High-reliability low-delay closing circuit in special transformer acquisition terminal and electric energy meter

Abstract

The invention discloses a high-reliability low-delay closing circuit in a special transformer acquisition terminal and an electric energy meter, the high-reliability low-delay closing circuit comprises a power supply circuit and a driving circuit, the power supply circuit comprises an amplitude limiting circuit, a power failure monitoring circuit and a power supply control circuit, and the driving circuit comprises an instantaneous boost circuit. The amplitude limiting circuit and the power failure monitoring circuit can respectively judge whether the voltage of the USB power supply input end VDD is higher than or lower than a normal voltage range, and when the voltage exceeds the range, power supply is cut off through the power supply control circuit, so that the situations that components are damaged due to too high voltage and equipment is reset due to too low voltage are avoided. Moreover, the driving circuit can instantly increase the voltage of the coil to realize rapid closing when receiving a closing signal, and then gradually reduce the voltage to normal working voltage, thereby not only meeting the requirements of rapid closing and timely response, but also meeting the voltage-withstanding requirement of the relay, and maintaining lower power consumption during working.

Description

Technical Field

[0001] The invention relates to a closing circuit, in particular to a closing circuit in a special transformer acquisition terminal and an electric energy meter. Background Art

[0002] Most of the current designs of special transformer acquisition terminals and electric energy meters adopt the concept of hardware modularization and software appization. Like other USB slaves, the USB slave used for closing the switch communicates with the host MPU through the USB interface as an integrated module. The host sends the closing control command to the USB slave through the USB interface. The slave controls the relay action according to the control command and returns other signals at the same time.

[0003] The existing USB-based closing module (slave) has the following defects: 1. The USB slave cannot cope with the fluctuation of power supply voltage, resulting in device damage and abnormal reset. Specifically, the USB slave MCU power supply range can support up to 3.6V, and the power-off reset threshold is 1.8V. When a large surge voltage or high input voltage occurs, the components of the USB slave will be damaged. When the power supply voltage drops, the differential signal returned by the USB slave through the USB-HUB will also drop with the power supply voltage and cannot maintain a valid level. At this time, the host will determine that the USB-HUB is abnormal and automatically reset the USB-HUB, causing the entire product to fail to operate normally.

[0004] 2. Long relay response time. Relay action time is an important part of control command response time. The relay closing circuit widely used at present is as shown in the attached figure. Figure 3 As shown, it includes resistors R120, R122, transistor V64, diode V23 and relay K10. When the base of transistor V64 becomes high level, the coil is energized to open the relay. However, the response time of this circuit is long in practical application and cannot meet the real-time requirements of the site. Summary of the invention

[0005] The present invention proposes a high-reliability, low-delay closing circuit in a special transformer acquisition terminal and an electric energy meter, the purposes of which are: 1. to solve the problem of easy damage and abnormal reset of the USB slave when the power supply voltage fluctuates; 2. to solve the problem of long relay response time when closing.

[0006] The technical solution of the present invention is as follows: A high-reliability, low-delay closing circuit in a special transformer acquisition terminal and an electric energy meter, comprising a power supply circuit and a drive circuit, wherein the power output terminal VCC of the power supply circuit is used to power a control module in a USB slave where the closing circuit is located, and the control signal output terminal YK1 of the control module is connected to the drive circuit, and the drive circuit is connected to the coil of a closing relay; the power supply circuit comprises a limiting circuit, a power failure monitoring circuit and a power supply control circuit; the power supply control circuit is arranged between a USB power supply input terminal VDD and a power supply output terminal VCC, and is used to control the on-off of a line between the two; the limiting circuit is used to detect whether the voltage of the USB power supply input terminal VDD exceeds a first preset value and controls the power supply control circuit to disconnect when it exceeds a first preset value; the power failure monitoring circuit is used to detect whether the voltage of the USB power supply input terminal VDD is lower than a second preset value and controls the power supply control circuit to disconnect when it is lower; The drive circuit includes an instantaneous boost circuit. When the control signal output terminal YK1 sends a closing signal, the instantaneous boost circuit applies a drive voltage higher than the rated working voltage of the relay coil to the coil, and then controls the drive voltage to drop to a third preset value.

