Charging protection system for electric power operation recorder

Abstract

The utility model relates to the technical field of electric power instruments, and provides an electric power operation recorder charging protection system, which comprises an MOS tube Q2, a resistor R13, a resistor R14, a resistor R15 and a capacitor C2, the first end of the resistor R13 is connected with a switching power supply, the second end of the resistor R13 is grounded through the resistor R14, the capacitor C2 is connected in parallel with the resistor R14, the drain electrode of the MOS tube Q2 is connected with the switching power supply, and the drain electrode of the MOS tube Q2 is connected with the switching power supply. The source electrode of the MOS tube Q2 is connected with the host battery, and the grid electrode of the MOS tube Q2 is connected with the second end of the resistor R13 through the resistor R15. According to the technical scheme, the charging current is controlled, and the problem of peak current impact caused by frequent plugging and unplugging of a power supply is avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of electric power instruments, and in particular to a charging protection system for an electric power operation recorder. Background Art

[0002] Due to the rapid development of society, the demand for electricity in production and life is increasing. In order to ensure the normal and stable operation of the transmission lines, the staff must conduct regular inspections of the transmission lines. Line inspection is an important part of the safe production of power companies. If the line inspection is done effectively, defects in the equipment can be discovered in time, and major accidents can be avoided by handling them as soon as possible. Most of the existing power collection points are located in remote areas, and inspection vehicles cannot enter. Only staff can carry power recorders to enter for inspection.

[0003] At present, power recorders are usually charged using a universal serial bus (USB) interface, which may cause repeated unplugging and plugging of the USB port. Since there are multiple detection currents in the power recorder, there are capacitive devices inside. When plugged into the USB port, a rapid and large increase in current will be generated, resulting in a current overshoot problem. When the peak current is too large, the power recorder will be damaged. Utility Model Content

[0004] The utility model provides a charging protection system for an electric power operation recorder, which solves the problem in the prior art that the electric power recorder is damaged by the peak current during charging.

[0005] The technical solution of the utility model is as follows:

[0006] The charging protection system of the electric power operation recorder comprises a peak current buffer circuit, wherein the input end of the peak current buffer circuit is connected to a switching power supply, and the output end of the peak current buffer circuit is connected to a host battery.

[0007] The peak current buffer circuit includes a MOS tube Q2, a resistor R13, a resistor R14, a resistor R15 and a capacitor C2, wherein a first end of the resistor R13 is connected to a switching power supply, a second end of the resistor R13 is grounded through the resistor R14, the capacitor C2 is connected in parallel to the resistor R14, a drain of the MOS tube Q2 is connected to a switching power supply, a source of the MOS tube Q2 is connected to the host battery, and a gate of the MOS tube Q2 is connected to the second end of the resistor R13 through the resistor R15.

[0008] The working principle and beneficial effects of the utility model are:

[0009] In the utility model, when the switch power supply is turned on and charging begins, since the voltage across the capacitor C2 cannot change suddenly, the gate voltage of the MOS tube Q2 is clamped at 0V, and the MOS tube Q2 is cut off, and the host battery is not charged at this time. As the input voltage charges the capacitor C2 through the resistor R13, the gate voltage of the MOS tube Q2 gradually increases. After reaching the turn-on voltage, the MOS tube Q2 is turned on. As the charging voltage of the capacitor C2 continues to increase, the MOS tube Q2 is fully turned on and enters a normal charging state. The peak current buffer circuit adjusts the rising slope of the gate voltage of the MOS tube Q2 through the values ​​of the resistors R13, R14 and the capacitor C2, controls the size of the charging current, and avoids the peak current impact problem caused by frequent plugging and unplugging of the power supply.

[0010] The utility model is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 A circuit diagram of a peak current buffer circuit in the utility model;

[0012] Figure 2 It is a circuit diagram of the switch control branch in the utility model;

[0013] Figure 3 This is a circuit diagram of the voltage detection branch in the utility model;

[0014] Figure 4 This is a circuit diagram of the current detection branch in the utility model. DETAILED DESCRIPTION

[0015] The following will be combined with the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0016] Example 1

[0017] This embodiment proposes a charging protection system for an electric power operation recorder, including a peak current buffer circuit, wherein the input end of the peak current buffer circuit is connected to a switching power supply, and the output end of the peak current buffer circuit is connected to a host battery.

