CN103779839A - Automatic opening type starting circuit powered up by rechargeable battery - Google Patents

Abstract

The invention discloses a self-shutoff startup circuit powered by a rechargeable battery, comprising a rechargeable battery, a self-shutoff voltage regulator, an output voltage setting circuit, a current limiting resistor, a triode, and a load; wherein the output voltage The setting circuit is used to stably maintain the output voltage of the rechargeable battery at the set value; the current limiting resistor provides working current for the load by cooperating with the triode; the self-shutdown voltage regulator tube is used to provide the shutdown output voltage Control signal, when the output voltage of the rechargeable battery is lower than the self-shutdown voltage regulator input undervoltage protection, the control input load voltage is lower than the load's working voltage. The invention can effectively prevent over-discharge of the battery by adding a self-shutoff voltage stabilizing tube in the starting circuit, is suitable for the design of the starting circuit powered by a rechargeable battery, and has broad application prospects.

Description

A self-shutdown start-up circuit powered by a rechargeable battery

technical field

The invention relates to a self-shutdown starting circuit, in particular to the technical field of a rechargeable battery power supply system.

Background technique

With the popularity of portable electronic devices, electronic devices directly powered by rechargeable batteries have been widely used in various aspects of people's production and life.

With the increasing intelligence of electronic equipment, analog and digital chips are widely used in circuit design. Considering the volume and cost, the components required in the circuit are also limited. For low-cost, small-volume rechargeable battery-powered systems, issues such as battery life, cost, efficiency, and circuit protection should be considered comprehensively. The service life of rechargeable batteries is directly related to the degree of charge and discharge, which has strong nonlinear characteristics. As the discharge voltage varies, the battery terminal voltage and output current will vary greatly. At present, the cost and price of the battery charge and discharge management circuit with excellent performance are relatively high, which limits the application of the rechargeable battery protection circuit in low-cost occasions. Therefore, it is necessary to fully combine the working characteristics of the battery to study the control technology suitable for battery charge and discharge management in low-cost occasions.

The operating voltage of the starting circuit is set by the triode and the voltage stabilizing circuit to ensure the steady-state operating voltage required by the load IC circuit. It is widely used at low cost and has the advantages of simple control, high reliability, good stability and easy implementation. . This patent mainly improves the traditional start-up circuit to realize the control of the rechargeable battery power supply, prevent the battery from over-discharging and increase the service life.

Contents of the invention

The technical problem to be solved by the present invention is aimed at rechargeable battery-powered electronic equipment. In order to improve the service life of rechargeable batteries (lithium batteries, lead-acid batteries, etc.), a low-cost, high-reliability battery power supply management method is proposed. Through Control the output working voltage of the starting circuit to avoid battery over-discharge.

The present invention adopts the following technical solutions for solving the problems of the technologies described above:

The invention proposes a self-shutoff starting circuit powered by a rechargeable battery, including a rechargeable battery, a self-shutoff voltage regulator, an output voltage setting circuit, a current limiting resistor, and a triode; One end of the current resistance is connected to the collector of the triode; the other end of the current limiting resistor is connected to the cathode of the self-shutoff voltage regulator tube, and the anodes of the self-shutoff voltage regulator tube are connected to the output voltage setting circuit respectively. The input end and the base of the triode; the emitter of the triode are respectively connected to the output end of the output voltage setting circuit and one end of the load; the other end of the load is grounded.

When the voltage of the rechargeable battery is lower than the voltage of the self-shutoff voltage regulator tube, the self-shutoff voltage regulator tube blocks the operation of the start-up circuit, and the voltage at the output terminal of the start-up circuit is approximately 0;

When the voltage of the rechargeable battery minus the voltage of the self-shutdown voltage regulator tube is less than the normal working voltage required by the load, the output voltage of the start-up circuit is the rechargeable battery voltage minus the working voltage of the self-shutdown voltage regulator tube;

When the voltage of the rechargeable battery minus the self-shutdown voltage regulator tube voltage is greater than the normal operating voltage required by the load, the output voltage setting circuit keeps the output voltage of the starting circuit stable at the set value and provides it to the load.

As a further optimization scheme of the self-shutdown startup circuit of the present invention, the output voltage setting circuit includes a first capacitor, a voltage stabilizing chip TL431, a second resistor, a third resistor, and a voltage stabilizing capacitor; wherein, the self-shutoff The anode of the voltage regulator tube is respectively connected to the cathode of the voltage regulator chip TL431, one end of the first capacitor and the base of the triode; the reference port of the voltage regulator chip TL431 is respectively connected to one end of the second resistor and one end of the third resistor; The emitter of the triode is respectively connected to the other end of the second resistor, one end of the voltage stabilizing capacitor and one end of the load; the other end of the load, the other end of the voltage stabilizing capacitor, the other end of the third resistor, and the voltage stabilizing chip TL431 The anode of the first capacitor and the other end of the first capacitor are respectively connected to the negative pole of the rechargeable battery and then grounded.

