English Translation: Key Technologies for Power Compatibility Design of High-Voltage Dividers
1. Working Principles and Technical Parameters
High-voltage dividers convert high voltages proportionally via resistive or resistive-capacitive networks:
$$V_{\text{out}} = \frac{R_2}{R_1 + R_2} \times V_{\text{in}}$$
Critical parameters include:
Ratio & Accuracy: Typical ratio 1000:1, accuracy <0.1% full scale.
Bandwidth: DC to MHz range for lightning impulse measurement.
Temp Coefficient: <50ppm/°C to prevent drift.
Insulation Strength: Input/output isolation withstands multi-times operating voltage.
2. Power Compatibility Challenges
Three major interferences:
1. Conducted Noise: Switching power supply ripple coupled via power lines.
2. Radiated EMI: High-frequency fields (e.g., inverters) induce common-mode currents.
3. Ground Loops: Multi-point grounding causes potential differences.
3. Design Methods for Compatibility
1. EMI Shielding:
Active shielding (copper/aluminum enclosures) attenuates >30dB interference.
Single-point grounding for noise suppression.
Creepage distance: ≥2m for 100kV.
2. Filtering & Grounding:
π-type LC filters suppress MHz noise.
Single-point grounding (<1MHz); Multi-point grounding (>10MHz).
Decoupling capacitors (0.1μF per IC).
3. PCB Layout:
4+ layers with dedicated power/ground planes.
Avoid sharp traces; No silkscreen or plated holes in HV zones.
4. Thermal Management:
Metal-core substrates for resistors; Derating (components at ≤70% rated voltage).
4. Validation & Standards Compliance
Testing: Accuracy (<0.2%), EMC (CISPR 11/IEC 61000-4-5), thermal cycling.
Long-term Stability: Low-aging materials; Annual calibration.
Conclusion: Power compatibility requires low-noise transmission, high immunity, and thermal stability. Future applications of SiC/GaN semiconductors will drive dividers toward ultra-wideband and low-latency designs.