1、 Definition and working principle of fuse resistor
Fuse resistor is a special component that combines the functions of a resistor and a fuse. Its core function is to provide both current limiting protection and overload fuse function in the circuit. When the current exceeds the rated value, the conductive layer of the fuse resistor will melt due to overheating, thereby cutting off the circuit and avoiding damage to the subsequent equipment.
working principle:
Current limiting stage: During normal operation, the fuse resistor is used as a regular resistor to limit current and share power.
● Melting stage: When overcurrent or short circuit occurs, its conductive film layer (such as metalized film or alloy wire) quickly melts due to Joule heating, forming an open circuit. Partial recoverable fuse resistors are made of low melting point materials and can automatically recover after the fault is resolved.
2、 The core advantages of fuse resistors
advantage | technical performance |
| dual function | Integrating resistors and fuse functions to reduce circuit design complexity |
| high reliability | High temperature resistance (-55 ° C~155 ° C), sulfur resistance (ASTM B809 certification) |
| quick response | The melting time can be as low as pen seconds to protect sensitive devices such as IGBT and MOSFET |
| Compactness | Small package size (such as 0402/0603), suitable for high-density PCB layout |
3、 Application scenarios and technical requirements
Automotive electronics:
CAN bus protection: requires 120 Ω± 1% accuracy, certified by AEC-Q200 (such as Vishay CRCW-HP series).
BMS current detection: withstand pulse impact>10kV, low resistance (0.5m Ω~2m Ω) to reduce power consumption.
2. Photovoltaic inverter:
DC side protection: withstand voltage ≥ 1500V, breaking capacity ≥ 35kA (such as Anhui Saifu SP10M15 series).
3. Consumer electronics:
Power module: Low cost thick film resistor (± 5% accuracy), used for overcurrent protection.
4、 Cost and selection criteria
Cost influencing factors
factor | International brands (such as Vishay) | Domestic brands (such as Fenghua High Tech) |
| Material process | Metallized thin film process (cost accounting for 40%) | Fenghua High Tech) Thick film process (cost ratio 30% 6) |
| Certification fee | AEC-Q200/IATF16949 (Premium 20%) | Basic RoHS certification (cost accounting for 10%) |
| Delivery time | 8-12 weeks | 4-6 weeks |
|
Core principles of selection
Rated parameter matching:
Voltage: The rated voltage should be ≥ 1.5 times the maximum voltage of the circuit.
Current: Select the fuse current based on the load current (e.g. 1.5 times the load current).
2. Environmental adaptability:
Ceramic packaging is preferred for high temperature scenarios (temperature resistance>150 ° C);
High sulfur environments require sulfur resistant models (such as KOA RK73H-ET).
3. Certification requirements:
Automotive electronics require AEC-Q200 Grade 1 certification;
Industrial scenarios require UL/IEC certification.
5、 Comparison of Top Original Brands
BRAND
| Representative product | Technical advantages | Cost (unit price) |
| Vishay | CRCW-HP series | +0.5% accuracy, AEC-Q200 certification | $0.15~$0.50 |
| KOA | RK73H-ET | Sulfur resistant design, TCR ± 100ppm/C | $0.10~$0.30 |
| YAGEO | AC series | High power density（ 3W@1206 ) | $0.08~30-20 |
6、 Future Trends and Summary
Fused resistors are developing towards high integration and intelligence. For example, an intelligent fuse resistor integrated with a temperature sensor can monitor temperature rise in real-time and provide early warning of faults; The demand for self-healing products in photovoltaic energy storage systems has significantly increased.
Selection suggestion:
● High end scenarios (such as automobiles and photovoltaics): International brands such as Vishay and KOA are preferred;
Cost sensitive projects: Domestic Fenghua High tech and Anhui Saifu provide cost-effective solutions.
Through rational selection and supply chain management, fuse resistors can significantly improve system reliability while balancing cost and performance requirements.
