Fujitsu Corporation

Fujitsu Semiconductor Limited

Hirokazu Okada

Tachio Yuasa

A device includes a measurement target circuit including a first circuit, a switch provided to a measurement node of the first circuit and a second circuit connected to the measurement node of the first circuit through the switch; and a current measuring circuit including a reference current source group connected to the measurement node through the switch and making a reference current of a predetermined value flow into the first circuit, a sample hold circuit connected to the measurement node, and sampling and holding the potential of the measurement node when the first circuit is connected to the second circuit by the switch, and a comparator connected to the measurement node and an output of the sample hold circuit and comparing an output of the sample hold circuit with the potential of the measurement node when the first circuit is connected to the reference current source group by the switch.

Semiconductor device

A resistor string digital-analog conversion circuit includes three resistor strings connected in series, a controller, and a switch group. The controller controls switchover of the switch group according to a signal of m high-order bits of an input digital signal. Thus an analog output corresponding to the m high-order bits is obtained. Another controller varies potentials of two variable voltage sources according to a signal of n low-order bits of the input digital signal, while always keeping a potential difference across the three resistor strings constant. Thus an analog output corresponding to the n low-order bits is obtained. This analog output is output to an output terminal.

Growing community of inventors

Kawasaki, Japan

Hirokazu Okada