As a further optimization scheme of the self-shutdown startup circuit of the present invention, the output voltage setting circuit includes a first capacitor, a second voltage regulator tube, and a voltage regulator capacitor; wherein, the anodes of the self-shutoff voltage regulator tubes are respectively Connect one end of the first capacitor, the cathode of the second voltage stabilizing tube and the base of the triode; the emitter of the triode is respectively connected to one end of the stabilizing capacitor and one end of the load; the other end of the load, the other end of the stabilizing capacitor One end, the anode of the second regulator tube and the other end of the first capacitor are respectively connected to the negative pole of the rechargeable battery and then grounded.

As a further optimization scheme of the self-shutdown startup circuit of the present invention, the load is an analog IC chip or a digital IC chip.

As a further optimization scheme of the self-shutdown starting circuit of the present invention, the rechargeable battery is a lithium battery or a lead-acid battery or other types of rechargeable and discharging batteries.

Compared with the prior art, the present invention adopts the above technical scheme and has the following technical effects:

In the invention, by adding a voltage-stabilizing tube in the start-up circuit, the start-up circuit no longer provides the working voltage required by the IC chip load when the battery is lower than a certain voltage, thereby effectively preventing over-discharge of the battery. The invention has the advantages of less circuit components and low cost, and judges whether the output voltage of the starting circuit is a stable value by monitoring the input voltage of the battery. Through the control of the self-shutoff voltage regulator tube, it is beneficial to prevent the battery from over-discharging. This circuit is suitable for the design of rechargeable battery-powered starting circuit and has broad application prospects.

Description of drawings

Fig. 1 is a schematic diagram of the principle framework of a preferred embodiment of the present invention.

Fig. 2 is a schematic diagram of the voltage change of the starting circuit when the battery voltage changes.

Fig. 3 is a schematic diagram of an implementation method of another embodiment of the present invention.

Detailed ways

Below in conjunction with accompanying drawing, technical scheme of the present invention is described in further detail:

As shown in Fig. 1, it provides a schematic framework diagram of a preferred embodiment of the present invention. The V1 is a rechargeable battery, which can be lithium or lead-acid. R1 is a current-limiting resistor, which can be used in conjunction with Q1 to set the maximum operating current that can be provided to the load R4; Z1 is a self-shutdown voltage regulator tube, used to set the battery over-discharge protection voltage point. Capacitor C1, voltage stabilizing chip U1, resistor R2 and resistor R3 are the output voltage setting circuit to form a stable voltage on the load R4; C2 is the voltage stabilizing capacitor; R4 is the load of the startup circuit, which can be a digital microcontroller such as or analog chips.

When V1<Z1, the voltage at the output terminal of the start-up circuit is 0, and no power consumption is generated, as shown in Figure 2 in the first stage.

When V1-Z1<the working voltage of the digital or analog load chip IC, the output voltage of the start-up circuit cannot meet the normal operation of the digital or analog IC chip, and the required current is an extremely low leakage current. The second stage is shown in Figure 2.

When V1-Z1>the working voltage of the digital or analog load chip IC, the output terminal of the start-up circuit establishes a stable voltage, and the digital IC such as the single-chip microcomputer can work normally, such as +5V. The start-up circuit provides the tens of mA current required for steady-state operation. The third stage is shown in Figure 2.

As shown in Figure 2, when the battery voltage changes, the schematic diagram of the voltage change of the start-up circuit shows that only when the battery voltage is higher than a certain value, the output voltage of the start-up circuit is the stable voltage value required by the digital chip. When the input voltage is lower than 6V, the output voltage of the startup circuit is approximately 0. When the input voltage varies from 6V to 11V, the output voltage of the start-up circuit rises linearly, but it is lower than the steady-state working voltage of the digital chip, and the digital chip does not work, so the power consumption of the start-up circuit is extremely low. Only when the input voltage is higher than 11V, the output voltage of the start-up circuit can establish a stable value, and the digital chip can work normally. Therefore, through such a method, the discharge voltage of the battery can be controlled to prevent the over-discharge of the battery from affecting the service life. Of course, the input voltage point required for the stable operation of the startup circuit can be set arbitrarily by the value of the self-shutdown voltage regulator Z1 in FIG. 1 .

