A current sampling / over-temperature protection multiplexing circuit and method, power supply circuit and power supply chip

Abstract

The present disclosure relates to the technical field of power supply, in particular to a current sampling / over-temperature protection multiplexing circuit and method, a power supply circuit and a power supply chip, the power supply circuit comprising the current sampling / over-temperature protection multiplexing circuit, by setting a current transformer, a first rectifier diode, a first high-precision resistor, a second high-precision resistor and a bimetallic disc thermal protector in the current sampling / over-temperature protection multiplexing circuit, so as to accurately collect the voltage signal and the ambient temperature of the power supply circuit by the current sampling / over-temperature protection multiplexing circuit, so that the power supply chip can control the power supply circuit according to the comparison result between the preset voltage threshold value or the ambient temperature and the preset temperature reset value, and realize current protection and over-temperature protection. The present disclosure does not need to additionally set a temperature protection circuit, but increases the bimetallic disc thermal protector in the current sampling circuit, so as to realize the current monitoring and accurate over-temperature protection function, and the reliability is high.

Description

Technical Field

[0001] This disclosure relates to the field of power supply technology, specifically to a current sampling / over-temperature protection multiplexing circuit and method, a power supply circuit, and a power supply chip. Background Technology

[0002] In industrial, communications, and lighting applications, it is crucial to take immediate and effective protective measures when power module temperatures become abnormal. This is not only to prevent irreversible damage to the power system, but also to ensure the long-term stable operation of the systems in which the power supply is used.

[0003] Traditionally, to address potential temperature anomalies in power modules, the conventional approach is to add extra temperature protection circuits, which undoubtedly enhances the power module's safety capabilities. However, this solution also brings a series of problems: the circuit structure becomes more complex, increasing the complexity and workload of circuit design and debugging; furthermore, the added circuit components occupy valuable board space, placing more stringent requirements on board layout and wiring strategies; moreover, because the temperature protection circuit involves many components, its performance is easily affected by external factors such as ambient temperature and humidity, thus increasing the risk of circuit failure; more importantly, this solution may also lead to increased standby power consumption and a decline in the overall efficiency of the switching power supply, ultimately resulting in wasted energy and a shortened equipment lifespan. Therefore, the current technological field faces an urgent task: how to achieve a highly reliable and accurate temperature protection mechanism in power modules without relying on extra temperature protection circuits. Summary of the Invention

[0004] To address the problems in the related technologies, embodiments of this disclosure provide a current sampling / over-temperature protection multiplexing circuit and method, a power supply circuit, and a power supply chip.

[0005] In a first aspect, this disclosure provides a power supply circuit with a current sampling / over-temperature protection multiplexing circuit. The power supply circuit includes: a power chip, a first polarized capacitor, a transformer, an NMOS transistor, and a current sampling / over-temperature protection multiplexing circuit. The current sampling / over-temperature protection multiplexing circuit includes: a current transformer, a first rectifier diode, a first high-precision resistor, a second high-precision resistor, and a bimetallic disc thermal protector.

[0006] The positive terminal of the first polarized capacitor is connected to one end of the primary coil of the transformer, the negative terminal of the first polarized capacitor is grounded, and the other end of the primary coil of the transformer is connected to the drain of the NMOS transistor. The gate of the NMOS transistor is connected to the drive pin of the power chip, the source of the NMOS transistor is connected to the primary side P1 terminal of the current transformer, and the primary side P2 terminal of the current transformer is grounded. The secondary side K1 terminal of the current transformer is connected to the positive terminal of the first rectifier diode, the negative terminal of the first rectifier diode is connected to one end of the first high-precision resistor, and the secondary side K2 terminal of the current transformer is connected to one end of the second high-precision resistor. One end of the bimetallic disc thermal protector is connected to the other end of the first high-precision resistor and the other end of the second high-precision resistor, and the other end of the bimetallic disc thermal protector is connected to the current detection pin of the power chip. The bimetallic disc thermal protector is provided with a preset temperature reset value, and the power chip is provided with a preset voltage threshold. The current sampling / over-temperature protection multiplexing circuit collects the voltage signal and ambient temperature of the power supply circuit; when the collected voltage signal exceeds the preset voltage threshold or when the collected ambient temperature exceeds the preset temperature reset value, the power chip controls the power supply circuit to stop working, thereby realizing the current protection and over-temperature protection of the power supply circuit.

