Trimming circuit and semiconductor device
AssigneeSeiko Instruments Inc.
InventorsAtsushi Sakurai, Kazuaki Sano, Fumihiko Maetani, Satoshi Abe
Life of this patent
Estimating the term…
Abstract
Provided are a trimming circuit which does not need a dedicated terminal to which a current for cutting a fuse is input, and also a semiconductor device including the trimming circuit. The trimming circuit includes: an input terminal connected to a pad which is an external terminal of an internal circuit; a fuse provided between a power supply terminal and an output terminal; and a diode provided between the input terminal and the output terminal. The trimming circuit performs trimming by applying, to the pad, such a voltage that the diode is biased in the forward direction.
Claims5
A trimming circuit for trimming a resistor circuit, the resistor circuit including a plurality of resistors connected in series between a power supply terminal and a ground terminal, the trimming circuit comprising:
- an input terminal connected in common to a pad that comprises an external terminal of an internal circuit;
- an output terminal connected to the resistor circuit;
- a fuse directly connected to the output terminal and connected in parallel to a selected resistor of the plurality of resistors of the resistor circuit, the fuse and the selected resistor directly connected to either the power supply terminal or to the ground terminal;
- and
- a reverse biased diode directly connected to the input terminal and to the fuse,
- wherein the trimming circuit trims the resistor circuit by applying a voltage to the pad, such that a current flows from the pad to the power supply terminal or to the ground terminal only via the fuse and the reverse biased diode is biased in a forward direction.
A trimming circuit comprising:
- a resistor circuit including a plurality of resistors connected in series between a first power supply terminal and a second power supply terminal, the trimming circuit further comprising:
- an input terminal connected in common to a pad which is an external terminal of an internal circuit;
- an output terminal connected to the resistor circuit;
- a fuse between the first power supply terminal and the first output terminal and connected in parallel to one of the plurality of resistors of the resistor circuit;
- and
- a diode provided between the input terminal and the first output terminal;
- a current limiting resistor connected between the input terminal and the first output terminal and in series with the diode,
- wherein the trimming circuit performs trimming by applying, to the pad, such a voltage that the diode is biased in a forward direction.
A semiconductor device comprising:
- a resistor circuit including a plurality of series-connected resistors;
- an internal circuit having a predetermined function;
- a pad connected to the internal circuit, the pad comprising an external terminal;
- and
- a trimming circuit comprising:
- an input terminal connected in common to the pad;
- an output terminal connected to the resistor circuit;
- a fuse directly connected to the output terminal and connected in parallel to a selected resistor of the plurality of resistors of the resistor circuit, the fuse and the selected resistor directly connected to either the power supply terminal or to the ground terminal;
- and
- a reverse biased diode directly connected to the input terminal and to the fuse,
- wherein the trimming circuit trims the resistor circuit by applying a voltage to the pad, such that a current flows from the pad to the power supply terminal or to the ground terminal only via the fuse and the reverse biased diode is biased in a forward direction.
Dependencies are inferred from the claim text.