CN218216768U - Overcharge-proof device of charging test instrument - Google Patents
Overcharge-proof device of charging test instrument Download PDFInfo
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- CN218216768U CN218216768U CN202222685801.9U CN202222685801U CN218216768U CN 218216768 U CN218216768 U CN 218216768U CN 202222685801 U CN202222685801 U CN 202222685801U CN 218216768 U CN218216768 U CN 218216768U
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Abstract
The utility model discloses the overcharge device is prevented to the charge test instrument, the main circuit that charges receives charger output, switch on at thyristor VS1, when field effect transistor T1 switches on, battery P1 is charged, the charging current when charging of battery P1 that the threshold value of charging predetermines the circuit and receives current sensor detection, through converting into voltage, trigger thyristor VS2 switches on, charger output is the pressure regulating in advance, prevent overcharging, when battery P1 charging voltage is low or high, thyristor VS1 switches on or ends, prevent battery P1 overcharge, the temperature when overheat detection circuit detects battery P1 and charges, through calculating with the temperature threshold difference, the internal resistance of battery P1 that the thermoelectric voltage changes the charger and charges, turn-off protection circuit passes through the integrator and carries out the integral calculation to charging current respectively, the temperature when charging current is little, when the charging temperature is high, trigger field effect transistor T1 and turn-off fast, when the battery is full of electricity, can cut off fast, the reliability of preventing overcharging action has further been improved.
Description
Technical Field
The utility model relates to an experimental apparatus technical field, especially the overcharge device is prevented to test instrument that charges.
Background
The portable testing instrument is applied to various fields due to the characteristics of small volume, light weight, portability, flexibility, safety and the like, the portable testing instrument is usually supplied with power by a built-in storage battery, each instrument is provided with a charger special for the instrument, some chargers are independent, some chargers are integrated inside the testing instrument, the storage battery has strict requirements when being charged, the storage battery can not be overcharged or undercharged, overcharging not only wastes energy, but also easily causes the damage of the built-in storage battery, and the undercharging can influence the capacity of the battery.
In the prior art, generally, the temperature during charging is detected, when the temperature is abnormal, the power supply is cut off by a manual control switch to prevent overcharging, or the charging time is controlled to cut off the power supply to prevent overcharging when the charging time reaches (for example, a portable test equipment charging time controller with the application number of 201220128669.5), the former marks a parameter of overcharging characteristics through the temperature index to be used as a judgment basis, the control is influenced by the environmental temperature, the control has hysteresis, and the latter has the problems that the power supply is unstable and the storage battery parameters are different, the charging time is different, the reliability of the two is not high enough, the undercharging or the overcharging is caused, and the service life of the charger is influenced.
SUMMERY OF THE UTILITY MODEL
Not enough to prior art exists, the utility model aims at providing a test instrument that charges prevents overcharging device, the effectual prior art that has solved prevents overcharging and judges the not high enough problem of reliability.
The technical scheme for solving the problem is that the device comprises a charging main circuit, a charging threshold pre-judging circuit, an overheat detection circuit and a turn-off protection circuit, wherein the charging main circuit is respectively connected with the charging threshold pre-judging circuit, the overheat detection circuit and the turn-off protection circuit, and the turn-off protection circuit is respectively connected with the charging threshold pre-judging circuit and the overheat detection circuit.
Preferably, the turn-off protection circuit includes a resistor R6, one end of the resistor R6 is connected to the output end of the operational amplifier AR1, the other end of the resistor R6 is connected to one end of the capacitor C1 and the inverting input end of the operational amplifier AR2, the non-inverting input end of the operational amplifier AR2 is connected to ground, the output end of the operational amplifier AR2 is connected to the other end of the capacitor C1 and the pin 2 of the photocoupler U1, the pin 1 of the photocoupler U1 is connected to the output end of the operational amplifier AR3 and one end of the capacitor C2, the non-inverting input end of the operational amplifier AR3 is connected to ground, the inverting input end of the operational amplifier AR3 is connected to the other end of the capacitor C2 and one end of a resistor R14, the other end of the resistor R14 is connected to the positive electrode of the regulator tube Z3, the pin 3 of the photocoupler U1 is connected to the base of the triode Q2, the pin 4 of the photocoupler U1 is connected to the power supply +5V, the emitter of the triode Q2 is connected to ground, the collector of the triode Q2 is connected to one end of the resistor R9 is connected to the gate of the field effect tube T1.
