R-2R ladder resistor circuit, ladder resistor type D/A conversion circuit, and semiconductor device

Patent metadata

Field	Value
Publication number	US-9553603-B2
Application number	US-201615081162-A
Country	US
Kind code	B2
Filing date	Mar 25, 2016
Priority date	Mar 30, 2015
Publication date	Jan 24, 2017
Grant date	Jan 24, 2017

Abstract

An R-2R ladder resistor circuit including: plural first resistance elements, one end of each being connected to an input terminal; plural second resistance elements, one end of each being connected to a reference potential; plural third resistance elements, one end of each being connected to an output terminal; and plural switching connection sections that are each in correspondence relationships with the first resistance elements, the second resistance elements, and the third resistance elements, and that connect the input terminal and the output terminal according to a bit signal, wherein, according to the bit signal, each switching connection section switchably connects another end of the third resistance element to another end of the first resistance element or to another end of the second resistance element, among the first resistance element, the second resistance element, and the third resistance element corresponding thereto.

First claim

What is claimed is:

1. An R-2R ladder resistor circuit, comprising:
a plurality of first resistance elements, one end of each being connected to an input terminal;
a plurality of second resistance elements, one end of each being connected to a reference potential;
a plurality of third resistance elements, one end of each being connected to an output terminal;
a plurality of switching connection sections that are each in correspondence relationships with the plurality of first resistance elements, the plurality of second resistance elements, and the plurality of third resistance elements, and that connect the input terminal and the output terminal according to a bit signal, wherein, according to the bit signal, each switching connection section switchably connects another end of a third resistance element to another end of a first resistance element or to another end of a second resistance element, among the first resistance element, the second resistance element, and the third resistance element corresponding thereto,
wherein the switching connection sections each comprise a pair of CMOS switches that switch, according to the bit signal, between a first connection state in which the another end of the first resistance element and the another end of the third resistance element are connected without connecting the another end of the second resistance element and the another end of the third resistance element, and a second connection state in which the another end of the second resistance element and the another end of the third resistance element are connected without connecting the another end of the first resistance element and the another end of the third resistance element, and
wherein one CMOS switch of the pair of CMOS switches is inserted between the first resistance element and the third resistance element, another CMOS switch of the pair of CMOS switches is inserted between the second resistance element and the third resistance element, and the one CMOS switch and the another CMOS switch perform opposite switching operations according to the bit signal; and
a first CMOS switch, inserted between the one CMOS switch and the first resistance element, that includes a source and a drain that are short-circuited such that the one CMOS switch and the first resistance element are connected, and that performs a switching operation opposite to the one CMOS switch in the first connection state.

2. The R-2R ladder resistor circuit according to claim 1 , wherein the first resistance element and the third resistance element, connected via the switching connection section, correspond to a 2R portion of the R-2R ladder resistor circuit, and the second resistance element and the third resistance element, connected via the switching connection section, correspond to the 2R portion.

3. The R-2R ladder resistor circuit according to claim 1 , further comprising a second CMOS switch, inserted between the another CMOS switch and the second resistance element, that includes a source and a drain that are short-circuited such that the another CMOS switch and the second resistance element are connected, and that performs a switching operation opposite to the another CMOS switch in the second connection state.

4. A ladder resistor type D/A conversion circuit, comprising:
the R-2R ladder resistor circuit according to claim 1 ; and
an operational amplifier to which the output terminal included in the R-2R ladder resistor circuit is connected.

5. A semiconductor device, comprising:
the ladder resistor type D/A conversion circuit according to claim 4 ; and
a reference potential generation circuit that generates the reference potential and includes a supply terminal that supplies the generated reference potential to a plurality of circuits, including the ladder resistor type D/A conversion circuit, that require the reference potential.

6. An R-2R ladder resistor circuit, comprising:
a plurality of first resistance elements, one end of each being connected to an input terminal;
a plurality of second resistance elements, one end of each being connected to a reference potential that is different from a ground potential;
a plurality of third resistance elements, one end of each being connected to an output terminal;
a plurality of switching connection sections that are each in correspondence relationships with the plurality of first resistance elements, the plurality of second resistance elements, and the plurality of third resistance elements, wherein, according to a bit signal, each switching connection section switchably connects another end of a third resistance element to another end of a first resistance element or to another end of a second resistance element, among the first resistance element, the second resistance element, and the third resistance element corresponding thereto,
wherein the switching connection sections each comprise a pair of CMOS switches that switch, according to the bit signal, between a first connection state in which the another end of the first resistance element and the another end of the third resistance element are connected without connecting the another end of the second resistance element and the another end of the third resistance element, and a second connection state in which the another end of the second resistance element and the another end of the third resistance element are connected without connecting the another end of the first resistance element and the another end of the third resistance element,
wherein one CMOS switch of the pair of CMOS switches is inserted between the first resistance element and the third resistance element, another CMOS switch of the pair of CMOS switches is inserted between the second resistance element and the third resistance element, and the one CMOS switch and the another CMOS switch perform opposite switching operations according to the bit signal; and
a first CMOS switch, inserted between the one CMOS switch and the first resistance element, that includes a source and a drain that are short-circuited such that the one CMOS switch and the first resistance element are connected, and that performs a switching operation opposite to the one CMOS switch in the first connection state.

7. The R-2R ladder resistor circuit according to claim 6 , further comprising a reference potential generation circuit that generates the reference potential and includes a supply terminal that supplies the generated reference potential to a plurality of circuits that require the reference potential, wherein the one end of each of the plurality of second resistance elements is connected to the supply terminal of the reference potential generation circuit.

8. The R-2R ladder resistor circuit according to claim 6 , wherein the first resistance element and the third resistance element, connected via the switching connection section, correspond to a 2R portion of the R-2R ladder resistor circuit, and the second resistance element and the third resistance element, connected via the switching connection portion, correspond to the 2R portion.

9. The R-2R ladder resistor circuit according to claim 6 , further comprising a second CMOS switch, inserted between the another CMOS switch and the second resistance element, that includes a source and a drain that are short-circuited such that the another CMOS switch and the second resistance element are connected, and that performs a switching operation opposite to the another CMOS switch in the second connection state.

10. A ladder resistor type D/A conversion circuit, comprising:
the R-2R ladder resistor circuit according to claim 6 ; and
an operational amplifier to which the output terminal included in the R-2R ladder resistor circuit is connec

Assignees

• Lapis Semiconductor Co Ltd

Inventors

• Kikuta Hiroyuki

Classifications

• H03M1/785 Primary

  using resistors, i.e. R-2R ladders · CPC title

• H03M1/08

  of noise {(H03M1/0617 takes precedence)} · CPC title

• H03M1/0863 Primary

  of switching transients, e.g. glitches · CPC title

• H03M1/662

  Multiplexed conversion systems · CPC title