[0007] According to embodiments of this disclosure, the power chip internally includes an integrated comparator and a control unit; The power chip receives the voltage signal of the power circuit through the current detection pin. The integrated comparator compares the voltage signal of the power circuit with the preset voltage threshold and sends the comparison result of the voltage signal of the power circuit and the preset voltage threshold to the control unit.

[0008] According to embodiments of this disclosure, when the acquired voltage signal exceeds the preset voltage threshold or when the acquired ambient temperature exceeds the preset temperature reset value, the power chip controls the power circuit to stop working, including: When the comparison result indicates that the acquired voltage signal exceeds the preset voltage threshold, the control unit controls the drive pin to stop outputting the drive signal; or When the ambient temperature collected exceeds the preset temperature reset value, the contact switch of the bimetallic disc thermal protector is opened, the power chip cannot receive a current signal through the current detection pin, and the control unit controls the drive pin to stop outputting the drive signal.

[0009] According to an embodiment of this disclosure, after the power supply circuit stops working, when the acquired voltage signal drops below the preset voltage threshold or when the acquired ambient temperature drops to the preset temperature reset value, the power chip controls the power supply circuit to resume working.

[0010] According to embodiments of this disclosure, when the acquired voltage signal drops below the preset voltage threshold or when the acquired ambient temperature drops to the preset temperature reset value, the power chip controls the power circuit to resume operation, including: When the comparison result indicates that the acquired voltage signal drops below the preset voltage threshold, the control unit controls the drive pin to output a drive signal. or When the ambient temperature is reduced to the preset temperature reset value, the contact switch of the bimetallic disc thermal protector closes, and the control unit controls the drive pin to output a drive signal.

[0011] According to an embodiment of this disclosure, when the current sampling / over-temperature protection multiplexing circuit acquires the voltage signal of the power supply circuit and the ambient temperature, the current sampling / over-temperature protection multiplexing circuit uses the voltage value across the second high-precision resistor as the voltage signal of the power supply circuit.

[0012] According to embodiments of this disclosure, the power supply circuit further includes: a second rectifier diode and a second polarity capacitor; The positive terminal of the second rectifier diode is connected to one end of the secondary coil of the transformer, and the other end of the secondary coil is grounded. The negative terminal of the second rectifier diode is connected to the positive terminal of the second polarized capacitor, and the negative terminal of the second polarized capacitor is connected to the load ground of the user equipment.

[0013] Secondly, this disclosure provides a current sampling / over-temperature protection multiplexing circuit, configured in a power supply circuit. The power supply circuit further includes: a power chip, a first polarized capacitor, a transformer, and an NMOS transistor. The positive terminal of the first polarized capacitor is connected to one end of the primary winding of the transformer, and the negative terminal of the first polarized capacitor is grounded. The other end of the primary winding of the transformer is connected to the drain of the NMOS transistor, and the gate of the NMOS transistor is connected to the drive pin of the power chip. The power chip is configured with a preset voltage threshold. The current sampling / over-temperature protection multiplexing circuit includes: Current transformer, first rectifier diode, first high-precision resistor, second high-precision resistor and bimetallic disc thermal protector; The primary side P1 terminal of the current transformer is connected to the source of the NMOS transistor, and the primary side P2 terminal of the current transformer is grounded. The secondary side K1 terminal of the current transformer is connected to the positive terminal of the first rectifier diode, the negative terminal of the first rectifier diode is connected to one end of the first high-precision resistor, and the secondary side K2 terminal of the current transformer is connected to one end of the second high-precision resistor. One end of the bimetallic disc thermal protector is connected to the other end of the first high-precision resistor and the other end of the second high-precision resistor, and the other end of the bimetallic disc thermal protector is connected to the current detection pin of the power chip. The bimetallic disc thermal protector is provided with a preset temperature reset value. The current sampling / over-temperature protection multiplexing circuit collects the voltage signal and ambient temperature of the power supply circuit. The bimetallic disc thermal protector controls the opening and closing of the current sampling / over-temperature protection multiplexing circuit and the power chip based on the collected ambient temperature. The current sampling / over-temperature protection multiplexing circuit transmits the collected voltage signal of the power supply circuit to the power chip, so that the power chip controls the power supply circuit to achieve current protection and over-temperature protection according to the collected voltage signal of the power supply circuit or the opening and closing of the current sampling / over-temperature protection multiplexing circuit and the power chip.

