Pulse type load power supply circuit for intelligent electric energy meter

Abstract

The invention discloses a pulse type load power supply circuit for an intelligent electric energy meter. The pulse type load power supply circuit can realize a high-reliability linear power supply scheme and can provide pulse current for driving a load switch. The pulse type load power supply circuit comprises a linear power supply transformer step-down circuit, a rectification filter circuit, a DC-DC voltage stabilizing circuit and a boost management circuit, the input end of the linear power transformer step-down circuit is connected with a power supply end, the output end of the linear power transformer step-down circuit is connected with the input end of the rectification filter circuit, and the output end of the rectification filter circuit is connected with a first power output port and the input end of the DC-DC voltage stabilizing circuit. The output end of the DC-DC voltage stabilizing circuit is respectively connected with a second power supply output port and the input end of the boost management circuit, and the output end of the boost management circuit is connected with the second power supply output port; wherein the boost management circuit is used for providing pulse current for driving a load switch for the first power supply output port.

Description

Technical Field

[0001] This invention relates to the field of electrical control technology, and more specifically to a pulse-type load power supply circuit for a smart energy meter. Background Technology

[0002] Smart meters, especially single-phase smart meters, are generally limited by space constraints and typically use linear transformers to step down the mains voltage, followed by voltage stabilization via rectifier and filter circuits plus LDO / DC-DC circuits. The transformer conversion efficiency is around 30%~40%, providing no more than 5W of power to the downstream load. Additionally, to maintain clock accuracy, the power supply includes a backup power source, consisting of rechargeable supercapacitors and non-rechargeable disposable lithium batteries. However, due to changes in regulations, load switches with a power of around 10W have been added, which traditional linear power supply solutions can no longer meet. The conventional approach is to replace linear power supply solutions with switching power supply solutions. However, switching power supply solutions increase power supply complexity. Furthermore, due to the 24 / 7 operation mode of the meters and the diversity of the local power grid and loads, the stability and reliability of meters using switching power supply solutions are significantly lower than those using linear power supply solutions. Summary of the Invention

[0003] The purpose of this invention is to overcome the deficiencies in the prior art and provide a power supply circuit that can achieve both a highly reliable linear power supply scheme and provide pulse current to drive load switches.

[0004] To achieve the above objectives, the technical solution of the present invention is to design a pulse load power supply circuit for a smart energy meter, comprising: a linear power transformer step-down circuit, a rectifier filter circuit, a DC-DC voltage regulator circuit, and a boost management circuit. The input terminal of the linear power transformer step-down circuit is connected to the power supply terminal, and the output terminal is connected to the input terminal of the rectifier and filter circuit. The output terminal of the rectifier and filter circuit is connected to the first power output port and the input terminal of the DC-DC regulator circuit. The output terminal of the DC-DC regulator circuit is connected to the second power output port and the input terminal of the boost management circuit. The output terminal of the boost management circuit is connected to the second power output port. The boost management circuit is used to provide a pulsed current to drive the load switch to the first power output port.

[0005] Furthermore, the linear power transformer step-down circuit includes a linear transformer, and the rectifier filter circuit includes a rectifier bridge and a first capacitor; The positive and negative terminals of the linear transformer's input are connected to the positive and negative terminals of the power supply, respectively. The positive and negative terminals of the linear transformer's output are connected to the positive and negative terminals of the rectifier bridge's input, respectively. The positive terminal of the first capacitor is connected in parallel to the positive terminal of the rectifier bridge's output, and the negative terminal of the first capacitor is connected in parallel to the negative terminal of the rectifier bridge's output. The positive terminal of the rectifier bridge's output is connected to the first power supply output port and the input of the DC-DC voltage regulator circuit, respectively. The negative terminal of the rectifier bridge's output is connected to the common reference terminal.

[0006] Furthermore, the DC-DC voltage regulator circuit includes a DC-DC voltage regulator chip, a second capacitor, a first resistor, and a second resistor; The input pin and enable pin of the DC-DC regulator chip are connected in parallel to the output terminal of the rectifier filter circuit, the ground pin is connected to the common reference terminal, and the switch control pin is connected to the second power output port and the input terminal of the boost management circuit, respectively; the second capacitor is connected in parallel between the self-boost pin and the switch control pin of the DC-DC regulator chip, the first resistor is connected in parallel between the switch control pin and the output feedback pin of the DC-DC regulator chip, and the second resistor is connected in parallel between the output feedback pin and the ground pin of the DC-DC regulator chip.

