DC auxiliary power supply circuit for electricity meters with ultra-wide voltage input and ultra-wide voltage range

Abstract

This utility model discloses a DC auxiliary power supply circuit for an energy meter with an ultra-wide voltage input and ultra-wide voltage range, relating to the field of energy meters. Specifically, it discloses a DC auxiliary power supply circuit for an energy meter with an ultra-wide voltage input and ultra-wide voltage range, comprising: a negative voltage circuit, an input and negative voltage superposition circuit, and a flyback switching power supply circuit; the negative voltage circuit converts positive voltage to negative voltage output, and after voltage regulation, outputs a stable negative power supply; the input and negative voltage superposition circuit superimposes the positive voltage input and the stable negative power supply; the flyback switching power supply circuit outputs a multi-channel isolated voltage from the superimposed voltage. This utility model can meet the input range requirements of the flyback switching power supply, and the superimposed voltage can meet the voltage requirements of the multi-channel isolated voltage for use in energy meters.

Description

Technical Field

[0001] This utility model relates to the field of electricity meters, specifically to a DC auxiliary power supply circuit for electricity meters with an ultra-wide voltage input and ultra-wide voltage range. Background Technology

[0002] Due to the complexity of industrial environments, the power supplies for electricity meters are also diverse. To ensure the reliability of electricity meter operation, electrical isolation between the internal working circuits and external power supplies is required. For different industrial environments, low-voltage DC power supplies have rated voltages of 5V, 12V, 24V, 48V, etc. Current wide-range input DC-DC isolated power supply circuits typically use flyback switching power supplies. Flyback switching power supplies can support higher voltage inputs but cannot support low voltage inputs such as 5V and 12V. Bridge or push-pull driven DC-DC isolated power supplies only support a fixed, narrow voltage input range, with a fixed ratio of input to output voltage. Therefore, current auxiliary power supply circuits for electricity meters cannot simultaneously support low and high voltage inputs, only supporting 4.5V-5.5V, 9-36V, or 18-56V inputs, etc. Currently, a power supply circuit with specifications fully compatible with various DC power supply voltages in the aforementioned industrial environments is needed. Furthermore, conventional designs only support single-channel isolated power supply outputs. If multiple isolated power supplies are required, power expansion requires the use of modules such as 5V to 5V isolated power supplies, which is costly. Therefore, there is a current need for a DC auxiliary power supply circuit for energy meters with an ultra-wide voltage input and ultra-wide voltage range that can support multiple low-voltage and high-voltage inputs, meet the requirements of multiple isolated power supplies, and reduce costs. Utility Model Content

[0003] The technical problem this invention aims to solve is that the supported voltage range is small and the cost of multi-channel isolated power supplies is high. The purpose is to provide a DC auxiliary power supply circuit for an energy meter with an ultra-wide voltage input and ultra-wide voltage range. First, the input positive voltage is used to generate one negative voltage. Then, the negative voltage is superimposed on the positive voltage, so that the superimposed voltage value is higher than the positive voltage value than the negative voltage value. This can meet the input range of the flyback switching power supply. The superimposed voltage can meet the voltage requirements of multi-channel isolated voltages and be used for the energy meter.

[0004] This utility model is achieved through the following technical solution:

[0005] A DC auxiliary power supply circuit for an electricity meter with an ultra-wide voltage input and ultra-wide voltage range includes: a negative voltage circuit, an input and negative voltage superposition circuit, and a flyback switching power supply circuit; the negative voltage circuit is used to convert a positive voltage into a negative voltage output, and output a stable negative power supply after voltage regulation; the input and negative voltage superposition circuit is used to superimpose the positive voltage input and the stable negative power supply; the flyback switching power supply circuit is used to output a multi-channel isolated voltage from the superimposed voltage.

