CN101465641B

CN101465641B - Electric potential transfer circuit and method

Info

Publication number: CN101465641B
Application number: CN2007101600671A
Authority: CN
Inventors: 朱冠任; 吕建平
Original assignee: Richtek Technology Corp
Current assignee: Richtek Technology Corp
Priority date: 2007-12-21
Filing date: 2007-12-21
Publication date: 2011-12-07
Anticipated expiration: 2027-12-21
Also published as: CN101465641A

Abstract

The invention proposes a potential transfer circuit which comprises an input stage drive circuit, a capacitor, an output stage drive circuit and a feedback locking circuit; wherein, the first end of the capacitor is electrically connected with the output end of the input stage drive circuit; the output stage drive circuit is electrically connected with the second end of the capacitor; the feedback locking circuit is electrically connected between the output end of the output stage drive circuit and the second end of the capacitor to maintain the voltage level.

Description

Electric potential shifting circuit and method

Technical field

The present invention relates to a kind of electric potential shifting circuit (Level Shift Circuit), be meant especially a kind ofly can transfer positive supply voltage the electric potential shifting circuit of negative supply voltage to less elements, and the method that is associated.

Background technology

Electric potential shifting circuit is the circuit that is often used in the electronic circuit, and its purpose is to provide the accurate conversion in position of electronic signal.When must be with the high low level of operating voltage when VDD/0V is converted to 0V/-VDD, the prior art practice all must use considerable element just can reach.For example see also the prior art of Fig. 1, this kind practice is to convert high/low position standard to 1/2VDD/0V by VDD/0V earlier, converts 1/2VDD/-1/2VDD again to, converts 0V/-1/2VDD again to, converts 0V/-VDD again to.No matter obviously this kind practice is that energy operation efficiency, conversion speed, component number etc. are all also uneconomical.In some design, change the Pyatyi conversion into three grades of conversions, omitted the step that is converted to 1/2VDD/0V and 0V/-1/2VDD among Fig. 1, but still not ideal enough.

Fig. 2 marks the another kind of practice of prior art, though this circuit on conversion speed than Fig. 1 ideal, employed component number is still very high, and is still economical inadequately.

Because the shortcoming of above-mentioned prior art, the present invention proposes a kind of preferable electric potential shifting circuit and associated method, significantly reducing component number, and improves the conversion rate of circuit output.

Summary of the invention

First purpose of the present invention is to overcome the deficiencies in the prior art and defective, proposes a kind of electric potential shifting circuit, wherein uses fewer purpose element, reaches the signal level conversion of positive negative supply voltage.

Second purpose of the present invention is, proposes a kind of method of correspondence.

For reaching above-mentioned purpose, the invention provides a kind of electric potential shifting circuit, comprise: an input stage drive circuit; An electric capacity, its first end is electrically connected on the output of this input stage drive circuit; An output stage drive circuit is electrically connected on second end of this electric capacity; And a feedback fastens lock circuit, is electrically connected between the output and this electric capacity second end of this output stage drive circuit, to keep the voltage level of this electric capacity second end.

Feedback in the foregoing circuit is fastened lock circuit and be can be and fasten lock circuit (full latch) entirely or partly fasten lock circuit (half latch).

In addition, for reaching above-mentioned purpose, the present invention also provides a kind of electric potential shifting method, comprises: provide an input signal, the conversion between the high/low voltage of first work of this input signal; One electric capacity is provided, and on this electric capacity, produces a cross-pressure; According to this cross-pressure, drive an output circuit and produce output signal, this output signal is conversion between the high/low voltage of second work corresponding to input signal; And according to this output signal and the current potential of FEEDBACK CONTROL electric capacity one end.

Illustrate in detail below by specific embodiment, when the effect that is easier to understand purpose of the present invention, technology contents, characteristics and is reached.