[0007] Furthermore, the boost management circuit includes a boost chip, a supercapacitor, a first MOSFET, a third resistor, and a fourth resistor; The positive terminal of the supercapacitor is connected in parallel between the output terminal of the DC-DC regulator circuit and the path of the second power output port. The negative terminal of the supercapacitor is connected in parallel between the first terminal of the first MOSFET and the path of the common reference terminal. The first pin of the boost chip is connected in parallel between the positive terminal of the supercapacitor and the path of the output terminal of the DC-DC regulator circuit. The second and third pins of the boost chip are connected in parallel between the first pin of the boost chip and the path of the positive terminal of the supercapacitor. The fourth pin of the boost chip is connected to the second terminal of the first MOSFET. The fifth and sixth pins of the boost chip are connected in parallel between the path of the first terminal of the third resistor and the first terminal of the fourth resistor. The seventh pin of the boost chip is connected to the second terminal of the third resistor. The eighth pin of the boost chip is connected in parallel between the output terminal of the rectifier filter circuit and the path of the first power output port. The second terminal of the fourth resistor is connected in parallel between the fourth pin of the boost chip and the path of the second terminal of the first MOSFET. The gate of the first MOSFET is connected to the control pin.

[0008] Furthermore, the first MOSFET is a PMOSFET; The source of the PMOS transistor is connected to the ground pin of the boost chip, and the drain of the PMOS transistor is connected to the common reference terminal.

[0009] Furthermore, the pulsed load power supply circuit for the smart energy meter also includes a first diode; The anode of the first diode is connected to the output terminal of the DC-DC voltage regulator circuit, and the cathode is connected to the second power output port.

[0010] Furthermore, the pulsed load power supply circuit for the smart energy meter also includes a second diode and a third diode; The anode of the second diode is connected in parallel between the cathode of the first diode and the path of the second power output port. The cathode of the second diode is connected to the positive terminal of the supercapacitor. The anode of the third diode is connected in parallel between the cathode of the second diode and the path of the positive terminal of the supercapacitor. The cathode of the third diode is connected to the first pin of the boost chip.

[0011] Furthermore, the pulsed load power supply circuit for the smart energy meter also includes a fourth diode; The anode of the fourth diode is connected to the output terminal of the rectifier filter circuit, and the cathode is connected to the first power output port.

[0012] Furthermore, the pulsed load power supply circuit for the smart energy meter also includes a load switch drive circuit, which includes an H-bridge drive chip. The first pin of the H-bridge driver chip is connected to the first power output port, the second and third pins of the H-bridge driver chip are connected to the first control signal input terminal and the second control signal input terminal, respectively, the fourth pin of the H-bridge driver chip is connected to the first input pin and the second input pin of the load switch, the fifth pin of the H-bridge driver chip is connected to the third input pin and the fourth input pin of the load switch, and the sixth pin of the H-bridge driver chip is connected to the common reference terminal.

[0013] Furthermore, the load switch drive circuit also includes a third capacitor, a fourth capacitor, and a fifth capacitor; The third capacitor and the fourth capacitor are connected in series, and the third capacitor and the fourth capacitor are connected in parallel between the first pin and the sixth pin of the H-bridge driver chip. The fifth capacitor is connected in parallel between the fourth pin and the fifth pin of the H-bridge driver chip.

[0014] The advantages and beneficial effects of this invention are as follows: the linear power transformer step-down circuit, rectifier filter circuit, and DC-DC voltage regulator circuit realize a linear power supply scheme with controllable output. The pulse current required to drive the load switch is output through the boost management circuit. This not only realizes a highly reliable linear power supply scheme, but also meets the pulse current requirements for driving the load switch. Compared with the switching power supply scheme, it achieves cost reduction and efficiency improvement. The controllable output power supply can provide multiple voltage levels for extended functions such as power outage reporting. It improves the problem that the switching power supply scheme of smart energy meters cannot meet the complex field application conditions, and enhances the operational stability and reliability of the energy meter. Attached Figure Description

[0015] Figure 1 This is a circuit diagram of a pulse load power supply for a smart energy meter according to the present invention; Figure 2 This is a circuit diagram of the load switch drive circuit of the present invention.

