CN100574067C

CN100574067C - voltage switching device

Info

Publication number: CN100574067C
Application number: CNB2006100584268A
Authority: CN
Inventors: 陈天豪
Original assignee: Himax Technologies Ltd
Current assignee: Himax Technologies Ltd
Priority date: 2006-03-24
Filing date: 2006-03-24
Publication date: 2009-12-23
Anticipated expiration: 2026-03-24
Also published as: CN101043176A

Abstract

A voltage switching device is used for receiving a plurality of input voltages and outputting a switching voltage and comprises a first switching unit, a second switching unit and a self-biasing unit. The voltage switching device generates a switching voltage according to the outputs of the first switching unit and the second switching unit. The self-bias unit outputs a reference voltage to the second switching unit. The first switching unit outputs a first input voltage as a switching voltage according to a first enable signal. The second switching unit outputs a second input voltage as a switching voltage according to the reference voltage and the second enable signal.

Description

Voltage switching device

Technical field

The present invention relates to a kind of voltage switching device, and be particularly related to a kind of voltage switching device that uses self-bias circuit.

Background technology

Along with a large amount of appearance of portable product, efficient power management has become one of key factor of circuit design.On the design field of power-efficient, one of them is exactly to provide multiple different switched voltage at system element, to reach the high electronic product of low-power and degree of integration.

Fig. 1 is traditional voltage switching device, comprising switch S 11 and S12.Switch S 11 receives input voltage V respectively with first end of S12 _In11With Vi _N12, and second end of switch S 11 and S12 electrically interconnects and exports a switching voltage V _PP1Two non-overlapped (non-overlap) enable signal S _EN11With S _EN12Can be used for controlling this voltage switching device.Switch S 11 is according to enable signal S _EN11Conducting (turn on) two-end-point allows switched voltage V _PP1Be equal to input voltage V _In11, switch S 12 not conductings (turn off) this moment.Relative, when switch S 12 according to enable signal S _EN12During the conducting two-end-point, switch S 11 not conductings, switched voltage V _PP1Be equal to input voltage V _In12Therefore, along with enable signal S _EN11With S _EN12Control, traditional voltage switching device is with regard to the required switched voltage of exportable system element.

Yet, along with switched voltage V _PP1The high pressure demand, traditional voltage switching device is gone up at the circuit layout (layout) of reality needs to adopt the high-pressure process technology to realize.For example, such as switched voltage V _PP1Need switch on 1.8V and 7V.In order to meet switched voltage V _PP1Can be the demand of 7V, just must adopt operating voltage is that the high-pressure process technology of 7V realizes voltage switching device.Thus, not only increase the layout area of circuit, also consumed total system power.

Summary of the invention

The purpose of this invention is to provide a kind of voltage switching device, in order to provide system element required various different switched voltages.And compare with conventional architectures, the present invention need not adopt the high-pressure process technology just can reach identical circuit performance.

For reaching above-mentioned and other purpose, the present invention proposes a kind of voltage switching device, comprises first switch unit, second switch unit and self-bias unit.

Voltage switching device is the output according to first switch unit and second switch unit, produces switched voltage.When voltage switching device was exported switched voltage by first switch unit, first switch unit can be exported first input voltage and be used as switched voltage according to first enable signal.Relative, when voltage switching device was exported switched voltage by second switch unit, second switch unit then can be exported second input voltage and be used as switched voltage according to the reference voltage and second enable signal.Wherein, first input voltage is less than second input voltage, and the maximum level of reference voltage is greater than the maximum level of first enable signal and second enable signal, and the minimum level of reference voltage is greater than the minimum level of first enable signal and second enable signal.

Above-mentioned self-bias unit comprises two resistance and two switches of being made up of single N transistor npn npn.When first enable signal and second enable signal when respectively first switch unit and second switch unit being controlled, oneself's bias unit also utilizes first enable signal that switch own is controlled simultaneously, the reference voltage that allows self-bias unit export, can allow switch in second switch unit, operate as normal when high pressure switches.

Described according to preferred embodiment of the present invention, the present invention utilizes a self-bias unit allow voltage switching device, just can realize need not adopting under the high-pressure process technology.Thus, compare with traditional framework, the present invention has not only saved circuit layout area, the power that has also reduced total system and consumed.