[0014] According to an embodiment of this disclosure, the current sampling / over-temperature protection multiplexing circuit uses the voltage value across the second high-precision resistor as the voltage signal of the power supply circuit.

[0015] According to embodiments of this disclosure, the power chip controls the power circuit to achieve current protection and over-temperature protection based on the acquired voltage signal of the power circuit or the opening and closing of the current sampling / over-temperature protection multiplexing circuit and the power chip, including: The power chip compares the acquired voltage signal of the power circuit with the preset voltage threshold. When the acquired voltage signal exceeds the preset voltage threshold, or when the current sampling / over-temperature protection multiplexing circuit is disconnected from the power chip, the power chip controls the power circuit to stop working, thereby realizing the current protection and over-temperature protection of the power circuit.

[0016] Thirdly, this disclosure provides a power chip disposed in a power supply circuit. The power supply circuit further includes a first polarized capacitor, a transformer, an NMOS transistor, and a current sampling / over-temperature protection multiplexing circuit. The positive terminal of the first polarized capacitor is connected to one end of the primary coil of the transformer, and the negative terminal of the first polarized capacitor is grounded. The other end of the primary coil of the transformer is connected to the drain of the NMOS transistor. The gate of the NMOS transistor is connected to the drive pin of the power chip, and the source of the NMOS transistor is connected to one end of the current sampling / over-temperature protection multiplexing circuit. The other end of the current sampling / over-temperature protection multiplexing circuit is connected to the current detection pin of the power chip. The power chip includes a control unit and an integrated comparator. The control unit is configured to receive the voltage signal of the power supply circuit transmitted by the current sampling / over-temperature protection multiplexing circuit through the current detection pin, and send the voltage signal of the power supply circuit to the integrated comparator. The integrated comparator is configured to compare the voltage signal of the power supply circuit with a preset voltage threshold, and send the comparison result of the voltage signal of the power supply circuit and the preset voltage threshold to the control unit. The control unit is configured to control the drive pin to stop outputting the drive signal when the comparison result indicates that the voltage signal of the power supply circuit exceeds the preset voltage threshold, or when no current signal is received through the current detection pin.

[0017] Fourthly, this disclosure provides a method for providing current and over-temperature protection to a power supply circuit using a current sampling / over-temperature protection multiplexing circuit. The current sampling / over-temperature protection multiplexing circuit includes: a current transformer, a first rectifier diode, a first high-precision resistor, a second high-precision resistor, and a bimetallic disc thermal protector. The primary side P1 terminal of the current transformer is connected to the source of the NMOS transistor in the power supply circuit, and the primary side P2 terminal of the current transformer is grounded. The secondary side K1 terminal of the current transformer is connected to the anode of the first rectifier diode, the cathode of the first rectifier diode is connected to one end of the first high-precision resistor, and the secondary side K2 terminal of the current transformer is connected to one end of the second high-precision resistor. One end of the bimetallic disc thermal protector is connected to the other end of the first high-precision resistor and the other end of the second high-precision resistor, and the other end of the bimetallic disc thermal protector is connected to the current detection pin of the power supply chip in the power supply circuit. The bimetallic disc thermal protector is provided with a preset temperature reset value. The method includes: The current sampling / over-temperature protection multiplexing circuit collects the voltage signal and ambient temperature of the power supply circuit, and the bimetallic disc thermal protector controls the opening and closing of the current sampling / over-temperature protection multiplexing circuit and the power chip based on the collected ambient temperature. The current sampling / over-temperature protection multiplexing circuit transmits the collected voltage signal of the power supply circuit to the power chip. The power chip compares the acquired voltage signal of the power circuit with a preset voltage threshold. When the acquired voltage signal exceeds the preset voltage threshold, or when the current sampling / over-temperature protection multiplexing circuit is disconnected from the power chip, the power chip controls the power circuit to stop working, thereby realizing the current protection and over-temperature protection of the power circuit.

