 50mm mit Motor LAM 4K 50mm mit Motor HS1, HS2 - One Piece Heat Sink 10038775 12V 12V THFU 2 THFU 2 Clips for Mounting Devices onto 10065593 1 1 4 Heat Sink 4 Thermal Pad Thermal Pad Thermal Pad for Mounting SPK10-0.006-00-104 Devices onto Heat Sink 1 FAN AXIAL 40X10MM VAPO 12VDC Fan CFM-4010V-185-314 1 FINGER GUARD 40MM FINGER GUARD 40MM Finger guard for Fan 8149 METAL METAL 1 DIODE SCHOTTKY 40V 1A SOD123W D1 PMEG40T10ERX 1 BRIDGE RECT 1PHASE 600V 25A GBJ D2 GBJ2506-F 2 DIODE GEN PURP DIODE GEN PURP D3, D5 ES1J 1 DIODE SCHOTTKY DIODE SCHOTTKY D4 DB2S31000L 2 MOSFET N-CH 650V MOSFET N-CH 650V Q1, Q4 IPW60R017C7XKSA1 2 TP65H035G4WS TP65H035G4WS Q2, Q3 TP65H035G4WS 1 RELAY GEN PURPOSE RELAY GEN PURPOSE U1 JTN1AS-PA-F-DC12V SPST 30A 12V SPST 30A 12V May 25, 2021 evk0011.3 © 2021 Transphorm Inc. Subject to change without notice. 11 TDTTP4000W065AN_0V1 User Guide ` 1 IC CAPACITOR IC CAPACITOR DISCHARGE U2 CAP019DG-TL DISCHARGE 8SO 8SO DGTL ISO 2.5KV GATE DGTL ISO 2.5KV GATE U3, U4 SI8273BBD-IS1R DRVR 16SOIC DRVR 16SOIC 2 FERRITE BEAD 220 OHM 0603 1LN FB1, FB2 MMZ1608B221CTAH0 4 RES SMD 100K OHM 1% 1/10W 0603 R16, R17, R29, R30 RC0603FR-07100KL 2 RES SMD 15 OHM 5% 1/10W 0603 R33, R36 RC0603JR-0715RL 4 RES SMD 10K OHM 1% 1/10W 0603 R22, R25, R34, R37 RC0603FR-0710KL 4 RES SMD 33 OHM 1% 1/10W 0603 R19, R20, R31, R32 RC0603FR-0733RL 1 RES SMD 33K OHM 1% 1/10W 0603 R27 RC0603FR-0733KL 2 RES SMD 36 OHM 1% 1/10W 0603 R21, R24 RC0603FR-0736RL 1 RES SMD 49.9K OHM 1% 1/10W 0603 R26 RC0603FR-0749K9L 7 RES SMD 10 OHM 1206 3/4W 5% R2, R11, R12, R18, R23, R28, SR1206JR-7T10RL 2 R35 6 RES SMD 37.4K OHM 1% 1/4W 1206 R4, R5, R6, R7, R8, R9 RC1206FR-0737K4L 2 RES SMD 1206 RES SMD 1206 R10, R15 DNP 2 RES 0.004 OHM 1% 3W 2512 R13, R14 PA2512FKE7T0R004E 2 ICL 47 OHM 20% 3A 17.5MM R1, R3 MF72-047D15 4 CAP CER 100PF 25V NPO 0603 C12, C13, C20, C21 CC0603JRNPO8BN101 1 CAP CER 1UF 25V X5R 0603 C16 CC0603KRX5R8BB105 4 CAP CER 10UF 25V X5R 0805 C11, C14, C15, C22 GRM21BR61E106KA73L 2 CAP CER 10000PF 630V X7R 1206 C9, C10 CC1206KKX7RZBB103 4 CAP CER 22UF 25V X6S 1206 C17, C18, C19, C23 GRM31CC81E226ME11L 2 CAP CER SMD 1206 CAP CER SMD 1206 C1, C8 DNP 2 CAP FILM 4700PF 20% 630VDC RAD CY1, CY2 BFC233820472 2 CAP FILM 0.22UF 10% 310VAC RAD C2, C3 890334023028 3 CAP FILM 1.5UF 20% 630VDC RAD CX1, CX2, CX3 R463N415040N1M 4 CAP ALUM 470UF 20% 450V SNAP C4, C5, C6, C7 ALC10A471DF450 May 25, 2021 evk0011.3 © 2021 Transphorm Inc. Subject to change without notice. 12 TDTTP4000W065AN_0V1 User Guide ` 2 CMC_42X27MM_SM CMC_42X27MM_SM CMC1, CMC2 T60405-R6128-X225 1 DM-77071B DM-77071B L1 CWS-1SN-12606 - CWS 1 PFC_4KW INDUCTOR PFC_4KW INDUCTOR PFC_CHOKE T91880B - SUMIDA 11 stand off (nylon 1/2) stand off (nylon 1/2) standoff for pcb board 1902C 11 machine screw (ss 1/2) machine screw (ss 1/2) screw for stand off for pcb board 9902 4 machine screw (ss 5/8) machine screw (ss 5/8) screw for FAN to Heatsink 29316 Table 2. TDTTP4000W065AN_0V1 control board bill of materials (BOM) TDTTP4000W065AN_CTRLCARD - BOM Qt Value Device Parts Manufacturing PN 1 0R RES0603 R49 