CN205509603U - Double T L431 voltage monitoring circuit - Google Patents

Abstract

The utility model discloses a double T L431 voltage monitoring circuit belongs to voltage monitoring circuit technical field. The utility model aims to provide a whether the voltage that can judge the battery is in a certain settlement within range, moreover, the steam generator is simple in structure, use reliable voltage monitoring circuit, including voltage input unit and voltage comparing unit, voltage input unit includes input voltage vin, earthing terminal GND, current -limiting resistor R11, stabilivolt D1, electric capacity C1 and stabilivolt D1 are parallelly connected, voltage comparing unit includes U1, two TL431 of U2, U1's K extremely connects U2's the R utmost point, divider resistance connects U1 and U2, divider resistance satisfies (R1+R2) R3> (R4R5, ) R6, electric capacity C2 and R3 are parallelly connected, and electric capacity C3 and R6 are parallelly connected, and pilot lamp LED one end and U2's K extremely is connected, and input voltage vin is connected through current -limiting resistor R7 to the other end. It keeps watch on to be applicable to lead -acid batteries or lithium battery voltage.

Description

A Double TL431 Voltage Monitoring Circuit

technical field

The utility model specifically relates to a dual TL431 voltage monitoring circuit, which belongs to the technical field of voltage monitoring circuits.

Background technique

For lead-acid batteries or lithium batteries, if the battery is undervoltage or overvoltage during use, if measures are not taken in time, it will cause damage to the battery itself. Therefore, it is necessary to monitor the battery voltage. The general structure of the usual battery voltage monitoring device It is more complicated. The monitored voltage is generally a certain point value, and it cannot effectively monitor whether the voltage is within a certain range.

Utility model content

Therefore, the purpose of this utility model is to provide a dual TL431 voltage monitoring circuit that can judge whether the voltage of a lead-acid battery or a lithium battery is within a certain setting range, simple in structure, and reliable in use, including a voltage input unit and a voltage comparison unit , the voltage input unit includes an input voltage Vin, a ground terminal GND, a current limiting resistor R11, a voltage regulator tube D1, and a capacitor C1 connected in parallel with the voltage regulator tube D1. The voltage comparison unit includes two TL431 U1 and U2, and the K pole of U1 is connected The R pole of U2, the voltage divider resistors R1, R2, R3, R4, R5, R6 are connected to U1 and U2, the voltage divider resistor satisfies (R1+R2)/R3>(R4//R5)/R6, and the capacitor C2 is connected in parallel with R3 , the capacitor C3 is connected in parallel with R6, one end of the indicator LED is connected to the K pole of U2, and the other end is connected to the input voltage Vin through the current limiting resistor R7.

Further, the double TL431 voltage monitoring circuit also includes a voltage alarm unit, the voltage alarm unit includes triodes Q1 and Q2, the base of Q1 is connected to the input voltage Vin through a voltage regulator tube and bias resistors R8, R9, and the base of Q1 is connected to There is a resistor R21 and a capacitor C4 between the voltage regulator tubes, the emitter of Q1 is connected to the base of Q2, and there are voltage dividing resistors R23, R22, R24 and capacitor C5 between the emitter of Q1 and the base of Q2, and the alarm One end of BZ is connected to the collector of Q2, the other end is connected to the current-limiting resistor R25 and capacitor C6, the capacitor C6 is grounded, the current-limiting resistor R25 is connected to the alarm power supply, and the diode D3 is connected in parallel with the alarm BZ.

Further, the alarm BZ is a buzzer.

The beneficial effect of the utility model is that: the dual TL431 voltage monitoring circuit of the utility model utilizes the characteristics of TL431, uses two TL431, controls the on-off of the indicator light according to the limitation of its working conditions, and through the setting of the voltage dividing resistor, It can judge whether the battery voltage is within a certain voltage range. The structure is simple, the judgment is accurate, and the use is reliable. It can also send an alarm when under-voltage or over-voltage. It is suitable for voltage monitoring of lead-acid batteries or lithium batteries.

Description of drawings

Fig. 1 is a circuit diagram of a dual TL431 voltage monitoring circuit of the present invention.

detailed description

The specific embodiment of the utility model is described below in conjunction with accompanying drawing:

As shown in Figure 1, a dual TL431 voltage monitoring circuit includes a voltage input unit and a voltage comparison unit. The voltage input unit includes an input voltage Vin, a ground terminal GND, a current limiting resistor R11, a voltage regulator tube D1, a capacitor C1 and a voltage regulator The tube D1 is connected in parallel, and the voltage comparison unit includes two TL431s U1 and U2. The K pole of U1 is connected to the R pole of U2, and the voltage dividing resistors R1, R2, R3, R4, R5, and R6 are connected to U1 and U2. The voltage dividing resistors satisfy (R1 +R2)/R3>(R4//R5)/R6, capacitor C2 is connected in parallel with R3, capacitor C3 is connected in parallel with R6, one end of the indicator LED is connected to the K pole of U2, and the other end is connected to the input voltage Vin through the current limiting resistor R7.