[0018] According to embodiments of this disclosure: The power chip has an integrated comparator and control unit inside; The power chip compares the acquired voltage signal of the power circuit with a preset voltage threshold, including: the power chip receiving the voltage signal of the power circuit through the current detection pin; the integrated comparator comparing the voltage signal of the power circuit with the preset voltage threshold; and sending the comparison result of the voltage signal of the power circuit and the preset voltage threshold to the control unit.

[0019] According to embodiments of this disclosure, when the acquired voltage signal exceeds the preset voltage threshold, or when the current sampling / over-temperature protection multiplexing circuit is disconnected from the power chip, the power chip controls the power circuit to stop working, including: When the comparison result indicates that the acquired voltage signal exceeds the preset voltage threshold, the control unit controls the drive pin to stop outputting the drive signal; or When the ambient temperature collected exceeds the preset temperature reset value, the contact switch of the bimetallic disc thermal protector is opened, the power chip cannot receive a current signal through the current detection pin, and the control unit controls the drive pin to stop outputting the drive signal.

[0020] According to an embodiment of this disclosure, the method further includes: after the power supply circuit stops working, when the acquired voltage signal drops to within the preset voltage threshold or when the acquired ambient temperature drops to the preset temperature reset value, the power chip controls the power supply circuit to resume working.

[0021] According to the technical solution provided in the embodiments of this disclosure, the power supply circuit includes a current sampling / over-temperature protection multiplexing circuit. By setting a current transformer, a first rectifier diode, a first high-precision resistor, a second high-precision resistor, and a bimetallic disc thermal protector in the current sampling / over-temperature protection multiplexing circuit, the voltage signal and ambient temperature of the power supply circuit can be accurately acquired. This allows the power chip to control the power supply circuit based on a preset voltage threshold or a comparison between the ambient temperature and a preset temperature reset value, thereby achieving current protection and over-temperature protection.

[0022] This disclosure eliminates the need for additional temperature protection circuitry. Instead, it cleverly incorporates a bimetallic disc thermal protector into the current sampling circuit. This reused design of the current sampling circuit not only retains the original current detection function but also provides the power supply circuit with precise over-temperature protection. Simultaneously, it simplifies the circuit structure, greatly enhances ease of use, and effectively reduces the number of required components. As a result, the overall cost and power consumption of the power module are significantly reduced, and it can respond rapidly to abnormal temperature increases, providing precise over-temperature protection. This effectively prevents circuit damage or performance degradation caused by overheating, ensuring the long-term stable operation of the power system.

[0023] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

[0024] Other features, objects, and advantages of this disclosure will become more apparent from the following detailed description of non-limiting embodiments, taken in conjunction with the accompanying drawings. In the drawings: Figure 1 A logic structure diagram of a power supply circuit having a current sampling / over-temperature protection multiplexing circuit according to an embodiment of the present disclosure is shown. Figure 2 A schematic diagram of the circuit structure of a power supply circuit having a current sampling / over-temperature protection multiplexing circuit according to an embodiment of the present disclosure is shown. Figure 3 This diagram illustrates the structure of a power chip according to an embodiment of the present disclosure. Figure 4 A flowchart is shown illustrating a method for providing current protection and over-temperature protection to a power supply circuit using a current sampling / over-temperature protection multiplexing circuit according to an embodiment of the present disclosure. Detailed Implementation

[0025] In the following, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings to enable those skilled in the art to readily implement them. Furthermore, for clarity, portions unrelated to the description of exemplary embodiments have been omitted from the drawings.

[0026] In this disclosure, it should be understood that terms such as “comprising” or “having” are intended to indicate the presence of features, figures, steps, behaviors, components, parts or combinations thereof disclosed in this specification, and are not intended to exclude the possibility of the presence or addition of one or more other features, figures, steps, behaviors, components, parts or combinations thereof.