For above and other objects of the present invention, feature and advantage can be become apparent, the present invention's cited below particularly preferred embodiment, and conjunction with figs. are described in detail below.

Description of drawings

Fig. 1 is the circuit diagram of conventional voltage switching device shifter.

Fig. 2 is the Organization Chart of voltage switching device according to an embodiment of the invention.

Fig. 3 is the complete circuit according to the voltage switching device of present embodiment.

Fig. 4 is for can be applicable to the signal timing diagram of Fig. 3.

Fig. 5 and Fig. 6 are the operation principle schematic diagram of present embodiment.

The main element description of symbols

201: the first switch units

202: the second switch units

203: self-bias unit

211: clock generator

S11, S12, S21～S26: switch

R31, R32: resistance

S _EN21, S _EN22: enable signal

V _In21, V _In22: input voltage

V _Pp1, V _Pp2: switched voltage

V _REF: reference voltage V _N1, V _N2, V _N3, V _N4: node voltage

Embodiment

Fig. 2 is the Organization Chart of the voltage switching device of one embodiment of the invention.As shown in Figure 2, voltage switching device comprises first switch unit 201, second switch unit 202 and self-bias unit 203.First switch unit 201 and second switch unit 202 receive input voltage V respectively _In21With V _In22, and the output of the output of first switch unit 201 and second switch unit 202 electrically interconnects.Oneself's bias unit 203 is connected to second switch unit 202, in order to reference voltage V to be provided _REFTo second switch unit 202.In this voltage switching device, according to enable signal S _EN21Control first switch unit 201 and self-bias unit 203, according to enable signal S _EN22And reference voltage V _REFControl second switch unit 202, so that voltage switching device according to the output of first switch unit and second switch unit, produces switched voltage V _PP2, enable signal S wherein _EN21With S _EN22Be two phase non-overlapping copies (non-overlap) or be mutual anti-phase signal.

Fig. 3 is the detailed circuit diagram of the voltage switching device of present embodiment.First switch unit 201 of present embodiment comprises switch S 23 and S24, and 202 of second switch units comprise switch S 21 and S22, and self-bias unit 203 then comprises resistance R 31 and R32 and switch S 25 and S26.Wherein switch S 21～S23 is made up of single P transistor npn npn, and switch S 24～S26 then is made up of single N transistor npn npn.The annexation of each switch S 21～S26 and resistance R 31～R32 is described below.

Switch S 21 has: first end (source electrode of P transistor npn npn) receives input voltage V _In22Second end (drain electrode of P transistor npn npn) is connected to first end of switch S 22; The 3rd end (grid of P transistor npn npn) is according to reference voltage V _REFThe conducting state of determine switch itself.Switch S 22 has: first end (source electrode of P transistor npn npn) is connected to second end of switch S 21; Second end (drain electrode of P transistor npn npn) is connected to second end of switch S 24 and exports switched voltage V _PP2The 3rd end (grid of P transistor npn npn) is according to enable signal S _EN22The conducting state of determine switch itself.Switch S 23 has: first end (source electrode of P transistor npn npn) receives input voltage V _In21Second end (drain electrode of P transistor npn npn) is connected to first end of switch S 24; The 3rd end (grid of P transistor npn npn) is according to enable signal S _EN21The conducting state of determine switch itself.Switch S 24 has: first end (drain electrode of N transistor npn npn) is connected to second end of switch S 23; Second end (source electrode of N transistor npn npn) is connected to second end of switch S 22 and exports switched voltage V _PP2The 3rd end (grid of N transistor npn npn) is according to operating voltage V _DDThe conducting state of determine switch itself.Switch S 25 has: first end (drain electrode of N transistor npn npn) is connected to second end of resistance R 32; Second end (source electrode of N transistor npn npn) is connected to first end of switch S 26; The 3rd end (grid of N transistor npn npn) is according to operating voltage V _DDThe conducting state of determine switch itself.Switch S 26 has: first end (drain electrode of N transistor npn npn) is connected to second end of switch S 25; Second end (source electrode of N transistor npn npn), end with being connected to; The 3rd end (grid of N transistor npn npn) is according to enable signal S _EN21The conducting state of determine switch itself.

