CN101436082A

CN101436082A - Low voltage drop linear voltage-stabilizing apparatus

Info

Publication number: CN101436082A
Application number: CNA2007102025342A
Authority: CN
Inventors: 王辉; 侯震
Original assignee: Premier Image Technology China Ltd; Hon Hai Precision Industry Co Ltd
Current assignee: Premier Image Technology China Ltd; Hon Hai Precision Industry Co Ltd
Priority date: 2007-11-14
Filing date: 2007-11-14
Publication date: 2009-05-20
Anticipated expiration: 2027-11-14
Also published as: CN101436082B

Abstract

The invention relates to a low-dropout linear voltage stabilizing device, which comprises a low-dropout linear regulator and a voltage sampling module, wherein the low-dropout linear regulator is provided with an enabling control module which can output a second control logic; the voltage sampling module samples the output voltage of the low-dropout linear regulator and outputs a first control logic; and the first control logic and the second control logic form a third control logic. The low-dropout linear voltage stabilizing device controls the output state of the low-dropout linear regulator through the third control logic and avoids that the output state of the low-dropout linear regulator is in the failure mode caused by the fact that the enabling control module is in the floating state.

Description

Low voltage drop linear voltage-stabilizing apparatus

Technical field

The present invention relates to a kind of stable-pressure device, relate in particular to a kind of low voltage drop linear voltage-stabilizing apparatus.

Background technology

Low-voltage-drop linear voltage regulator (Low Drop-outLinear Regulator; LDO) be the voltage stabilizing chip that is widely used in the multiple consumer electronics products such as mobile phone, DVD, digital camera and Mp3, in order to satisfy the requirement of these precise electronic products, input end at power supply adds linear voltage regulator, to guarantee that supply voltage is constant and to realize active noise filtering.In addition, these electronic products have only Battery pack power supply usually, in order to save the electric weight for battery, wish that LDO works in sleep state when equipment is not worked.For this reason, most of LDO has the control function of enabling, thereby makes things convenient for the user to control use.

But, this LDO is in convenient the use, exist the logic working level that makes energy control module of unavoidable problem a: LDO to have no idea to cover a continuous operation level, thereby cause when control signal is in this discontinuous operation level, make energy control module be in quick condition (a uncontrollable stage between high level H and low level L), thereby LDO lose the control to output state.

Summary of the invention

In view of this, be necessary to provide a kind of low-voltage-drop linear voltage regulator that solves to lose low voltage drop linear voltage-stabilizing apparatus to the control problem of output state.

A kind of low voltage drop linear voltage-stabilizing apparatus, it comprises a low-voltage-drop linear voltage regulator and a voltage sample module, this low-voltage-drop linear voltage regulator has the energy control module that makes that can export second steering logic, this voltage sample module is sampled to the output voltage of this low-voltage-drop linear voltage regulator, and export first steering logic, this first steering logic and this second steering logic constitute the 3rd steering logic.

Described low voltage drop linear voltage-stabilizing apparatus, control the output state of this low-voltage-drop linear voltage regulator by the 3rd steering logic, avoided causing the output state of this low-voltage-drop linear voltage regulator to be in failure mode because of this makes energy control module be in quick condition.

Description of drawings

The functional structure chart of the low voltage drop linear voltage-stabilizing apparatus that Fig. 1 provides for first embodiment of the invention.

The output voltage and the time relation curve map of linear voltage regulator falls in Fig. 2 for Fig. 1 mesolow.

Fig. 3 is the synoptic diagram that concerns of the logic level of sampled voltage among Fig. 2 and output voltage.

The functional structure chart of the low voltage drop linear voltage-stabilizing apparatus that Fig. 4 provides for second embodiment of the invention.

Embodiment

Below in conjunction with accompanying drawing embodiment of the present invention is described in further detail.

See also Fig. 1, be a kind of low voltage drop linear voltage-stabilizing apparatus 100 that first embodiment of the invention provides, this low voltage drop linear voltage-stabilizing apparatus 100 comprises a low-voltage-drop linear voltage regulator 101 and a voltage sample module 102.This low-voltage-drop linear voltage regulator 101 comprises that one makes energy control module 1011, MOS driver module 1012, MOS switch module 1013, the 4th comparison amplifier 1014 and feedback module 1015.This voltage sample module 102 includes a logic module output 1024, a comparison amplifier module 1025 and a Postponement module 1026, and this comparison amplifier module 1025 has first comparison amplifier 10251 and second comparison amplifier 10252.