The utility model has the advantages that:
1, threshold judgment is respectively carried out through charging current, temperature and charging voltage during charging, and when overcharging occurs, a thyristor VS1 is triggered to automatically disconnect a charging circuit and a field effect transistor T1 drain-source resistance changes the internal resistance of a storage battery charged by a charger, so that overcharging is prevented, automatic protection is realized, and reliability is high;
2, carry out the integral calculation to charging current, temperature when charging respectively through the integrator, add photoelectric coupler U1's input, when charging current is little, charging temperature is high, photoelectric coupler U1 switches on, triode Q1 switches on, triggers field effect transistor T1 and turns off fast, realizes when the battery is full of the electricity, can cut off the power supply fast, has further improved the reliability of preventing the overcharge action.
Drawings
Fig. 1 is a diagram of a main charging circuit of the present invention.
Fig. 2 is the circuit diagram for pre-judging the charging threshold of the present invention.
Fig. 3 is a circuit diagram of the overheat detection circuit of the present invention.
Fig. 4 is a circuit diagram of the turn-off protection circuit of the present invention.
Detailed Description
The foregoing and other technical and other features and advantages of the invention will be apparent from the following more particular description of the embodiments of the invention, as illustrated in the accompanying drawings in which reference is made to figures 1 to 4. The structural contents mentioned in the following embodiments are all referred to the attached drawings of the specification.
Exemplary embodiments of the present invention will be described below with reference to the accompanying drawings.
The overcharge-preventing device for the charge test instrument comprises a main charge circuit, a charge threshold pre-judging circuit, an overheat detection circuit and an off-state protection circuit, wherein the main charge circuit receives a power supply output by a charger, the positive electrode of the power supply is added to the positive electrode of a storage battery P1 through a thyristor VS1, the negative electrode of the storage battery P1 is connected to the negative electrode of the power supply through the drain-source electrode of a field effect tube T1, when the thyristor VS1 is switched on and the field effect tube T1 is switched on, the storage battery P1 is charged, the thyristor VS1 and the field effect tube T1 are controlled by the off-state protection circuit, the charge threshold pre-judging circuit and the overheat detection circuit, in particular, the charge threshold pre-judging circuit receives a charge current detected by a current sensor when the storage battery P1 is charged, the charge current is converted into a voltage through a current-voltage converter, when the charge current does not reach a threshold of 90%, a voltage regulator Z2 and the thyristor VS2 is cut off, when the charge current reaches the threshold of 90%, the voltage regulator Z2 breaks down, the thyristor VS2 is conducted, the output power supply of the charger is regulated in advance to prevent overcharge, when the charging voltage of the storage battery P1 is low, the thyristor VS1 is conducted, when the charging voltage of the storage battery P1 is high, the voltage regulator tube Z1 clamps, the current of the resistor R2 is reversed, the thyristor VS1 is cut off to prevent the overcharge of the storage battery P1, the overheat detection circuit detects the temperature of the storage battery P1 during charging through the thermistor RT1, when the temperature is higher than a temperature threshold value by 90 percent, the voltage regulator tube Z3 breaks down, the voltage is added to the non-inverting input end of the operational amplifier AR4 through charging and is operated with the temperature threshold value difference value of the inverting input end, when the temperature during charging is higher than the threshold value, the voltage with a positive output difference value is large, the voltage is added to the grid electrode of the field effect tube T1 through reverse charging, the resistance value between the drain and the source of the field effect tube T1 is changed through the temperature difference voltage, the internal resistance value of the storage battery P1 charged by the charger is changed, and the turn-off protection circuit respectively conducts the charging current through the integrator, the temperature during charging carries out integral calculation, adds to photoelectric coupler U1's input, and charging current is little, when charging temperature is high, photoelectric coupler U1 switches on, triode Q1 switches on, triggers field effect transistor T1 and switches off fast, realizes when the battery is full of the electricity, can cut off the power supply fast, has further improved the reliability of preventing overcharging action.
