1. Technical Field
The present invention relates to signal level conversion circuits, physical quantity detection devices, and electronic apparatuses.
2. Related Art
A variety of electronic apparatuses and systems that use various types of sensors such as gyro-sensors and acceleration sensors and perform predetermined control based on detected signals provided by the sensors, such as, car-navigation devices and personal navigation devices (PND) are widely used.
Such electronic apparatuses and systems may be configured to amplify a sensor signal with a reference voltage signal in order to match the level of the sensor signal with a signal level required in a set of succeeding stages. For example, JP-A-07-046055 proposes a signal amplifier circuit having amplifiers connected in two stages and capable of independently performing an offset adjustment and a spun adjustment. Also, JP-A-07-038354 proposes a gain switching circuit having amplifiers connected in two stages and capable of amplifying an analog signal with high accuracy.
However, when a sensor signal is amplified with a reference voltage signal, noise that the reference voltage itself has would be superposed on the sensor signal, which makes it difficult to achieve a low-noise implementation.