CN101697564B - Circuit structure capable of realizing critical failure signal generation function on network communication terminal equipment - Google Patents

Abstract

The invention relates to a circuit structure capable of realizing a critical failure signal generation function based on a TL431 chip on network communication terminal equipment, wherein the TL431 chip comprises a reference terminal, a positive terminal and a negative terminal, and the circuit structure comprises a power supply module, a first resistance, a second resistance, a third resistance, a fourth resistance, a switch triode and a seventh resistance. Because a differential amplifier in the TL431 chip, an NPN triode and the circuit structure of a reference voltage source are skillfully used and the switch triode and the relative resistances in the periphery circuit are utilized, the circuit structure capable of realizing the critical failure signal generation function based on the TL431 chip on the network communication terminal equipment not only has simple and practical structure, but also has the advantages of low cost, stable and reliable work performance and wider application range, and establishes a solid foundation for the further development of network communication terminal products.

Description

Network communication terminal equipment realizes that the critical failure signal produces the circuit structure of function

Technical field

The present invention relates to electronic technology field, particularly the network communication equipment electronic circuit field specifically is meant on a kind of network communication terminal equipment and realizes that based on the TL431 chip critical failure (Dying Gasp) signal produces the circuit structure of function.

Background technology

In the network communication terminal product; Critical failure (Dying Gasp) signal is meant: when system's input voltage can't satisfy system's operate as normal; System can send out a signal automatically and give local side; Tell that this ustomer premises access equipment of local side (CPE) voltage is low and arrived that can't normal operating conditions, local side is made respective reaction, discharges original that passage of arranging to give CPE.

Dying Gasp function is the indispensable function on the telecom terminal products such as present DSL/VDSL.System Dyinggasp commonly used realizes that principle is: general chip manufacturer can design a Dying gasp performance module in chip in design chips, and this module realizes Dying gasp function through the monitoring external input voltage.

The universal design that realizes Dying Gasp function at present is to use the reset control chip of 708S/R series to realize; But can bring the increase of complexity raising and cost like this to chip design; And range of application has received certain restriction, large-scale application preferably.

Summary of the invention

The objective of the invention is to have overcome above-mentioned shortcoming of the prior art, provide a kind of can ingeniously utilize the prior function chip realize the critical failure signal produce function, simple and practical, cost is lower, stable and reliable working performance, the scope of application realize that based on the TL431 chip critical failure signal produces the circuit structure of function on the network communication terminal equipment comparatively widely.

In order to realize above-mentioned purpose, realize that based on the TL431 chip circuit structure of critical failure signal generation function has following formation on the network communication terminal equipment of the present invention:

Realize that based on the TL431 chip critical failure signal produces the circuit structure of function on this network communication terminal equipment; Comprise power supply module; Described TL431 chip comprises reference edge, anode and negative terminal; Its principal feature is; Comprise first resistance, second resistance, the 3rd resistance, the 4th resistance, switch triode and the 7th resistance in the described circuit structure, described first resistance, second resistance series connection cross-over connection are between the positive pole and ground of described power supply module, and the reference edge of described TL431 chip is connected between described first resistance and second resistance; The negativing ending grounding of described TL431 chip; Described the 4th resistance string is connected between the anode of anodal and described TL431 chip of described power supply module, and the base stage that just is terminated at described switch triode of this TL431 chip, and described the 3rd resistance string is connected between the emitter of anodal and described switch triode of described power supply module; The collector of described switch triode is connected with the critical failure signal input tube pin of the central processing module of network communication terminal equipment, and the collector of this switch triode is through described the 7th resistance eutral grounding.

Also comprise voltage stabilizing diode in the circuit structure based on TL431 chip realization critical failure signal generation function on this network communication terminal equipment, described voltage stabilizing diode is parallel to described the 7th resistance two ends.

Clamp voltage based on the voltage stabilizing diode in the circuit structure of TL431 chip realization critical failure signal generation function on this network communication terminal equipment is 3.24V.

Realize based on the TL431 chip that the critical failure signal produces in the circuit structure of function on this network communication terminal equipment and also comprise the 6th resistance that the collector of described switch triode is connected with the critical failure signal input tube pin of the central processing module of described the 7th resistance, voltage stabilizing diode and network communication terminal equipment respectively through the 6th resistance.

Also comprise the 5th resistance in the circuit structure based on TL431 chip realization critical failure signal generation function on this network communication terminal equipment; Described the 5th resistance is connected between the anode of described the 4th resistance and described TL431 chip, and the base stage of described switch triode is connected between described the 5th resistance and the 4th resistance.