TL431 is a controllable precision voltage regulator. Its output voltage can be arbitrarily set to any value from 2.5V to 36V with two resistors. The typical dynamic impedance of this device is 0.2Ω, and it is used to replace Zener diodes in many applications, such as digital voltmeters, operational amplifier circuits, adjustable voltage power supplies, switching power supplies, etc. The so-called TL431 is a three-terminal adjustable shunt reference source with good thermal stability.

The working principle of the dual TL431 voltage monitoring circuit is that if the input voltage Vin is greater than 2.5*(R1+R2)/R3, U1 works normally, and at the same time the cathode K of U1 flows a certain current, which will form a voltage on R5 and R4. drop, forcing down the voltage on R6, so that U2 does not work normally, no current flows through the indicator LED, and it cannot emit light. If the input voltage Vin is less than 2.5*(R4//R5)/R6, both U1 and U2 will not work normally, and no current will flow through the indicator LED, which will not emit light. If the input voltage Vin is between 2.5*(R1+R2)/R3 and 2.5*(R4//R5)/R6, U4 works normally, and the cathode K absorbs current to cause the indicator LED to light up. In this way, it can be judged whether the voltage of the lead-acid battery or lithium battery is within a certain voltage range, and the voltage monitoring range can also be adjusted by adjusting the resistance value of the voltage dividing resistor and the connection mode.

As a preferred embodiment, the double TL431 voltage monitoring circuit also includes a voltage alarm unit, the voltage alarm unit includes triodes Q1 and Q2, the base of Q1 is connected to the input voltage Vin through a voltage regulator tube and bias resistors R8, R9, and the base of Q1 There is a resistor R21 and a capacitor C4 between the voltage regulator tube, the emitter of Q1 is connected to the base of Q2, and the voltage dividing resistors R23, R22, R24 and capacitor C5 are set between the emitter of Q1 and the base of Q2, and the alarm One end of the device BZ is connected to the collector of Q2, the other end is connected to the current limiting resistor R25 and capacitor C6, the capacitor C6 is grounded, the current limiting resistor R25 is connected to the alarm power supply, and the diode D3 is connected in parallel with the alarm BZ.

As a preferred embodiment, the alarm BZ is a buzzer.

When the input voltage Vin is not between 2.5*(R1+R2)/R3 and 2.5*(R4//R5)/R6, due to the interaction between electrical components, the transistor Q2 is turned on, and the alarm, the buzzer, works .

This circuit can be used to detect the input voltage within a certain range. For example, the input terminal is a lead-acid or lithium battery. When the battery voltage is undervoltage or overvoltage, the buzzer will alarm, and when the battery voltage is normal, the LED light will be on.

The foregoing is a preferred embodiment of the present utility model, and it should be pointed out that for those of ordinary skill in the art, some improvements and modifications can be made without departing from the principle of the present utility model. Retouching should also be regarded as the scope of protection of the present utility model.

Claims (3)

1. double TL431 voltage monitoring circuits, including voltage input unit and voltage comparison unit, voltage input unit includes Input voltage vin, earth terminal GND, current-limiting resistance R11, stabilivolt D1, electric capacity C1 are in parallel with stabilivolt D1, it is characterised in that institute State voltage comparison unit and include that the K pole of U1, U2 two TL431, U1 connects the R pole of U2, divider resistance R1, R2, R3, R4, R5, R6 Connecting U1 and U2, divider resistance meets (R1+R2)/R3 > (R4//R5)/R6, and electric capacity C2 with R3 is in parallel, and electric capacity C3 with R6 is in parallel, Display lamp LED one end is connected with the K pole of U2, and the other end connects input voltage vin through current-limiting resistance R7.

2. double TL431 voltage monitoring circuit as claimed in claim 1, it is characterised in that described pair of TL431 voltage monitoring circuit Also including that voltage alarm unit, voltage alarm unit include audion Q1 and Q2, the base stage of Q1 passes through stabilivolt and biasing resistor R8, R9 connect input voltage vin, are provided with resistance R21 and electric capacity C4 between base stage and the stabilivolt of Q1, and the emitter stage of Q1 connects Q2 Base stage, be provided with divider resistance R23, R22, R24 and electric capacity C5 between emitter stage and the base stage of Q2 of Q1, alarm BZ one end is even Connecing the colelctor electrode of Q2, the other end connects current-limiting resistance R25 and electric capacity C6, electric capacity C6 ground connection, and current-limiting resistance R25 connects alarm electricity Source, diode D3 is in parallel with alarm BZ.

3. double TL431 voltage monitoring circuit as claimed in claim 2, it is characterised in that described alarm BZ is buzzer.