[0007] As a further improvement of the high-reliability, low-delay closing circuit in the special transformer acquisition terminal and the electric energy meter: the limiting circuit includes a resistor R246, a resistor R247 and a voltage-stabilizing diode V59; The USB power supply input terminal VDD is connected to the cathode of the voltage zener diode V59, and the anode of the voltage zener diode V59 is grounded through the resistor R246 and the resistor R247 in sequence.

[0008] As a further improvement of the high-reliability, low-delay closing circuit in the dedicated transformer acquisition terminal and the electric energy meter: the power failure monitoring circuit includes a voltage-stabilizing diode V60, a resistor R15 and an NPN transistor V12; The connection point between the resistor R246 and the resistor R247 is connected to the base of the NPN transistor V12; The USB power supply input terminal VDD is connected to the cathode of the voltage zener diode V60, the anode of the voltage zener diode V60 is connected to the collector of the NPN transistor V12 through the resistor R15, and the emitter of the NPN transistor V12 is grounded; The collector of the NPN transistor V12 is connected to the control end of the power supply control circuit.

[0009] As a further improvement of the high-reliability and low-delay closing circuit in the special transformer acquisition terminal and the electric energy meter: the power supply control circuit includes a MOS tube V56, an NPN transistor V22, a resistor R96 and a resistor R97; The base of the NPN transistor V22 is the control end of the power supply control circuit; The source of the MOS tube V56 is connected to the USB power supply input terminal VDD, and the drain is connected to the power supply output terminal VCC; the resistor R97 is connected between the source and the gate of the MOS tube V56, and the gate of the MOS tube V56 is also connected to the collector of the NPN transistor V22 through the resistor R96, and the emitter of the NPN transistor V22 is grounded.

[0010] As a further improvement of the high-reliability, low-delay closing circuit in the special transformer acquisition terminal and the electric energy meter: the base of the NPN transistor V22 is also grounded through a resistor R95.

[0011] As a further improvement of the high-reliability, low-delay closing circuit in the special transformer acquisition terminal and the electric energy meter: the power supply control circuit also includes a capacitor C134 connected in parallel with the resistor R97.

[0012] As a further improvement of the high-reliability, low-delay closing circuit in the special transformer acquisition terminal and the electric energy meter: the power supply circuit also includes a fast discharge circuit; The fast discharge circuit includes a resistor R19 and a MOS tube V10; The power output terminal VCC is connected to the drain of the MOS tube V10 through the resistor R19, the source of the MOS tube V10 is grounded, and the gate of the MOS tube V10 is connected to the collector of the NPN transistor V22.

[0013] As a further improvement of the high-reliability, low-delay closing circuit in the special transformer acquisition terminal and the electric energy meter: the driving circuit also includes a resistor R123, a resistor R125 and an NPN transistor V65; The control signal output terminal YK1 is connected to the base of the NPN transistor V65 through the resistor R123, and the resistor R125 is also connected between the base and emitter of the NPN transistor V65; the collector of the NPN transistor V65 is connected to the instantaneous boost circuit, and the emitter of the NPN transistor V65 is grounded.

[0014] As a further improvement of the high-reliability and low-delay closing circuit in the special transformer acquisition terminal and the electric energy meter: the instantaneous boost circuit includes a resistor R151, a resistor R152, a resistor R153, a resistor R156, a voltage regulator diode V69, a voltage regulator diode V72, a capacitor C12, a capacitor C15, a PNP transistor V51 and a diode V25; The driving power supply terminal VRLY is connected to the positive electrode of the voltage zener diode V69 through the resistor R151 and the resistor R153 in sequence, and the negative electrode of the voltage zener diode V69 is connected to the collector of the NPN transistor V65; The connection point between the resistor R151 and the resistor R153 is connected to the base of the PNP transistor V51 through the resistor R152, the emitter of the PNP transistor V51 is connected to the driving power supply terminal VRLY, and the collector is grounded through the capacitor C15 and the resistor R156 in sequence; The driving power supply terminal VRLY is also connected to the positive electrode of the diode V25, and the negative electrode of the diode V25 is connected to the collector of the PNP transistor V51 through the capacitor C12; the negative electrode of the diode V25 is also connected to one end of the coil; The other end of the coil is also connected to the cathode of the Zener diode V69 and the cathode of the Zener diode V72, and the anode of the Zener diode V72 is grounded.

