CN106033243A

CN106033243A - Low-power DC voltage comparison circuit

Info

Publication number: CN106033243A
Application number: CN201510121663.3A
Authority: CN
Inventors: 吕海峰; 李鹏; 张大语
Original assignee: Shanghai Beiling Co Ltd
Current assignee: Shanghai Beiling Co Ltd
Priority date: 2015-03-19
Filing date: 2015-03-19
Publication date: 2016-10-19
Anticipated expiration: 2035-03-19
Also published as: CN106033243B

Abstract

The invention provides a low-power DC voltage comparison circuit including an input end for inputting an input voltage and an output end for outputting a detection voltage, a first resistor and a fifth resistor successively and serially connected between the input end and the ground, the connection node of the first resistor and the fifth resistor is a first node, the emitter electrode of a first transistor is connected with a power supply via a second resistor, the collector electrode is grounded via a sixth resistor, the base electrode is connected with the power supply via a ninth resistor, the base electrode of the first transistor is connected with the first node, the collector electrode of a second transistor is connected with the power supply of a seventh resistor, the base electrode is connected with the collector electrode of the first transistor via an eighth resistor, the emitter electrode is grounded via a third resistor, the resistance value of the seventh resistor is greater than that of the third resistor, and the collector electrode of the second transistor is connected with the output end. The low-power DC voltage comparison circuit can detect the voltage change in time and improve the safety of the system, meanwhile, the power consumption is low and the reaction speed is fast.

Description

A kind of low-power consumption DC voltage compares circuit

Technical field

The present invention relates to a kind of low-power consumption DC voltage and compare circuit.

Background technology

In common industry or civilian application circuit system, system master controller single-chip microcomputer be by One mu balanced circuit is powered, generally use LDO circuit (low-dropout linear voltage-regulating circuit) or DCDC circuit (DC-DC transfer circuit) realize, its power supply input be one higher, no Stable input voltage VHH, usually 9V, 12V or higher, it is output as a stable low electricity Pressure value VCC, voltage 5V or 3.3V etc. that usually system single-chip microcomputer uses.

When system power supply end breaks down, during such as grid power blackout, owing to outer power voltage does not has , input voltage VHH can start to fall from normal voltage levvl, drops into mu balanced circuit and wants Below the minimum input voltage asked, the running voltage of system also fails, and at this moment Circuits System is just Do not work.If this power-off is unexpected, especially apply heavier when Circuits System In the work wanted, such as gas density collection, or Valve controlling etc., if when power-off occurs being System does not has well in advance to prepare, so it is possible to cause sensitive data because of this unexpected power-off Loss, or because not taking protection act to bring potential risk.

Actually, input voltage VHH falls from starting, and exports complete failure to mu balanced circuit, Centre has the time interval of tens to hundreds of millisecond, and (this depends on the input and output of mu balanced circuit The size of the electric capacity of voltage regulation used, and mu balanced circuit normally export electric current), if system Microcontroller can just obtain early warning signal input voltage VHH starts to fall when, System voltage not yet drop to power-off before this tens to time of hundreds of millisecond, take in time Protection act, by important data backup to can the nonvolatile memory such as NVRAM of no write de-lay Or in ferroelectric memory, just it is prevented from this system risk.

Summary of the invention

Present invention seek to address that above-mentioned technical problem, it is provided that a kind of low-power consumption DC voltage is more electric Road, it is possible to drop into fast less than during by threshold voltage set by resistance at input voltage VHH Speed response, output alarm signal, thus ensure the safety of system.

The present invention provides a kind of low-power consumption DC voltage to compare circuit, including for input electricity The input pressed and the outfan being used for output detections voltage, also include:

The first resistance between described input and ground in sequential series and the 5th resistance, described The node that one resistance is connected with described 5th resistance is primary nodal point；

The first transistor, the emitter stage of described the first transistor is connected with power supply by the second resistance Connecing, colelctor electrode passes through the 6th resistance eutral grounding, and base stage is connected with power supply by the 9th resistance；

The base stage of the first transistor is connected with primary nodal point；

Transistor seconds, the colelctor electrode of described transistor seconds is connected with power supply by the 7th resistance Connecing, base stage is connected with the colelctor electrode of described the first transistor by the 8th resistance, and emitter stage leads to Crossing the 3rd resistance eutral grounding, described 7th resistance is more than described 3rd resistance；

The colelctor electrode of described transistor seconds is connected with described outfan.

