Patent Number: 6,297,756

Title: Analog-to-digital conversion device

Abstract: An A/D conversion device has a signal input terminal for receiving an analog signal, an A/D converter for converting the received analog signal into a digital signal, and a signal output terminal for outputting the digital signal. The A/D conversion device also has a direct-current voltage input terminal for receiving a direct-current voltage from a direct-current voltage source whose output voltage can be varied. To the direct-current voltage input terminal, a first resistor, a second resistor, and a constant voltage source are connected in series in this order. To the node between the first and second resistors, the input terminal of an amplifier is connected. Between the signal input terminal and the A/D converter, an operational amplifier is connected. The operational amplifier has first and second input terminals and an output terminal, with the first input terminal connected to the signal input terminal, and with the second input terminal connected through a third resistor to the output terminal of the operational amplifier itself and connected also to the output terminal of the amplifier.

Inventors: Horimoto; Masashi (Kyoto, JP)

Assignee: Rohm Co., Ltd.

International Classification: H03M 1/12 (20060101); H03M 001/12 ()

Expiration Date: 10/02/2018