[0018] like Figure 1As shown, the peak current buffer circuit includes a MOS tube Q2, a resistor R13, a resistor R14, a resistor R15 and a capacitor C2, the first end of the resistor R13 is connected to the switching power supply, the second end of the resistor R13 is grounded through the resistor R14, the capacitor C2 is connected in parallel to the resistor R14, the drain of the MOS tube Q2 is connected to the switching power supply, the source of the MOS tube Q2 is connected to the host battery, and the gate of the MOS tube Q2 is connected to the second end of the resistor R13 through the resistor R15.

[0019] In this embodiment, the MOS tube Q2 is an N-channel MOSFET field effect tube, the resistors R13 and R14 are voltage-dividing resistors, R15 is a current-limiting resistor, and C2 is a charging capacitor. When the switch power supply is turned on and charging begins, since the voltage across the capacitor C2 cannot change suddenly, the gate voltage of the MOS tube Q2 is clamped at 0V, and the MOS tube Q2 is cut off, and the host battery is not charged at this time. As the input voltage charges the capacitor C2 through the resistor R13, the gate voltage of the MOS tube Q2 gradually increases. After reaching the turn-on voltage, the MOS tube Q2 is turned on. As the charging voltage of the capacitor C2 continues to increase, the MOS tube Q2 is fully turned on and enters a normal charging state. The peak current buffer circuit adjusts the rising slope of the gate voltage of the MOS tube Q2 through the values ​​of the resistors R13, R14 and the capacitor C2, controls the size of the charging current, and avoids the peak current impact problem caused by frequent plugging and unplugging of the power supply.

[0020] Further, if Figure 1 As shown, the peak current buffer circuit further includes a Zener diode D3, a cathode of the Zener diode D3 is connected to the second end of the resistor R13, and an anode of the Zener diode D3 is grounded.

[0021] In this embodiment, the function of the voltage stabilizing diode D3 is to maintain the on-state voltage of the gate after the MOS tube is turned on and enters the normal charging state, thereby further maintaining the stability of the peak current buffer circuit.

[0022] Furthermore, this embodiment also includes a charging control circuit, which includes a voltage detection branch, a current detection branch and a switch control branch, the input end of the voltage detection branch is connected to the output end of the peak circuit buffer circuit, the output end of the voltage detection branch is connected to the first input end of the switch control branch, the input end of the current detection branch is connected to the output end of the peak circuit buffer circuit, the output end of the current detection branch is connected to the second input end of the switch control branch, and the output end of the switch control branch is used to control the switching power supply.

[0023] Further, if Figure 2As shown, the switch control branch includes a resistor R6, a resistor R7, a resistor R12, an operational amplifier U1.2 and an optical coupler U3, the non-inverting input terminal of the operational amplifier U1.2 serves as the first input terminal of the switch control branch, the first end of the resistor R6 serves as the second input terminal of the switch control branch, the second end of the resistor R6 is connected to the VCC power supply through the resistor R7, the second end of the resistor R6 is connected to the inverting input terminal of the operational amplifier U1.2, the output terminal of the operational amplifier U1.2 is connected to the first input terminal of the optical coupler U3 through the resistor U12, the second input terminal of the optical coupler U3 is grounded, and the output terminal of the optical coupler U3 is used to control the switching power supply.

[0024] In this embodiment, the charging state of the switching power supply is controlled by turning on and off the optocoupler U3. When the voltage signal received by the in-phase input terminal of the operational amplifier U1.2 from the voltage detection branch is greater than the voltage signal received by the inverting input terminal from the current detection branch, the operational amplifier U1.2 outputs a high level, driving the optocoupler U3 to conduct, and the output terminal of the optocoupler U3 stops charging by short-circuiting the switch power supply enable terminal. When the voltage signal received by the in-phase input terminal of the operational amplifier U1.2 from the voltage detection branch is less than the voltage signal received by the inverting input terminal from the current detection branch, the operational amplifier U1.2 outputs a low level, the optocoupler U3 is not turned on, and the normal charging state is maintained.

[0025] Further, if Figure 3 As shown, the voltage detection branch includes a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a capacitor C1, a voltage regulator diode D1 and an operational amplifier U1.1. The first end of the resistor R1 is connected to the output end of the peak current buffer circuit, the second end of the resistor R1 is grounded through the resistor R2, the capacitor C1 is connected in parallel to the resistor R2, the second end of the resistor R1 is connected to the non-inverting input end of the operational amplifier U1.1, the inverting input end of the operational amplifier U1.1 is connected to the reference voltage verf1, the output end of the operational amplifier U1.1 is connected to the first end of the resistor R4 through the resistor R3, the second end of the resistor R4 is grounded through the resistor R5, the cathode of the voltage regulator diode D1 is connected to the first end of the resistor R4, the anode of the voltage regulator diode D1 is grounded, and the second end of the resistor R4 is connected to the first input end of the switch control branch.