Preferably, also including the 4th resistance, the base stage of described the first transistor passes through the described 4th Resistance is connected with described primary nodal point；

Concrete, the resistance of described first resistance sets according to comparing threshold size.

Preferably, the resistance of described 7th resistance is 10K Ω, and the resistance of described 3rd resistance is 10Ω。

Preferably, described the first transistor is PNP transistor, and described transistor seconds is NPN Transistor.

The low-power consumption DC voltage utilizing the present invention compares circuit, it is possible to start to fall at input voltage Just obtain early warning signal when of falling, utilize before system cut-off this tens to hundreds of millisecond time Between, to take protection act in time, improve security of system, power consumption the most own is relatively low, reaction speed Degree is fast.

Accompanying drawing explanation

Fig. 1 is the circuit structure diagram that the low-power consumption DC voltage of the present invention compares circuit；

Fig. 2 is the graph of a relation of input voltage and output detections voltage；

Fig. 3 is magnified partial view in Fig. 2.

Detailed description of the invention

Below in conjunction with accompanying drawing, the low-power consumption DC voltage of the present invention is compared circuit to do specifically Bright.Fig. 1 is the circuit structure diagram that the low-power consumption DC voltage of the present invention compares circuit, such as figure institute Showing, the outfan of this circuit is used for inputting input voltage VHH, and outfan is for output detections electricity Pressure V_DETECTION, the first resistance R1 are for arranging the comparison threshold value of this comparison circuit V_GATE, by regulating the resistance of the first resistance R1, arranges and compares threshold value V_GATE, tool Body relation is as shown in the table:

R1(KΩ)	Relatively threshold value V_GATE (V)
		220	9.8
180	8.8
		150	8
110	7

Table 1 first resistance and the relation comparing threshold value

First resistance R1 and the 5th resistance R5 in sequential series between input and earth terminal, first Node between resistance R1 and the 5th resistance R5 is as primary nodal point.

The emitter stage of the first PNP pipe Q2 is connected with power supply V1 by the second resistance R2, collection Electrode passes through the 6th resistance R6 ground connection, and base stage is connected with power supply V1 by the 9th resistance R9.

Base stage the 4th resistance R4 of the first PNP pipe Q2 is connected with primary nodal point simultaneously.

The colelctor electrode of the 2nd NPN pipe Q7 is connected by the 7th resistance R7 and power supply V1, sends out Emitter-base bandgap grading passes through the 3rd resistance R3 ground connection, and base stage passes through the 8th resistance R8 and the first PNP pipe Q2 Colelctor electrode be connected, the 7th resistance R7 resistance be much larger than the 3rd resistance R3 resistance, the 2nd NPN The node that the colelctor electrode of pipe Q7 and the 7th resistance are connected, as outfan, is believed for output detections Number V_DETECTION.

In present embodiment, supply voltage V1 is 5V, and the resistance of the 4th resistance R4 is 100 Ω, The resistance of the 5th resistance R5 is 120K Ω, and the second resistance R2 resistance is 0 Ω, the 6th resistance R6 Resistance be 10K Ω, the resistance of the 8th resistance R8 is 2K Ω, and the resistance of the 7th resistance R7 is 10K Ω, the resistance of the 3rd resistance R3 is 10 Ω, and the first PNP pipe selects model to be 2N2907 Transistor, the 2nd NPN pipe selects model to be 2N2222 transistor.