[0016] In the diagram: T1, linear transformer; D1, rectifier bridge; D2, first diode; D3, second diode; D4, third diode; Q1, first MOSFET; C1, first capacitor; C2, second capacitor; C3, supercapacitor; C4, third capacitor; C5, fourth capacitor; C6, fifth capacitor; U1, DC-DC regulator chip; U2, boost converter chip; U3, H-bridge driver chip; R1, first resistor; R2, second resistor; R3, third resistor; R4, fourth resistor; R5, fifth resistor; R6, sixth resistor; R7, seventh resistor; R9, eighth resistor; R10, ninth resistor. Detailed Implementation

[0017] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings and examples. The following examples are only used to more clearly illustrate the technical solutions of the present invention and should not be construed as limiting the scope of protection of the present invention.

[0018] according to Figures 1-2 As shown, the present invention is a pulse load power supply circuit for a smart energy meter, comprising: a linear power transformer step-down circuit, a rectifier filter circuit, a DC-DC voltage regulator circuit, and a boost management circuit; The input terminal of the linear power transformer step-down circuit is connected to the power supply terminal, and the output terminal is connected to the input terminal of the rectifier and filter circuit. The output terminal of the rectifier and filter circuit is connected to the first power output port and the input terminal of the DC-DC regulator circuit. The output terminal of the DC-DC regulator circuit is connected to the second power output port and the input terminal of the boost management circuit. The output terminal of the boost management circuit is connected to the second power output port. The boost management circuit is used to provide the first power output port with a pulsed current to drive the load switch.

[0019] Figure 1The AC input serves as the power supply terminal, the +12V output port serves as the first power output port, and the VCC output port serves as the second power output port. The boost management circuit can provide pulsed current to the +12V output port. Figure 2 The switching drive circuit shown provides sufficient drive power, solving the problem of insufficient drive power in the linear power supply scheme composed of a linear power transformer step-down circuit and a DC-DC regulated power supply. Simultaneously, the controllable output of the DC-DC regulated power supply provides multiple voltage levels of VCC power, which can be used for extended functions such as power outage reporting, improving the problem that switching power supply schemes used in smart meters cannot meet the needs of complex field applications.

[0020] To ensure a more stable and reliable linear power output in the pulse load power supply circuit of a smart energy meter, a preferred embodiment of this invention includes a linear power transformer step-down circuit comprising a linear transformer T1, and a rectifier filter circuit comprising a rectifier bridge D1 and a first capacitor C1. The positive and negative terminals of the input of the linear transformer T1 are connected to the positive and negative terminals of the power supply, respectively. The positive and negative terminals of the output of the linear transformer T1 are connected to the positive and negative terminals of the input of the rectifier bridge D1, respectively. The positive terminal of the first capacitor C1 is connected in parallel to the positive terminal of the output of the rectifier bridge D1, and the negative terminal of the first capacitor C1 is connected in parallel to the negative terminal of the output of the rectifier bridge D1. The positive terminal of the output of the rectifier bridge D1 is connected to the first power output port and the input of the DC-DC voltage regulator circuit, respectively. The negative terminal of the output of the rectifier bridge D1 is connected to the common reference terminal AGND.

[0021] The AC power input is stepped down by the linear transformer T1, and then converted to DC power by the rectifier bridge D1. After being filtered by the first capacitor C1, it can be converted into a stable +12V power output.

[0022] To obtain a controllable power output with more stable voltage and ripple, a preferred embodiment of the present invention includes a DC-DC voltage regulator circuit comprising a DC-DC voltage regulator chip U1, a second capacitor C2, a first resistor R1, and a second resistor R2; the input pin 5 (VIN) and enable pin 4 (EN) of the DC-DC voltage regulator chip U1 are connected in parallel to the output of the rectifier filter circuit, the ground pin 2 (GND) is connected to the common reference terminal AGND, and the switch control pin 6 (SW) is connected to the second power output port VCC and the input of the boost management circuit, respectively; the second capacitor C2 is connected in parallel between the self-boost pin 1 (BST) and the switch control pin 6 of the DC-DC voltage regulator chip, the first resistor R1 is connected in parallel between the switch control pin 6 and the output feedback pin 3 (FB) of the DC-DC voltage regulator chip U1, and the second resistor R2 is connected in parallel between the output feedback pin 3 and the ground pin 2 of the DC-DC voltage regulator chip U1.

[0023] The DC-DC regulator chip U1 converts the output of the rectifier and filter circuit into a more stable DC voltage output. Capacitor C2 filters the output VCC, reducing noise and resulting in a more stable VCC output with lower voltage and ripple. This allows for more stable power supply to components in smart meters that require more stable power, such as MCUs and components that implement extended functions like power outage reporting. The DC-DC regulator chip U1 adjusts the output voltage of pin 6 via pin 3 (FB). Resistors R1 and R2 enhance the circuit safety of the DC-DC regulator chip U1.