RC0603JR-070RL 4 1Meg RES0603 R7, R22, R52, R60 RC0603FR-071ML 3 1k RES0603 R21, R54, R62 RC0603FR-071KL 1 1n CAP0603 C14 C0603C102K3RACTU 1 1n, 10V CAP0603 C12 2 1n, 25V CAP0603 C8, C37 C0603C102K3RACTU 1 1n5, 10V CAP0603 C1 C0603C152J8RACTU 8 1u, 25V CAP0603 C21, C22, C23, C24, C36, C39, C0603C105K3RACTU y C40, C45 1 4u7, 10V CAP0603 C4 CC0603MRX5R6BB47 5 2 5k1 RES0603 R8, R23 RC0603FR-075K1L 4 10k RES0603 R26, R42, R44, R51 RC0603FR-0710KL 3 10n, 25V CAP0603 C28, C32, C38 C0603C103J3GACTU 2 10n, 630V CAP1206 C34, C35 CC1206KKX7RZBB10 3 May 25, 2021 evk0011.3 © 2021 Transphorm Inc. Subject to change without notice. 13 TDTTP4000W065AN_0V1 User Guide ` 13 10u, 25V CAP0805 C15, C16, C17, C18, C19, C20, C0805C106K3PAC78 C29, C30, C31, C41, C42, C43, 00 C44 3 12k1 RES0603 R48, R58, R65 RC0603FR-0712K1L 1 16k RES0603 R4 RC0603FR-0716KL 1 22k1 RES0603 R45 RC0603FR-0722K1L 1 22n, 25V CAP0603 C33 C0603C223K3RACTU 2 22p, 25V CAP0603 C7, C10 C0603C220K3GACTU 2 22u, 25V CAP1206 C26, C27 GRM31CC81E226ME1 1L 3 24k9 RES0603 R53, R61, R63 RC0603FR-0724K9L 2 30k RES0603 R6, R24 RC0603FR-0730KL 1 33k RES0603 R2 RC0603FR-0733KL 2 39k2 RES0603 R39, R64 RC0603FR-0739K2L 1 40k2 RES0603 R25 RC0603FR-0740K2L 2 48k7 RES0603 R46, R56 RC0603FR-0748K7L 2 49R9 RES0603 R36, R40 RC0603FR-0749R9L 2 49k9 RES0603 R50, R59 RC0603FR-0749K9L 2 61k9 RES0603 R16, R55 RC0603FR-0761K9L 2 100k RES0603 R20, R37 RC0603FR-07100KL 6 100p, 25V CAP0603 C2, C5, C6, C9, C11, C13 C0603C101J3GACTU 1 124k RES0603 R57 RC0603FR-07124KL 1 220k RES0603 R47 RC0603FR-07220KL 1 330R RES0603 R1 RC0603JR-07330RL 1 470R RES0603 R43 RC0603JR-07470RL 15 470k RES1206 R9, R10, R11, R12, R13, R14, R17, RC1206FR-07470KL R18, R19, R28, R29, R30, R33, R34, R35 1 560n, 10V May 25, 2021 evk0011.3 CAP0603 C3 C0603C564K8PACTU © 2021 Transphorm Inc. Subject to change without notice. 14 TDTTP4000W065AN_0V1 User Guide ` 1 750316413 750314352_750314352 T1 750316413 1 74438323047 INDUCTOR_SMD1008 L1 74438323047 4 DB2S31000L DIODE_SSMINI2 D1, D9, D10, D11 DB2S31000L 1 DB3X313N0L DIODE_CC_SOT23 D2 DB3X313N0L 2 CMC_ACT45 CMC_ACT45 CMC1, CMC2 CMC_ACT45 1 APXG160ARA221MF80G APXG160ARA221MF80G C25 APXG160ARA221MF8 0G 1 BSS138N BSS138-7-F Q1 BSS138NH6327XTSA2 5 5P_HEADER_2MM 5P_HEADER_2MM X1, X2, X3, X4, X5 TMM-105-01-L-S-RA 1 CZRU52C4V7 CZRU52C4V7 Z1 CZRU52C4V7 6 ES1J DIODE_DO214 D3, D4, D5, D6, D7, D8 ES1J 1 FODM8801A FODM8801A_MINIFLAT04 U9 FODM8801A 2 LDK320M-R LDK320M_SOT23-5L U13, U14 LDK320M-R 1 LMV761MF MAX9030 U4 LMV761MF 1 MMZ1608B601 RES0603 FB1 MMZ1608B601 1 NCP432BISNT TL431 U10 NCP432BISNT 1 NCP1063AD060R NCP1063_SO16 U11 NCP1063AD060R 1 Rdc: 1.8k RES0603 R15 RC0603JR-071K8L 1 Rdt1: 2.61k RES0603 R3 RC0603FR-072K61L 1 Rdt2: 3.57k RES0603 R5 RC0603FR-073K57L 1 Rlocurr: 20k RES0603 R41 RC0603FR-0720KL 1 Rzc: 1.21k RES0603 R27 AC0603FR-071K21L 1 SMAJ170A ZENER_DO214AC Z2 SMAJ170A 1 SMAZ16-13-F ZENER_DO214AC Z3 SMAZ16-13-F 1 SN74AC04PWR SN74AC04_PW U6 SN74AC04PWR 2 SN74AC08PWR SN74AC08_PW U7, U8 SN74AC08PWR 1 SN74AC32PWR SN74AC32_PW U5 SN74AC32PWR 2 SSM3J334R PMOS_SOT23 Q2, Q3 SSM3J334R,LF May 25, 2021 evk0011.3 © 2021 Transphorm Inc. Subject to change without notice. 