Realize that based on the TL431 chip critical failure signal produces the resistance Ω of first resistance in the circuit structure of function on this network communication terminal equipment _R1, second resistance resistance Ω _R2, described TL431 chip reference voltage threshold V _Th, described power supply module normal output voltage U between satisfy below relation:

$V_{\mathrm{th}}\&le;U\&times;\left(\frac{{\mathrm{\&Omega;}}_{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="H2009102050945E00011.png,H2009102050945E00021.png"\; state="\{\{state\}\}">R</figure-callout>}2}}{{\mathrm{\&Omega;}}_{\mathrm{<figure-callout\; id="1"\; label="R"\; filenames="H2009102050945E00011.png"\; state="\{\{state\}\}">R</figure-callout>}1}+{\mathrm{\&Omega;}}_{R2}}\right).$

Realize that based on the TL431 chip critical failure signal produces the resistance Ω that critical failure signal in the circuit structure of function produces threshold level V and described first resistance on this network communication terminal equipment _R1, second resistance resistance Ω _R2, described TL431 chip reference voltage threshold V _ThBetween satisfy below relation:

$V=V_{\mathrm{th}}\&times;\left(\frac{{\mathrm{\&Omega;}}_{\mathrm{<figure-callout\; id="1"\; label="R"\; filenames="H2009102050945E00011.png"\; state="\{\{state\}\}">R</figure-callout>}1}+{\mathrm{\&Omega;}}_{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="H2009102050945E00011.png,H2009102050945E00021.png"\; state="\{\{state\}\}">R</figure-callout>}2}}{{\mathrm{\&Omega;}}_{R2}}\right).$

Adopted on the network communication terminal equipment of this invention and realized that based on the TL431 chip critical failure signal produces the circuit structure of function; Because its ingenious circuit structure that has utilized differential amplifier, NPN triode and reference voltage source in the TL431 chip; And utilize the switch triode in the peripheral circuit to realize jointly that with corresponding resistance, voltage stabilizing diode critical failure (DyingGasp) signal produces function; Not only simple and practical, and cost is lower, stable and reliable working performance; The scope of application is comparatively extensive, has established solid foundation for further developing of network communication terminal product.

Description of drawings

Fig. 1 is that network communication terminal equipment of the present invention realizes that the critical failure signal produces the internal circuit configuration principle schematic of TL431 chip in the circuit structure of function.

Fig. 2 is that network communication terminal equipment of the present invention realizes that the critical failure signal produces the principle of work application circuit structural representation of TL431 chip in the circuit structure of function.

Fig. 3 is that network communication terminal equipment of the present invention realizes that the critical failure signal produces the integrated circuit schematic diagram of the circuit structure of function.

Embodiment

In order more to be expressly understood technology contents of the present invention, the special following examples of lifting specify.

See also Fig. 1 to shown in Figure 3; Realize that based on the TL431 chip critical failure signal produces the circuit structure of function on this network communication terminal equipment; Comprise power supply module; Described TL431 chip comprises reference edge, anode and negative terminal; Its principal feature is; Comprise first resistance R 1, second resistance R 2, the 3rd resistance R 3, the 4th resistance R 4, switch triode Q1 and the 7th resistance R 7 in the described circuit structure, described first resistance R 1, the 2 series connection cross-over connections of second resistance R are between the positive pole and ground of described power supply module, and the reference edge of described TL431 chip U1 is connected between described first resistance R 1 and second resistance R 2; The negativing ending grounding of described TL431 chip U1; Described the 4th resistance R 4 is serially connected with between the anode of anodal and described TL431 chip U1 of described power supply module, and the base stage that just is terminated at described switch triode Q1 of this TL431 chip U1, and described the 3rd resistance R 3 is serially connected with between the emitter of anodal and described switch triode Q1 of described power supply module; The collector of described switch triode Q1 is connected with the critical failure signal input tube pin of the central processing module of network communication terminal equipment, and the collector of this switch triode Q1 is through described the 7th resistance R 7 ground connection.

XMM1 among the figure is multimeter (multimeter), and it is the virtual instrument among the circuit simulating software multisim (perhaps EWB).The voltage of measuring on the circuit any that can be real-time.Represent multimeter test signal in the figure.

Wherein, also comprise voltage stabilizing diode D1 in the circuit structure based on TL431 chip realization critical failure signal generation function on this network communication terminal equipment, described voltage stabilizing diode D1 is parallel to described the 7th resistance R 7 two ends; The clamp voltage of this voltage stabilizing diode D1 is 3.24V.

Simultaneously; Realize based on the TL431 chip that the critical failure signal produces in the circuit structure of function on this network communication terminal equipment and also comprise the 6th resistance R 6 that the collector of described switch triode Q1 is connected with the critical failure signal input tube pin of the central processing module of described the 7th resistance R 7, voltage stabilizing diode D1 and network communication terminal equipment respectively through the 6th resistance R 6; Also comprise the 5th resistance R 5 in this circuit structure, described the 5th resistance R 5 is connected between the anode of described the 4th resistance R 4 and described TL431 chip U1, and the base stage of described switch triode Q1 is connected between described the 5th resistance R 5 and the 4th resistance R 4.