[0015] As a further improvement of the high-reliability and low-delay closing circuit in the special transformer acquisition terminal and the electric energy meter: After power-on and when the control signal output terminal YK1 is at a low level, the drive circuit is in the preparation stage: the NPN transistor V65 is in the cut-off state, and the PNP transistor V51 is in the cut-off state. At this time, the drive power supply terminal VRLY charges the capacitor C12 and the capacitor C15 through the diode V25 and the resistor R156. After full charge, the voltage of the capacitor C12 is 0.3 to 0.8 times the voltage of the drive power supply terminal VRLY, and the sum of the voltages of the capacitor C12 and the capacitor C15 is equal to the voltage of the drive power supply terminal VRLY; in the preparation stage, the voltage difference between the two ends of the coil is 0V, and the relay does not operate; After the capacitor C12 is fully charged and the control signal output terminal YK1 is at a high level, the drive circuit is in the closing stage: the NPN transistor V65 is turned on, and the PNP transistor V51 is turned on. At the moment when the PNP transistor V51 is turned on, the voltage at the connection point between the capacitor C12 and the capacitor C15 is doubled to the VRLY voltage at the drive power supply end. At the same time, since the voltage difference across the capacitor C12 cannot change suddenly, the voltage at the end of the coil connected to the capacitor C12 is the sum of the VRLY voltage at the drive power supply end and the voltage after the capacitor C12 is charged. At the same time, the other end of the coil is grounded, so that the relay is driven to quickly operate with a voltage higher than the VRLY voltage at the drive power supply end to achieve closing. After that, the capacitor C12 and the capacitor C15 are discharged along the loop formed by the two and the coil, the NPN transistor V65 and the resistor R156. After the discharge is completed, the voltage on the coil is equal to the VRLY voltage at the drive power supply end and the closed state is maintained. After the closing is completed and the control signal output terminal YK1 becomes a low level, the drive circuit is in the reset stage: the NPN transistor V65 switches to the cut-off state, the coil is powered off, the relay is reset, and then the drive circuit automatically switches to the preparation stage.

[0016] Compared with the prior art, the present invention has the following positive effects: 1. The limiting circuit and power-off monitoring circuit in the present invention can respectively determine whether the voltage of the USB power supply input terminal VDD is higher or lower than the normal voltage range. When it exceeds the range, the power supply will be disconnected through the power supply control circuit, thereby avoiding the situation where the voltage is too high and the components are damaged, and the voltage is too low and the device is reset.

[0017] 2. The present invention also includes a fast discharge circuit. After the power supply is disconnected, the MOS tube V10 in the fast discharge circuit will be turned on synchronously, and the power supply voltage of the slave will be quickly returned to zero through the small resistance resistor R19, so as to avoid the slave system from freezing when it is powered on again.

[0018] 3. When receiving the closing signal, the drive circuit can use the fully charged capacitor C12 to instantly increase the coil voltage to 1.3 to 1.8 times the VRLY voltage at the drive power supply end, thereby achieving rapid closing, and the voltage at both ends of the coil will gradually decrease to the normal working voltage, which not only meets the needs of rapid closing and timely response, but also meets the withstand voltage requirements of the relay, maintaining low power consumption during operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A circuit diagram of a closing power supply circuit of the present invention; Figure 2 A circuit diagram of a closing drive circuit of the present invention; Figure 3 It is a circuit diagram of a closing drive circuit in the prior art. DETAILED DESCRIPTION

[0020] The technical solution of the present invention is described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0021] A high-reliability, low-delay closing circuit in a special transformer acquisition terminal and an electric energy meter comprises a power supply circuit and a drive circuit.

[0022] The power supply circuit comprises a USB power supply input terminal VDD and a power supply output terminal VCC, wherein the power supply output terminal VCC is used to supply power to a control module in the USB slave device where the closing circuit is located.

