+5V/12-24V DC IN
│
▼
[Voltage Regulator (3.3V)] ──▶ Logic VDD
│
▼
[STEP + DIR + UART RX/TX] ──▶ [TMC2209-like ASIC]
│ │
▼ ▼
[Charge Pump / Gate Driver] ◀── [Sense Resistors]
│
▼
[Power MOSFETs H-Bridge] ──▶ Motor Coils A+/A-, B+/B-
│
▼
[Current Sense / Overcurrent Protection]
The JY-MC220BI is a specific model of a 2.2-inch TFT LCD display module widely used in the electronics hobbyist and embedded development community. While often unlabeled in generic bulk sales, this module is typically based on the Ilitek ILI9225 driver IC. It is favored for offering a resolution of 176x220 pixels with an SPI interface in a compact form factor, making it ideal for Arduino, STM32, and ESP32 projects.
Because "JY" usually refers to the manufacturer (Jingyi / JY-LCM) and specific schematics for these generic "eBay/AliExpress modules" are rarely officially published, this article reconstructs the full schematic based on the standard application circuit for the ILI9225 driver and the typical PCB layout found on these modules.
Even without the official PDF, standard reverse engineering reveals that the JYMC220BI follows a classic topology. Here are the core components you will find on the board:
| Pin | Name | Description | Typical Voltage | |-----|------|-------------|-----------------| | 1 | VIN | Input voltage (4.5 – 38 V) | – | | 2 | GND | Ground (common) | 0 V | | 3 | SW | Switching node (connects to the internal MOSFET) | Pulses between VIN and GND | | 4 | FB | Feedback (fixed internally for 5 V/12 V; external for adjustable) | ≈ 0.6 V (reference) | | 5 | EN | Enable pin (active‑high). Pull high to turn on; pull low to shut down. | 0 V or 3.3 V | | 6 | SS | Soft‑start control (optional). Usually left unconnected; pulling low reduces inrush current. | – | | 7 | TEMP | Internal temperature sensor (not usually accessed). | – | jymc220bi schematic full
Key Electrical Specs (5 V version)
| Parameter | Value (typ.) | Unit | |-----------|--------------|------| | Output Voltage (VOUT) | 5.0 | V | | Output Current (IOUT) | 1.0 | A | | Switching Frequency | 250 | kHz | | Efficiency (typ.) | 85–90 | % | | UVLO Threshold | 4.0 (low) / 4.5 (high) | V | | Over‑Current Protection | 1.2 × IOUT (trip) | A | | Operating Temperature | –40 ~ +85 | °C |
(The 12 V version simply doubles the output voltage and halves the maximum current rating; see the datasheet for exact numbers.) +5V/12-24V DC IN │ ▼ [Voltage Regulator (3
If you cannot locate the full schematic, you can still fix the board using logical deduction.
Symptom A: No power, no standby light.
Symptom B: Power cycling / Blinking standby light. The JY-MC220BI is a specific model of a 2
Symptom C: Backlight flickers or turns off after 2 seconds.
Below is a functional block diagram that abstracts the internal architecture (no copyrighted layout, only a conceptual view).
+ Vin (4.5‑38 V)
│
▼
┌─────────────┐
│ Power │ ← Input filter (CIN, optional L in)
│ Stage │
└─────┬───────┘
│
┌─────▼─────┐ ┌─────────────────┐
│ PWM │ →────►│ MOSFET (Q) │
│ Controller (IC) │ + Inductor L │───► VSW (switch node)
└─────┬─────┘ └───────┬─────────┘
│ │
┌─────▼─────┐ ┌─────▼─────┐
│ Feedback │◄───────│ DIODE │ (Schottky, fast recovery)
│ Network │ │ (D1) │
└─────┬─────┘ └─────┬─────┘
│ │
┌─────▼─────┐ ┌─────▼─────┐
│ Output │ │ Output │
│ Filter │ │ Capacitor│
│ (COUT) │ │ (COUT) │
└─────┬─────┘ └─────┬─────┘
│ │
▼ ▼
VOUT (5 V/12 V) GND