[0024] To meet the requirements of providing pulsed current to drive the load switch and to reduce power consumption when the power supply is lost, a preferred embodiment of the present invention includes a boost management circuit comprising a boost chip U2, a supercapacitor C3, a first MOSFET Q1, a third resistor R3, and a fourth resistor R4. The positive terminal of the supercapacitor C3 is connected in parallel between the output terminal of the DC-DC regulator circuit and the path between the second power output port; the negative terminal of the supercapacitor C3 is connected in parallel between the first terminal of the first MOSFET Q1 and the path between the common reference terminal AGND; the first pin 1 of the boost chip U2 is connected in parallel between the positive terminal of the supercapacitor C3 and the path between the output terminal of the DC-DC regulator circuit; and the second pin 2 and the third pin 3 of the boost chip U2 are connected in parallel. The first pin 1 of the boost chip U2 is connected in parallel between the positive terminal of the supercapacitor C3. The fourth pin 4 of the boost chip U2 is connected to the second terminal of the first MOSFET Q1. The fifth pin 5 and the sixth pin 6 of the boost chip U2 are connected in parallel between the first terminal of the third resistor R3 and the first terminal of the fourth resistor R4. The seventh pin 7 of the boost chip U2 is connected to the second terminal of the third resistor R3. The eighth pin 8 of the boost chip U2 is connected in parallel between the output terminal of the rectifier filter circuit and the first power output port. The second terminal of the fourth resistor R4 is connected in parallel between the fourth pin 4 of the boost chip U2 and the second terminal of the first MOSFET Q1. The gate of the first MOSFET Q1 is connected to the control pin CONTROL.

[0025] In the boost chip U2, pin 1 is the input pin (VIN), pin 2 is the enable pin (EN), pin 3 is the compensation pin (Comp), pin 4 is the ground pin (GND), pin 5 is the protection pin (PG), pin 6 is the switch control pin (SW), pin 7 is the self-boosting pin (BST), and pin 8 is the output pin (VOUT). When powered by AC input, the current output from the DC-DC regulator circuit charges the supercapacitor C3. When the voltage across supercapacitor C3 exceeds a certain value, the boost chip U2 is activated through its enable pin. Supercapacitor C3 provides a 1A@200ms pulse current for the +12V output, which is boosted by the boost chip U2 and output to the +12V output, thus solving the problem of insufficient drive power in linear power supply solutions. Meanwhile, in order to reduce the static power consumption of the smart energy meter in the non-working state, a true turn-off circuit of MOSFET Q1 was designed. After the smart energy meter MCU detects the mains power failure, it completely turns off the path between the supercapacitor C3 and the boost chip U2 through the CONTROL control pin to prevent the supercapacitor C3 from continuing to discharge after the power failure.

[0026] In order to achieve the control logic of low-level conduction and high-level shutdown and reduce energy consumption, the preferred embodiment of the present invention is that the first MOSFET Q1 is a PMOSFET; the source of the PMOSFET is connected to the ground pin of the boost chip, and the drain of the PMOSFET is connected to the common reference terminal.

[0027] The PMOS transistor turns on when its gate voltage is lower than its source voltage and turns off when its gate voltage is higher than its source voltage. This allows for a low-level-to-turn-on, high-level-to-turn-off control logic, reducing the energy consumption required for control. If an NMOS transistor is used as the first MOSFET, a switching control logic is required.

[0028] To prevent current backflow between the second power output port and the DC-DC voltage regulator circuit and improve circuit safety, a preferred embodiment of the present invention is that the pulse load power supply circuit for the smart energy meter further includes a first diode D2; the anode of the first diode D2 is connected to the output terminal of the DC-DC voltage regulator circuit, and the cathode is connected to the second power output port.

[0029] To prevent current backflow between the supercapacitor and the DC-DC regulator circuit, and between the boost chip and the supercapacitor, and to improve circuit safety, a preferred embodiment of the present invention includes a second diode D3 and a third diode D4 in the pulse load power supply circuit for the smart energy meter. The anode of the second diode D3 is connected in parallel between the cathode of the first diode D2 and the path of the second power output port, and the cathode of the second diode D3 is connected to the positive terminal of the supercapacitor C3. The anode of the third diode D4 is connected in parallel between the cathode of the second diode D3 and the path of the positive terminal of the supercapacitor C3, and the cathode of the third diode D4 is connected to the first pin 1 of the boost chip U2.