[0006] The negative voltage circuit includes a switching power supply chip; the switching power supply chip integrates a first high-frequency switching transistor, a control logic module, and a voltage conversion module; the first high-frequency switching transistor is used to switch on and off via high-frequency pulses; the control logic module is used to provide voltage regulation and protection for the positive voltage; the voltage conversion module is used to convert the positive voltage into a negative voltage; the switching power supply chip has a first VIN pin, a first SW pin, a first FB pin, a BST pin, and an EN pin; the first VIN pin is used to connect the positive voltage to the first high-frequency switching transistor; the first SW pin is used to connect the high-frequency pulse to the first high-frequency switching transistor; the input of the first FB pin is used to connect the sampled negative voltage to the control logic module; the BST pin is used to provide a drive voltage to the first high-frequency switching transistor; the EN pin is used to control the first high-frequency switching transistor to start.

[0007] The negative voltage circuit also includes an input filtering module; the input filtering module is connected to the output of the first VIN pin and is used to filter the positive voltage.

[0008] The negative voltage circuit also includes an energy conversion module; the energy conversion module is used to store energy when the first high-frequency switching transistor is turned on, and to supply power to the switching power supply chip when it is turned off.

[0009] The negative voltage circuit further includes an output voltage regulation and feedback module; the output voltage regulation and feedback module includes a voltage divider feedback module and a compensation network module; the voltage divider feedback module is used to send the sampled negative voltage back to the first FB pin; the compensation network module is used to provide phase compensation for the voltage divider feedback module.

[0010] The negative voltage circuit further includes a filtering and ripple suppression module; the filtering and ripple suppression module includes an output filtering module and a ripple smoothing module; the output filtering module is used to filter the negative voltage; the ripple smoothing module is used to smooth the negative voltage.

[0011] The negative voltage circuit also includes an auxiliary module; the auxiliary module includes a voltage driving module and an overcurrent protection module; the voltage driving module is connected to the input of the BST pin to provide the driving voltage; the overcurrent protection module is connected to the input of the EN pin for overcurrent protection.

[0012] The input and negative voltage superposition circuit includes a capacitive coupling module and a voltage regulation module; the capacitive coupling module is used to superimpose the positive voltage and the negative voltage; the voltage regulation module is used to regulate and store the voltage after the voltage is superimposed.

[0013] The flyback switching power supply circuit includes an input voltage regulator and filter module, a main control chip, a transformer, a secondary rectification and output module, a feedback and voltage regulator module, and a protection module. The input voltage regulator and filter module includes a filter capacitor and a Zener diode. The filter capacitor is connected to the positive voltage output to filter out high-frequency noise. The Zener diode is used to break down the positive voltage when it is too high. The main control chip is used for high-frequency switching control of the transformer for energy storage. The transformer includes a primary winding, a secondary winding, and an auxiliary winding. When the primary winding is conducting the main control chip, it stores energy; when it is off, the primary winding supplies power to the main control chip. The secondary winding... The turns ratio of the outputs of the group corresponds to the multi-channel output, which adjusts the output voltage. The auxiliary winding provides power to the main control chip after startup. The secondary rectification and output module includes a rectifier diode module, a filter and voltage regulator module, and a feedback and voltage regulator module. When the rectifier diode module senses the power supply of the primary winding, it conducts and rectifies the pulse voltage into a DC voltage. The filter and voltage regulator module is used to filter and stabilize the pulse voltage and the DC voltage. The feedback and voltage regulator module is used to isolate and stabilize the feedback loop of voltage changes in the primary winding and the secondary winding. The protection module is used to protect the primary winding, the primary winding, and the auxiliary winding.

[0014] The main control chip integrates a second high-frequency switch, a PWM controller, and a feedback voltage regulator module. The main control chip has a second VIN pin, a second SW pin, a second FB pin, and a COMP / RT pin. The input of the second VIN pin is connected to the power supply terminal. The second SW pin is used to connect the input terminal of the primary winding to the second high-frequency switch to switch the primary winding on and off at high frequency. The second FB pin is used to connect the input terminal of the secondary winding to the feedback voltage regulator module to stabilize the feedback signal of the secondary winding. The input terminal of the COMP / RT pin is used to connect the output terminal of the feedback voltage regulator module and the input terminal of the second high-frequency switch to the PWM controller, so that the PWM controller can dynamically adjust the duty cycle of the PWM controller and set the switching frequency of the second high-frequency switch based on the feedback signal of the secondary winding.

