The **LED2000DR** is a high-efficiency monolithic step-down (buck) current source specifically designed for driving high-power LEDs. Manufactured by STMicroelectronics, it is widely used in automotive lighting, industrial signage, and architectural lighting. --- ### ## 1. Key Technical Specifications The LED2000DR operates as a DC-DC converter with an integrated power MOSFET. | Feature | Specification | | :--- | :--- | | **Input Voltage Range** | 3.0V to 18V | | **Output Current** | Up to 3A | | **Switching Frequency** | 850 kHz (Internal) | | **Feedback Voltage** | 100 mV (Low power dissipation) | | **Package Type** | SO-8 (Exposed Pad) | | **Efficiency** | Up to 95% | --- ### ## 2. Core Internal Electronic Components The device integrates several critical circuits into a single silicon die: * **Integrated Power MOSFET:** A low $R_{DS(on)}$ N-channel DMOS transistor that acts as the high-side switch to control current flow. * **Current Sense Amplifier:** Monitors the voltage across an external sense resistor ($R_s$). Because the reference voltage is only 100mV, it minimizes heat loss at the resistor. * **PWM Control Logic:** Supports dedicated dimming. It has a specific **DIM pin** that allows for logic-level PWM signals to control LED brightness without shifting the color spectrum. * **Error Amplifier:** Compares the feedback voltage with the internal 100mV reference to maintain a constant current output. --- ### ## 3. External Component Requirements To function, the LED2000DR requires a few high-quality external passive components: 1. **Inductor ($L$):** Stores energy during the "ON" cycle. Typically ranges from $2.2\mu H$ to $10\mu H$ depending on the desired ripple. 2. **Catch Diode ($D$):** A Schottky diode is required to provide a path for the inductor current when the internal switch is "OFF." 3. **Input/Output Capacitors ($C$):** Ceramic capacitors (MLCC) are recommended for their low ESR to filter noise and stabilize voltage. 4. **Sense Resistor ($R_s$):** Determines the output current ($I_{out}$) based on the formula: `I_out = 0.1V / R_s` --- ### ## 4. Protection Features The chip includes robust circuitry to protect both the driver and the LEDs: * **Overcurrent Protection (OCP):** Pulse-by-pulse current limiting. * **Thermal Shutdown:** Automatically turns off the device if the junction temperature exceeds $150^\circ C$. * **Soft Start:** Prevents inrush current during power-up. ---