[0023] like Figure 1, the power supply circuit includes a limiter circuit 1, a power failure monitoring circuit 2 and a power supply control circuit 3. The power supply control circuit 3 is arranged between the USB power supply input terminal VDD and the power supply output terminal VCC, and is used to control the on-off of the line between the two. The limiter circuit 1 is used to detect whether the voltage of the USB power supply input terminal VDD exceeds a first preset value (3.6V in this embodiment) and control the power supply control circuit 3 to disconnect when it exceeds. The power failure monitoring circuit 2 is used to detect whether the voltage of the USB power supply input terminal VDD is lower than a second preset value (2.4V in this embodiment) and control the power supply control circuit 3 to disconnect when it is lower.

[0024] Specifically, the amplitude limiting circuit 1 includes resistors R246, R247 and a voltage stabilizing diode V59. The USB power supply input terminal VDD is connected to the cathode of the voltage stabilizing diode V59 (breakdown voltage is 3.6V), and the anode of the voltage stabilizing diode V59 is grounded through resistors R246 and R247 in sequence.

[0025] The power-off monitoring circuit 2 includes a voltage-stabilizing diode V60, a resistor R15, and an NPN transistor V12. The connection point between the resistor R246 and the resistor R247 is connected to the base of the NPN transistor V12. The USB power supply input terminal VDD is connected to the cathode of the voltage-stabilizing diode V60 (breakdown voltage is 2.4V), the anode of the voltage-stabilizing diode V60 is connected to the collector of the NPN transistor V12 through the resistor R15, and the emitter of the NPN transistor V12 is grounded. The collector of the NPN transistor V12 is connected to the control terminal of the power supply control circuit 3.

[0026] The power supply control circuit 3 includes a MOS transistor V56, an NPN transistor V22, a resistor R96 and a resistor R97. The base of the NPN transistor V22 is the control end of the power supply control circuit 3. The source of the MOS transistor V56 is connected to the USB power supply input terminal VDD, and the drain is connected to the power supply output terminal VCC; the resistor R97 is connected between the source and the gate of the MOS transistor V56, and the gate of the MOS transistor V56 is also connected to the collector of the NPN transistor V22 through the resistor R96, and the emitter of the NPN transistor V22 is grounded. The base of the NPN transistor V22 is also grounded through the resistor R95. The power supply control circuit 3 also includes a capacitor C134 connected in parallel with the resistor R97, which plays a role of slow start to avoid the drop of the front-stage power supply due to too fast start.

[0027] During normal operation, the input voltage of the USB power supply input terminal VDD is greater than or equal to 2.4V and less than or equal to 3.6V, the Zener diode V59 is in a non-breakdown state, the transistor V12 is cut off, and the Zener diode V60 is in a breakdown state. The base voltage of the transistor V22 is equal to the input voltage of the USB power supply input terminal VDD minus the voltage of the Zener diode V60 and the voltage divided by the resistors R15 and R95. V22 is turned on, thereby turning on the MOS tube V56 to realize power supply.

[0028] When the input voltage exceeds 3.6V, the Zener diode V59 and the Zener diode V60 are both in a breakdown state, the transistor V12 is turned on, and the base of the transistor V22 becomes a low level and is cut off, thereby turning off the MOS tube V56 and disconnecting the power supply to the power output terminal VCC to prevent excessive voltage from damaging the subsequent components.

[0029] When the input voltage is lower than 2.4V, the Zener diode V59 and the Zener diode V60 are both in a non-breakdown state, the base of the transistor V22 has no voltage and is cut off, the MOS tube V56 is disconnected and the power supply stops, thereby preventing the control module of the USB slave from returning an abnormal signal with a low voltage value and triggering the reset of the entire USB-HUB.

[0030] Furthermore, the power supply circuit also includes a fast discharge circuit 4. The fast discharge circuit 4 includes a resistor R19 and a MOS tube V10. The power output terminal VCC is connected to the drain of the MOS tube V10 through the resistor R19, the source of the MOS tube V10 is grounded, and the gate of the MOS tube V10 is connected to the collector of the NPN transistor V22. When the power supply of the slave control module MCU is cut off, the MOS tube V10 of the accelerated discharge circuit is automatically turned on, and fast discharge is performed through the small resistance resistor R19.

[0031] Furthermore, the control signal output terminal YK1 of the control module is connected to the drive circuit, and the drive circuit is connected to the coil of the closing relay.