Resistance R 31 has: first end receives input voltage V _In22Second end is connected to first end and the output reference voltage V of resistance R 32 _REFResistance R 32 has: first end is connected to second end and the output reference voltage V of resistance R 31 _REFSecond end is connected to first end of switch S 25.

The operation principle of present embodiment can be with reference to the sequential chart of Fig. 4, and with operating voltage V _DDBe 5V, two input voltage V _In21With V _In22Being respectively 1.8V and 7V is that example explains orally.Convenient for following explanation, Fig. 4 marks node N1～N4 in addition.As enable signal S _EN21Be low level (0V), and enable signal S _EN22During for high level (5V), the action of all switch S 21～S26 just as shown in Figure 5.Grid bias at switch S 25 and S26 (being made up of the N transistor npn npn) is respectively operating voltage V _DDUnder the situation of low level (0V), by the node voltage V among Fig. 4 _N3With V _N4, the gate-source voltage that can confirm two switches is less than transistorized critical voltage, so two switch S 25 and not conductings of S26.Oneself's bias unit 203 under the situation of switch S 25 and not conducting of S26, the input voltage V that is received _In22Pressure drop is on resistance R 31 fully.Therefore the reference voltage V that exported of self-bias unit 203 _REFJust be equal to input voltage V _In22(7V).At this moment, because of reference voltage V _REFWith enable signal S _EN22Be respectively under the situation of 7V and high level (5V) two switch S 21 and not conducting of S22 in second switch unit 202, the switched voltage V that voltage switching device is exported _PP2By 201 decisions of first switch unit.In first switch unit 201, because of the enable signal S of low level (0V) _EN21Be coupled to the grid of the switch S of being formed by the P transistor npn npn 23, and the grid bias of the switch S of being made up of the N transistor npn npn 24 is under the situation of high level (5V), two switch S 23 and S24 conducting respectively, first switch unit, 201 output switched voltage V _PP2, input voltage V just _In21(1.8V).About the confirmation of the switch S 21～S24 conducting state in first switch unit 201 and second switch unit 202, can contrast the node voltage V of Fig. 4 _N1With V _N2.

Relative, as enable signal S _EN21Be high level (5V), and enable signal S _EN22During for low level (0V), the action of all switch S 21～S26 just as shown in Figure 6.Contrast Fig. 4 node voltage V _N3With V _N4, this moment switch S 25 with the gate-source voltage of S26 respectively greater than transistorized critical voltage itself, therefore two switch S 25 and S26 conductings.Oneself's bias unit 203 under the situation of switch S 25 and S26 conducting, the input voltage V that is received _In22Pressure drop is on resistance R 31 and R32.At this moment, the reference voltage V that exported of self-bias unit 203 _REF, decide by the resistance size of two resistance R 31 with R32.In the present embodiment, in order to allow second switch unit 202 at output switched voltage V _PP2The time, can keep the normal change action of switch S 21, therefore the resistance size selection principle of two resistance R 31 and R32 is to allow the voltage V of switch S21 as the formula (1) _SG21(that is input voltage V _In22With reference voltage V _REFBetween pressure reduction) greater than critical voltage (V own _TH) and less than operating voltage V _DD(5V).

|V _TH|＜V _SG21＜V _DD (1)

Thus, switch S 21 and S22 in second switch unit 202 are because of voltage V _SG21Greater than transistorized critical voltage, and enable signal S _EN22Be low level (0V) that therefore two switch S 21 and S22 are respectively in conducting state.In this, the switched voltage V that second switch unit 202 is exported _PP2Equal input voltage V _In22(7V).Two switch S 23 and S24 of first switch unit 201 are because of enable signal S _EN21Be high level (5V), and the grid bias of the switch S of being made up of the N transistor npn npn 24 is under the situation of high level (5V) two switch S 23 and S24 not conducting respectively.At this moment, the switched voltage V that exports of voltage switching device _PP2By 202 decisions of second switch unit.Similar, about the confirmation of the switch S 21～S24 conducting state in first switch unit 201 and second switch unit 202, can contrast the node voltage V of Fig. 4 _N1With V _N2.