[0027] It should also be noted that, unless otherwise specified, the embodiments and features described in this disclosure can be combined with each other. This disclosure will now be described in detail with reference to the accompanying drawings and embodiments.

[0028] In this disclosure, any operation involving the acquisition of user information or user data, or the display of user information or user data to others, is an operation authorized or confirmed by the user, or actively selected by the user.

[0029] As mentioned earlier, adding an extra temperature protection circuit brings about a series of problems: 1. The circuit structure becomes more complex, which increases the complexity and workload of circuit design and debugging.

[0030] 2. The additional circuit components occupy valuable circuit board space, placing more stringent requirements on circuit board layout and routing strategies.

[0031] 3. Because temperature protection circuits involve many components, their performance is easily affected by external factors such as ambient temperature and humidity, which increases the risk of circuit failure.

[0032] 4. Increased standby power consumption and decreased overall efficiency of switching power supplies lead to energy waste and reduced equipment lifespan.

[0033] This disclosure provides a power supply circuit with a current sampling / over-temperature protection multiplexing circuit, including: a power supply chip, a first polarized capacitor, a transformer, an NMOS transistor, and a current sampling / over-temperature protection multiplexing circuit. The current sampling / over-temperature protection multiplexing circuit includes: a current transformer, a first rectifier diode, a first high-precision resistor, a second high-precision resistor, and a bimetallic disc thermal protector. The positive terminal of the first polarized capacitor is connected to one end of the primary winding of the transformer, and the negative terminal of the first polarized capacitor is grounded. The other end of the primary winding of the transformer is connected to the drain of the NMOS transistor. The gate of the NMOS transistor is connected to the drive pin of the power supply chip, and the source of the NMOS transistor is connected to the primary side P1 terminal of the current transformer. The primary side P2 terminal of the current transformer is grounded. The secondary side K1 terminal of the current transformer is connected to the positive terminal of the first rectifier diode. The negative terminal of the first rectifier diode is connected to one end of the first high-precision resistor, and the secondary side K2 terminal of the current transformer is connected to one end of the second high-precision resistor; one end of the bimetallic disc thermal protector is connected to the other end of the first high-precision resistor and the other end of the second high-precision resistor, and the other end of the bimetallic disc thermal protector is connected to the current detection pin of the power chip; wherein, the bimetallic disc thermal protector is set with a preset temperature reset value, and the power chip is set with a preset voltage threshold; the current sampling / over-temperature protection multiplexing circuit collects the voltage signal of the power circuit and the ambient temperature; when the collected voltage signal exceeds the preset voltage threshold or when the collected ambient temperature exceeds the preset temperature reset value, the power chip controls the power circuit to stop working, thereby realizing the current protection and over-temperature protection of the power circuit.

[0034] This disclosure eliminates the need for an additional temperature protection circuit. Instead, it cleverly incorporates a bimetallic disc thermal protector into the current sampling circuit. This reusable design not only retains the original current monitoring function but also provides the power supply circuit with precise over-temperature protection. Simultaneously, it simplifies the circuit structure and effectively reduces the number of required components. This lowers the cost of the power module and enables a rapid response when the power module temperature rises abnormally, providing accurate over-temperature protection and effectively preventing circuit damage or performance degradation due to overheating, thus ensuring the long-term stable operation of the power system.

[0035] Figure 1 A logic diagram of a power supply circuit having a current sampling / over-temperature protection multiplexing circuit according to an embodiment of the present disclosure is shown.

[0036] like Figure 1 As shown, the power supply circuit includes: a power chip, a first polarity capacitor, a transformer, an NMOS transistor, and a current sampling / over-temperature protection multiplexing circuit.

[0037] The first polarity capacitor acts as a filter element, filtering out the AC component (ripple) in the DC voltage, making the output voltage more stable.

[0038] A transformer transmits and distributes electrical energy by changing the amplitude and phase of the filtered voltage.

[0039] NMOS transistors are used to control the flow of current based on an input signal (obtained from a power supply chip).

[0040] A current sampling / over-temperature protection multiplexing circuit can simultaneously achieve current sampling and over-temperature protection in the power supply circuit.