On the basis of the scheme, the charging main circuit receives an output power supply of a charger, the positive pole of the power supply is added to the positive pole of a storage battery P1 through a thyristor VS1, the negative pole of the storage battery P1 is connected to the negative pole of the power supply through the drain-source pole of a field effect transistor T1, when the thyristor VS1 is conducted and the field effect transistor T1 is conducted, the storage battery P1 is charged, specifically, when the charging current does not reach a threshold value, the thyristor VS2 is cut off and does not work, when the charging voltage of the storage battery P1 is low, the thyristor VS1 is conducted, when the charging voltage of the storage battery P1 is high, a voltage stabilizing tube Z1 clamps, the current of a resistor R2 is reversed, the thyristor VS1 is cut off to prevent the storage battery P1 from being overcharged, when the temperature of the field effect transistor T1 during charging is lower than the threshold value, the voltage stabilizing tube Z4 does not work, and the field effect transistor T1 is in a conducting state by +2.7V, the storage battery P1 is normally charged, when the temperature during charging is higher than a threshold value, the temperature difference voltage changes the resistance value between the drain and the source of the field effect transistor T1, the internal resistance of the storage battery P1 charged by a charger is changed, overcharge is prevented, automatic protection and high reliability are achieved, the storage battery P comprises a thyristor VS1, the cathode of the thyristor VS1 is respectively connected with one end of a resistor R1 and the cathode of a thyristor VS2, the other end of the resistor R1 is respectively connected with the cathode of a voltage stabilizing tube Z1 and one end of a resistor R2, the anode of the thyristor VS1 is respectively connected with the other end of the resistor R2 and the anode of the storage battery P1, the cathode of the storage battery P1 is connected with the drain of the field effect transistor T1, and the source of the field effect transistor T1, the anode of the voltage stabilizing tube Z1 and the anode of the thyristor VS2 are connected with the ground.
On the basis of the scheme, the charging threshold pre-judging circuit receives charging current detected by a current sensor when a storage battery P1 is charged, the charging current is converted into voltage through a current-voltage converter consisting of an operational amplifier AR1 and a resistor R3-a resistor R5, when the charging current does not reach a threshold value of 90%, a voltage stabilizing tube Z2 does not work, a thyristor VS2 is cut off, when the charging current reaches the threshold value of 90%, the voltage stabilizing tube Z2 breaks down, the thyristor VS2 is conducted, a charger output power supply is regulated in advance, overcharge is prevented, when the charging voltage of the storage battery P1 is low, the thyristor VS1 is conducted, when the charging voltage of the storage battery P1 is high, the thyristor Z1 clamps, the current of the resistor R2 is reversed, the VS1 is cut off, the overcharge of the storage battery P1 is prevented, the charging current pre-judging circuit comprises the operational amplifier AR1, the non-inverting input end of the operational amplifier AR1 and one end of a grounding resistor R3 are connected with charging current signals, the inverting input end of the operational amplifier AR1 is respectively connected with one end of a grounding resistor R4 and one end of the resistor R5, the negative electrode of the positive electrode of the thyristor Z2 is connected with the other end of the resistor R5, and the negative electrode of the positive electrode of the voltage stabilizing tube VS 2.
