Electronics shares a brushless motor drive technology knowledge

There will always be some conflicts in the cooperation of hardware and software. The author stumbled upon this article and shared these contents with you, hoping to help you solve some problems. One, 1, the width of the power line is above 20mil. 2. It is best not to wire the back of the chip to maintain the integrity of the ground copper coating (see sample 1). 3. All signal lines must pass through decoupling and filter capacitors before they can enter the corresponding component pins. Decoupling and filter capacitors cannot be placed aside. (Example 1) Second, 1. Connect a ceramic decoupling capacitor greater than or equal to 1uF at the AVDD pin. 2. The distance between the AVDD pin and the decoupling capacitor is less than 2cm (see sample 1). 3. There is no via hole between the AVDD pin and the connection line of the decoupling capacitor. Three, 1. The matching resistance of the input terminal of the op amp should be less than 2cm from the chip pin (see sample 2), and the two sets of resistors cannot be separated (see sample 9). 2. The leads connecting the matching resistance of the input terminal of the op amp to the source and drain of the corresponding MOS transistor (or both ends of the sampling resistor) should be a differential line. The system ground line cannot be selected nearby (see sample 10). 3. Minimize the number of vias as much as possible for the wiring between the input terminal of the op amp and the connected matching resistor to the final sampling resistor (see sample 10). Four, 1, the ground terminal of the decoupling capacitor of AVDD, the ground terminal of the reset circuit capacitor of RESET, and the ground (AVSS) of the chip are all covered with ground (on the back of the chip), and the ground enclosed by this area is not Split by other traces (see example 1). 2. The RC reset circuit of RESET is within 1cm of the chip (see sample 1) 3. The top and bottom layers of the PCB have more than 5 vias per square centimeter (see sample 1). 4. The grounding terminal of the AVDD/RESET filter capacitor needs to be drilled to the large-area back ground through more than 2 vias, and the chip ground needs to be grounded to the back through more than 6 vias. 5. The switching power supply part cannot be covered with the ground, and the large-area ground should be kept at least 3mm away from the switching power supply part. Five, 1, the inner diameter of the via hole is not less than 15mil. 2. All the analog input terminals of the chip cannot be left floating, such as OPA_IP OPA_IN, etc., they need to be grounded when not in use. 3. No magnetic beads can be connected to the signal wire and the ground wire. Six, 1, the design using the integrated pre-driver chip, the GND pin of the integrated pre-driver chip is grounded through vias, and at least two vias are used (see sample three). 2. Use the design of the integrated pre-driver chip. If the VCC pin of the integrated pre-driver chip is connected to the power supply through a via hole, at least two via holes are used. 3. Using the design of integrated pre-driver chip, in order to reduce signal reflection, a 1K resistor needs to be added to the two input terminals of the pre-driver chip (see sample 4). 4. The VS terminal of the pre-drive chip must pass through the Boost capacitor and then to the phase line. A serpentine line is required on the PCB to form a small inductance to reduce the influence of the large dV/dt of the phase line on the pre-drive chip (see Sample eight). Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous: Lithium battery manufacturers talk about the development prospects and future of power lithium batteries