Moreover, realize that based on the TL431 chip critical failure signal produces the resistance Ω of first resistance R 1 in the circuit structure of function on this network communication terminal equipment _R1, second resistance R 2 resistance Ω _R2, described TL431 chip U1 reference voltage threshold V _Th, described power supply module normal output voltage U between satisfy below relation:

$V_{\mathrm{th}}\&le;U\&times;\left(\frac{{\mathrm{\&Omega;}}_{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="H2009102050945E00011.png,H2009102050945E00021.png"\; state="\{\{state\}\}">R</figure-callout>}2}}{{\mathrm{\&Omega;}}_{\mathrm{<figure-callout\; id="1"\; label="R"\; filenames="H2009102050945E00011.png"\; state="\{\{state\}\}">R</figure-callout>}1}+{\mathrm{\&Omega;}}_{R2}}\right).$

Critical failure signal in this circuit structure produces the resistance Ω of threshold level V and described first resistance R 1 _R1, second resistance R 2 resistance Ω _R2, described TL431 chip U1 reference voltage threshold V _ThBetween satisfy below relation:

$V=V_{\mathrm{th}}\&times;\left(\frac{{\mathrm{\&Omega;}}_{\mathrm{<figure-callout\; id="1"\; label="R"\; filenames="H2009102050945E00011.png"\; state="\{\{state\}\}">R</figure-callout>}1}+{\mathrm{\&Omega;}}_{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="H2009102050945E00011.png,H2009102050945E00021.png"\; state="\{\{state\}\}">R</figure-callout>}2}}{{\mathrm{\&Omega;}}_{R2}}\right).$

In the middle of practical application; At first see also shown in Figure 1; The inside theory diagram that has wherein shown the TL431 chip; In the structure of TL431 chip, there are a differential amplifier, NPN triode and a 2.5V reference voltage source (the concrete difference of the TL431 of different model can be found) in TL431 inside in the databook that chip manufacturer provides.

Corresponding pin definitions is following:

Pin one---reference edge (Reference)

Pin two---anode (Anode)

Pin 3---negative terminal (Cathode)

Introduce the voltage comparative characteristic of TL431 chip below:

See also shown in Figure 2ly, TL431 has the function of single supply comparer, wherein, and V _OutOutput characteristics following:

V ref	≥V th	≤V th
			V out	≈1.07V	V3
I out	10.8mA	1.9uA

V wherein _Th=2.5V.

Realize the principle of work of Dying Gasp for the TL431 chip, see also shown in Figure 3ly, wherein suppose product power supply uses+12V, occur Dying Gasp when power supply drops into 10V and alarm, then circuit can design.Wherein V1 and V2 have represented the input voltage 12V and the 10V of product respectively; D1 is a stabilivolt, and its negative pole is received the Dying Gasp module interface of CPU, V _Th=2.55V.

When system power supply maintained 12V, the Reference pin of U1 level after R1 and R2 dividing potential drop was:

V1×[R2÷(R1+R2)]≈2.98V≥V _th

The voltage of the 1st pin of U1 approximately is 1.07V at this moment, and electric current is V1 ÷ (R4+R5+Rs ^*) ≈ 1.27mA, satisfy the base stage saturation current I that makes the Q1 conducting _BE(from the handbook of 2N3906, can find I _BEWhen saturated 1mA).The Q1 saturation conduction, the dividing potential drop through R6 and R7 makes Dying Gasp signal level be about [V1 ÷ (R3+R6+R7)] * R7=6.2V, and this voltage passes through behind the D1 stabilivolt clamping to about the 3.24V.This moment, CPU judged that Dying Gasp signal is a high level.

When system power supply begins step-down by 12V, (threshold value is 10.27V when reaching 10V ^*):

The Reference pin of U1 level after R1 and R2 dividing potential drop is:

V1×[R2÷(R1+R2)]≈2.48V≤V _th

According to the voltage comparator characteristic of TL431 chip, the voltage of the 1st pin of U1 equals V2 at this moment, i.e. 10V.At this moment the electric current that passes through of U1 is the uA level, can not satisfy the base stage saturation current I of Q1 conducting _BE, Q1 is in cut-off state.The DyingGasp voltage of signals is pulled down to ground by R7 this moment, becomes 0V.CPU judges that Dying Gasp signal is a low level, will report product power fail warning information to cpe end, thereby realizes Dying Gasp function.

The Dying Gasp signal retention time of this circuit is by the capacitor discharge time decision of 12V in the system.

