CN101498949A

CN101498949A - Accurate matching current mirror

Info

Publication number: CN101498949A
Application number: CNA200810033155XA
Authority: CN
Inventors: 曹先国
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-01-28
Filing date: 2008-01-28
Publication date: 2009-08-05

Abstract

An accurate matching current mirror is used for analog-to-digital (A/D) converter. The comparator realizes the sampling function according to the input ends of a first switch K1 and a first inverter INV1, realizes amplifying function according to the first inverter INV1, realizes regenerating function according to a fourth switch K4 and a second inverter INV2, realizes comparing and locking comparing function according to the first inverter INV1 and second inverter INV2 and a third switch K3 and a fourth switch K4. The comparator samples an input signal according to the first switch K1 and first inverter INV1, samples the reference signal according to the second switch K2 and the second inverter INV2; the comparator obtains higher comparing precision and comparing speed according to less transistor numbers.

Description

Accurate matching current mirror

Technical field

The present invention relates to be used for the current mirror of current ratio conversion.Especially, it relates to and a kind of reference current is converted to accurately the fixedly current ratio switching current mirror of multiple electric current.

Background technology

Simple and the most general well-known A/D converter as shown in Figure 1, it carries out the simulating signal of input fast coding and converts it to the flash form A/D converter of digital signal.When forming such A/D converter in the chip area of SIC (semiconductor integrated circuit), each comparer occupies the area of chip size, has determined whole A/D converter chip area size.

Summary of the invention:

The present invention proposes in order to solve aforementioned two problems, the present invention proposes a kind of circuit component seldom, and the comparer that speed is very fast provides circuit component seldom, the A/D converter that speed is very fast.The basic structure of comparer provided by the invention comprises: first K switch 1, and bring in from input signal its; The first phase inverter INV1, its input end links to each other with the other end of described first K switch 1; Second switch K2, self-reference voltage is brought in its; The second phase inverter INV2, its input end links to each other with the other end of described second switch K2; The 3rd K switch 3, its end links to each other with the input end of the described first phase inverter INV1, and the other end links to each other with the output terminal of the described second phase inverter INV2; The 4th K switch 4, its end links to each other with the input end of the described second phase inverter INV2, and the other end links to each other with the output terminal of the described first phase inverter INV1.

The basic structure of comparer provided by the invention and traditional comparator configuration are inequality fully, traditional comparator configuration and traditional two-level operating amplifier similar, this comparator configuration circuit component is many, and speed high request power consumption more is big more, faces the influence of big offset voltage simultaneously; The basic structure circuit component of comparer provided by the invention is few, its power consumption mainly spends in amplifies and the regeneration stage, and is to finish the work in clock effect following moment promptly to reach stable during this period of time, so the time is quite of short duration, power consumption is very low, and rate request be can not show a candle to traditional comparer sensitivity.The offset voltage of comparer provided by the invention is very little simultaneously.The basic structure of comparer provided by the invention and chopper comparator structure are also inequality fully, the chopper comparator structure that provides in the patent of publication number for CN1388647A has adopted capacity cell, and there is a switch to be connected across the input/output terminal of phase inverter, during this switch closure, by the input/output terminal short circuit of the phase inverter of this switch cross-over connection, it is very big to flow through electric current, and power consumption is quite high; Do not have capacity cell in the basic structure of comparer provided by the invention, also the neither one switch is connected across the input/output terminal of phase inverter,

Description of drawings

Will be better appreciated by following public the present invention with reference to accompanying drawing, wherein:

Fig. 1 is for showing the circuit block diagram of general flash form A/D converter example

Embodiment

The working condition of comparer is described below.

The invention provides a kind of relatively comparer of speed that improved, reduced component number in the comparator circuit.Simultaneously the basic structure of comparer provided by the invention not only can single-ended output but also can the output of both-end difference, and the design of latch thereafter can be quite versatile and flexible, also reduced circuit component quantity.In addition, as a kind of application of the present invention, also realized a kind of A/D converter.