[0015] Compared with the prior art, this utility model has the following advantages and beneficial effects:

[0016] This invention provides a DC auxiliary power supply circuit for an energy meter with an ultra-wide voltage input and ultra-wide voltage range. It includes: a negative voltage circuit, an input and negative voltage superposition circuit, and a flyback switching power supply circuit. A positive voltage is input to the negative voltage circuit; the negative voltage circuit converts the positive voltage into a negative voltage output, which is then regulated to output a stable negative power supply; the input and negative voltage superposition circuit superimposes the positive voltage input and the stable negative power supply. The technical problem this invention aims to solve is the limited voltage range it supports and the high cost of multi-channel isolated power supplies. The goal is to provide a DC auxiliary power supply circuit for an energy meter with an ultra-wide voltage input and ultra-wide voltage range. This power supply circuit first generates a negative voltage from the input positive voltage, then superimposes the negative voltage with the positive voltage. The superimposed voltage is higher than the positive voltage, thus meeting the input range requirements of the flyback switching power supply. The superimposed voltage also meets the voltage requirements of multi-channel isolated voltages, providing power for the energy meter. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the exemplary embodiments of this utility model, the drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this utility model and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings:

[0018] Figure 1 This is a schematic diagram of the DC auxiliary power supply circuit for the ultra-wide voltage input and ultra-wide voltage range of the energy meter according to this application;

[0019] Figure 2 This is a schematic diagram of the negative voltage circuit according to an embodiment of this application;

[0020] Figure 3 This is a schematic diagram of the input and negative voltage superposition circuit according to an embodiment of this application;

[0021] Figure 4 This is a schematic diagram of a flyback switching power supply circuit according to an embodiment of this application. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of this utility model are only used to explain this utility model and are not intended to limit this utility model.

[0023] Example

[0024] like Figures 1-4As shown in the figure, this application embodiment provides a DC auxiliary power supply circuit for an energy meter with an ultra-wide voltage input and ultra-wide voltage range, including: a negative voltage circuit, an input and negative voltage superposition circuit, and a flyback switching power supply circuit; the negative voltage circuit is used to convert a positive voltage into a negative voltage output, and output a stable negative power supply after voltage regulation; the input and negative voltage superposition circuit is used to superimpose the positive voltage input and the stable negative power supply; the flyback switching power supply circuit is used to output a multi-channel isolated voltage from the voltage after level superposition.

[0025] The negative voltage circuit includes a switching power supply chip; the switching power supply chip integrates a first high-frequency switching transistor, a control logic module, and a voltage conversion module; the first high-frequency switching transistor is used to switch on and off via high-frequency pulses; the control logic module is used to provide voltage regulation and protection for the positive voltage; the voltage conversion module is used to convert the positive voltage into a negative voltage; the switching power supply chip has a first VIN pin, a first SW pin, a first FB pin, a BST pin, and an EN pin; the first VIN pin is used to connect the positive voltage to the first high-frequency switching transistor; the first SW pin is used to connect the high-frequency pulse to the first high-frequency switching transistor; the input of the first FB pin is used to connect the sampled negative voltage to the control logic module; the BST pin is used to provide a drive voltage to the first high-frequency switching transistor; the EN pin is used to control the first high-frequency switching transistor to start.

[0026] The negative voltage circuit also includes an input filtering module; the input filtering module is connected to the output of the first VIN pin and is used to filter the positive voltage.

[0027] The negative voltage circuit also includes an energy conversion module; the energy conversion module is used to store energy when the first high-frequency switching transistor is turned on, and to supply power to the switching power supply chip when it is turned off.

