Electrical Connections and Operations (Direct Hardware Risks)
- Incorrect/Reversed Wiring: The most direct cause of hardware damage. It may allow power to surge directly into signal lines or driver chips, causing instant burnout.
- Hot Plugging/Unplugging: The act of connecting or disconnecting under power generates significant induced electromotive force (EMF) and contact sparks, which can easily puncture internal MOSFETs or control ICs.
- Operation in Electrostatic Environments: Human body or environmental static electricity can reach several thousand volts, directly breaking down the sensitive gate oxide layer (especially in the drive circuit's MOSFETs).
Power Supply and Energy (Overvoltage/Overcurrent/Overheating)
- Excessively High Voltage: Exceeding the rated voltage of power components (MOSFETs, driver ICs) leads to breakdown.
- Power Supply Spikes: Switching Spikes: Generated by mechanical switches, relay operations, or the start/stop of large equipment elsewhere, creating high-frequency, high-voltage transients on the power rails. Flyback/Inductive Kick Spikes: It is prohibited to control start/stop by cutting the ground (GND) path. Motor windings are inductive loads, and current cannot change instantaneously. If the circuit is suddenly interrupted, the energy stored in the winding has no release path, generating extremely high back-EMF (voltage) that directly breaks down the power transistors. A flyback diode or an RC snubber circuit must be connected in parallel across the power terminals (motor winding). It is recommended to use the PWM pin for pump control. If using a relay or P-type MOSFET/transistor for high-side control of the pump power, sufficient filtering capacitance must be added after the switching device to prevent instantaneous voltage spikes from damaging internal power components. Avoid using an N-type transistor to cut off the GND path, as it prevents the winding current from having a discharge path during switching, generating high voltage and damaging internal circuits.
- Frequent Thermal Protection Triggering: A result of continuous overload or poor heat dissipation. Frequent triggering keeps components in a state of thermal stress, leading to eventual failure.
Control Signals and Logic
- PWM Signal Interference: Strong noise can be misinterpreted as control signals, causing both high-side and low-side MOSFETs in a half-bridge to turn on simultaneously (shoot-through), creating a short circuit and instant burnout.
- Frequent Direction Reversal Before Complete Stop: Suddenly reversing direction while the motor is running at high speed generates massive reverse current and mechanical stress, causing drive circuit overcurrent and mechanical damage.
System Design and Testing
- Insufficient Circuit Protection Design: Power Input: Should include ferrite beads (suppress high-frequency noise) and ceramic capacitors (absorb spikes). Power Output: The motor terminals must have a designed flyback/snubber circuit. Signal Isolation: In complex industrial environments, it is best to isolate PWM control signals using optocouplers or isolation chips.
- Test Fixture Issues: Test fixtures using mechanical switches are a primary source of power supply spikes. It is essential to incorporate protection circuits on the fixture that match or exceed the level used in the product under test.
Summary of Core Prevention Strategies
- Strict Operational Protocols: Prohibit hot plugging, ensure correct wiring, and implement anti-static measures.
- Optimize Power Supply Design: Add TVS diodes, voltage regulation circuits, and sufficient filter capacitors at the power input.
- Enhance Drive Protection: Ensure correct logic to prevent shoot-through. A discharge path for the motor winding current is mandatory. Fully utilize the enable and fault pins of the driver chip.
- Improve Signal Integrity: Keep PWM signal lines short, use twisted-pair or shielded cables, and implement isolation when necessary.
- Prioritize Thermal Management: Ensure the motor operates within its rated load and provide adequate heat dissipation to prevent thermal buildup.