The voltage switching device of present embodiment can utilize operating voltage V _DDFor the technology of 5V realizes, make switched voltage V _PP2Can be 1.8V or 7V.Yet present embodiment also can be via resistance R 31 and the R32 in the self-bias unit of fine setting 203, and allows voltage switching device change operating voltage V _DDWith switched voltage V _PP2Under the situation of scope, still can pass through reference voltage V _REFVoltage V with switch S 21 _SG21, maintain under the selection principle of formula (1), allow in order to switch second switch unit 202 of high pressure (for example being 7V in the present embodiment), available lower operating voltage V _DD(for example being 5V in the present embodiment) realizes.

For example, switched voltage is the voltage switching device of 2.5V or 8V, if need be implemented in the low operating voltage V of 5V _DDDown, then, can pass through semifixed resistor R31 and R32, allow reference voltage V in order to switch second switch unit 202 of high pressure (8V) _REFVoltage V with switch S 21 _SG21Maintain under the selection principle of formula (1), just can reach the target that is implemented in low pressure (5V) technology, and must be as prior art, cause second switch unit 202 is subject to the switched voltage of 8V, and voltage switching device just must adopt the technology of high pressure (8V).Thus, present embodiment is by the movement of semifixed resistor, allows the operating voltage V of voltage switching device _DD, no longer be subject to switched voltage V _PP2Requirement, and then voltage switching device can be implemented under the low pressure process technology.

On the other hand, present embodiment also can be applicable to the voltage commutation circuit in the power supply circuit of flash memory (flash memory).For example, when flash memory when programming mode (programming mode), present embodiment is under Fig. 6 state, the higher switched voltage (7V) that is provided just can be as flash memory required supply voltage this moment.Relative, when flash memory was in general modfel (normal mode), present embodiment was under Fig. 5 state, and the low switched voltage (1.8V) that is provided just meets the requirement of flash memory supply voltage this moment.

In addition, in the present embodiment, bleeder circuit (originally being made of resistance) also can utilize modes such as the diode of series connection or MOS transistor to reach.

In sum, the present invention utilizes self-bias unit allow voltage switching device, can adopt the low pressure process technology to realize.Thus, voltage switching device of the present invention is compared down with traditional framework, and the present invention has not only saved circuit layout area, the power that has also reduced total system and consumed.

Though the present invention discloses as above with preferred embodiment; right its is not in order to limit the present invention; any person of ordinary skill in the field; without departing from the spirit and scope of the present invention; when can doing a little change and improvement, so protection scope of the present invention is as the criterion when looking the claim person of defining.

Claims

1. A voltage switching device, which receives a first and a second input voltage, and outputs a switching voltage according to a first and a second enable signal, and is characterized in that the voltage switching device comprises:

a first switching unit, receiving the first input voltage, and outputting the switching voltage according to the first enabling signal;

The self-bias unit receives the second input voltage and outputs a reference voltage according to the first enabling signal, wherein the first input voltage is smaller than the second input voltage, and the highest level of the reference voltage is greater than the first consistent voltage. the highest level of the enable signal and the second enable signal, and the lowest level of the reference voltage is greater than the lowest level of the first enable signal and the second enable signal; and

a second switching unit, connected to the first switching unit, receiving the second input voltage, and outputting the switching voltage according to the reference voltage and the second enabling signal;

When the first switching unit outputs the switching voltage, the switching voltage is related to the first input voltage; and when the second switching unit outputs the switching voltage, the switching voltage is related to the second input voltage.

2. The voltage switching device according to claim 1, wherein when the first switching unit outputs the switching voltage, the switching voltage is equal to the first input voltage.

3. The voltage switching device according to claim 1, wherein when the second switching unit outputs the switching voltage, the switching voltage is equal to the second input voltage.

4. The voltage switching device according to claim 1, wherein the first enable signal and the second enable signal do not overlap with each other.

5. The voltage switching device according to claim 1, wherein the first switching unit comprises:

a first switch, the first end of which receives the first input voltage, and is used to determine the conduction state between the first end and the second end of the first switch according to the first enabling signal; and

The first end of the second switch is connected to the second end of the first switch, and the second end of the second switch outputs the switching voltage, which is used to determine the first end of the second switch and the second end according to the operating voltage. The conduction state between the two terminals.

6. The voltage switching device according to claim 5, wherein the first switch is composed of a P-type transistor, and the second switch is composed of an N-type transistor.