[0041] Figure 2 A schematic diagram of the circuit structure of a power supply circuit having a current sampling / over-temperature protection multiplexing circuit according to an embodiment of the present disclosure is shown.

[0042] like Figure 2 As shown, the power supply circuit includes: a power chip, a first polarized capacitor C1, a transformer T1, an NMOS transistor Q1, and a current sampling / over-temperature protection multiplexing circuit; wherein, the current sampling / over-temperature protection multiplexing circuit includes: a current transformer T2, a first rectifier diode D1, a first high-precision resistor R1, a second high-precision resistor R2, and a bimetallic disc thermal protector RT.

[0043] Specifically, the positive terminal of the first polarized capacitor C1 is connected to one end of the primary coil of the transformer T1, the negative terminal of the first polarized capacitor C1 is grounded, and the other end of the primary coil of the transformer T1 is connected to the drain of the NMOS transistor Q1; the gate of the NMOS transistor Q1 is connected to the drive pin of the power supply chip, the source of the NMOS transistor Q1 is connected to the primary side P1 terminal of the current transformer T2, and the primary side P2 terminal of the current transformer T2 is grounded; the secondary side K1 terminal of the current transformer T2 is connected to the positive terminal of the first rectifier diode D1, the negative terminal of the first rectifier diode D1 is connected to one end of the first high-precision resistor R1, and the secondary side K2 terminal of the current transformer T2 is connected to one end of the second high-precision resistor R2; one end of the bimetallic disc thermal protector RT is connected to the other end of the first high-precision resistor R1 and the other end of the second high-precision resistor R2, and the other end of the bimetallic disc thermal protector RT is connected to the current detection pin of the power supply chip.

[0044] The bimetallic disc thermal protector RT is equipped with a preset temperature reset value, and the power chip is equipped with a preset voltage threshold.

[0045] This disclosure implements current sampling and over-temperature protection through the aforementioned current sampling / over-temperature protection multiplexing circuit, specifically as follows: The current sampling / over-temperature protection multiplexing circuit collects the voltage signal and ambient temperature of the power supply circuit. When the collected voltage signal exceeds the preset voltage threshold or when the collected ambient temperature exceeds the preset temperature reset value, the power chip controls the power supply circuit to stop working, thereby realizing the current protection and over-temperature protection of the power supply circuit.

[0046] During normal operation, the power chip outputs a pulse width modulation (PWM) drive signal through its drive pin to drive and control the power circuit. However, when the acquired voltage signal exceeds the preset voltage threshold or the acquired ambient temperature exceeds the preset temperature reset value, the power chip will activate a protection mechanism, stopping the output of the PWM drive signal and halting the operation of the power circuit.

[0047] The following is a more detailed explanation of how the current sampling / over-temperature protection multiplexing circuit implements current sampling and over-temperature protection: In this disclosure, over-temperature protection is achieved through the current sampling / over-temperature protection multiplexing circuit as follows: a bimetallic disc thermal protector is used to sense changes in the ambient temperature via its internal bimetallic strip to collect ambient temperature data. When the ambient temperature rises, the bimetallic strip bends and deforms, the degree of which is related to the amount of change in ambient temperature. When the ambient temperature exceeds a preset temperature reset value, the bimetallic strip bends sufficiently to push the contact switch to disconnect the circuit. When the ambient temperature drops below the preset temperature reset value, the bimetallic strip returns to its original shape, and the contact switch closes again.

[0048] Therefore, when the collected ambient temperature exceeds the preset temperature reset value, the power chip controls the power circuit to stop working. That is, when the collected ambient temperature exceeds the preset temperature reset value, the contact switch of the bimetallic disc thermal protector is opened, the power chip cannot receive a current signal through the current detection pin, and the control unit controls the drive pin to stop outputting the drive signal.

[0049] After the power circuit stops working, when the collected ambient temperature drops to the preset temperature reset value, the power chip controls the power circuit to resume working. That is, when the collected ambient temperature drops to the preset temperature reset value, the contacts of the bimetallic disc thermal protector close, and the control unit controls the drive pin to output a drive signal.

