Driving circuit for fluxgate type Earth Magnetic Sensor

摘要

The improved drive circuit of a fluxgate-type geomagnetic sensor which can be applied to the mobile phone is started. Comprises a geomagnetic sensor unit x, y, z three directions arranged at least one flux gate type geomagnetic sensor, each of the terrestrial magnetism sensor outputs a detection signal when the drive signal is input at intervals corresponding to the orientation of their placed. Timing mark Timing mark portion produces a signal that can identify the start and end of the interval of the detection signal between receiving the detection signal generated by each of the geomagnetic sensor. Time-to-digital converter (TDC) is to measure the time between its start and end point, receiving the timing mark signal, and converts that value to a digital value. The memory has a first and second look-up table that defines the relationship between the azimuth and obtained, TDC output measured data by using a mobile phone is stored. DSP calculates an azimuth corresponding to the TDC of the output data by looking up the first and second look-up table. Memory and DSP can also take advantage of the phone's memory and the CPU.