15 TDTTP4000W065AN_0V1 User Guide ` 2 TS393IDT LM293_SO8 U2, U12 TS393IDT 1 TSX712IYDT LMX58_DT U3 TSX712IYDT 1 UCC28180_SO8 UCC28180_SO8 U1 UCC28180DR For this evaluation board, the PFC circuit has been implemented on a 4-layer PCB. The GaN FET half-bridge is built with TP65H035G4WS (0.035 ohm) devices by Transphorm, Inc. The slow Si switches are IPW60R017C7XKSA1super junction MOSFETs with 0.017 ohm on-resistance. The inductor is made of a High Flux core with the inductance of 480 uH and a dc resistance of 0.025 Ohm, designed to operate at 65 kHz. A simple 2 A rated high/low side driver IC (Si8273) with 0/12 V as on/off states directly drives each GaN FETs. A TI UCC28180DR controller handles the control algorithm. The voltage and current loop controls are similar to conventional boost PFC converter. The feedback signals are dc output voltage (VO), ac input potentials (VACP and VACN) and inductor current (IL). The input voltage polarity and RMS value are determined from VACP and VACN. The outer voltage loop output multiplied by |V AC| gives a sinusoidal current reference. The current loop gives the proper duty ratio for the boost circuit. The polarity determines how PWM signal is distributed to drive Q1 and Q2. A soft-start sequence with a duty ratio ramp is employed for a short period at each ac zero-crossing for better stability. (a) PCB top layer May 25, 2021 evk0011.3 © 2021 Transphorm Inc. Subject to change without notice. 16 ` TDTTP4000W065AN_0V1 User Guide (b) PCB bottom layer (c) PCB inner layer 2 (ground plane) + inner layer 3 (power plane) Figure 9. PCB layers May 25, 2021 evk0011.3 © 2021 Transphorm Inc. Subject to change without notice. 17 TDTTP4000W065AN_0V1 User Guide ` Using the board The board can be used for evaluation of Transphorm GaN 0.035 ohm FETs in a Bridge-less totem-pole PFC circuit. It is not a complete circuit, but rather a building block. Turn on Sequences: 1) Connect an Electronic / resistive load to the corresponding marking (CN2). The requirement for the resistive load: – At 115 Vac input: 0 W and ≤ 2000 W – At 230 Vac input: 0 W and ≤ 4000 W 2) With HV power off, connect the high-voltage AC power input to the corresponding marking (CN1) on the PCB; -N and L (PE: potential ground) 3) Turn on the AC power input (85 Vac to 265 Vac; 50 – 60Hz) a. Minimum recommended power load for turn-on sequence is 400W. Monitor CN2 output voltage with Vdc meter to verify 385V +/- 5V is generated. b. Electronic / resistive load can be increased while AC supply is ON and board is functional. Turn off sequences: 1) Switch off the high-voltage AC power input; 2) Verify Input and Output voltage = 0. Operational Waveforms Fig 10a and 10b below shows the converter start-up procedure at 0W and 350W for Low line input: CH1 shows the DC input current; CH2 is the DC bus voltage waveform and CH3 is the PWM, and CH4 is the Vac input voltage. For the start-up, there are three phases to charge the DC bus to a reference voltage. In the beginning, the