As shown in FIG. 3 , it shows a schematic diagram of a self-shutdown starting circuit of another example of the present invention. The V1 is a rechargeable battery, which can be lithium or lead-acid. R1 is a current limiting resistor, which can be used in conjunction with Q1 tube to set the maximum operating current that can be provided to the load R2; Z1 is a self-shutdown voltage regulator tube, used to set the battery over-discharge protection voltage point. Capacitor C1 and voltage regulator tube Z2 are the output voltage setting circuit to form a stable voltage on the load R2; C2 is the voltage stabilizing capacitor; R2 is the load of the startup circuit, which can be a digital or analog chip such as a single-chip microcomputer.

The specific parameters of the preferred example of the present invention are as follows:

The undervoltage protection point of the rechargeable battery is 11VDC; the output voltage set by the starting circuit is 4.5VDC; the output current is 50mA; the output filter capacitor C2 is 2μF; the self-shutoff voltage regulator Z1 is a 6.2V regulator, and the current limiting resistor R1 It is 1K; the power transistor Q1 is 2SD882; the filter capacitor C1 is 0.1μF, U1 is TL431, R2 is 7K, R3 is 10K; R4 is the load, which is essentially a digital chip or an analog chip such as a single-chip microcomputer with a certain steady-state working voltage requirement.

Claims (6)

1. the start-up circuit of shutoff certainly that adopts rechargeable battery power supply, is characterized in that: comprise rechargeable battery, from shutoff voltage voltage-stabiliser tube, output voltage initialization circuit, current-limiting resistance, triode; The positive pole of rechargeable battery is connected with one end of current-limiting resistance, the collector electrode of triode respectively; The other end of described current-limiting resistance be connected from the negative electrode of shutoff voltage voltage-stabiliser tube, the described anode from shutoff voltage voltage-stabiliser tube connects respectively the input of output voltage initialization circuit, the base stage of triode; The emitter of described triode connects respectively the output of output voltage initialization circuit, one end of load; The other end ground connection of load.

2. a kind of start-up circuit of shutoff certainly that adopts rechargeable battery power supply according to claim 1, is characterized in that: described output voltage initialization circuit comprises the first electric capacity (C1), voltage stabilizing chip (U1), the second resistance (R2), the 3rd resistance (R3), electric capacity of voltage regulation (C2); Wherein, the described anode from shutoff voltage voltage-stabiliser tube (Z1) connects respectively negative electrode, one end of the first electric capacity (C1) and the base stage of triode (Q1) of voltage stabilizing chip (U1); The benchmark port of described voltage stabilizing chip (U1) is connected with one end of the second resistance (R2), one end of the 3rd resistance (R3) respectively; The emitter of described triode (Q1) connects respectively the other end, one end of electric capacity of voltage regulation (C2) and one end of load (R4) of the second resistance (R2); Ground connection after the other end, the anode of voltage stabilizing chip (U1) and the other end of the first electric capacity (C1) of the other end of described load (R4), the other end of electric capacity of voltage regulation (C2), the 3rd resistance (R3) is connected with the negative pole of rechargeable battery (V1) respectively.

3. a kind of start-up circuit of shutoff certainly that adopts rechargeable battery power supply according to claim 2, is characterized in that: the model of described voltage stabilizing chip (U1) is TL431.

4. a kind of start-up circuit of shutoff certainly that adopts rechargeable battery power supply according to claim 1, is characterized in that: described output voltage initialization circuit comprises the first electric capacity (C1), the second voltage-stabiliser tube (Z2) and electric capacity of voltage regulation (C2); Wherein, the described anode from shutoff voltage voltage-stabiliser tube (Z1) connects respectively one end, the negative electrode of the second voltage-stabiliser tube (Z2) and the base stage of triode (Q1) of the first electric capacity (C1); The emitter of described triode (Q1) connects respectively one end of electric capacity of voltage regulation (C2) and one end of load (R2); Ground connection after the other end of described load (R2), the other end of electric capacity of voltage regulation (C2), the anode of the second voltage-stabiliser tube (Z2) and the other end of the first electric capacity (C1) are connected with the negative pole of rechargeable battery (V1) respectively.

5. according to the arbitrary described a kind of start-up circuit of shutoff certainly that adopts rechargeable battery power supply of claim 1 to 4, it is characterized in that: described load is analog IC chip or digital IC chip.

6. according to the arbitrary described a kind of start-up circuit of shutoff certainly that adopts rechargeable battery power supply of claim 1 to 4, it is characterized in that: described rechargeable battery is that lithium battery or lead-acid battery or other types discharge and recharge battery.

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