Wherein, Rs refers to the dynamic resistance of TL431, the chances are 0.22 Ω; 10.27V be through [(R1+R2)/R2] * V _ThThe threshold level that calculates can be adjusted according to the selection of R1, R2.

Adopted on the above-mentioned network communication terminal equipment and realized that based on the TL431 chip critical failure signal produces the circuit structure of function; Because its ingenious circuit structure that has utilized differential amplifier, NPN triode and reference voltage source in the TL431 chip; And utilize the switch triode in the peripheral circuit to realize jointly that with corresponding resistance, voltage stabilizing diode critical failure (DyingGasp) signal produces function; Not only simple and practical, and cost is lower, stable and reliable working performance; The scope of application is comparatively extensive, has established solid foundation for further developing of network communication terminal product.

In this instructions, the present invention is described with reference to its certain embodiments.But, still can make various modifications and conversion obviously and not deviate from the spirit and scope of the present invention.Therefore, instructions and accompanying drawing are regarded in an illustrative, rather than a restrictive.

Claims (6)

1. realize that based on the TL431 chip critical failure signal produces the circuit structure of function on a network communication terminal equipment; Comprise power supply module; Described TL431 chip comprises reference edge, anode and negative terminal; It is characterized in that; Comprise first resistance (R1), second resistance (R2), the 3rd resistance (R3), the 4th resistance (R4), switch triode (Q1) and the 7th resistance (R7) in the described circuit structure; Described first resistance (R1), second resistance (R2) series connection cross-over connection are between the positive pole and ground of described power supply module; The reference edge of described TL431 chip (U1) is connected between described first resistance (R1) and second resistance (R2), and the negativing ending grounding of described TL431 chip (U1), described the 4th resistance (R4) are serially connected with between the anode of positive pole and described TL431 chip (U1) of described power supply module; And the base stage that just is terminated at described switch triode (Q1) of this TL431 chip (U1); Described the 3rd resistance (R3) is serially connected with between the emitter of positive pole and described switch triode (Q1) of described power supply module, and the collector of described switch triode (Q1) is connected with the critical failure signal input tube pin of the central processing module of network communication terminal equipment, and the collector of this switch triode (Q1) is through described the 7th resistance (R7) ground connection; Also comprise voltage stabilizing diode (D1) in the described circuit structure, described voltage stabilizing diode (D1) is parallel to described the 7th resistance (R7) two ends.

2. realize that based on the TL431 chip critical failure signal produces the circuit structure of function, is characterized in that the clamp voltage of described voltage stabilizing diode (D1) is 3.24V on the network communication terminal equipment according to claim 1.

3. realize that based on the TL431 chip critical failure signal produces the circuit structure of function on the network communication terminal equipment according to claim 1; It is characterized in that; Also comprise the 6th resistance (R6) in the described circuit structure, the collector of described switch triode (Q1) is connected with the critical failure signal input tube pin of the central processing module of described the 7th resistance (R7), voltage stabilizing diode (D1) and network communication terminal equipment respectively through the 6th resistance (R6).

4. realize that based on the TL431 chip critical failure signal produces the circuit structure of function on the network communication terminal equipment according to claim 1; It is characterized in that; Also comprise the 5th resistance (R5) in the described circuit structure; Described the 5th resistance (R5) is connected between the anode of described the 4th resistance (R4) and described TL431 chip (U1), and the base stage of described switch triode (Q1) is connected between described the 5th resistance (R5) and the 4th resistance (R4).

5. according to realizing that based on the TL431 chip critical failure signal produces the circuit structure of function, is characterized in that the resistance Ω of described first resistance (R1) on each described network communication terminal equipment in the claim 1 to 4 _R1, second resistance (R2) resistance Ω _R2, described TL431 chip (U1) reference voltage threshold V _Th, described power supply module normal output voltage U between satisfy below relation:

$V_{\mathrm{th}}\&le;U\&times;\left(\frac{{\mathrm{\&Omega;}}_{R2}}{{\mathrm{\&Omega;}}_{R1}+{\mathrm{\&Omega;}}_{R2}}\right).$

6. according to realizing that based on the TL431 chip critical failure signal produces the circuit structure of function on each described network communication terminal equipment in the claim 1 to 4; It is characterized in that the critical failure signal of described circuit structure produces the resistance Ω of threshold level V and described first resistance (R1) _R1, second resistance (R2) resistance Ω _R2, described TL431 chip (U1) reference voltage threshold V _ThBetween satisfy below relation:

$V=V_{\mathrm{th}}\&times;\left(\frac{{\mathrm{\&Omega;}}_{R1}+{\mathrm{\&Omega;}}_{R2}}{{\mathrm{\&Omega;}}_{R2}}\right).$

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