7. The voltage switching device according to claim 5, wherein the second switching unit comprises:

a third switch, the first end of which receives the second input voltage, and is used to determine the conduction state between the first end and the second end of the third switch according to the reference voltage; and

The fourth switch, the first end of which is connected to the second end of the third switch, and the second end of the fourth switch outputs the switching voltage, which is used to determine the second end of the fourth switch according to the second enabling signal. Conduction state between one end and the second end, wherein the lowest level of the first and the second enable signal is the ground voltage, and the highest level of the first and the second enable signal is the operating voltage .

8. The voltage switching device according to claim 7, wherein the first input voltage is lower than the operating voltage, and the operating voltage is lower than the second input voltage, and the highest level of the reference voltage is the second input voltage, the minimum level of this reference voltage conforms to the following formula:

(V _in2 −|V _TH |)>V _REF >V _in2 −V _DD , where V _in2 represents the second input voltage, V _TH represents the threshold voltage of the third switch, and V _REF represents the The reference voltage, V _DD, is used to represent the operating voltage.

9. The voltage switching device according to claim 7, wherein the third switch and the fourth switch are respectively composed of P-type transistors.

10. The voltage switching device according to claim 5, wherein the self-biasing unit comprises:

a first resistor, the first end of which is connected to the second input voltage, and the second end of the first resistor outputs the reference voltage;

a second resistor, the first end of which is connected to the second end of the first resistor;

a fifth switch, the first end of which is connected to the second end of the second resistor, and is used to determine the conduction state between the first end and the second end of the fifth switch according to the operating voltage; and

The sixth switch, the first end of which is connected to the second end of the fifth switch, and the second end of the sixth switch is connected to the ground end, and is used to determine the second end of the sixth switch according to the first enabling signal. The conduction state between one end and the second end.

11. The voltage switching device according to claim 10, wherein the fifth switch and the sixth switch are respectively composed of N-type transistors.

12. A voltage switching device, which receives first and second input voltages, and outputs switching voltages according to first and second enable signals, characterized in that the voltage switching device comprises:

The first switch receives the first input voltage and determines whether to turn on the first input voltage according to the first enable signal;

a second switch connected to the first switch, the second switch determines whether to output the first input voltage turned on by the first switch into the switching voltage according to an operating voltage;

The self-bias unit receives the second input voltage and outputs a reference voltage according to the first enabling signal, wherein the first input voltage is smaller than the second input voltage, and the highest level of the reference voltage is greater than the first consistent voltage. the highest level of the enable signal and the second enable signal, and the lowest level of the reference voltage is greater than the lowest level of the first enable signal and the second enable signal;

a third switch, receiving the second input voltage, and determining whether to turn on the second input voltage according to the reference voltage; and

The fourth switch is connected to the third switch, and determines whether to output the second input voltage turned on by the third switch as the switching voltage according to the second enabling signal;

Wherein, when the first enabling signal is in the first logic state, the switching voltage is related to the first input voltage; when the first enabling signal is in the second logic state, the switching voltage is related to the second input Voltage.

13. The voltage switching device according to claim 12, wherein the first switch, the third switch and the fourth switch are respectively composed of P-type transistors, and the second switch is composed of N-type transistors .

14. The voltage switching device according to claim 12, wherein the self-biasing unit comprises:

a fifth switch, connected to the second terminal of the second resistor, and determining the conduction state of the fifth switch according to the operating voltage; and

The sixth switch is connected between the fifth switch and the ground, and determines the conduction state of the sixth switch according to the first enabling signal.

15. The voltage switching device according to claim 14, wherein the fifth switch and the sixth switch are respectively composed of N-type transistors.

16. The voltage switching device according to claim 12, wherein when the second switch outputs the switching voltage, the switching voltage is equal to the first input voltage.

17. The voltage switching device according to claim 12, wherein when the fourth switch outputs the switching voltage, the switching voltage is equal to the second input voltage.

18. The voltage switching device according to claim 12, wherein the lowest level of the first and the second enable signal is the ground voltage, and the highest level of the first and the second enable signal is the ground voltage. operating voltage, and the highest level of the reference voltage is the second input voltage, and the lowest level of the reference voltage conforms to the following formula:

19. The voltage switching device according to claim 12, wherein the first enable signal and the second enable signal do not overlap with each other.