On the basis of the scheme, the overheat detection circuit detects the temperature of the storage battery P1 during charging through a thermistor RT1, when the temperature is higher than a temperature threshold value by 90%, a voltage-regulator tube Z3 is broken down, the temperature is charged through a resistor R12 and an electrolytic capacitor E2 and then is added to the non-inverting input end of an operational amplifier AR4, the temperature difference value of the temperature and the threshold value of the inverting input end is calculated, when the temperature during charging is higher than the threshold value and the output positive difference value voltage is large, the voltage is reversely charged through the voltage-regulator tube Z4, a resistor R8 and the electrolytic capacitor E1 and is added to the grid electrode of a field-effect tube T1, the resistance value between the drain and the source of the field-effect tube T1 is changed through the temperature difference voltage, the internal resistance of the storage battery P1 charged by a charger is changed, the internal resistance of the thermistor RT1 is provided, one end of the thermistor RT1 is connected with a power supply of +2.7V, the other end of the thermistor RT1 is respectively connected with one end of a grounding resistor R10, one end of a grounding capacitor C3, one end of a resistor R11 and the negative electrode of a voltage-regulator tube Z3, the positive electrode of the voltage-regulator tube Z3 is respectively connected with the other end of the resistor R11 and one end of a resistor R12, the other end of the resistor R12 is respectively connected with the positive electrode of an electrolytic capacitor E2 and the inverting input end of an operational amplifier AR4, the non-inverting input end of the operational amplifier AR4 is connected with a temperature threshold signal, the output end of the operational amplifier AR4 is respectively connected with one end of a resistor R13 and the negative electrode of the voltage-regulator tube Z4, the other end of the resistor R13 is respectively connected with the positive electrode of the voltage-regulator tube Z4, one end of a resistor R8 and the negative electrode of the electrolytic capacitor E1, and the other end of the resistor R8 is respectively connected with one end of a resistor R7 and the grid electrode of the field effect tube T1.
On the basis of the scheme, the turn-off protection circuit respectively carries out integral calculation on the charging current and the temperature during charging through an integrator consisting of an operational amplifier AR3, a capacitor C2 and a resistor R12 and an integrator consisting of an operational amplifier AR2, a capacitor C1 and a resistor R6, the integration calculation is added to the input end of a photoelectric coupler U1, when the charging current is small and the charging temperature is high, the photoelectric coupler U1 is switched on, a triode Q1 is switched on, and a field effect tube T1 is triggered to be rapidly turned off, so that the power can be rapidly cut off when the storage battery is fully charged, the reliability of the over-charging prevention action is further improved, the turn-off protection circuit comprises a resistor R6, one end of the resistor R6 is connected with the output end of the operational amplifier AR1, the other end of the resistor R6 is respectively connected with one end of the capacitor C1 and the inverting input end of the operational amplifier AR2, the in-phase input end of the operational amplifier AR2 is connected to the ground, the output end of the operational amplifier AR2 is connected to the other end of the capacitor C1 and a pin 2 of the photoelectric coupler U1, a pin 1 of the photoelectric coupler U1 is connected to the output end of the operational amplifier AR3 and one end of the capacitor C2, the in-phase input end of the operational amplifier AR3 is connected to the ground, the reverse-phase input end of the operational amplifier AR3 is connected to the other end of the capacitor C2 and one end of the resistor R14, the other end of the resistor R14 is connected to the positive electrode of the voltage regulator tube Z3, a pin 3 of the photoelectric coupler U1 is connected to the base electrode of the triode Q2, a pin 4 of the photoelectric coupler U1 is connected to the +5V power supply, the emitter of the triode Q2 is connected to the ground, the collector of the triode Q2 is connected to one end of the resistor R9, and the other end of the resistor R9 is connected to the grid electrode of the field effect tube T1.
The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be regarded as equivalent replacements within the scope of the present invention.
Claims (5)
1. The anti-overcharging device of the charging test instrument comprises a charging main circuit, a charging threshold pre-judging circuit, an overheating detection circuit and a turn-off protection circuit, and is characterized in that the charging main circuit is respectively connected with the charging threshold pre-judging circuit, the overheating detection circuit and the turn-off protection circuit, and the turn-off protection circuit is respectively connected with the charging threshold pre-judging circuit and the overheating detection circuit.
