Semiconductor device and semiconductor system having the same
AssigneeRenesas Electronics Corporation
InventorMasahiro Araki
Life of this patent
Estimating the term…
Abstract
A semiconductor device comprises a pulse signal output circuit providing a pulse signal for a transmission electrode of an electrode pair, a current converter converting a first current generated on the reception electrode to a second current, a current-controlled oscillator outputting an oscillation signal having a frequency depending on the second current, and a counter counting a number of oscillating times of the oscillation signal per a predetermined period; wherein the current converter comprises a first constant current source and output a combined current of the first constant current of the first constant current source and the first current as the second current in response to the pulse signal, so that the semiconductor device suppresses an increase circuit size.
Claims13
A semiconductor device comprising:
- a pulse signal output circuit providing a pulse signal to a transmission electrode of an electrode pair including the transmission electrode and a reception electrode;
- a current converter converting a first current generated on the reception electrode into a second current;
- a current-controlled oscillator outputting an oscillation signal having a frequency depending on the second current, and
- a counter counting a number of oscillating times of the oscillation signal per a predetermined period,
- wherein the current converter comprises a first constant current source outputting a first constant current, and converts a combined current of the first constant current and the first current into the second current, and
- wherein the current converter further comprises:
- a first transistor that is diode-connected and has a source-drain path through which the combined current flows;
- a second transistor that is current mirror connected to the first transistor;
- and
- a third transistor that is coupled in series to the second transistor and outputs the second current by switching ON/OFF in response to the pulse signal.
Dependencies are inferred from the claim text.