[0026] After entering the normal charging state, the charging voltage BAT_in2 output from the peak current buffer current to the host battery is added to the non-inverting input terminal of the operational amplifier U1.1 through the resistor R1 and R2 voltage divider, and the reference voltage verf1 is added to the inverting input terminal of the operational amplifier U1.1. Due to the existence of capacitor C1, the voltage at the non-inverting input terminal of the operational amplifier U1.1 will not change suddenly, but will be lower than the voltage at the inverting input terminal first. The operational amplifier U1.1 outputs a low level, the voltage zener diode D1 is cut off, and the voltage output to the first input terminal of the switch control branch through the resistor R4 and R5 voltage divider is 0. At this time, there is no voltage at the non-inverting input terminal of the operational amplifier U1.2, and the inverting input terminal is added to VCC through the resistor R7 to maintain the normal charging working state.

[0027] Further, if Figure 4 As shown, the current detection branch includes a current sensing resistor, a resistor R9, a resistor R10 and an operational amplifier U2.1. The current sensing resistor is connected in series between the output end of the peak current buffer circuit and the host battery. The first end of the current sensing resistor is connected to the non-inverting input end of the operational amplifier U2.1 through the resistor R10, the second end of the current sensing resistor is connected to the inverting input end of the operational amplifier U2.1 through the resistor R9, and the output end of the operational amplifier U2.1 is connected to the second input end of the switch control branch.

[0028] After entering the normal charging state, the host battery is first charged with a large current at a constant current. The voltage on the current-sensing resistor is amplified by the operational amplifier U2.1, so that the voltage at the inverting input terminal of the operational amplifier U2.2 is higher than the voltage at the non-inverting input terminal and a low-level signal is output. The transistor Q1 is cut off and has no effect on the voltage detection branch. Due to the constant current charging state, the output of the charging power supply BAT_in2 is less than the rated output voltage. This voltage is added to the non-inverting input terminal of the operational amplifier U1A through the resistor R1 and R5 voltage divider, but it is lower than the voltage at the inverting input terminal, so the charging process is still maintained.

[0029] As the charging time increases, the host battery voltage gradually rises, and the output voltage of the charging power supply rises accordingly. When the voltage reaches the rated voltage, the charging current decreases accordingly. At this time, the 28.5V output by the charging power supply is divided by R1 and R2 to make the voltage reference voltage verf1 at the non-inverting input of the op amp U1.1. The op amp U1.1 outputs a high level, driving the voltage zener diode D1 to turn on. After the voltage is divided by resistors R4 and R5, it is added to the non-inverting input of U1.2. However, since the charging current is greater than 0.5A, the voltage output by the op amp U2.1 makes the inverting input of the op amp U1.2 still greater than the non-inverting input, so the charging process is still maintained.

[0030] After that, it enters the trickle charging state. As time goes by, the charging current gradually decreases. When the current is less than 0.5A, the output voltage of op amp U2.1 makes the inverting input terminal of op amp U1.2 smaller than the non-inverting input terminal. Then op amp U1.2 outputs a high level, and the optocoupler U3 works, turning off the charging state, and charging ends.

[0031] Further, if Figure 4 As shown, the current detection branch also includes a resistor R8, a resistor R11, an operational amplifier U2.2 and a transistor Q1. The inverting input terminal of the operational amplifier U2.2 is connected to the output terminal of the operational amplifier U2.1 through the resistor R8, the non-inverting input terminal of the operational amplifier U2.2 is connected to the reference voltage verf2, the output terminal of the operational amplifier U2.1 is connected to the base of the transistor Q1 through the resistor R11, the emitter of the transistor Q1 is grounded, and the collector of the transistor Q1 is connected to the second end of the resistor R1.

[0032] When the host battery is not properly connected to the circuit due to human error or contact failure, the charging current is zero because the battery is not connected, so the voltage on the current-sense resistor representing the charging current is also zero, that is, the input voltage of op amp U2.1 is zero. This voltage is applied to the inverting input of op amp U2.2, which is less than the reference voltage verf2 at the non-inverting input. Op amp U2.2 outputs a high level, driving transistor Q1 to turn on, and grounding the non-inverting input of op amp U1.1. The same working principle as above still ensures the normal output of the switching power supply.

[0033] In this embodiment, the reference voltage verf1 and the reference voltage verf2 can obtain appropriate parameters by dividing the VCC power supply through resistors, which will not be described in detail here.

