1. Comparison of Core Technical Parameters

　　CCTV-grade 300W switching power supplies focus on compatibility with 12V/24V camera systems, outdoor environmental resilience, and multi-device power distribution, with parameters aligned to security and protection industry standards (information integrated from security power technical specs and vendor datasheets):

　　Mean Well MEA-300-12 (Indoor Centralized Power Supply): Accepts 90-264VAC wide input (adapts to global grids), delivering 12V/25A single-output. Features 1000VAC isolation, 92% peak efficiency, and 0~+60℃ operating temperature. Equipped with overload (110-150% rated current) and overtemperature (85℃ shutdown) protection, ripple/noise ≤120mVp-p. Adopts fanless convection cooling with aluminum alloy housing, MTBF ≥500,000 hours, dimensions 198×115×35mm (wall-mountable).

　　Megmeet MCP-300-12 (Outdoor Camera): Input range 90-264VAC, 12V/25A output with ±5% adjustable voltage. Achieves 90% efficiency at full load, IP65 dust/waterproof rating (complies with IEC 60529). Protection includes 6kV surge (IEC 61000-4-5), short-circuit (auto-recovery), and reverse polarity. Supports -40~+70℃ wide-temperature operation, fanless design with anti-corrosion treatment, size 165×56×26mm.

　　TP-Link TL-PoE300G (PoE IP Cameras): 100-240VAC input, 48V/6.25A PoE output (compatible with 802.3af/at standards). Integrates 4 PoE ports (total 300W), 1500VAC isolation, and 88% efficiency. Equipped with port-level overload protection, ESD 8kV contact protection, and operating temperature 0~+40℃. Dimensions 210×125×44mm, supports 1U rack mounting.

　　2. Key Selection Criteria for CCTV Adaptation

　　2.1 Output Matching Principle

　　Single Camera (Indoor): 12V/2A typical load, select 12V single-output models (e.g., Mean Well MEA-300-12) for 12-device centralized powering.

　　PTZ/Outdoor Cameras: 24V/4A high-power load, choose 24V models (e.g., Megmeet MCP-300-24) with voltage regulation ±10%.

　　PoE Systems: 48V PoE++ models (TP-Link TL-PoE300G) for IP cameras, ensuring 15.4W per port (802.3af) or 30W per port (802.3at).

　　2.2 Environmental Resilience Requirements

　　Outdoor Deployment: Mandatory IP65+ waterproof (prevents rain infiltration), -40~+70℃ wide-temperature (adapts to extreme climates), and 6kV surge protection (resists lightning strikes).

　　Humid Areas: Anti-condensation design (relative humidity 20-90% non-condensing) and PCB conformal coating.

　　Indoor Public Spaces: Fire-retardant plastic housing (UL94 V-0) and low noise ≤30dB (for shopping malls).

　　2.3 Reliability & Protection Standards

　　Protection Functions: Must include short-circuit (auto-recovery), overvoltage (13.8V for 12V models), overcurrent (120% rated current), and overtemperature protection.

　　MTBF Requirement: ≥500,000 hours (ensures 24/7 uninterrupted operation for 57 years).

　　Component Grade: Industrial-grade capacitors (10,000h @105℃) to avoid bulging in high-temperature environments.

　　2.4 Mandatory Certifications

　　Global compliance required:

　　China: 3C (safety certification, mandatory for domestic sales)

　　North America: UL 60950-1 (information technology equipment safety)

　　Europe: CE (EN 55022 Class B EMC, avoids video signal interference)

　　ROHS: Restricts hazardous substances (for environmental protection)

　　3. Mainstream Products and Application Scenarios

　　Mean Well MEA-300-12: Key advantages include 12V stable output, 92% efficiency, and 3C/UL dual certification. Ideal for indoor centralized systems (e.g., 12×2A dome cameras in office buildings), reference price \(180-\)220, 3-year warranty.

　　Megmeet MCP-300-12: Highlights IP65 waterproof, -40℃ cold start, and 6kV surge protection. Suitable for outdoor bullet cameras (road monitoring, residential communities), price \(230-\)280, anti-corrosion housing .

　　TP-Link TL-PoE300G: Strengths in 4-port PoE distribution and plug-and-play. Used for PoE IP cameras (retail stores, parking lots), price \(200-\)250, supports NVR linkage (e.g., alarm-triggered recording and video pop-up) .

　　4. Key Design and Application Considerations

　　4.1 Centralized Power Distribution Design

　　Load calculation: 300W 12V system (25A) can power 12×2A cameras (reserves 1A margin). Use 2.5mm² copper wires (voltage drop ≤0.5V within 50m).

　　Circuit protection: Install 30A circuit breakers per branch, avoid cascading failures from single camera short-circuit.

　　4.2 Outdoor Waterproof & Lightning Protection

　　Waterproof implementation: Use IP68 cable glands for wiring, seal housing joints with silicone gaskets (compression rate ≥30%).

　　Lightning protection: Deploy 6kV gas discharge tubes (GDT) at AC input and SMBJ15CA TVS diodes at DC output (suppresses induced surges).

　　4.3 EMC Optimization for Video Signal

　　Filtering design: Add 470μF low-ESR capacitors (Rubycon ZLH series) at output to reduce ripple <100mVp-p (avoids video snow noise).

　　Wiring separation: Keep power cables ≥30cm away from coaxial/video cables, use shielded wires for DC output.

　　4.4 Maintenance & Monitoring Strategy

　　Routine inspection: Check waterproof glands quarterly (outdoor models), test output voltage annually (deviation ≤±2%).

　　Fault diagnosis: Integrate LED indicators (power on: green; fault: red) for quick troubleshooting.

　　Backup design: Critical sites (bank ATMs) adopt 1+1 redundant configuration (2×300W units) with automatic switchover <10ms.

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