Capacitance detecting device, touch device and terminal device

A touch device, comprising:

• a capacitance detecting device;
• wherein the capacitance detecting device comprising:
• a charging module, configured to charge a base capacitor between a detecting electrode and system ground;
• an integrating circuit comprising an amplifier and an integrating capacitor, wherein the integrating capacitor is connected in parallel with the amplifier, and the integrating circuit is configured to integrate, through the integrating capacitor, charges transferred from the base capacitor;
• a cancellation capacitor, configured to cancel a contribution of the base capacitor to an output voltage of the amplifier;
• and
• a controlling module, configured to control the charging module to charge the base capacitor in a first phase, control the charging module to stop charging the base capacitor in a second phase, and control transfer of the charges on the base capacitor to the integrating capacitor in a third phase;
• wherein a charging voltage of the charging module, a capacitance of the integrating capacitor and a capacitance of the cancellation capacitor cause the contribution of the base capacitor to the output voltage of the amplifier to be zero.

A terminal device, comprising:

• a capacitance detecting device;
• wherein the capacitance detecting device comprising:
• a charging module, configured to charge a base capacitor between a detecting electrode and system ground;
• an integrating circuit comprising an amplifier and an integrating capacitor, wherein the integrating capacitor is connected in parallel with the amplifier, and the integrating circuit is configured to integrate, through the integrating capacitor, charges transferred from the base capacitor;
• a cancellation capacitor, configured to cancel a contribution of the base capacitor to an output voltage of the amplifier;
• and
• a controlling module, configured to control the charging module to charge the base capacitor in a first phase, control the charging module to stop charging the base capacitor in a second phase, and control transfer of the charges on the base capacitor to the integrating capacitor in a third phase;
• wherein a charging voltage of the charging module, a capacitance of the integrating capacitor and a capacitance of the cancellation capacitor cause the contribution of the base capacitor to the output voltage of the amplifier to be zero.