[0028] The negative voltage circuit further includes an output voltage regulation and feedback module; the output voltage regulation and feedback module includes a voltage divider feedback module and a compensation network module; the voltage divider feedback module is used to send the sampled negative voltage back to the first FB pin; the compensation network module is used to provide phase compensation for the voltage divider feedback module.

[0029] The negative voltage circuit further includes a filtering and ripple suppression module; the filtering and ripple suppression module includes an output filtering module and a ripple smoothing module; the output filtering module is used to filter the negative voltage; the ripple smoothing module is used to smooth the negative voltage.

[0030] The negative voltage circuit also includes an auxiliary module; the auxiliary module includes a voltage driving module and an overcurrent protection module; the voltage driving module is connected to the input of the BST pin to provide the driving voltage; the overcurrent protection module is connected to the input of the EN pin for overcurrent protection.

[0031] The input and negative voltage superposition circuit includes a capacitive coupling module and a voltage regulation module; the capacitive coupling module is used to superimpose the positive voltage and the negative voltage; the voltage regulation module is used to regulate and store the voltage after the voltage is superimposed.

[0032] The flyback switching power supply circuit includes an input voltage regulator and filter module, a main control chip, a transformer, a secondary rectification and output module, a feedback and voltage regulator module, and a protection module. The input voltage regulator and filter module includes a filter capacitor and a Zener diode. The filter capacitor is connected to the positive voltage output to filter out high-frequency noise. The Zener diode is used to break down the positive voltage when it is too high. The main control chip is used for high-frequency switching control of the transformer for energy storage. The transformer includes a primary winding, a secondary winding, and an auxiliary winding. When the primary winding is conducting the main control chip, it stores energy; when it is off, the primary winding supplies power to the main control chip. The secondary winding... The turns ratio of the outputs of the group corresponds to the multi-channel output, which adjusts the output voltage. The auxiliary winding provides power to the main control chip after startup. The secondary rectification and output module includes a rectifier diode module, a filter and voltage regulator module, and a feedback and voltage regulator module. When the rectifier diode module senses the power supply of the primary winding, it conducts and rectifies the pulse voltage into a DC voltage. The filter and voltage regulator module is used to filter and stabilize the pulse voltage and the DC voltage. The feedback and voltage regulator module is used to isolate and stabilize the feedback loop of voltage changes in the primary winding and the secondary winding. The protection module is used to protect the primary winding, the primary winding, and the auxiliary winding.

[0033] The main control chip integrates a second high-frequency switch, a PWM controller, and a feedback voltage regulator module. The main control chip has a second VIN pin, a second SW pin, a second FB pin, and a COMP / RT pin. The input of the second VIN pin is connected to the power supply terminal. The second SW pin is used to connect the input terminal of the primary winding to the second high-frequency switch to switch the primary winding on and off at high frequency. The second FB pin is used to connect the input terminal of the secondary winding to the feedback voltage regulator module to stabilize the feedback signal of the secondary winding. The input terminal of the COMP / RT pin is used to connect the output terminal of the feedback voltage regulator module and the input terminal of the second high-frequency switch to the PWM controller, so that the PWM controller can dynamically adjust the duty cycle of the PWM controller and set the switching frequency of the second high-frequency switch based on the feedback signal of the secondary winding.

[0034] A positive voltage (Vin+, Vin-) is input to the negative voltage circuit, which then outputs a negative voltage (Vin-, Vf-). The negative voltage circuit works as follows: it uses a switching power supply chip (U17) to convert the positive voltage input into a negative voltage output. Through high-frequency switching, inductor energy storage, and feedback regulation, a stable negative power supply is output. Specifically, the switching power supply chip (U17) integrates a first high-frequency switching transistor (for high-frequency switching on and off) and a control logic module (for voltage regulation and protection), converting the input positive voltage (Vin+ / -) into a negative voltage (Vf-).

