RDK-851

Reference Design Report for a 50 W TM Title 3-Phase Inverter Using BridgeSwitch BRD1260C 270 VDC 365 VDC Input Specification 50 W Continuous Inverter Output Power, 0.22 A Continuous Motor RMS Current High-Voltage Brushless DC (BLDC) Motor for Application Fan Application Author Applications Engineering Department Document No. RDR-851 Date February 4, 2020 Revision 1.0 Summary and Features BridgeSwitch high-voltage half-bridge motor driver Integrated 600 V FREDFETs with ultra-soft, fast recovery diodes Three-phase inverter design for high-voltage BLDC fan applications up to 50 W Fully self-biased operation on the BridgeSwitch devices with an on-board external bias option Instantaneous phase current output signal on each BridgeSwitch device Single wire status update communication bus External system sensing input Integrated high-side and low-side cycle-by-cycle current limit on each BridgeSwitch devices Device over-temperature protection High-voltage bus monitor with four undervoltage threshold and one overvoltage threshold PCB size customized for inverter fan designs 88 mm diameter round shaped PCB in double- sided layout Enhanced PCB clearance / creepage >2.2 mm No external heat sink Supports trapezoidal and sinusoidal commutation control schemes PATENT INFORMATION The products and applications illustrated herein (including transformer construction and circuits external to the products) may be covered by one or more U.S. and foreign patents, or potentially by pending U.S. and foreign patent applications assigned to Power Integrations. A complete list of Power Integrations patents may be found at www.power.com. Power Integrations grants its customers a license under certain patent rights as set forth at RDR-851 BridgeSwitch BRD1260C 3-Phase Inverter 02-Feb-20 Table of Contents 1 Introduction ............................................................................................................... 4 2 Inverter Specification ................................................................................................. 5 3 Schematic .................................................................................................................. 6 4 Circuit Description ..................................................................................................... 7 4.1 High-Voltage Input .............................................................................................. 7 4.2 Three-phase Inverter Stage ................................................................................ 7 4.2.1 Self-Supply Operation .................................................................................. 7 4.2.2 Control Inputs ............................................................................................... 7 4.2.3 Cycle-by-Cycle Current Limit ........................................................................ 8 4.2.4 Instantaneous Phase Current Information .................................................... 8 4.2.5 System Undervoltage and Overvoltage Monitoring and Protection .............. 8 4.2.6 External System Sense Input ....................................................................... 8 4.2.7 Status Communication Bus .......................................................................... 8 4.2.8 Device ID ...................................................................................................... 8 4.3 Microcontroller Interface ..................................................................................... 9 4.4 External Device Supply ...................................................................................... 9 4.5 Three-Phase Output Connector ......................................................................... 9 5 Printed Circuit Board Layout .................................................................................... 10 6 Bill of Materials ........................................................................................................ 11 7 Performance Data .................................................................................................... 12 7.1 Start-up Operation ............................................................................................ 12 7.2 Steady-State Operation .................................................................................... 13 7.2.1 Phase Currents During Steady-State ......................................................... 13 7.2.2 Half-Bridge Voltage Signals During Steady-State ...................................... 14 7.2.3 /INH and INL Input Signals During Steady-State ........................................ 14 7.2.4 BYPASS Pin Voltage Signals During Steady-State .................................... 15 7.2.5 Phase Current Information Signal (IPH) ..................................................... 15 7.2.6 FREDFET Drain-voltage Slew Rate at Full Load ....................................... 16 7.3 Thermal Performance ....................................................................................... 17 7.4 No-Load Power Consumption .......................................................................... 20 7.5 Efficiency .......................................................................................................... 21 7.6 Device and System Level Protection and Monitoring ....................................... 23 7.6.1 Device Level Protection .............................................................................. 23 7.6.2 System Level Monitoring ............................................................................ 25 7.7 Abnormal Motor Operation Tests ..................................................................... 28 7.7.1 Operation Under Stalled (Motor) Conditions .............................................. 28 7.7.2 Operation with One Motor Winding Disconnected ...................................... 30 7.7.3 Running Overload Test .............................................................................. 32 8 Appendix .................................................................................................................. 33 8.1 Inverter Circuit Board Manual ........................................................................... 33 8.1.1 Inverter Connectors and Pin Assignments ................................................. 34 8.2 Status Word Encoding ...................................................................................... 36 8.3 Test Bench Set-up ............................................................................................ 37 8.4 Inverter Output Power Measurement ............................................................... 38 Power Integrations, Inc. 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