Description of drawings

Fig. 1 and Fig. 2 are the circuit diagram that the positive voltage of prior art changes the electric potential shifting circuit of negative voltage;

Fig. 3 illustrates notion of the present invention;

Fig. 4 is the circuit diagram of the electric potential shifting circuit of first embodiment of the invention;

The operational scenario of Fig. 5 and Fig. 6 key diagram 4 embodiment;

Fig. 7 and Fig. 8 mark two embodiment in addition of the present invention.

Symbol description among the figure

10 input stage drive circuit

15 electric capacity

20 output-stage circuits

22 feedbacks are fastened lock circuit

24 output stage drive circuits

A, the B node

GND ground connection

The IN input

M11, M12, M21, M22, M23, M24 transistor

OUT output

VDD supplies voltage

Embodiment

Please refer to Fig. 3, at first the mode with schematic circuit diagram illustrates notion of the present invention.As shown in the figure, the practice of the present invention provides the high/low position of a work standard and is the input stage drive circuit 10 of VDD/0V, and its output is connected with electric capacity 15, utilizes this electric capacity 15 to store potential difference; In addition and an output-stage circuit 20 is provided, be connected with electric capacity 15, comprise the high/low position of a work standard in this circuit 20 and be the output stage drive circuit 24 of 0V/-VDD, and a feedback fastens lock circuit 22, and utilizing this feedback to fasten lock circuit 22, that the input node A of output stage drive circuit 24 is remained on correct position is accurate.

The foregoing circuit notion can have multiple concrete enforcement kenel, act one is Fig. 4 for example, in the electric potential shifting circuit of present embodiment, constitute input stage drive circuit 10 by PMOS transistor M11 and nmos pass transistor M12, and constitute output-stage circuit 20 by PMOS transistor M21, M22 and nmos pass transistor M23, M24.PMOS transistor M22 and nmos pass transistor M24 constitute output stage drive circuit 24, PMOS transistor M21 and nmos pass transistor M23 then constitute feedback and fasten lock circuit 22, it is for fastening lock circuit (full latch, meaning is promptly all fed back and fastened lock) entirely under the situation of any standard of output end signal.

In detail, by grid, can guarantee that node A is accurate in correct position from output OUT FEEDBACK CONTROL transistor M21 and M23; When being output as high levels (0V), node A be low level (VDD), and (VDD) time, node A is high levels (0V) when being output as low level.Guarantee that node A is accurate in correct position, its effect is a cross-pressure of keeping electric capacity 15 two ends, makes the in time unlikely and misalignment of signal.

The operational scenario of Fig. 4 embodiment please refer to Fig. 5 and Fig. 6.Suppose that VDD is 5V, when whole electric potential shifting circuit be input as 0V the time, PMOS transistor M11 conducting, nmos pass transistor M12 close, so the voltage of electric capacity 15 left end Node B is 5V, the initial voltage of right-hand member node A is 0V, so has produced the cross-pressure of 5V on the electric capacity 15.Because of node A is 0V, so nmos pass transistor M24 conducting, PMOS transistor M22 close, and makes output end voltage be-5V.In addition, from the grid of output FEEDBACK CONTROL transistor M21 and M23, A remains on 0V with node, so shown in arrow among the figure, constitute a loop to electric capacity 15 chargings from VDD (5V)-M11-B-electric capacity 15-A-M21-GND, makes the cross-pressure of electric capacity 15 be maintained 5V.

On the other hand, when whole electric potential shifting circuit be input as 5V the time, PMOS transistor M11 closes, nmos pass transistor M12 conducting, so the voltage of electric capacity 15 left end Node B is 0V, cross-pressure because of electric capacity, the voltage of right-hand member node A is become-5V, and PMOS transistor M22 conducting, nmos pass transistor M24 are closed, so output end voltage becomes 0V.Grid from output FEEDBACK CONTROL transistor M21 and M23 remains on node A-5V, so shown in arrow among the figure, (5V) constitute a loop to electric capacity 15 chargings, make the cross-pressure of electric capacity 15 be maintained 5V from GND-M12-B-electric capacity 15-A-M23--VDD.