relay K1 is open, and DC bus capacitors are charged by input voltage through NTC and Diode Bridge. When the Vdc is over 100V, the relay K1 is closed to bypass the NTC, and the Vdc increase to the peak of the input voltage. After 100ms, the GaN FETs leg is engaged in voltage closed-loop control, in which the DC bus voltage reference slowly increases to the rated voltage 385V. The NTC and diode bridge are applied in this circuit to avoid high inrush current flow through the GaN FETs. May 25, 2021 evk0011.3 © 2021 Transphorm Inc. Subject to change without notice. 18 TDTTP4000W065AN_0V1 User Guide ` Fig 10a. Start-up of the Bridge-less totem-pole PFC (CH1: Iac(in), Ch2: Vdc(out), CH3: PWM, Ch4: Vac(in)) 120Vac with 0W load Fig 10b. Start-up of the Bridge-less totem-pole PFC (CH1: Iac(in), Ch2: Vdc(out), CH3: PWM, Ch4: Vac(in)) 120Vac with 350W load May 25, 2021 evk0011.3 © 2021 Transphorm Inc. Subject to change without notice. 19 TDTTP4000W065AN_0V1 User Guide ` Fig 11a and 11b below shows the converter start-up procedure at 0W and 350W for High line input: Fig 11a. Start-up of the Bridge-less totem-pole PFC (CH1: Iac(in), Ch2: Vdc(out), CH3: PWM, Ch4: Vac(in)) 230Vac with 0W load Fig 11b. Start-up of the Bridge-less totem-pole PFC (CH1: Iac(in), Ch2: Vdc(out), CH3: PWM, Ch4: Vac(in)) 230Vac with 350W load May 25, 2021 evk0011.3 © 2021 Transphorm Inc. Subject to change without notice. 20 ` TDTTP4000W065AN_0V1 User Guide Fig 12 below shows the Vds of Q2 at 3.5k. It can be seen that the voltage spike is 56V at iL = 20A. In this circuit, the RC snubber and Rg help to reduce voltage spikes. Fig 12. Waveforms of Vds of Q2 at iL = 20A. CH1: input current Iin (10A/div) ; CH4: (a) Vds (100V/div) Efficiency Sweep and THDi For the efficiency measurement, the input/output voltage and current will be measured for the input/output power calculation with a power analyzer. Efficiency has been measured at 120 Vac or 230 Vac input and 400 Vdc output using the WT1800 precision power analyzer from Yokogawa. The efficiency results for this Totem Pole PFC board are shown in Fig.13. The extremely high efficiency of 99% at 230Vac input, and > 98% at 120V ac input is the highest among PFC designs with similar PWM frequency; this high efficiency will enable customers to reach peak system efficiency to meet and exceed Titanium standards. May 25, 2021 evk0011.3 © 2021 Transphorm Inc. Subject to change without notice. 21 TDTTP4000W065AN_0V1 User Guide ` TDTTP4000W065AN Efficiency Sweep 99.5 99 98.5 98 97.5 97 0 500 1000 1500 2000 2500 3000 3500 lowline - onboard fan highline - onboard fan lowline - external fan highline - external fan 4000 4500 Figure 13. The efficiency results for Bridge-less Totem-pole PFC Evaluation Board. The THDi is measured using WT1800 at the condition of input THDv 3.8%. As shown in Fig 14 below, it meets the standard of IEC61000-3-12. Fig 14. THDi meets IEC61000-3-12 (>16A) May 25, 2021 evk0011.3 © 2021 Transphorm Inc. Subject to change without notice. 