[0035] like Figure 2 As shown, the first VIN pin (pin 3) of the switching power supply chip receives a positive voltage input and is powered by an external Vin+ supply. The first SW pin (pin 5) is the switching node, a high-frequency pulse output terminal, connected to an inductor (L2) to achieve energy transfer. The first FB pin (pin 1) is the feedback pin, which samples the output voltage through a voltage divider resistor (R86 / R87) to dynamically adjust the switching duty cycle and stabilize the negative voltage. The EN pin (pin 7) is the enable terminal, which uses capacitor C29 to achieve power-on delay enable and noise filtering, controlling the chip startup.

[0036] The input filtering module includes C102 and C32, which filter the input positive voltage (Vin+ / -) to remove high-frequency noise (such as ripple and interference from the preceding circuit) and ensure stable operation of the chip.

[0037] The energy conversion module consists of an inductor (L2) and a diode (D3). When the first high-frequency switch is turned on, current flows through L2 and stores energy; when the first high-frequency switch is turned off, L2 releases energy and supplies power in reverse through the freewheeling diode (D3). Utilizing the characteristic that the inductor current cannot change abruptly, the voltage is reversed to a negative voltage. Diode D3 acts as a freewheeling diode, providing a circuit for the current in L2 when the first high-frequency switch is turned off, maintaining a negative voltage output.

[0038] In the output voltage regulation and feedback module: the voltage divider feedback module includes R86 and R87, which samples the output negative voltage (Vf-) and sends the divided signal back to the chip's first FB pin. The chip then adjusts the on-time (duty cycle) of the first high-frequency switch based on the feedback voltage to stabilize the output negative voltage (increasing the duty cycle to boost the voltage if it's too low, and decreasing it if it's too high). The compensation network module includes R30 and C26, providing phase compensation for the feedback loop to prevent high-frequency oscillations and improve the stability of the voltage regulation system.

[0039] In the filtering and ripple suppression, the output filtering module includes C106, which filters the final output negative voltage (Vf-), and the ripple smoothing module includes C33, which makes the negative voltage purer and meets the power supply accuracy requirements of subsequent circuits such as operational amplifiers and analog circuits.

[0040] In the auxiliary module: R29 is connected to the BST pin, which is the "bootstrap pin." Together with the external capacitor C104, it provides the drive voltage for the first high-frequency switching transistor inside the switching power supply chip. C29 is connected to the EN pin: This enables soft start or noise filtering. Upon power-up, C29 charges slowly, gradually increasing the EN pin voltage to avoid sudden large current surges in the chip; it also filters high-frequency interference at the EN pin.

[0041] Specifically, the input voltage (Vin+, Vin-) and the negative voltage (Vin-, Vf-) are simultaneously input to the input and negative voltage superposition circuit for voltage superposition. The superimposed voltage is (Vs+, Vs-) = (Vin+, Vf-). For example... Figure 3 As shown, the working principle of the input and negative voltage superposition circuit is as follows: the input voltage (Vin+, Vin-) and the negative voltage (Vin-, Vf-) are superimposed through the capacitive coupling of capacitors C103 and C105 and connected to the voltage node, and then the voltage is regulated and stored through CS1.

[0042] The superimposed voltages (Vs+, Vs-) are input to the flyback switching power supply circuit, which outputs multiple isolated voltages. For example... Figure 1 , Figure 4 As shown, taking a 3-channel isolation voltage as an example, the output has 3 isolation voltages: (Vo1+, GND1), (Vo2+, GND2), and (Vo3+, GND3). The working principle of the flyback switching power supply circuit is as follows: In the input voltage regulation and filtering module, CS2 (filter capacitor) is used to filter out high-frequency noise in the input voltage and stabilize the input; DS2 (zener diode) is used for overvoltage protection. When the input voltage is too high (such as a surge), DS2 breaks down the voltage regulator, protecting the subsequent circuits. The main control chip (US1) integrates a second high-frequency switching transistor, corresponding to the second SW pin, which controls the switching between the primary winding of the transformer and Vs-. The feedback voltage regulator circuit, corresponding to the second FB pin, is connected to the feedback input of the feedback optocoupler and the voltage divider resistor, and provides a comparison signal with the internal 1.2V reference to the PWM controller. The PWM controller receives the comparison signal from the feedback voltage regulator circuit, adjusts the switching frequency / duty cycle, and stabilizes the output voltage. The undervoltage and overvoltage protection module, corresponding to the second LINE pin, is connected to a voltage detection circuit composed of resistors RS2, RS3, and RS4. When the input voltage is undervoltage or overvoltage, the second high-frequency switching transistor is turned off to protect the circuit.