Fig. 4 embodiment is depicted as the conservative practice, in fact feedback is fastened lock circuit 22 and needn't be used and fasten lock circuit entirely, can more save element, please refer to second embodiment of Fig. 7, in this embodiment, only the lock circuit (half latch) of partly fastening that constitutes with transistor M21 is used as feedback and fastens lock circuit 22, only just the position of FEEDBACK CONTROL node A is accurate when output is low level for this circuit, the 3rd embodiment for example shown in Figure 8 again, in this embodiment, only the lock circuit of partly fastening that constitutes with transistor M23 is used as feedback and fastens lock circuit 22, and only just the position of FEEDBACK CONTROL node A is accurate when output is high levels for this circuit.Fig. 7 and Fig. 8 embodiment also are the feasible practice.

Below at preferred embodiment the present invention is described, but the above for making those skilled in the art be easy to understand content of the present invention, is not to be used for limiting interest field of the present invention only.For those skilled in the art, when can within notion of the present invention, thinking immediately and various equivalence variation.For example, the mode of FEEDBACK CONTROL node A can use other to fasten lock circuit; And for example, the invention is not restricted to be applied in positive supply voltage and change negative supply voltage or the like.So all according to a notion of the present invention and spirit impartial for it a variation or modification, all should be included in the claim scope of the present invention.

Claims

1. an electric potential shifting circuit is characterized in that, comprises:

An input stage drive circuit;

An electric capacity, its first end is electrically connected on the output of this input stage drive circuit;

An output stage drive circuit is electrically connected on second end of this electric capacity; And

A feedback is fastened lock circuit, is electrically connected between the output and this electric capacity second end of this output stage drive circuit, to keep the voltage level of this electric capacity second end.

2. electric potential shifting circuit as claimed in claim 1, wherein, the high/low voltage of the work of this input stage drive circuit is respectively positive supply voltage and 0V.

3. electric potential shifting circuit as claimed in claim 1, wherein, the high/low voltage of the work of this output stage drive circuit is respectively 0V and negative supply voltage.

4. electric potential shifting circuit as claimed in claim 1, wherein, this feedback is fastened lock circuit for fastening lock circuit entirely.

5. electric potential shifting circuit as claimed in claim 4, wherein, this fastens a pair of PMOS transistor AND gate nmos pass transistor that lock circuit comprises drain electrode interconnection and gate interconnection entirely.

6. electric potential shifting circuit as claimed in claim 1, wherein, this feedback is fastened lock circuit for partly fastening lock circuit.

7. electric potential shifting circuit as claimed in claim 6, wherein, this is partly fastened lock circuit and comprises a transistor, and its grid is controlled by the output of this output stage drive circuit, and its drain electrode is electrically connected with this electric capacity second end.

8. electric potential shifting circuit as claimed in claim 1, wherein, this input stage drive circuit is an inverter, comprises a pair of PMOS transistor AND gate nmos pass transistor of drain electrode interconnection and gate interconnection, the drain electrode of this interconnection is as the output of this input stage drive circuit.

9. electric potential shifting circuit as claimed in claim 1, wherein, this output stage drive circuit is an inverter, comprises a pair of PMOS transistor AND gate nmos pass transistor of drain electrode interconnection and gate interconnection, the drain electrode of this interconnection is as the output of this input stage drive circuit.

10. an electric potential shifting method is characterized in that, comprises:

Provide an input signal, the conversion between the high/low voltage of first work of this input signal;

One electric capacity is provided, and on this electric capacity, produces a cross-pressure;

According to this cross-pressure, drive an output circuit and produce output signal, this output signal is conversion between the high/low voltage of second work corresponding to input signal; And

According to this output signal and the current potential of FEEDBACK CONTROL electric capacity one end.

11. electric potential shifting method as claimed in claim 10, wherein, the high/low voltage of this first work is respectively positive supply voltage and 0V.

12. electric potential shifting circuit as claimed in claim 10, wherein, the high/low voltage of this second work is respectively 0V and negative supply voltage.