22 TDTTP4000W065AN_0V1 User Guide ` Maximum Load Limit: The TDTTP4000W065AN Bridge-less totem-pole PFC eval board is allowed to run overload in a short time. The rated input current for < 230Vac input is 18A, and the 10% overload current can be 19.8A. The input OCP will be triggered when the current is over 21A. Fig 15 below shows the input voltage and current waveforms at max power for low line and high line operation Fig 15. Input voltage and current operating waveforms – max power (low line and high line) WARNINGS: This demo board is intended to demonstrate GaN FET technology. While it provides the main features of a totem-pole PFC, it is not intended to be a finished product and does not have all the protection features found in commercial power supplies. Along with this explanation go a few warnings which should be kept in mind: 1. An isolated AC source should be used as input; an isolated lab bench grade power supply or the included AUX DC supply should also be used for the 12V DC power supply. Float the oscilloscope by using an isolated oscilloscope or by disabling the PE (Protective Earth) pin in the power plug. Float the current probe power supply (if any) by disabling the PE pin in the power plug. 2. Use a resistive load only. The Totem-pole PFC kit can work at zero load with burst mode. The output voltage will be swinging between 375V and 385V during burst mode. May 25, 2021 evk0011.3 © 2021 Transphorm Inc. Subject to change without notice. 23 ` TDTTP4000W065AN_0V1 User Guide 3. The demo board is not fully tested at large load steps. DO NOT apply a very large step in the load (>2000W) when it is running. 4. DO NOT manually probe the waveforms when the demo is running. Set up probing before powering up the demo board. 5. The auxiliary Vdc supply must be 12 V. The demo board will not work under, for example, 10 V or over 15V Vdc. 6. DO NOT touch any part of the demo board when it is running. 7. When plugging the control cards into the socket, make sure the control cards are fully pushed down with a clicking sound. 8. If the demo circuit goes into protection mode it will work as a diode bridge by shutting down all PWM functions. Recycle the bias power supply to reset the DSP and exit protection mode. 9. DO NOT use a passive probe to measure control circuit signals and power circuit signals in the same time. GND1 and AGND are not the same ground. 10. To get clean Vgs of low side GaN FET, it is recommended not to measure the Vds at the same time. 11. It is not recommended using passive voltage probe for Vds, Vgs measurement and using differential voltage probe for Vin measure measurement at the same time unless the differential probe has very good dv/dt immunity. REFERENCE: [1]. Liang Zhou, Yi-Feng Wu and Umesh Mishra, “True Bridge-less Totem-pole PFC based on GaN FETs”, PCIM Europe 2013, 1416 May, 2013, pp.1017-1022. [2]. L. Huber, Y. Jang, and M. M. Jovanovic, “Performance evaluation of Bridge-less PFC boost rectifiers,” IEEE Transactions on Power Electronics, Vol. 23, No. 3, pp. 1381-1390, May 2008. May 25, 2021 evk0011.3 © 2021 Transphorm Inc. Subject to change without notice. 24