[0043] Key functions of the pins: Second VIN pin: Input voltage power supply terminal; Second SW pin: Connects to the primary winding (Np) of the transformer, controlling energy storage through high-frequency switching; Second FB pin: Receives the secondary winding voltage feedback signal, dynamically adjusts the duty cycle of the PWM controller, and stabilizes the output voltage; COMP pin: Connects to the feedback loop compensation circuit to stabilize the PWM controller; RT pin: Connects to external resistor RS5 and capacitor CS3 to set the switching frequency.

[0044] Transformer (T1): Primary winding (Np): Connected in series with the second high-frequency switching transistor (corresponding to the second SW pin of US1), it stores energy when turned on and releases energy when turned off via flyback; Secondary winding (multiple sets): Corresponds to multiple outputs (Vo1+, Vo2+, Vo3+, etc.), and the output voltage is adjusted by the turns ratio. The more turns, the higher the output voltage; Auxiliary winding (Naux): Connected to diode DS4 for rectification, filtered by diode DS5 and capacitor CS5, and supplies power to the VCC pin of US1, providing the operating power VCCS for the main control chip US1, realizing self-sustaining power supply after startup.

[0045] The secondary rectification and output module includes: several rectifier diodes (DS1, DS7, DS8): when the switching transistor is turned off, a reverse voltage (flyback voltage) is induced in the secondary winding, the diodes conduct, and the pulse voltage is rectified into DC; the filtering and voltage regulation module includes: several inductors (LS3, LS4): energy storage and filtering to smooth the rectified pulse voltage; several capacitors (CS11, CS15, CS20, etc.): filtering out high-frequency ripple and stabilizing the output DC voltage; and several dummy loads (resistors RS1, RS17, RS18): maintaining voltage stability under light load, as flyback power supplies are prone to oscillation under light load, and the dummy loads consume a small current to ensure output.

[0046] The feedback and voltage regulation module includes: an optocoupler (OPS1): This provides safe feedback isolation between the primary and secondary windings, preventing high voltage from entering the control circuit. When the secondary winding voltage changes, the voltage is sampled via resistors RS15 and RS12, driving a change in the LED intensity inside the OPS1 input side. This change then drives the current flowing through the phototransistor inside the OPS1 output terminal, feeding back to the second FB pin of the main control chip US1 to dynamically adjust the duty cycle of the PWM controller and stabilize the output voltage. A compensation network (including resistors RS8 and RS9, capacitor CS7, etc.) provides phase compensation for the feedback loop, preventing high-frequency oscillations and ensuring the stability of the voltage regulation system.

[0047] The protection module circuit includes: a clamping diode (DS3) and an RC snubber circuit (resistor RS6, capacitor CS4): When the switching transistor is turned off, the leakage inductance energy of the transformer will generate a high voltage spike at the second SW pin (pin 8) of chip US1. Diode DS3, resistor RS6, and capacitor CS4 form an RCD clamping circuit to absorb the spike voltage and protect the switching transistor in US1; Zener diode DS6 regulates the chip power supply VCCS: When the chip power supply voltage VCCS is higher than the chip's normal operating voltage, the Zener diode breaks down in reverse, clamping the VCCS voltage and stabilizing the VCCS voltage to supply power to the main control chip US1, preventing damage to the chip due to excessive voltage; Undervoltage / Overvoltage protection: Input voltage is sampled through components such as resistor RS2, resistor RS3, and resistor RS4. When an abnormal input voltage is detected, the switching transistor is turned off to protect the circuit.