This low-voltage-drop linear voltage regulator 101 receives external input voltage V _In, through the inter-process output voltage V _Out, to guarantee that supply voltage is constant and to realize active noise filtering.The output voltage V of 102 pairs of these low-voltage-drop linear voltage regulators 101 of this voltage sample module _OutCarry out time sharing sampling, obtain the first sampled voltage V ₁With the second sampled voltage V ₂, and judge this double sampling voltage V ₁, V ₂Logic level, obtain the first sampled voltage V ₁Logic level A ₁With the second sampled voltage V ₂Logic level A ₂, last, with A ₁With A ₂Constitute one first steering logic Y ₁

The output that makes energy control module 1011 of this low voltage drop linear voltage-stabilizing apparatus 100 has a reference voltage V _RefWith one second steering logic Y ₂The output voltage V of 1015 pairs of these low-voltage-drop linear voltage regulators 101 of this feedback module _OutCarry out real-time sampling, and send into the 4th comparison amplifier 1014, this first comparison amplifier 10251 and this Postponement module 1026 respectively.The 4th comparison amplifier 1014 receives output signal and this reference voltage V of this feedback module 1015 _Ref, and the output after these two signals are compared and enlarged is used for driving this MOS driver module 1012.This first comparison amplifier 10251 is at first moment t ₁Receive the output signal of this feedback module 1015, obtain the first sampled voltage V ₁This first comparison amplifier 10251 is with this first sampled voltage V ₁With this reference voltage V _RefConstitute the first logic level A ₁This second comparison amplifier 10252 is because the existence of this Postponement module 1026, so, at second t constantly ₂Receive the output signal of this feedback module 1015, obtain the second sampled voltage V ₂This second comparison amplifier 10252 is with this second sampled voltage V ₂With this reference voltage V _RefConstitute the second logic level A ₂This logic module output 1024 receives these two logic level A ₁, A ₂, and constitute this first steering logic Y ₁This MOS driver module 1012 receives output signal, this second steering logic Y of the 4th comparison amplifier module 1014 ₂And this first steering logic Y ₁, and with this second steering logic Y ₂With this first steering logic Y ₁Constitute the 3rd steering logic Y.This MOS switch module 1013 receives the external input voltage V of this low-voltage-drop linear voltage regulator 101 _InWith the 3rd steering logic Y, be used for controlling the output voltage V of this low-voltage-drop linear voltage regulator 101 _Out

See also Fig. 2, fall the output voltage V of linear voltage regulator 101 for Fig. 1 mesolow _OutGraph of relation with time t.The output voltage V of this low-voltage-drop linear voltage regulator 101 _OutWith the relation curve of time t be L ₁, this voltage sample module 102 is at t ₁, t ₂Constantly to output voltage V _OutSampled voltage be respectively V ₁, V ₂

See also Fig. 3, be sampled voltage V among Fig. 2 ₁, V ₂Corresponding logic level A ₁, A ₂With output voltage V _OutConcern synoptic diagram.t ₁With t ₂Between the time interval be T, in the present embodiment, t ₁With t ₂Between time interval T greater than the soft-start time of this low-voltage-drop linear voltage regulator 101, cause misoperation to avoid load to change suddenly.By judging V ₁, V ₂Corresponding logic level A ₁, A ₂, obtain this first steering logic Y ₁, its logical relation is converted into truth table can be by shown in the following table 1.

Table 1

The second steering logic Y that makes energy control module 1011 of this low-voltage-drop linear voltage regulator 101 ₂With this first steering logic Y ₁, constituting the 3rd steering logic Y, its logical relation is converted into truth table can be by shown in the following table 2.

Table 2

Because Y ₁By this V ₁, V ₂Corresponding logic level A ₁, A ₂Logical relation constitute, so, this A ₁, A ₂With this second steering logic Y ₂, the 3rd steering logic Y logical relation be converted into truth table can be by shown in the following table 3.