[0032] like Figure 2 The driving circuit includes a resistor R123, a resistor R125 and an NPN transistor V65, and also includes an instantaneous boost circuit 5. When the control signal output terminal YK1 sends a closing signal, the instantaneous boost circuit 5 applies a driving voltage higher than the rated working voltage of the relay coil to the coil, and then controls the driving voltage to drop to a third preset value.

[0033] Specifically, the control signal output terminal YK1 is connected to the base of the NPN transistor V65 through the resistor R123, and the resistor R125 is also connected between the base and emitter of the NPN transistor V65. The collector of the NPN transistor V65 is connected to the instantaneous boost circuit 5, and the emitter of the NPN transistor V65 is grounded.

[0034] The instantaneous boost circuit 5 includes a resistor R151, a resistor R152, a resistor R153, a resistor R156, a voltage regulator diode V69, a voltage regulator diode V72, a capacitor C12, a capacitor C15, a PNP transistor V51 and a diode V25.

[0035] The driving power supply terminal VRLY is connected to the positive electrode of the voltage stabilizing diode V69 through the resistors R151 and R153 in sequence, and the negative electrode of the voltage stabilizing diode V69 is connected to the collector of the NPN transistor V65. In this embodiment, the voltage of the driving power supply terminal VRLY is 12V, which is the third preset value.

[0036] The connection point between the resistor R151 and the resistor R153 is connected to the base of the PNP transistor V51 through the resistor R152. The emitter of the PNP transistor V51 is connected to the driving power supply terminal VRLY, and the collector is grounded through the capacitor C15 and the resistor R156 in turn.

[0037] The driving power supply terminal VRLY is also connected to the positive electrode of the diode V25, and the negative electrode of the diode V25 is connected to the collector of the PNP transistor V51 through the capacitor C12. The negative electrode of the diode V25 is also connected to one end of the coil. The role of the diode V25 is to prevent the capacitor C12 from discharging the driving power supply terminal VRLY.

[0038] The other end of the coil is also connected to the cathode of the voltage zener diode V69 and the cathode of the voltage zener diode V72, and the anode of the voltage zener diode V72 is grounded. The voltage zener diode V69 and the voltage zener diode V72 can protect the transistors V51 and V65 when the reverse electromotive force is generated when the relay is disconnected.

[0039] After power-on and when the control signal output terminal YK1 is at a low level, the drive circuit is in the preparation stage: the NPN transistor V65 is in the cut-off state, and the PNP transistor V51 is in the cut-off state. At this time, the driving power supply terminal VRLY charges the capacitor C12 and the capacitor C15 through the diode V25 and the resistor R156. After full charge, the voltage of the capacitor C12 is 0.3 to 0.8 times (0.5 times in this embodiment) the voltage of the driving power supply terminal VRLY. The sum of the voltages of the capacitor C12 and the capacitor C15 is equal to the voltage of the driving power supply terminal VRLY. The capacitor C15 is used for voltage division. In the preparation stage, the voltage difference between the two ends of the coil is 0V, and the relay does not operate.

[0040] After the capacitor C12 is charged and the control signal output terminal YK1 is at a high level, the drive circuit is in the closing stage: the NPN transistor V65 is turned on, the PNP transistor V51 is turned on, and at the moment when the PNP transistor V51 is turned on, the voltage at the connection point between the capacitor C12 and the capacitor C15 is raised to the VRLY voltage of the driving power supply terminal. At the same time, since the voltage difference across the capacitor C12 cannot change suddenly, the voltage at the end of the coil connected to the capacitor C12 is the sum of the VRLY voltage of the driving power supply terminal and the voltage after the capacitor C12 is charged, that is, 1.5 times the VRLY voltage of the driving power supply terminal. At the same time, the other end of the coil is grounded, so that the voltage higher than the VRLY voltage of the driving power supply terminal drives the relay to quickly operate and close the switch. After that, the capacitor C12 and the capacitor C15 are discharged along the loop formed by the two, the coil, the NPN transistor V65 and the resistor R156. After the discharge is completed, the voltage on the coil is equal to the VRLY voltage of the driving power supply terminal and the closed state is maintained, which reduces the static power consumption of the coil when it is working normally.

