Detection circuit for detecting signals produced by bridge circuit sensor

A detection circuit for detecting signals produced by a bridge circuit sensor, comprising:

• an amplifier circuit, configured to amplify the signals produced by the bridge circuit sensor and output an output voltage Vo corresponding the signals;
• a first resistor R1 and a second resistor R2;
• a first comparator comprising a first inverting input port, a first non-inverting input port, and a first output port;
• a second comparator comprising a second inverting input port, a second non-inverting input port, and a second output port;
• a rechargeable unit comprising a first terminal and a second terminal, wherein, the first terminal is electrically connected to the amplifier circuit via the first resistor R1 and the second resistor R2 and is further connected to the first inverting input port, the second terminal is connected to both of the first output port and the second non-inverting input port;
• a reference voltage providing circuit, connected to the first non-inverting input port of the first comparator and the second inverting input port of the second comparator, configured to provide a first reference voltage Vref1 to the first non-inverting input port, and provide a second reference voltage Vref2 to the second inverting input port;
• a discharge switch, connected between a voltage port VCC and a connection node of the first resistor R1 and the second resistor R2;
• and
• a processing unit, connected to the discharge switch and the second output port of the second comparator;
• wherein, when the detection circuit receives the signals from the bridge circuit sensor, the processing unit controls the discharge switch to turn on, the rechargeable unit is discharged via the first resistor R1 and the turned on discharge switch, and a discharged current is (Vref1−VCC)/R1, a voltage of the second terminal of the rechargeable unit is decreased when the rechargeable unit is discharged, when the voltage of the second terminal is decreased to a value less than the second reference voltage Vref2, the second output port outputs a first low voltage signal to the processing unit, the processing unit controls the discharge switch to turn off and starts to time when receiving the first low voltage signal, then the rechargeable unit is charged via the first resistor R1 and the second resistor R2, and the charge current is (Vref1−Vo)/(R1+R2);
• the processing unit further controls the discharge switch to turn on and restarts to time when the time is equal to a first time period T1, then the rechargeable unit is discharged again and the voltage of the second terminal of the rechargeable unit is decreased gradually, and the second output port outputs the second low voltage signal again when the voltage of the second terminal is less than the second reference voltage Vref2, when the processing unit receives the second low voltage signal, the processing unit stops timing and obtains a second time period T2;
• wherein, the processing unit calculates the output voltage Vo according to an equation:
• (Vref1−Vo)×T1/(R1+R2)=(Vref1−VCC)*T2/R1, and then obtains the sense signal according to the calculated output voltage Vo.