Claims

1, a kind of accurate matching current mirror comprises:

The one PMOS pipe, its drain electrode is from the input reference current signal, and its source electrode links to each other with voltage source, and its grid links to each other with the grid of the 2nd PMOS pipe, and its substrate links to each other with voltage source;

The 2nd PMOS pipe, its drain electrode is from the output reference current signal, and its source electrode links to each other with voltage source, and its grid links to each other with the grid of a PMOS pipe, and its substrate links to each other with voltage source;

The 3rd operational amplifier, its output terminal links to each other with the grid of a PMOS pipe, and the grid of the 2nd PMOS pipe is continuous, and its positive input terminal links to each other with the drain electrode of a PMOS pipe, and its negative input end links to each other with the drain electrode of the 2nd PMOS pipe;

The 4th level shifting circuit, its input end links to each other with the drain electrode of described the 2nd PMOS pipe;

The 5th NMOS pipe, its drain electrode links to each other with the output terminal of described the 4th level shifting circuit, and its substrate links to each other with ground;

The 6th NMOS pipe, its drain electrode links to each other with the source electrode of described the 5th NMOS pipe, and its grid links to each other with the output terminal of described the 4th level shifting circuit, and links to each other with the drain electrode of described the 5th NMOS pipe, and its source electrode links to each other with ground, and its substrate links to each other with ground;

The 7th operational amplifier, its output terminal links to each other with the grid of the 5th NMOS pipe, and its positive input terminal links to each other with a reference voltage, and its negative input end links to each other with the source electrode of described the 5th NMOS pipe, and links to each other with the drain electrode of described the 6th NMOS pipe.

According to the described accurate matching current mirror of claim 1, it is characterized in that 2, this circuit structure can be realized by single integrated circuit, also can be realized by discrete component and integrated circuit block combination;

3, according to the described accurate matching current mirror of claim 1, it is characterized in that, the input reference current signal that links to each other with the drain electrode of a described PMOS pipe, can realize by any circuit of current signal generation of in integrated circuit, realizing, also can realize by the circuit that any discrete component realization current signal produces, also can realize, also can realize by discrete component and integrated circuit block combination by the circuit that any integrated circuit block realization current signal produces;

4, according to the described accurate matching current mirror of claim 1, it is characterized in that, described the 4th level shifting circuit, its input end links to each other with the drain electrode of described the 2nd PMOS pipe, its output terminal links to each other with the drain electrode of described the 5th NMOS pipe, it can be realized by any circuit of voltage level conversion of realizing in integrated circuit, also can realize by the circuit of any discrete component realization voltage level conversion, also, also can realize by discrete component and integrated circuit block combination to realize by the circuit of any integrated circuit block realization voltage level conversion;

5, according to the described accurate matching current mirror of claim 1, it is characterized in that, described the 3rd operational amplifier, its output terminal links to each other with the grid of a PMOS pipe and the grid of the 2nd PMOS pipe, its positive input terminal links to each other with the drain electrode of a PMOS pipe, its negative input end links to each other with the drain electrode of the 2nd PMOS pipe, guaranteed a PMOS pipe equal with gate source voltage the 2nd PMOS pipe, guaranteed that simultaneously a PMOS pipe and drain-source voltage the 2nd PMOS pipe equate, thereby ensured the electric current that flows through a PMOS pipe and flow through the breadth length ratio of ratio and a PMOS pipe of electric current of the 2nd PMOS pipe and the ratio of the breadth length ratio of the 2nd PMOS pipe equates;

6, according to the described accurate matching current mirror of claim 1, it is characterized in that, described the 7th operational amplifier, its output terminal links to each other with the grid of the 5th NMOS pipe, its positive input terminal links to each other with a reference voltage, its negative input end links to each other with the source electrode of described the 5th NMOS pipe, and links to each other with the drain electrode of described the 6th NMOS pipe, has guaranteed that the drain-source voltage of described the 6th NMOS pipe and the positive input terminal reference voltage voltage of described the 7th operational amplifier equate;

7, according to the described accurate matching current mirror of claim 1, it is characterized in that, described the 6th NMOS pipe, its drain electrode links to each other with the source electrode of described the 5th NMOS pipe, its grid links to each other with the output terminal of described the 4th level shifting circuit, and link to each other with the drain electrode of described the 5th NMOS pipe, its source electrode links to each other with ground, its substrate links to each other with ground, guaranteed that the gate source voltage of described the 6th NMOS pipe and the drain voltage of described the 5th NMOS pipe equate, thereby guaranteed that the source-drain current that flows through described the 6th NMOS pipe equates with the source-drain current that flows through described the 2nd PMOS pipe.