A sensing circuit includes a sensing stage. The sensing stage includes a voltage clamp, a P-type transistor and an N-type transistor. The voltage clamp receives a first power supply voltage and generates a second power supply voltage. The source terminal of the P-type transistor receives the second power supply voltage. The gate terminal of the P-type transistor receives a cell current from a selected circuit of a non-volatile memory. The drain terminal of the N-type transistor is connected with the drain terminal of the P-type transistor. The gate terminal of the N-type transistor receives a bias voltage. The source terminal of the N-type transistor receives a ground voltage. In a sensing period, the second power supply voltage from the voltage clamp is fixed and lower than the first power supply voltage.