[0034] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. The charging protection system of the electric power operation recorder is characterized by: It includes a peak current buffer circuit, the input end of the peak current buffer circuit is connected to the switching power supply, and the output end of the peak current buffer circuit is connected to the host battery. The peak current buffer circuit includes a MOS tube Q2, a resistor R13, a resistor R14, a resistor R15 and a capacitor C2, wherein a first end of the resistor R13 is connected to a switching power supply, a second end of the resistor R13 is grounded through the resistor R14, the capacitor C2 is connected in parallel to the resistor R14, a drain of the MOS tube Q2 is connected to a switching power supply, a source of the MOS tube Q2 is connected to the host battery, and a gate of the MOS tube Q2 is connected to the second end of the resistor R13 through the resistor R15.

2. The charging protection system for the electric power operation recorder according to claim 1, characterized in that: The peak current buffer circuit further includes a voltage regulator diode D3 , a cathode of the voltage regulator diode D3 is connected to the second end of the resistor R13 , and an anode of the voltage regulator diode D3 is grounded.

3. The charging protection system for the electric power operation recorder according to claim 1, characterized in that: It also includes a charging control circuit, which includes a voltage detection branch, a current detection branch and a switch control branch. The input end of the voltage detection branch is connected to the output end of the peak current buffer circuit, the output end of the voltage detection branch is connected to the first input end of the switch control branch, the input end of the current detection branch is connected to the output end of the peak current buffer circuit, the output end of the current detection branch is connected to the second input end of the switch control branch, and the output end of the switch control branch is used to control the switching power supply.

4. The charging protection system for the electric power operation recorder according to claim 3, characterized in that: The switch control branch includes resistor R6, resistor R7, resistor R12, operational amplifier U1.2 and optocoupler U3. The in-phase input terminal of the operational amplifier U1.2 serves as the first input terminal of the switch control branch, the first end of the resistor R6 serves as the second input terminal of the switch control branch, the second end of the resistor R6 is connected to the VCC power supply through the resistor R7, the second end of the resistor R6 is connected to the inverting input terminal of the operational amplifier U1.2, the output terminal of the operational amplifier U1.2 is connected to the first input terminal of the optocoupler U3 through the resistor U12, the second input terminal of the optocoupler U3 is grounded, and the output terminal of the optocoupler U3 is used to control the switching power supply.

5. The charging protection system for the electric power operation recorder according to claim 4, characterized in that: The voltage detection branch includes resistor R1, resistor R2, resistor R3, resistor R4, resistor R5, capacitor C1, voltage regulator diode D1 and operational amplifier U1.

1. The first end of the resistor R1 is connected to the output end of the peak current buffer circuit, the second end of the resistor R1 is grounded through the resistor R2, the capacitor C1 is connected in parallel to the resistor R2, the second end of the resistor R1 is connected to the non-inverting input end of the operational amplifier U1.1, the inverting input end of the operational amplifier U1.1 is connected to the reference voltage verf1, the output end of the operational amplifier U1.1 is connected to the first end of the resistor R4 through the resistor R3, the second end of the resistor R4 is grounded through the resistor R5, the cathode of the voltage regulator diode D1 is connected to the first end of the resistor R4, the anode of the voltage regulator diode D1 is grounded, and the second end of the resistor R4 is connected to the first input end of the switch control branch.

6. The charging protection system for the electric power operation recorder according to claim 5, characterized in that: The current detection branch includes a current sensing resistor, a resistor R9, a resistor R10 and an operational amplifier U2.

1. The current sensing resistor is connected in series between the output end of the peak current buffer circuit and the host battery. The first end of the current sensing resistor is connected to the non-inverting input end of the operational amplifier U2.1 through the resistor R10, the second end of the current sensing resistor is connected to the inverting input end of the operational amplifier U2.1 through the resistor R9, and the output end of the operational amplifier U2.1 is connected to the second input end of the switch control branch.

7. The charging protection system for the electric power operation recorder according to claim 5, characterized in that: The current detection branch also includes a resistor R8, a resistor R11, an operational amplifier U2.2 and a transistor Q1. The inverting input terminal of the operational amplifier U2.2 is connected to the output terminal of the operational amplifier U2.1 through the resistor R8. The non-inverting input terminal of the operational amplifier U2.2 is connected to the reference voltage verf2. The output terminal of the operational amplifier U2.1 is connected to the base of the transistor Q1 through the resistor R11. The emitter of the transistor Q1 is grounded, and the collector of the transistor Q1 is connected to the second end of the resistor R1.

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