Gongtian F95D Mini Fan Teardown and Analysis: Injoinic IP5353 + EVE 21700 (Fan That Can Double as a Power Bank)

Industry Exchange Product Review & Teardown
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Gongtian F95D Portable Mini Fan Teardown Analysis: Circuit Review.

I recently bought a small fan with 4 speed levels, 18W fast charging, a 5000mAh battery, and a USB-C port that supports both input and output, so it can also be used 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/

Teardown video: https://www.bilibili.com/video/BV1er8u6cEvp/

Product Specifications

  • Product name: Portable multifunction charging fan
  • Product model: F95D
  • Power: 8W
  • Product weight: 222g
  • Battery capacity: 5000mAh
  • Runtime: 2-24h
  • Main unit dimensions: 106x43x140mm
  • Packaging dimensions: 109x46x178mm

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

Fan Exterior Photos

Front view of the fan. There are two buttons on the front: the left one is the OFF button, and the right one is the ON button. Each press of the ON button increases the speed by one level. When the fan is in the fourth speed level, pressing ON again turns it off directly. Pressing the OFF button at any speed level immediately shuts the fan off. In the middle, 4 red LEDs and 4 green LEDs indicate the speed level and battery level respectively. The green battery-level LEDs only light up while charging. To the left of the first-speed indicator is a blue LED with a lightning-bolt symbol, which is the fast-charging indicator and only lights up when fast charging is triggered.

Rear view of the fan. A label is attached in the middle, showing specifications in Chinese and English. The Chinese text is in Traditional Chinese:

  • Product name: 便攜式風扇
  • Input voltage: 5-12V
  • Input current: 2A (Max)
  • Fan power: 8W (Max)
  • 請勿在機器運行時將手指伸入進防護網內，謹防被割傷。

The bottom is the battery compartment, which supports ternary lithium batteries in 21700 and 18650 formats.

Charging Power and Heat Test

The charger is a Huawei 100W fast charger that supports the PD fast-charging protocol. The fan battery is at 2 bars, and the measured charging power is about 18W, with a requested voltage of 12V.

The thermal image of the front of the circuit board after ten minutes of charging is shown below. The ambient temperature is about 23°C. The charging chip temperature is around 56.5°C, and the temperature of the charging chip’s DC-DC inductor is around 57.8°C.

Speed Test

Use the Tiansheng TA500A laser tachometer to test the fan speed. First, attach reflective tape to the fan blades.

First-speed rotation speed: 1565 RPM. (RPM: revolutions per minute)

Second speed: 2541 rpm.

Third-speed rotation speed: 3613 RPM.

Fourth-speed rotation speed: 4695 RPM.

Teardown

Remove the four screws on the back of the fan, and you can take off the front panel. The motor has four sets of stator coils and is likely a two-phase BLDC motor. The wire from the main board to the motor is 2P.

Viewed from the side of the motor, there is drive circuitry underneath it. This motor should be the same type as those used in cooling fans: two phases, four coil sets, and built-in drive circuitry.

The included battery is an EVE INR21700/50E cylindrical ternary lithium-ion cell. The nominal capacity is 5000mAh, it bears the 3C mark, and the cell size is 21700, with a diameter of 21mm and a height of 70mm.

After removing the main board, you can see through-hole battery holder contact tabs soldered to the back of the board. There is also a QR code printed on it. The information scanned from the QR code is F95D-V3.3IP4_1cq9n5_21787. There is also a rectangular solder-mask opening in the middle of the PCB, used for heat dissipation by the fast-charging chip.

Front of the main board. The upper-right corner shows the model and version number F95D-V3.3IP4B. The center has the Gongtian logo, and there are also 9 LEDs in the middle.

First, let’s look at the charging circuit. The charging chip is the IP5353, a power bank power management SoC from INJOINIC in Zhuhai. A single chip handles lithium battery charging, boost output, and battery-level indication for this fan.

IP5353 Core Specifications (AI-generated):

  • Core functions: Integrates synchronous boost/buck conversion and lithium battery charge management, with built-in power MOSFETs. It uses a single inductor for charging and discharging, and 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 and discharge specs: 18W charging, up to 5A battery-side current; maximum discharge output of 22.5W ([email protected] / [email protected] / [email protected]), with 95% efficiency at 5V@2A.

  • Package and batch: QFN32 surface-mount package (5mm×5mm). The integrated molded power inductor next to it confirms the single-inductor design. The marking 1X46.1DQ is batch information.

  • Application positioning: Commonly used in fast-charging power banks and portable energy storage; here it is cross-applied in the charging circuit of a portable fan.

Next, I used an RK-X3 Pro fast-charging tester to check which fast-charging protocols the fan’s USB-C output supports. It supports PD22W, SCP25W, QC, FCP, AFC, and other protocols.

In the middle of the PCB is an 8-pin chip with its marking polished off. It is likely a microcontroller (MCU), responsible for speed-level switching and display, as well as outputting PWM to control fan speed. Pin 1 of this chip is likely the positive supply input; the supply passes through RC filtering before reaching pin 1, and pin 8 is likely GND.

U2 is an NMOS chip with the marking 7122A. I couldn’t find datasheets for this MOSFET. The MOSFET gate is connected to pin 5 of the MCU through a 10Ω resistor. The MOSFET drain (D) is connected to the motor’s black wire, and the source (S) is connected to GND. The fan speed is controlled by adjusting the duty cycle, i.e., the time ratio of the motor supply negative terminal being switched on and off.

The circuit below the fan connector. Near the battery negative terminal pad, there is also a separate lithium battery protection circuit, consisting of one protection IC 2604 (reference designator U4), two MOSFETs 7122A (reference designators UF1/UF2), and two Suzhou Xisheng Micro XB4908 two-in-one protection ICs (reference designators UB1/UB2).

Motor Control Waveforms at Different Speed Levels

Use an oscilloscope to measure the waveform of the motor supply wire. Connect the probe positive lead to the motor negative terminal and the probe negative lead to the motor positive terminal. With the fan at the first speed level, the measured PWM frequency is 19.9kHz, with a duty cycle of 35.7% (because the probe is connected in reverse, both the waveform and duty cycle are inverted).

Fan at the second speed level. The measured PWM frequency is 19.9kHz, with a duty cycle of 50.6%.

Fan at the third speed level. The measured PWM frequency is 19.9kHz, with a duty cycle of 70.6%.

Fan at the fourth speed level. The duty cycle is 100%, meaning it remains constantly on.

Recommended Reading

English Version of the Article: https://blog.zeruns.top/archives/98.html