[0041] After the closing is completed and the control signal output terminal YK1 becomes a low level, the drive circuit is in the reset stage: the NPN transistor V65 switches to the cut-off state, the coil is powered off, the relay is reset, and then the drive circuit automatically switches to the preparation stage.

[0042] It should be noted that it is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. The scope of the present invention is defined by the claims rather than the above description.

Claims

1. A high-reliability, low-delay closing circuit in a special transformer acquisition terminal and an electric energy meter, comprising a power supply circuit and a drive circuit, wherein the power supply output terminal VCC of the power supply circuit is used to power a control module in a USB slave where the closing circuit is located, and the control signal output terminal YK1 of the control module is connected to the drive circuit, and the drive circuit is connected to the coil of the closing relay, characterized in that: The power supply circuit comprises a limiting circuit (1), a power failure monitoring circuit (2) and a power supply control circuit (3); the power supply control circuit (3) is arranged between a USB power supply input terminal VDD and a power supply output terminal VCC, and is used to control the on-off of a line between the two; the limiting circuit (1) is used to detect whether the voltage of the USB power supply input terminal VDD exceeds a first preset value and control the power supply control circuit (3) to disconnect when the voltage exceeds a first preset value; the power failure monitoring circuit (2) is used to detect whether the voltage of the USB power supply input terminal VDD is lower than a second preset value and control the power supply control circuit (3) to disconnect when the voltage is lower than a second preset value; The drive circuit comprises an instantaneous boost circuit (5). When the control signal output terminal YK1 sends a closing signal, the instantaneous boost circuit (5) applies a drive voltage higher than the rated working voltage of the relay coil to the coil, and then controls the drive voltage to drop to a third preset value.

2. The high-reliability, low-delay closing circuit in the dedicated transformer acquisition terminal and the electric energy meter as claimed in claim 1, characterized in that: The limiting circuit (1) comprises a resistor R246, a resistor R247 and a voltage stabilizing diode V59; The USB power supply input terminal VDD is connected to the cathode of the voltage zener diode V59, and the anode of the voltage zener diode V59 is grounded through the resistor R246 and the resistor R247 in sequence.

3. The high-reliability, low-delay closing circuit in the dedicated transformer acquisition terminal and the electric energy meter as claimed in claim 2, characterized in that: The power failure monitoring circuit (2) comprises a voltage stabilizing diode V60, a resistor R15 and an NPN transistor V12; The connection point between the resistor R246 and the resistor R247 is connected to the base of the NPN transistor V12; The USB power supply input terminal VDD is connected to the cathode of the voltage zener diode V60, the anode of the voltage zener diode V60 is connected to the collector of the NPN transistor V12 through the resistor R15, and the emitter of the NPN transistor V12 is grounded; The collector of the NPN transistor V12 is connected to the control end of the power supply control circuit (3).

4. The high-reliability, low-delay closing circuit in the dedicated transformer acquisition terminal and the electric energy meter as claimed in claim 1, characterized in that: The power supply control circuit (3) comprises a MOS transistor V56, an NPN transistor V22, a resistor R96 and a resistor R97; The base of the NPN transistor V22 is the control terminal of the power supply control circuit (3); The source of the MOS tube V56 is connected to the USB power supply input terminal VDD, and the drain is connected to the power supply output terminal VCC; the resistor R97 is connected between the source and the gate of the MOS tube V56, and the gate of the MOS tube V56 is also connected to the collector of the NPN transistor V22 through the resistor R96, and the emitter of the NPN transistor V22 is grounded.

5. The high-reliability, low-delay closing circuit in the dedicated transformer acquisition terminal and the electric energy meter as claimed in claim 4, characterized in that: The base of the NPN transistor V22 is also grounded via a resistor R95.

6. The high-reliability, low-delay closing circuit in the dedicated transformer acquisition terminal and the electric energy meter as claimed in claim 4, characterized in that: The power supply control circuit (3) further includes a capacitor C134 connected in parallel with the resistor R97.