[0030] To prevent current backflow between the first power output port and the rectifier filter circuit and improve circuit safety, a preferred embodiment of the present invention is that the pulse load power supply circuit for the smart energy meter further includes a fourth diode D5; the anode of the fourth diode D5 is connected to the output terminal of the rectifier filter circuit, and the cathode is connected to the first power output port.

[0031] To achieve precise control of the load switch, a preferred embodiment of the present invention further includes a load switch drive circuit for the pulse-type load power supply circuit of the smart energy meter. The load switch drive circuit includes an H-bridge driver chip U3. The first pin 1 of the H-bridge driver chip is connected to the first power output port. The second pin 2 and the third pin 3 of the H-bridge driver chip U3 are respectively connected to the first control signal input terminal INA and the second control signal input terminal INB. The fourth pin 4 of the H-bridge driver chip U3 is connected to the first input pin 1 and the second input pin 2 of the load switch. The fifth pin 5 of the H-bridge driver chip U3 is connected to the third input pin 3 and the fourth input pin 4 of the load switch. The sixth pin 6 of the H-bridge driver chip U3 is connected to the common reference terminal AGND.

[0032] Among them, pin 1 of the H-bridge driver chip U3 is the power input pin, pins 2 and 3 are the control signal input pins, pins 4 and 5 are the output pins, and pin 6 is the ground pin.

[0033] H-bridge driver chips can provide reliable drive capability for DC brushed motors. They have built-in gate drive circuits with low on-resistance power NMOS, enabling four functions: forward rotation, reverse rotation, stop, and braking of the motor. By controlling the input signals (INA and INB) of the H-bridge driver chip, precise control of the load switch can be achieved.

[0034] To improve the stability and reliability of the load switch drive circuit, a preferred embodiment of the present invention further includes a third capacitor C4, a fourth capacitor C5, and a fifth capacitor C6; the third capacitor C4 and the fourth capacitor C5 are connected in series, and the third capacitor C4 and the fourth capacitor C5 are connected in parallel between the first pin 1 and the sixth pin 6 of the H-bridge driver chip U3, and the fifth capacitor C6 is connected in parallel between the fourth pin 4 and the fifth pin 5 of the H-bridge driver chip U3.

[0035] The third capacitor C4, the fourth capacitor C5, the fifth capacitor C6, and the fifth resistor R5, the sixth resistor R6, the seventh resistor R7, the eighth resistor R9, and the ninth resistor R10 in the load switch drive circuit play the roles of filtering, current limiting, and voltage stabilization, thereby improving the stability and reliability of the load switch drive circuit.

[0036] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A pulse-type load power supply circuit for a smart energy meter, characterized in that, include: Linear power transformer step-down circuit, rectifier and filter circuit, DC-DC voltage regulator circuit and boost management circuit; The input terminal of the linear power transformer step-down circuit is connected to the power supply terminal, and the output terminal is connected to the input terminal of the rectifier and filter circuit. The output terminal of the rectifier and filter circuit is connected to the first power output port and the input terminal of the DC-DC regulator circuit. The output terminal of the DC-DC regulator circuit is connected to the second power output port and the input terminal of the boost management circuit. The output terminal of the boost management circuit is connected to the second power output port. The boost management circuit is used to provide a pulsed current to drive the load switch to the first power output port.

2. The pulse-type load power supply circuit for a smart energy meter according to claim 1, characterized in that, The linear power transformer step-down circuit includes a linear transformer, and the rectifier filter circuit includes a rectifier bridge and a first capacitor. The positive and negative terminals of the linear transformer's input are connected to the positive and negative terminals of the power supply, respectively. The positive and negative terminals of the linear transformer's output are connected to the positive and negative terminals of the rectifier bridge's input, respectively. The positive terminal of the first capacitor is connected in parallel to the positive terminal of the rectifier bridge's output, and the negative terminal of the first capacitor is connected in parallel to the negative terminal of the rectifier bridge's output. The positive terminal of the rectifier bridge's output is connected to the first power supply output port and the input of the DC-DC voltage regulator circuit, respectively. The negative terminal of the rectifier bridge's output is connected to the common reference terminal.