[0050] In this disclosure, current sampling is achieved through the current sampling / over-temperature protection multiplexing circuit as follows: An integrated comparator and control unit are internally integrated into the power chip. The power chip receives the voltage signal from the power circuit through the current detection pin. The integrated comparator compares the voltage signal from the power circuit with a preset voltage threshold and sends the comparison result to the control unit. The current sampling / over-temperature protection multiplexing circuit uses the voltage value across the second high-precision resistor as the voltage signal from the power circuit.

[0051] When the acquired voltage signal exceeds the preset voltage threshold, the power chip controls the power circuit to stop working. That is, when the acquired voltage signal exceeds the preset voltage threshold, the control unit controls the drive pin to stop outputting the drive signal.

[0052] After the power supply circuit stops working, when the acquired voltage signal drops to within the preset voltage threshold, the power chip controls the power supply circuit to resume working. That is, when the acquired voltage signal drops to within the preset voltage threshold, the control unit controls the drive pin to output a drive signal.

[0053] This disclosure utilizes a current sampling / over-temperature protection multiplexing circuit. By adding a bimetallic disc thermal protector to the current sampling circuit of the power supply circuit, over-temperature protection is multiplexed. The structure is relatively simple, without complex electronic components or circuits, and has high reliability. It also has a fast response speed to temperature changes, can sense and respond to temperature changes in a short time, and can respond quickly when the power module temperature rises abnormally, providing accurate over-temperature protection.

[0054] Therefore, this disclosure, while retaining current detection, endows the power supply circuit with precise over-temperature protection capabilities, effectively reducing the number of required components and simplifying the circuit structure. As a result, the overall cost and power consumption of the power module are significantly reduced, and it can respond rapidly to abnormal temperature increases, providing precise over-temperature protection. This effectively prevents circuit damage or performance degradation caused by overheating, ensuring the long-term stable operation of the power system.

[0055] The power supply circuit disclosed herein further includes: a second rectifier diode D2 and a second polarized capacitor C2; the positive terminal of the second rectifier diode D2 is connected to one end of the secondary coil of the transformer T1, the other end of the secondary coil is grounded, the negative terminal of the second rectifier diode D2 is connected to the positive terminal of the second polarized capacitor C2, and the negative terminal of the second polarized capacitor C2 is connected to the load ground of the user equipment.

[0056] During operation, the negative terminal of the second polarity capacitor C2 serves as the output return path of the power supply, connecting to the load ground of the user equipment. The load ground of the user equipment refers to the grounding reference point or current return path of the user equipment itself, thereby supplying power to the user equipment through this power supply circuit.

[0057] This disclosure also provides a current sampling / over-temperature protection multiplexing circuit, disposed in a power supply circuit. The power supply circuit further includes: a power chip, a first polarized capacitor, a transformer, and an NMOS transistor. The positive terminal of the first polarized capacitor is connected to one end of the primary winding of the transformer, and the negative terminal of the first polarized capacitor is grounded. The other end of the primary winding of the transformer is connected to the drain of the NMOS transistor, and the gate of the NMOS transistor is connected to the drive pin of the power chip. The power chip is provided with a preset voltage threshold. The current sampling / over-temperature protection multiplexing circuit includes: Current transformer, first rectifier diode, first high-precision resistor, second high-precision resistor and bimetallic disc thermal protector; The primary side P1 terminal of the current transformer is connected to the source of the NMOS transistor, and the primary side P2 terminal of the current transformer is grounded. The secondary side K1 terminal of the current transformer is connected to the positive terminal of the first rectifier diode, the negative terminal of the first rectifier diode is connected to one end of the first high-precision resistor, and the secondary side K2 terminal of the current transformer is connected to one end of the second high-precision resistor. One end of the bimetallic disc thermal protector is connected to the other end of the first high-precision resistor and the other end of the second high-precision resistor, and the other end of the bimetallic disc thermal protector is connected to the current detection pin of the power chip. The bimetallic disc thermal protector is provided with a preset temperature reset value. The current sampling / over-temperature protection multiplexing circuit collects the voltage signal and ambient temperature of the power supply circuit. The bimetallic disc thermal protector controls the opening and closing of the current sampling / over-temperature protection multiplexing circuit and the power chip based on the collected ambient temperature. The current sampling / over-temperature protection multiplexing circuit transmits the collected voltage signal of the power supply circuit to the power chip, so that the power chip controls the power supply circuit to achieve current protection and over-temperature protection according to the collected voltage signal of the power supply circuit or the opening and closing of the current sampling / over-temperature protection multiplexing circuit and the power chip.

