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Gongtian F95D Mini Fan Teardown & Analysis — Circuit Analysis of a Portable Rechargeable Fan

Reviews & Teardown
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2026-08-14
Gongtian F95D Mini Fan Teardown & Analysis — Circuit Analysis of a Portable Rechargeable Fan

A teardown and circuit analysis of the Gongtian F95D portable mini fan.

I recently bought a small fan — 4-speed adjustment, 18W fast charging, 5000mAh battery, and a USB-C port that supports both input and output, so it doubles as a power bank. In this article, I'll take it apart and analyze the circuit.

Other teardown articles: https://blog.zeruns.com/tag/拆解/

Product Specifications

  • Product Name: Portable Multifunction Rechargeable Fan
  • Model: F95D
  • Power: 8W
  • Weight: 222g
  • Battery Capacity: 5000mAh
  • Runtime: 2–24h
  • Dimensions: 106×43×140mm
  • Package Dimensions: 109×46×178mm

Purchase link: https://s.click.taobao.com/nVQY0qj

Fan Appearance

Front view of the fan — two buttons on the front. The left one is the OFF button, and the right one is the ON button. Each press of ON steps up one speed level; pressing ON again while on the fourth level turns the fan off directly. Pressing OFF in any level turns the fan off immediately. In the middle are 4 red LEDs + 4 green LEDs for speed-level and battery-level indication respectively — the green battery LEDs only light up while charging. To the left of the level-1 indicator is a blue LED with a lightning symbol, which is the fast-charging indicator; it only lights up when fast charging is triggered.

Back view of the fan — a label in the middle with parameters printed in both Chinese and English (the Chinese is in Traditional characters):

  • Product: Portable Fan
  • Input Voltage: 5–12V
  • Input Current: 2A (Max)
  • Fan Power: 8W (Max)
  • Do not insert fingers into the protective grille while the fan is running, to avoid injury.

The bottom is the battery compartment, which supports both 21700 and 18650 ternary lithium-ion batteries.

Charging Power & Heat Test

The charger is a Huawei 100W fast charger supporting the PD fast-charging protocol. With the fan battery at 2 bars, the measured charging power was about 18W, requesting 12V.

Thermal image of the front of the PCB after ten minutes of charging — ambient temperature was around 23°C, the charging chip reached about 56.5°C, and the DC-DC inductor next to it reached about 57.8°C.

Speed Test

I used a TASI TA500A laser tachometer to measure the fan speed. First, you need to stick a reflective sticker onto the fan blade.

Level 1 speed: 1565 RPM. (RPM: revolutions per minute)

Level 2: 2541 RPM.

Level 3 speed: 3613 RPM.

Level 4 speed: 4695 RPM.

Teardown

Unscrew the 4 screws on the back of the fan to remove the front panel. The motor has 4 sets of stator coils, so it's likely a two-phase BLDC (Brushless DC Motor). The wire from the mainboard to the motor is a 2-pin connector.

Looking at the motor from the side, there's a driver circuit underneath it. This motor is the same type as the ones used in cooling fans — 2-phase, 4 coil groups, with a built-in driver circuit.

The included battery is an EVE INR21700/50E cylindrical ternary lithium-ion cell, rated at 5000mAh, with a 3C marking. The cell is 21700 format — 21mm in diameter and 70mm in height.

After removing the mainboard, you can see the through-hole battery-contact tabs soldered on the back, along with a QR code. Scanning the code reveals the information F95D-V3.3IP4_1cq9n5_21787. In the middle of the PCB there's a rectangular tinned opening — that's the heatsink area for the fast-charging chip.

Front of the mainboard — the model and version number F95D-V3.3IP4B are printed in the upper-right corner, with the Gontian logo in the middle and 9 LED indicators.

Let's start with the charging circuit. The charging chip is the IP5353, a power-bank power-management SoC from Zhuhai Injoinic Technology. A single chip handles the fan's lithium battery charging, boost output, and battery-level indication.

IP5353 Key Specifications (AI-generated):

  • Core function: Integrates synchronous buck/boost conversion and lithium battery charge management, with built-in power MOSFETs. A single inductor handles both charge and discharge. Supports buttons, 4-LED battery indication, and lighting drive.
  • Fast-charging protocols: Supports PD2.0/PD3.0 (including PPS), QC2.0/QC3.0, Huawei SCP, FCP/AFC, and is compatible with BC1.2/Apple/Samsung.
  • Charge/discharge specs: 18W charging, up to 5A battery-side current; max 22.5W discharge ([email protected] / [email protected] / [email protected]), 95% efficiency at 5V@2A.
  • Package/batch: QFN32 surface-mount package (5mm×5mm); the molded power inductor next to it confirms the single-inductor design. The silkscreen 1X46.1DQ is batch information.
  • Application positioning: Mainly used in fast-charging power banks and portable energy storage; here it's cross-applied to a portable fan's charging circuit.

Next, I used an RK-X3 Pro fast-charging tester to test the fast-charging protocols supported by the fan's USB-C output. It supports PD 22W, SCP 25W, QC, FCP, AFC, and other protocols.

In the middle of the PCB there's an 8-pin chip with its silkscreen sanded off — it should be a microcontroller (MCU), responsible for speed-level switching and display, as well as outputting PWM to control the fan speed. Pin 1 of this chip appears to be the positive power supply (power goes through an RC filter to pin 1), and pin 8 appears to be GND.

U2 is an N-channel MOSFET with silkscreen 7122A. I couldn't find the datasheet for this MOSFET. Its gate is connected to pin 5 of the MCU through a 10Ω resistor; the drain (D) connects to the motor's black wire, and the source (S) connects to GND. The fan speed is controlled by varying the duty cycle of the negative power rail to the motor.

Below the fan connector, near the battery negative pad, there's an independent lithium battery protection circuit. It consists of a protection IC 2604 (designator U4), two MOSFETs 7122A (designators UF1/UF2), plus two Suzhou Xysemi XB4908 combo protection ICs (designators UB1/UB2).

Motor Control Waveforms at Different Speed Levels

I used an oscilloscope to measure the waveform on the motor power wires — probe positive on the motor's negative wire and probe negative on the motor's positive wire. At fan level 1, the measured PWM frequency was 19.9kHz with a duty cycle of 35.7% (because the probe was connected in reverse, both the waveform and the duty cycle are inverted).

Fan level 2: PWM frequency 19.9kHz, duty cycle 50.6%.

Fan level 3: PWM frequency 19.9kHz, duty cycle 70.6%.

Fan level 4: duty cycle 100%, meaning it stays fully on.

#F95D1#Mini Fan1#Fan1#Teardown15#Injoinic1#IP53531#Charger4#BLDC2#Motor1#Review12
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