Sense amplifier circuit, memory circuit, and sensing method thereof

A memory circuit, comprising:

• a differential amplifier, comprising a first input node, a second input node, a first output node and a second output node, wherein the differential amplifier amplifies a voltage difference of the first output node and the second output node according to a first input voltage of the first input node and a second input voltage of the second input node;
• a first switch, wherein a control node of the first switch is coupled to a control line, a first node of the first switch is coupled to the first input node, and a second node of the first switch is coupled to the first output node, the first switch is configured to pre-charge the first input node by a first output voltage of the first output node while the control line is received a select signal where the sense amplifier circuit is enabled by the select signal;
• and
• a second switch, wherein a control node of the second switch is coupled to a control line, a first node of the second switch is coupled to the second input node and a second node of the second switch is coupled to the second output node, the second switch is configured to pre-charge the second input node by a second output voltage of the second output node while the control line is received the select signal where the sense amplifier circuit is enabled by the select signal;
• and
• a matching capacitor, coupled to the first switch and the second switch, wherein the matching capacitor is configured to keep a voltage difference between the first input voltage of the first input node and the second input voltage of the second input node at a fixed value during a sensing period.

A sensing method of a sense amplifier circuit, comprising:

• receiving a first input voltage of a first input node from a first data line and a second input voltage of a second input node from a second data line;
• pre-charging the first input node by a first output voltage of a first output node while a control line is received a select signal where the sense amplifier circuit is enabled by the select signal and pre-charging a second input node by a second output voltage of the second output node while the control line is received the select signal where the sense amplifier circuit is enabled by the select signal, wherein a voltage level of the first output node is the same as the first input voltage of a first input node;
• discharging the first input voltage of the first input node and the second input voltage of the second input node by a pull-down circuit;
• keeping a voltage difference between the first input voltage of the first input node and the second input voltage of the second input node at a fixed value by a matching capacitor of the sense amplifier during a sensing period;
• amplifying a voltage difference of the first output node and the second output node according to the first input voltage of the first input node and the second input voltage of the second input node;
• and
• outputting a sensing voltage at an output node of the sense amplifier circuit.