In present embodiment, arrange that to compare threshold value V_GATE be 9V, therefore select the R1 to be 180KΩ。

Low-power consumption DC voltage to the present invention compares the principle of circuit and is described briefly below.By Emitter stage in the first PNP pipe Q2 connects power supply V1 by the second resistance R2, and colelctor electrode leads to Crossing the 6th resistance R6 ground connection, base stage connects power supply V1 by the 9th resistance R9, therefore first The base stage of PNP pipe Q2 forms an on state threshold voltage, is about 4.3V in present embodiment.

Input voltage VHH divides through the first resistance R1, the 5th resistance R5 and the 4th resistance R4 After pressure, if the voltage in the first PNP pipe Q2 base stage is higher than above-mentioned on state threshold voltage, the One PNP pipe cut-off, therefore the 2nd NPN pipe Q7 base voltage is also close to 0V, and therefore the Two NPN pipe Q7 cut-offs, the detection voltage V_DETECION that outfan is exported is high electricity Flat.

Along with the decline of input voltage VHH, at the base stage in the first PNP pipe Q2, voltage is low When this on state threshold voltage, the first PNP pipe Q2 turns on rapidly, therefore the 2nd NPN pipe The base-emitter voltage difference of Q7 is higher than 0.7V, therefore the 2nd NPN pipe Q7 conducting, now Its collector emitter voltage difference is minimum, therefore, detection voltage V_DETECTION value by 3rd resistance R3 and the 7th resistance R7 dividing potential drop determine, owing to the resistance of the 3rd resistance R3 is the least In the 7th resistance R7, therefore detection voltage V_DETECTION is low level, close to 0V.

Owing to during normal work, input voltage VHH is in cut-off higher than threshold value, two transistors State, the most whole circuit power consumption is only consumed by the first resistance R1 and the 5th resistance R5, is treated Machine power consumption is relatively low.

Fig. 2～Fig. 3 is the computer analog oscillogram of this circuit, as it can be seen, during work, input Voltage VHH starts linear decline from 12V, is down to and threshold voltage when about 55ms V_GATE is identical, about during 200ms, reduces to 0.Detection output voltage V_DETECTION, As in figure 2 it is shown, along with the reduction at input voltage VHH, detect voltage V_DETECTION Dropping near equal with threshold voltage V_GATE at input voltage VHH, the present embodiment is 8.8V, becomes low level from high level, logic level is equivalent to become 0 from 1.By inversion portion Point amplify as it is shown on figure 3, whole change the time into 1.1ms, input voltage in this 1.1ms The amplitude of falling of VHH is 8.7846-8.7184=0.06V, it is seen that the low-power consumption unidirectional current of the present invention Pressure comparison circuit has response speed faster, it is possible to falling of the most corresponding input voltage, And the low-power consumption DC voltage of the present embodiment compares circuital current and is only 39.3 μ A, whole circuit merit Consumption is 4.6 μ W, it is achieved that low-power consumption.

The low-power consumption DC voltage of the present invention compares circuit and can fall at input voltage VHH React rapidly during threshold voltage V_GATE, output voltage is reversed to low level 0, it is possible to Holding the voltage detecting of the highest 40V, highly sensitive, the fuzzy excessive window of detection voltage is less than 0.1V, the response time, power consumption was less than 0.01 μ W, and simple in construction realizes low cost less than 1ms.

Claims

1. low-power consumption DC voltage compares a circuit, including the input for inputting input voltage End and the outfan for output detections voltage, it is characterised in that also include:

The base stage of the first transistor is connected with primary nodal point；

2. the low-power consumption DC voltage recorded such as claim 1 compares circuit, it is characterised in that Also including the 4th resistance, the base stage of described the first transistor is by described 4th resistance and described the One node is connected.

3. the low-power consumption DC voltage recorded such as claim 2 compares circuit, it is characterised in that The resistance of described first resistance sets according to comparing threshold size.

4. the low-power consumption DC voltage recorded such as claim 2 compares circuit, it is characterised in that The resistance of described 7th resistance is 10K Ω, and the resistance of described 3rd resistance is 10 Ω.

5. the low-power consumption DC voltage recorded such as claim 2 compares circuit, it is characterised in that Described the first transistor is PNP transistor, and described transistor seconds is NPN transistor.