3. The pulse-type load power supply circuit for a smart energy meter according to claim 1, characterized in that, The DC-DC voltage regulator circuit includes a DC-DC voltage regulator chip, a second capacitor, a first resistor, and a second resistor; The input pin and enable pin of the DC-DC regulator chip are connected in parallel to the output terminal of the rectifier filter circuit, the ground pin is connected to the common reference terminal, and the switch control pin is connected to the second power output port and the input terminal of the boost management circuit, respectively; the second capacitor is connected in parallel between the self-boost pin and the switch control pin of the DC-DC regulator chip, the first resistor is connected in parallel between the switch control pin and the output feedback pin of the DC-DC regulator chip, and the second resistor is connected in parallel between the output feedback pin and the ground pin of the DC-DC regulator chip.

4. The pulse-type load power supply circuit for a smart energy meter according to claim 1, characterized in that, The boost management circuit includes a boost chip, a supercapacitor, a first MOSFET, a third resistor, and a fourth resistor; The positive terminal of the supercapacitor is connected in parallel between the output terminal of the DC-DC regulator circuit and the path of the second power output port. The negative terminal of the supercapacitor is connected in parallel between the first terminal of the first MOSFET and the path of the common reference terminal. The first pin of the boost chip is connected in parallel between the positive terminal of the supercapacitor and the path of the output terminal of the DC-DC regulator circuit. The second and third pins of the boost chip are connected in parallel between the first pin of the boost chip and the path of the positive terminal of the supercapacitor. The fourth pin of the boost chip is connected to the second terminal of the first MOSFET. The fifth and sixth pins of the boost chip are connected in parallel between the path of the first terminal of the third resistor and the first terminal of the fourth resistor. The seventh pin of the boost chip is connected to the second terminal of the third resistor. The eighth pin of the boost chip is connected in parallel between the output terminal of the rectifier filter circuit and the path of the first power output port. The second terminal of the fourth resistor is connected in parallel between the fourth pin of the boost chip and the path of the second terminal of the first MOSFET. The gate of the first MOSFET is connected to the control pin.

5. The pulse-type load power supply circuit for a smart energy meter according to claim 4, characterized in that, The first MOSFET is a PMOSFET; The source of the PMOS transistor is connected to the ground pin of the boost chip, and the drain of the PMOS transistor is connected to the common reference terminal.

6. The pulse-type load power supply circuit for a smart energy meter according to claim 4, characterized in that, The pulsed load power supply circuit for the smart energy meter also includes a first diode; The anode of the first diode is connected to the output terminal of the DC-DC voltage regulator circuit, and the cathode is connected to the second power output port.

7. The pulse-type load power supply circuit for a smart energy meter according to claim 6, characterized in that, The pulse load power supply circuit for the smart energy meter also includes a second diode and a third diode; The anode of the second diode is connected in parallel between the cathode of the first diode and the path of the second power output port. The cathode of the second diode is connected to the positive terminal of the supercapacitor. The anode of the third diode is connected in parallel between the cathode of the second diode and the path of the positive terminal of the supercapacitor. The cathode of the third diode is connected to the first pin of the boost chip.

8. The pulse-type load power supply circuit for a smart energy meter according to claim 1, characterized in that, The pulse load power supply circuit for the smart energy meter also includes a fourth diode. The anode of the fourth diode is connected to the output terminal of the rectifier filter circuit, and the cathode is connected to the first power output port.

9. The pulse-type load power supply circuit for a smart energy meter according to claim 1, characterized in that, The pulsed load power supply circuit for the smart energy meter also includes a load switch drive circuit, which includes an H-bridge drive chip. The first pin of the H-bridge driver chip is connected to the first power output port, the second and third pins of the H-bridge driver chip are connected to the first control signal input terminal and the second control signal input terminal, respectively, the fourth pin of the H-bridge driver chip is connected to the first input pin and the second input pin of the load switch, the fifth pin of the H-bridge driver chip is connected to the third input pin and the fourth input pin of the load switch, and the sixth pin of the H-bridge driver chip is connected to the common reference terminal.

10. The pulse-type load power supply circuit for a smart energy meter according to claim 1, characterized in that, The load switch drive circuit also includes a third capacitor, a fourth capacitor, and a fifth capacitor; The third capacitor and the fourth capacitor are connected in series, and the third capacitor and the fourth capacitor are connected in parallel between the first pin and the sixth pin of the H-bridge driver chip. The fifth capacitor is connected in parallel between the fourth pin and the fifth pin of the H-bridge driver chip.

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