Rohm Co., Ltd.

Yoshiyuki Karasawa

Ichiro Yokomizo

Noboru Kagemoto

Trimming by disconnecting a fuse connected in parallel to a feedback resistor of an amplifier circuit would cause a variation in voltage value due to a remaining resistance component. A voltage generator circuit is provided therein with a D/A converter circuit of an R-2R ladder resistor network type circuit. The D/A converter circuit is provided with a first switch circuit to an eighth switch circuit, corresponding to each bit, which are switched to set a digital value. Each switch circuit, which is provided with a fuse for providing a fixed voltage value, allows the fuse to be disconnected to fix the voltage value to a value obtained by inverting the initial value. The setting circuit controls the switching operation of each switch circuit, thereby simulating an electrical state of a fuse being disconnected before the fuse is actually disconnected.

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Kyoto, Japan

Yoshiyuki Karasawa