2. The overcharge protection device of claim 1, wherein the main charging circuit includes a thyristor VS1, a cathode of the thyristor VS1 is connected to one end of a resistor R1 and a cathode of the thyristor VS2, respectively, another end of the resistor R1 is connected to a negative electrode of a voltage regulator tube Z1 and one end of a resistor R2, respectively, an anode of the thyristor VS1 is connected to another end of the resistor R2 and an anode of a storage battery P1, a negative electrode of the storage battery P1 is connected to a drain of a field effect tube T1, and a source of the field effect tube T1, an anode of the voltage regulator tube Z1 and an anode of the thyristor VS2 are connected to ground.
3. The overcharge protection device of the charging test instrument of claim 1, wherein the charging threshold pre-determining circuit includes an operational amplifier AR1, a non-inverting input terminal of the operational amplifier AR1 and one end of a ground resistor R3 are connected to the charging current signal, an inverting input terminal of the operational amplifier AR1 is connected to one end of a ground resistor R4 and one end of a resistor R5, respectively, an output terminal of the operational amplifier AR1 is connected to the other end of the resistor R5 and a negative electrode of a voltage regulator tube Z2, respectively, and a positive electrode of the voltage regulator tube Z2 is connected to a control electrode of a thyristor VS 2.
4. The overcharge protection device for the charge test instrument according to claim 1, wherein the overheat detection circuit comprises a thermistor RT1, one end of the thermistor RT1 is connected to +2.7V, the other end of the thermistor RT1 is connected to one end of a ground resistor R10, one end of a ground capacitor C3, one end of a resistor R11, and a negative electrode of a regulator tube Z3, an anode of the regulator tube Z3 is connected to the other end of the resistor R11 and one end of a resistor R12, the other end of the resistor R12 is connected to an anode of an electrolytic capacitor E2 and a negative-phase input end of an operational amplifier AR4, a non-inverting-phase input end of the operational amplifier AR4 is connected to a temperature threshold signal, an output end of the operational amplifier AR4 is connected to one end of a resistor R13 and a negative electrode of the regulator tube Z4, the other end of the resistor R13 is connected to an anode of the regulator tube Z4, one end of a resistor R8 and a negative electrode of the electrolytic capacitor E1, and the other end of the resistor R8 is connected to one end of the resistor R7 and a gate of the field effect transistor T1.
5. The overcharge protection device of claim 1, wherein the turn-off protection circuit includes a resistor R6, one end of the resistor R6 is connected to an output terminal of the operational amplifier AR1, the other end of the resistor R6 is connected to one end of the capacitor C1 and an inverting input terminal of the operational amplifier AR2, a non-inverting input terminal of the operational amplifier AR2 is connected to ground, an output terminal of the operational amplifier AR2 is connected to the other end of the capacitor C1 and a pin 2 of the photocoupler U1, the pin 1 of the photocoupler U1 is connected to an output terminal of the operational amplifier AR3 and an end of the capacitor C2, a non-inverting input terminal of the operational amplifier AR3 is connected to ground, the inverting input terminal of the operational amplifier AR3 is connected to the other end of the capacitor C2 and the one end of the resistor R14, the other end of the resistor R14 is connected to an anode of the stabilivolt Z3, the pin 3 of the photocoupler U1 is connected to a base of the triode Q2, the pin 4 of the photocoupler U1 is connected to a +5V, an emitter of the triode Q2 is connected to ground, a collector of the triode Q2 is connected to one end of the resistor R9, and a gate of the fet T1 is connected to a gate of the fet.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202222685801.9U CN218216768U (en) | 2022-10-12 | 2022-10-12 | Overcharge-proof device of charging test instrument |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202222685801.9U CN218216768U (en) | 2022-10-12 | 2022-10-12 | Overcharge-proof device of charging test instrument |
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| Publication Number | Publication Date |
|---|---|
| CN218216768U true CN218216768U (en) | 2023-01-03 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202222685801.9U Active CN218216768U (en) | 2022-10-12 | 2022-10-12 | Overcharge-proof device of charging test instrument |
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| Country | Link |
|---|---|
| CN (1) | CN218216768U (en) |
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- 2022-10-12 CN CN202222685801.9U patent/CN218216768U/en active Active
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