Table 3

See also Fig. 4, be a kind of low voltage drop linear voltage-stabilizing apparatus 200 that second embodiment of the invention provides, this low voltage drop linear voltage-stabilizing apparatus 200 comprises a low-voltage-drop linear voltage regulator 101 and a voltage sample module 103.The difference of this second embodiment and this first embodiment is, the output voltage V of 103 pairs of these low-voltage-drop linear voltage regulators 101 of this voltage sample module _OutCarry out real-time sampling, this voltage sample module 103 includes one the 3rd comparison amplifier 10253, and this voltage sample module 103 receives an external reference voltage V ' _RefThis external reference voltage V ' _RefDemand according to the user is provided with, because this external reference voltage V ' _RefDetermined the output voltage of this low-voltage-drop linear voltage regulator 101, so this external reference voltage V ' _RefMake the reference voltage V of energy control module 1011 less than this _RefThe 3rd comparison amplifier 10253 is at t ₃Constantly, receive the output signal of this feedback module 1015, obtain the 3rd output voltage V ₃The 3rd comparison amplifier 10253 is with the 3rd output voltage V ₃With this external reference voltage V ' _RefConstitute this first steering logic Y ₁

In sum in first, second embodiment, as the logic output Y of this voltage sample module 102 ₁During for high level H, no matter this makes the logic output Y of energy control module 1011 ₂Be in what state, total logic output Y closes this MOS switch module 1013; Work as Y ₁During for low level L, Y ₂During for high level H, this MOS switch module 1013 is also closed Y ₂During for low level L, this MOS switch module 1013 is not done control.Like this, occur because of this makes energy control module 1011 be in the problem that output state that quick condition makes this low-voltage-drop linear voltage regulator 101 is in failure mode with regard to avoiding.

Though the present invention discloses as above with better embodiment,, it is not in order to qualification the present invention, and in addition, those skilled in the art can also do other variation etc. in spirit of the present invention.Certainly, the variation that these are done according to spirit of the present invention all should be included within the present invention's scope required for protection.

Claims

[claim 1] a kind of low voltage drop linear voltage-stabilizing apparatus, it comprises:

A low-voltage-drop linear voltage regulator, this low-voltage-drop linear voltage regulator have the energy control module that makes that can export second steering logic;

It is characterized in that, this low voltage drop linear voltage-stabilizing apparatus further comprises a voltage sample module, this voltage sample module is sampled to the output voltage of this low-voltage-drop linear voltage regulator, and export first steering logic, this first steering logic and this second steering logic constitute the 3rd steering logic, and the 3rd steering logic is used to control the output of this low-voltage-drop linear voltage regulator.
[claim 2] low voltage drop linear voltage-stabilizing apparatus as claimed in claim 1 is characterized in that, this first steering logic, this second steering logic and the 3rd steering logic satisfy following logical relation: $Y = \overset{&OverBar;}{Y_{1}} \times Y_{2} + Y_{1}$

Wherein, Y1 is this first steering logic;

Y2 is this second steering logic;

Y is the 3rd steering logic.
[claim 3] low voltage drop linear voltage-stabilizing apparatus as claimed in claim 1, it is characterized in that, this makes the output of energy control module also have a reference voltage, this voltage sample module has a logic module output, a comparison amplifier module and a Postponement module, this voltage sample module is carried out time sharing sampling by this Postponement module to the output voltage of this low-voltage-drop linear voltage regulator, obtain first output voltage and second output voltage, this comparison amplifier module has first comparison amplifier and second comparison amplifier, this first comparison amplifier receives this first output voltage and this makes the reference voltage of energy control module, and constitute first logic level, this second comparison amplifier receives this second output voltage and this makes the reference voltage of energy control module, and constituting second logic level, this logic module output constitutes this first steering logic with these two logic levels.
[claim 4] low voltage drop linear voltage-stabilizing apparatus as claimed in claim 1, it is characterized in that, this makes the output of energy control module also have a reference voltage, this voltage sample module has one the 3rd comparison amplifier, and this voltage sample module receives an external reference voltage, and the output voltage of this low-voltage-drop linear voltage regulator carried out real-time sampling, obtain the 3rd output voltage, the 3rd comparison amplifier receives the 3rd output voltage and this external reference voltage, and constitutes this first steering logic.
[claim 5] low voltage drop linear voltage-stabilizing apparatus as claimed in claim 3 is characterized in that the time delay of this Postponement module is greater than the soft-start time of this low-voltage-drop linear voltage regulator.
[claim 6] low voltage drop linear voltage-stabilizing apparatus as claimed in claim 3 is characterized in that, this first logic level, this second logic level and this first steering logic satisfy following logical relation: $Y_{1} = \overset{&OverBar;}{A_{1}} \times A_{2}$

Wherein, Y1 is this first steering logic;

A1 is this first logic level;

A2 is this second logic level.
[claim 7] low voltage drop linear voltage-stabilizing apparatus as claimed in claim 4 is characterized in that this external reference voltage is provided with according to user's demand, and makes the reference voltage of energy control module less than this.