The **ZWS75BAF-5/CO2** is an industrial-grade, open-frame AC-DC power supply manufactured by TDK-Lambda. This specific model is part of the ZWS-BAF series, known for its high efficiency and high reliability. --- ## 1. Model Breakdown To understand the electronic parts, it is essential to decode the model suffix: | Part Segment | Meaning | Specification | | :--- | :--- | :--- | | **ZWS75** | Series & Power | 75 Watts Output Power | | **BAF** | Topology | High Efficiency (PFC included) | | **5** | Output Voltage | 5V DC | | **/CO2** | Option Code | Conformal Coating on both sides of the PCB | --- ## 2. Key Electronic Components & Features ### A. Power Factor Correction (PFC) Unlike standard low-cost power supplies, the "BAF" series includes **Active PFC** circuitry. * **Purpose:** Minimizes harmonic current and ensures compliance with IEC61000-3-2 standards. * **Parts involved:** Integrated PFC controller IC, a dedicated power inductor, and high-voltage MOSFETs. ### B. Input Stage (AC Side) * **EMI Filter:** Includes X and Y capacitors and common-mode chokes to reduce electromagnetic interference. * **Bridge Rectifier:** Converts the 85-265VAC input into high-voltage DC. * **Inrush Current Limiter:** Typically a thermistor (NTC) to prevent component damage during initial power-up. ### C. Output Stage (DC Side) * **Voltage Regulator:** A 5V fixed output with an adjustment range of approximately 4.5V to 5.5V via a built-in potentiometer (VR). * **Smoothing Capacitors:** High-quality electrolytic capacitors designed for low ESR (Equivalent Series Resistance) to ensure low ripple and noise (typically 120mVp-p). ### D. Conformal Coating (/CO2) The `/CO2` designation indicates that the electronic assembly is treated with a **Conformal Coating**. * **Function:** A thin polymeric film applied to the circuit board. * **Protection:** Shields electronic components from moisture, dust, and chemical contaminants, preventing short circuits and corrosion in harsh environments. --- ## 3. Technical Specifications | Parameter | Value | | :--- | :--- | | **Input Voltage Range** | 85 - 265 VAC (47-63Hz) or 120 - 370 VDC | | **Efficiency** | ~82% (at 200VAC input) | | **Maximum Output Current** | 15A | | **Cooling** | Convection cooling (no fans required) | | **Operating Temp** | -10°C to +70°C (derating applies above 50°C) | | **Protections** | Overcurrent (OCP) and Overvoltage (OVP) | --- ## 4. Physical Construction * **Open Frame:** The PCB is exposed (not in a metal box) to allow for better heat dissipation via natural air convection. * **Connectors:** Uses JST or similar crimp-style connectors for Input (CN1) and Output (CN21).