Semiconductor stress sensor

A semiconductor stress sensor comprising:

• a field-effect transistor for producing a drain output commensurate with a stress applied thereto,
• biasing means for applying a gate bias voltage to said field-effect transistor,
• converting means for converting the drain output from said field-effect transistor into a detected output signal, and
• control means for varying a gate-to-source voltage of said field-effect transistor to reduce said drain output in a standby mode when no stress is to be detected,
• wherein said converting means comprises an operational amplifier having a first input terminal for receiving the drain output from said field-effect transistor, and a second input terminal, said control means comprising a switch having a movable contact connected to said second input terminal a first fixed terminal connected to ground, and a second fixed terminal connected to a voltage supply, whereby said gate-to-source voltage of the field-effect transistor can be varied when said movable contact is switched either from said first fixed terminal to said second fixed terminal or from said second fixed terminal to said first fixed terminal.

A semiconductor stress sensor comprising:

• a field-effect transistor for producing a drain output commensurate with a stress applied thereto,
• biasing means for applying a gate bias voltage to said field-effect transistor,
• converting means for converting the drain output from said field-effect transistor into a detected output signal, and
• control means for varying a gate-to-source voltage of said field-effect transistor to reduce said drain output in a standby mode when no stress is to be detected, wherein said control means sets said gate-to-source voltage close to a threshold voltage of said field-effect transistor when in said standby mode.

A semiconductor stress sensor comprising:

• a field-effect transistor for producing a drain output commensurate with a stress applied thereto,
• biasing means for applying a gate bias voltage to said field-effect transistor,
• converting means for converting the drain output from said field-effect transistor into a detected output signal, and
• control means for varying a gate-to-source voltage of said field-effect transistor to reduce said drain output in a standby mode when no stress is to be detected, wherein said control means varies said gate-to-source voltage only slightly when switching to and from said standby mode.

A semiconductor stress sensor comprising:

• a field-effect transistor for producing a drain output commensurate with a stress applied thereto,
• biasing means for applying a gate bias voltage to said field-effect transistor,
• converting means for converting the drain output from said field-effect transistor into a detected output signal, and
• control means for varying a gate-to-source voltage of said field-effect transistor to reduce said drain output in a standby mode when no stress is to be detected, wherein said control means varies said gate-to-source voltage such that said field-effect transistor operates near a cut-off region when in said standby mode.