Semiconductor apparatus with AD converter

A data transmitting apparatus comprising:

• a sensor;
• and
• a semiconductor apparatus configured to generate a digital data based on a sensor signal outputted from said sensor,
• wherein said semiconductor apparatus includes:
• a amplifying circuit configured to includes a amplifying unit and a bias controlling unit, said amplifying unit amplifies said sensor signal to output an amplified signal, and said bias controlling unit generates a bias voltage to be applied to said sensor signal,
• an AD converting circuit configured to AD-convert said amplified signal into an output signal;
• and
• a micro computer configured to output an control signal to said bias controlling unit based on an AD conversion value indicated by said output signal,
• wherein said micro computer outputs said control signal when said AD conversion value is equal to a predetermined value, and
• said bias controlling unit changes said bias voltage in response to said control signal.

A computer program product embodied on a computer-readable medium to operate a data transmitting apparatus used in a tire pressure monitoring system and provided inside a tire, and comprising code that, when executed, causes a computer to perform the following:

• (a) controlling a bias controlling unit to generate a bias voltage to be applied to an input signal of an amplifying unit;
• (b) controlling an AD converting unit to AD-convert an amplified signal outputted from said amplifying unit into an output signal indicating an AD conversion value;
• and
• (c) controlling said bias controlling unit to change said bias voltage when said AD conversion value is equal to a predetermined value.

A method for changing a conversion range of an AD converting circuit, said method comprising:

• (a) generating a bias voltage to be applied to an input signal of an amplifying unit;
• (b) AD-converting an amplified signal outputted from said amplifying unit into an output signal indicating an AD conversion value;
• and
• (c) changing said bias voltage when said AD conversion value is equal to a predetermined value.