[0048] In application, the input range of the flyback switching power supply is DC 18V-100V. The input voltage design range of the electricity meter power supply is DC 4.5V-72V. The negative voltage value (Vin-, Vf-) output by the negative voltage circuit can be adjusted according to the specific flyback power supply scheme used. For example, the negative voltage value is designed to be 15V, i.e., (Vin-, Vf-) = 15V. When the electricity meter power supply input (Vin+, Vin-) = 4.5V, the flyback switching power supply input (Vs+, Vs-) = (Vin+, Vf-) = 19.5V; when the electricity meter power supply input (Vin+, Vin-) = 72V, the flyback switching power supply input (Vs+, Vs-) = (Vin+, Vf-) = 87V; therefore, when the electricity meter power supply input is 4.5V and 72V, the requirement of the flyback switching power supply input range of DC 18V-100V is met.

[0049] This application significantly extends the input voltage range to DC 4.5V-72V, making it compatible with various low-voltage DC power supply voltages in industrial environments. Furthermore, the power supply circuit of this application features multiple isolated outputs, substantially reducing the cost of the power supply circuit in the energy meter and improving power supply reliability.

[0050] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this utility model. It should be understood that the above description is only a specific embodiment of this utility model and is not intended to limit the scope of protection of this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. A DC auxiliary power supply circuit for an electricity meter with an ultra-wide voltage input and ultra-wide voltage range, characterized in that, include: Negative voltage circuit, input and negative voltage superposition circuit, and flyback switching power supply circuit; The negative voltage circuit is used to convert the positive voltage into a negative voltage output, and after voltage regulation, outputs a stable negative power supply; the input and negative voltage superposition circuit is used to superimpose the positive voltage input and the stable negative power supply; the flyback switching power supply circuit is used to output a multi-channel isolated voltage from the superimposed voltage.

2. The DC auxiliary power supply circuit for an energy meter with an ultra-wide voltage input and ultra-wide voltage range according to claim 1, characterized in that, The negative voltage circuit includes a switching power supply chip; the switching power supply chip integrates a first high-frequency switching transistor, a control logic module, and a voltage conversion module; the first high-frequency switching transistor is used to switch on and off via high-frequency pulses; the control logic module is used to provide voltage regulation and protection for the positive voltage; the voltage conversion module is used to convert the positive voltage into a negative voltage; the switching power supply chip has a first VIN pin, a first SW pin, a first FB pin, a BST pin, and an EN pin; the first VIN pin is used to connect the positive voltage to the first high-frequency switching transistor; the first SW pin is used to connect the high-frequency pulse to the first high-frequency switching transistor; the input of the first FB pin is used to connect the sampled negative voltage to the control logic module; the BST pin is used to provide a drive voltage to the first high-frequency switching transistor; the EN pin is used to control the first high-frequency switching transistor to start.

3. The DC auxiliary power supply circuit for an energy meter with an ultra-wide voltage input and ultra-wide voltage range according to claim 2, characterized in that, The negative voltage circuit also includes an input filtering module; the input filtering module is connected to the output of the first VIN pin and is used to filter the positive voltage.

4. The DC auxiliary power supply circuit for an energy meter with an ultra-wide voltage input and ultra-wide voltage range according to claim 3, characterized in that, The negative voltage circuit also includes an energy conversion module; the energy conversion module is used to store energy when the first high-frequency switching transistor is turned on, and to supply power to the switching power supply chip when it is turned off.

