In today's rapidly evolving drone technology landscape, designers are striving for lighter, stronger, and more reliable aircraft. Drones are highly integrated internally, with each component—from motors and batteries to communication modules—operating in complex and ever-changing environments and influencing each other.

To ensure drones fly stably, last long, and are safe and reliable, designing appropriate protection schemes for critical circuits is crucial. This not only improves flight performance but is also the core of guaranteeing the drone's lifespan and safety.

🔍 Why do drones absolutely need circuit protection?

1.Power System Noise and Transient Interference

Drone motors (especially BLDC brushless motors) generate back electromotive force, voltage spikes, and significant electromagnetic noise during high-speed switching.

This interference is conducted along the path from AC input → power protection → AC/DC → battery/wireless charging module, potentially causing MCU reset, sensor drift, or even damage to the power management IC.

➡ Typical Protection Nodes: Power Protection, AC/DC, Battery Management, Current/Voltage Detection

2.High Risk of Electrostatic Discharge (ESD)

Friction during flight and takeoff/landing in dry environments can cause a large amount of static electricity to accumulate on the aircraft, easily discharging at the following interfaces:

  • USB
  • Antenna Interface
  • Wired Interfaces such as RS485
  • Touch Buttons, Audio Module
  • Battery Insertion Terminals

➡ Typical Protection Nodes: USB, Antenna, RS485, Touch Keys

3.Lightning Surges

Although drones are not easily struck directly, the electrostatic field of clouds can generate strong induced surges, affecting:

  • Power Path
  • Communication Link
  • Antenna RF Front End

➡ Typical Protection Nodes: AC Input, Wireless Interface, Antenna

4.High-Frequency Radio Interference (EMI)

  • Flight controllers, GPS, and image transmission modules are highly sensitive to EMI.
  • Flying near high-power wireless devices may cause positioning anomalies, image transmission delays, and other problems.

➡ Typical Protection Nodes: Antenna, Wireless Interface, MCU Peripheral

5.Hot-Swapping and Wiring Errors

During battery maintenance, replacement, and module connection:

  • Reversed polarity
  • Transient surges caused by plugging/unplugging
  • Inadequate wiring leading to momentary power outages

➡ Typical Protection Nodes: Battery, DC/DC, LDO, USB

In response, Semiware designed a complete circuit protection solution.

Comprehensive Circuit Protection Solutions for UAV Systems-Protection Devices-TVS Diodes-ESD Protection devices-Gas Discharge Tube-Thyristor-Pled Protectors-Mov

The specific solutions are as follows:

🔴 1. AC Input / Power Protection

Function: To handle lightning strikes, power grid surges, and motor reverse voltage.

Recommended Components:

  • GDT Gas Discharge Tube – SG2R08B6000A Used for absorbing high-energy surges, such as 600V, 20kA scenarios.
  • Varistor Varistor – 14D561K Used for transient overvoltage clamping, stabilizing AC/DC input stability.

🔴 2. Battery Protection

Function: To protect against hot-plug surges, internal battery transients, and battery replacement shocks.

Recommended Components:

  • PPTC Resettable Fuse (overcurrent protection)
  • TVS Diode (to suppress hot-plug spikes)

🔴 3. RS485 / USB / Antenna (Interfaces)

This is where drones are most vulnerable to ESD. Affected Areas:

  • USB: Frequent user operations
  • Antenna: RF ports are highly susceptible to high-energy discharge
  • RS485: Long-distance communication is easily affected by external interference

Recommended Components:

  • USB-specific low-capacitance ESD protection
  • RF antenna-specific ESD protection (does not affect S-parameters)
  • RS485 common-mode/differential-mode surge TVS

🔴 4. Touch Keys / Audio (User Interface)

Touch keys and audio interfaces are extremely sensitive to ESD.

Using low-capacitance ESD protection effectively improves durability.

🛡️ Semiware's Drone Circuit Protection Solutions

  • Suitable for critical modules such as flight controllers, ESCs, power management, image transmission, and GPS.
  • Optimized for the high-noise, high-transient, and high-sensitivity environments of drones.
  • Provides a complete protection combination of GDT + MOV + TVS + PPTC + ESD.
  • Improves reliability without adding extra weight or complexity.

Semiware offers a complete suite of protection devices, reference designs, and application guidance for the drone industry:

👉 Visit the solutions page: https://en.semiware.com/applications/uav/