Semiconductor device

摘要

A semiconductor device using analog-to digital (AD) conversion realizes reliable control so that, at the time of AD converting reference voltage, a low-voltage transistor in a reference voltage generating circuit is not destroyed by voltage held in a sample and hold circuit. In a semiconductor device, when an instruction of detecting a reference voltage value is received, a switch control unit controlling switching of an input signal of an internal AD converter temporarily automatically couples an input node of a sample and hold circuit and a ground node and, after that, couples the input node of the sample and hold circuit and an output node of a reference voltage generating circuit.

主权项

1. A semiconductor device comprising:
a sample and hold circuit; an AD converter for AD (Analog-to-Digital) converting an output of the sample and hold circuit; a signal terminal for receiving an analog signal from the outside; a reference voltage generating circuit for generating and outputting a reference voltage; a switching unit for coupling an input node of the sample and hold circuit to any of the signal terminal, an output node of the reference voltage generating circuit, and a ground node; and a switch control unit for controlling the switching unit in accordance with a control signal, wherein when a first control signal is activated, the switch control unit temporarily couples the input node of the sample and hold circuit with the ground node by the switching unit and, after that, couples the input node of the sample and hold circuit with the output node of the reference voltage generating circuit.