7. The high-reliability, low-delay closing circuit in the dedicated transformer acquisition terminal and the electric energy meter as claimed in claim 4, characterized in that: The power supply circuit also includes a fast discharge circuit (4); The fast discharge circuit (4) comprises a resistor R19 and a MOS tube V10; The power output terminal VCC is connected to the drain of the MOS tube V10 through the resistor R19, the source of the MOS tube V10 is grounded, and the gate of the MOS tube V10 is connected to the collector of the NPN transistor V22.

8. The high-reliability, low-delay closing circuit in the dedicated transformer acquisition terminal and the electric energy meter according to any one of claims 1 to 7, characterized in that: The driving circuit also includes a resistor R123, a resistor R125 and an NPN transistor V65; The control signal output terminal YK1 is connected to the base of the NPN transistor V65 through the resistor R123, and the resistor R125 is also connected between the base and emitter of the NPN transistor V65; the collector of the NPN transistor V65 is connected to the instantaneous boost circuit (5), and the emitter of the NPN transistor V65 is grounded.

9. The high-reliability, low-delay closing circuit in the dedicated transformer acquisition terminal and the electric energy meter as claimed in claim 8, characterized in that: The instantaneous boost circuit (5) comprises a resistor R151, a resistor R152, a resistor R153, a resistor R156, a voltage regulator diode V69, a voltage regulator diode V72, a capacitor C12, a capacitor C15, a PNP transistor V51 and a diode V25; The driving power supply terminal VRLY is connected to the positive electrode of the voltage zener diode V69 through the resistor R151 and the resistor R153 in sequence, and the negative electrode of the voltage zener diode V69 is connected to the collector of the NPN transistor V65; The connection point between the resistor R151 and the resistor R153 is connected to the base of the PNP transistor V51 through the resistor R152, the emitter of the PNP transistor V51 is connected to the driving power supply terminal VRLY, and the collector is grounded through the capacitor C15 and the resistor R156 in sequence; The driving power supply terminal VRLY is also connected to the positive electrode of the diode V25, and the negative electrode of the diode V25 is connected to the collector of the PNP transistor V51 through the capacitor C12; the negative electrode of the diode V25 is also connected to one end of the coil; The other end of the coil is also connected to the cathode of the Zener diode V69 and the cathode of the Zener diode V72, and the anode of the Zener diode V72 is grounded.

10. The high-reliability, low-delay closing circuit in the dedicated transformer acquisition terminal and the electric energy meter as claimed in claim 9, characterized in that: After power-on and when the control signal output terminal YK1 is at a low level, the drive circuit is in the preparation stage: the NPN transistor V65 is in the cut-off state, and the PNP transistor V51 is in the cut-off state. At this time, the drive power supply terminal VRLY charges the capacitor C12 and the capacitor C15 through the diode V25 and the resistor R156. After full charge, the voltage of the capacitor C12 is 0.3 to 0.8 times the voltage of the drive power supply terminal VRLY, and the sum of the voltages of the capacitor C12 and the capacitor C15 is equal to the voltage of the drive power supply terminal VRLY; in the preparation stage, the voltage difference between the two ends of the coil is 0V, and the relay does not operate; After the capacitor C12 is fully charged and the control signal output terminal YK1 is at a high level, the drive circuit is in the closing stage: the NPN transistor V65 is turned on, and the PNP transistor V51 is turned on. At the moment when the PNP transistor V51 is turned on, the voltage at the connection point between the capacitor C12 and the capacitor C15 is doubled to the VRLY voltage at the drive power supply end. At the same time, since the voltage difference across the capacitor C12 cannot change suddenly, the voltage at the end of the coil connected to the capacitor C12 is the sum of the VRLY voltage at the drive power supply end and the voltage after the capacitor C12 is charged. At the same time, the other end of the coil is grounded, so that the relay is driven to quickly operate with a voltage higher than the VRLY voltage at the drive power supply end to achieve closing. After that, the capacitor C12 and the capacitor C15 are discharged along the loop formed by the two and the coil, the NPN transistor V65 and the resistor R156. After the discharge is completed, the voltage on the coil is equal to the VRLY voltage at the drive power supply end and the closed state is maintained. After the closing is completed and the control signal output terminal YK1 becomes a low level, the drive circuit is in the reset stage: the NPN transistor V65 switches to the cut-off state, the coil is powered off, the relay is reset, and then the drive circuit automatically switches to the preparation stage.

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