A new logic control method of the high precision current/frequency converter

The current/frequency converter is mainly used to measure the output current of accelerometers,the logic control method of typical extended width reset charge balance current /frequency converter has a great influence on the accuracy. To overcome the control logic shortage of typical logic control method, a new logic control method is given. The integrator output of the circuit realizes the analog-to-digital conversion output through the primary D trigger as the comparison circuit,then the counter start trigger pulse is generated by the self-locking circuit formed by the second D trigger and the and gate, finally the switch control logic is formed by counting of the counter circuit. The new method avoids the constraint of integration time in typical method ,and reduces the difference of the average value of the integrator output waveform between high current input and low current input, thus the circuit accuracy is effectively improved. The performance of the same hardware circuit is tested by writing different CPLD algorithmic programs, the results show that the new method can significantly improve the circuit accuracy compared with the typical method.