5. The DC auxiliary power supply circuit for an energy meter with an ultra-wide voltage input and ultra-wide voltage range according to claim 4, characterized in that, The negative voltage circuit further includes an output voltage regulation and feedback module; the output voltage regulation and feedback module includes a voltage divider feedback module and a compensation network module; the voltage divider feedback module is used to send the sampled negative voltage back to the first FB pin; the compensation network module is used to provide phase compensation for the voltage divider feedback module.

6. The DC auxiliary power supply circuit for an energy meter with an ultra-wide voltage input and ultra-wide voltage range according to claim 5, characterized in that, The negative voltage circuit further includes a filtering and ripple suppression module; the filtering and ripple suppression module includes an output filtering module and a ripple smoothing module; the output filtering module is used to filter the negative voltage; the ripple smoothing module is used to smooth the negative voltage.

7. The DC auxiliary power supply circuit for an energy meter with an ultra-wide voltage input and ultra-wide voltage range according to claim 6, characterized in that, The negative voltage circuit also includes an auxiliary module; the auxiliary module includes a voltage driving module and an overcurrent protection module; the voltage driving module is connected to the input of the BST pin to provide the driving voltage; The overcurrent protection module is connected to the input of the EN pin for overcurrent protection.

8. The DC auxiliary power supply circuit for an energy meter with an ultra-wide voltage input and ultra-wide voltage range according to claim 7, characterized in that, The input and negative voltage superposition circuit includes a capacitive coupling module and a voltage regulation module; the capacitive coupling module is used to superimpose the positive voltage and the negative voltage; the voltage regulation module is used to regulate and store the voltage after the voltage is superimposed.

9. The DC auxiliary power supply circuit for an energy meter with an ultra-wide voltage input and ultra-wide voltage range according to claim 1, characterized in that, The flyback switching power supply circuit includes an input voltage regulator and filter module, a main control chip, a transformer, a secondary rectification and output module, a feedback and voltage regulator module, and a protection module. The input voltage regulator and filter module includes a filter capacitor and a Zener diode. The filter capacitor is connected to the positive voltage output to filter out high-frequency noise. The Zener diode is used to break down the positive voltage when it is too high. The main control chip is used for high-frequency switching control of the transformer for energy storage. The transformer includes a primary winding, a secondary winding, and an auxiliary winding. When the primary winding is conducting the main control chip, it stores energy; when it is off, the primary winding supplies power to the main control chip. The secondary winding... The turns ratio of the outputs of the group corresponds to the multi-channel output, which adjusts the output voltage. The auxiliary winding provides power to the main control chip after startup. The secondary rectification and output module includes a rectifier diode module, a filter and voltage regulator module, and a feedback and voltage regulator module. When the rectifier diode module senses the power supply of the primary winding, it conducts and rectifies the pulse voltage into a DC voltage. The filter and voltage regulator module is used to filter and stabilize the pulse voltage and the DC voltage. The feedback and voltage regulator module is used to isolate and stabilize the feedback loop of voltage changes in the primary winding and the secondary winding. The protection module is used to protect the primary winding, the primary winding, and the auxiliary winding.

10. The DC auxiliary power supply circuit for an energy meter with an ultra-wide voltage input and ultra-wide voltage range according to claim 9, characterized in that, The main control chip integrates a second high-frequency switch, a PWM controller, and a feedback voltage regulator module. The main control chip has a second VIN pin, a second SW pin, a second FB pin, and a COMP / RT pin. The input of the second VIN pin is connected to the power supply terminal. The second SW pin is used to connect the input terminal of the primary winding to the second high-frequency switch to switch the primary winding on and off at high frequency. The second FB pin is used to connect the input terminal of the secondary winding to the feedback voltage regulator module to stabilize the feedback signal of the secondary winding. The input terminal of the COMP / RT pin is used to connect the output terminal of the feedback voltage regulator module and the input terminal of the second high-frequency switch to the PWM controller, so that the PWM controller can dynamically adjust the duty cycle of the PWM controller and set the switching frequency of the second high-frequency switch based on the feedback signal of the secondary winding.

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