### AL1663RS-13 Overview The **AL1663RS-13** is a high-performance, single-stage flyback and buck-boost controller specifically designed for LED lighting applications. It is manufactured by Diodes Incorporated and is known for its high power factor correction (PFC) and high precision constant current (CC) control. --- ### Key Technical Specifications | Parameter | Description | | :--- | :--- | | **Manufacturer** | Diodes Incorporated | | **Package Type** | SO-8 (Surface Mount) | | **Operating Voltage (VCC)** | 9V to 25V | | **Function** | Constant Current LED Driver | | **Topology** | Flyback, Buck-Boost | | **Dimming Support** | Analog and PWM Dimming | | **Power Factor** | > 0.9 | | **Efficiency** | Up to 90% | --- ### Core Internal Functions The AL1663RS-13 integrates several electronic subsystems to ensure stable LED operation: 1. **Primary Side Regulation (PSR):** * It eliminates the need for an optocoupler and a secondary-side control circuit. This reduces the overall Bill of Materials (BOM) cost and PCB size. 2. **Power Factor Correction (PFC):** * It operates in Boundary Conduction Mode (BCM) to achieve a high power factor and low Total Harmonic Distortion (THD), meeting global energy standards. 3. **Dimming Interface:** * The **APWM pin** can accept either a DC voltage (Analog) or a PWM signal to adjust the output current, providing flexibility for smart lighting designs. 4. **Protection Mechanisms:** * **Under Voltage Lockout (UVLO):** Ensures the chip operates only when the supply voltage is within a safe range. * **Over Voltage Protection (OVP):** Protects the circuit if the LED string becomes open. * **Short Circuit Protection (SCP):** Guards against output shorts. * **Over Temperature Protection (OTP):** Reduces output current or shuts down if the chip gets too hot. --- ### Typical Application Circuit Parts When building a circuit with the AL1663RS-13, you will typically find these accompanying electronic components: * **MOSFET:** An external N-channel power MOSFET is required to switch the primary winding of the transformer. * **Transformer/Inductor:** Used for energy storage and isolation (in flyback mode). * **Current Sense Resistor ($R_{CS}$):** Connected to the CS pin to monitor the peak primary current. * **Auxiliary Winding:** Used to provide feedback to the FB pin for voltage sensing and to power the VCC pin after startup. --- ### Pin Configuration (SO-8) | Pin # | Name | Description | | :--- | :--- | :--- | | 1 | **PWM/ADJ** | Dimming input (Analog or PWM) | | 2 | **FB** | Feedback pin for output voltage sensing | | 3 | **COMP** | Loop compensation pin | | 4 | **CS** | Primary current sense input | | 5 | **GATE** | Gate drive output for external MOSFET | | 6 | **VCC** | Power supply input | | 7 | **GND** | Ground | | 8 | **NC** | No internal connection |