The AC is converted to DC. This stage often includes a large heat sink (like the JYMC-220-I
+ 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 jymc220bi schematic full
First, let's decode the board. The JYMC220BI is typically an integrated and LED driver board . It is commonly sourced from Chinese OEM manufacturers and found in budget-friendly LCD TVs from brands like Hisense, Element, Sceptre, or even generic commercial displays. The AC is converted to DC
[ V_OUT = V_REF \times \left(1 + \fracR_1R_2\right) ] It is commonly sourced from Chinese OEM manufacturers
The "220" in the name often correlates to the input voltage compatibility (100-240V AC) or the maximum backlight current, while "BI" suggests a specific revision involving LED backlight inversion. Understanding this is critical: without a , diagnosing interdependent faults between the primary (high voltage AC side) and secondary (low voltage DC side) is nearly impossible.
