3-phase Sensorless BLDC Motor Control Power Supply

The power stage DC bus voltage is directly supplied from VBAT and is reverse battery protected. The MC33903D System Basis Chip (SBC) linear regulator provides 5V voltage (VDD) for on-board circuitry. An LED L5 monitors the presence of the VDD voltage. The VDD voltage is split into: 5V supplying the on-board digital circuitry and 5V providing the supply voltage, reference voltage to analog peripherals, and voltage to the on-board analog circuitry. The MCZ33903CD5EK integrates a 5V linear voltage regulator, LIN and CAN physical layer interfaces. As the SBC includes safety features such as the watchdog, supply voltage monitoring, VDD voltage level monitoring, VDD linear voltage regulator temperature monitoring: the behavior of the SBC in the Fail-safe mode needs to be configured. The SBC Fail-safe mode is configurable by the jumper array J1. The SBC Fail-safe mode A is enabled by default. In this mode, the VDD regulator remains ON under fault conditions, retaining power for the microcontroller and remaining on-board circuitry. The MC33903D LIN transceiver is used as the on-board LIN physical interface hardware. The LIN node is configured in slave mode by default. To configure it to master mode, D3 and R10 have to be assembled. Similarly, the MC33903D CAN transceiver is used as the CAN physical interface hardware. The default 120Ω node termination is enabled by the assembled R8, R9 resistors. The connector J74 includes both the LIN and CAN signals.

The 3-phase sensorless BLDC motor control power supply exhibits the suitability and advantages of the Freescale semiconductor CAN physical interface transceiver MCZ33903CD5EK. This design targets the automotive applications, such as: heating, ventilation, and air conditioning (HVAC), electric pumps, and motor control auxiliaries.