The current fluxgate typed current sensors for the high-voltage battery management systems face the several challenges including the complex circuit structures, limited measurement ranges, high power consumption, and difficulty of balancing range expansion with power control. Accordingly, this study proposes a novel full-bridge self-excited fluxgate high-current sensor design based on open-loop principles. By integrating a self-excitation bridge structure based on the Schmitt trigger mechanism, the dead zone limitations of traditional designs are effectively eliminated and the corresponding circuit complexity is reduced. The in-depth analysis of the full-bridge excitation circuit′s operational mechanism establishes the precise mathematical models as function of average excitation current, excitation voltage duty cycle, and measured current. This provides a theoretical foundation for the current detection with the fullbridge excitation circuit, which also identifies the key parameters influencing the sensor′s measurement range and power consumption. Simulation results demonstrate that the designed current sensor achieves wide-range measurement with the excellent stability and linearity while effectively controlling power consumption. The theoretical nonlinearity error remains below 0.06% across all measurement ranges, and the experimental comparison tests confirm the sensor′s capability of measuring currents up to ±1 500 A. The maximum power consumption within the full-scale range was only 5.4 W during the power consumption testing, which provides the synergistic optimization and effectively resolves the trade-off between range expansion and power consumption control of high-current detection scenarios. Compared to the mainstream commercial fluxgate sensors and the traditional excitation schemes, the proposed design demonstrates significant advantages in range, power consumption, and linearity. In conclusion, this research provides an effective solution for the high-current detection in the high-voltage battery management systems, demonstrating the important application value.