[0058] According to an embodiment of this disclosure, the current sampling / over-temperature protection multiplexing circuit uses the voltage value across the second high-precision resistor as the voltage signal of the power supply circuit.

[0059] According to an embodiment of this disclosure, the power chip compares the acquired voltage signal of the power circuit with the preset voltage threshold. When the acquired voltage signal exceeds the preset voltage threshold, or when the current sampling / over-temperature protection multiplexing circuit is disconnected from the power chip, the power chip controls the power circuit to stop working, thereby realizing the current protection and over-temperature protection of the power circuit.

[0060] The current sampling / over-temperature protection multiplexed circuit disclosed herein can simultaneously achieve current detection and over-temperature protection, effectively reducing the number of required components and simplifying the circuit structure. Therefore, when this disclosure is designed into a power supply circuit, it can provide accurate over-temperature protection, effectively preventing power supply circuit damage or performance degradation caused by overheating.

[0061] Figure 3 A schematic diagram of the structure of a power chip according to an embodiment of the present disclosure is shown.

[0062] like Figure 3 As shown, a power chip is disposed in a power supply circuit, which further includes a first polarized capacitor, a transformer, an NMOS transistor, and a current sampling / over-temperature protection multiplexing circuit. The positive terminal of the first polarized capacitor is connected to one end of the primary coil of the transformer, and the negative terminal of the first polarized capacitor is grounded. The other end of the primary coil of the transformer is connected to the drain of the NMOS transistor. The gate of the NMOS transistor is connected to the drive pin of the power chip, and the source of the NMOS transistor is connected to one end of the current sampling / over-temperature protection multiplexing circuit. The other end of the current sampling / over-temperature protection multiplexing circuit is connected to the current detection pin of the power chip.

[0063] The power chip includes a control unit and an integrated comparator.

[0064] The control unit is configured to receive the voltage signal of the power supply circuit transmitted by the current sampling / over-temperature protection multiplexing circuit through the current detection pin, and send the voltage signal of the power supply circuit to the integrated comparator. The integrated comparator is configured to compare the voltage signal of the power supply circuit with a preset voltage threshold, and send the comparison result of the voltage signal of the power supply circuit and the preset voltage threshold to the control unit. The control unit is configured to control the drive pin to stop outputting the drive signal when the comparison result indicates that the voltage signal of the power supply circuit exceeds the preset voltage threshold, or when no current signal is received through the current detection pin.

[0065] Figure 4This diagram illustrates a method for providing current and over-temperature protection to a power supply circuit using a current sampling / over-temperature protection multiplexing circuit according to an embodiment of this disclosure. The current sampling / over-temperature protection multiplexing circuit includes: a current transformer, a first rectifier diode, a first high-precision resistor, a second high-precision resistor, and a bimetallic disc thermal protector. The primary side P1 terminal of the current transformer is connected to the source of an NMOS transistor in the power supply circuit, and the primary side P2 terminal of the current transformer is grounded. The secondary side K1 terminal of the current transformer is connected to the anode of the first rectifier diode, the cathode of the first rectifier diode is connected to one end of the first high-precision resistor, and the secondary side K2 terminal of the current transformer is connected to one end of the second high-precision resistor. One end of the bimetallic disc thermal protector is connected to the other end of the first high-precision resistor and the other end of the second high-precision resistor, and the other end of the bimetallic disc thermal protector is connected to the current detection pin of the power supply chip in the power supply circuit. The bimetallic disc thermal protector is provided with a preset temperature reset value.

[0066] like Figure 4 As shown, the method includes: steps S401-S403: In step S401, the current sampling / over-temperature protection multiplexing circuit collects the voltage signal and ambient temperature of the power supply circuit, and the bimetallic disc thermal protector controls the opening and closing of the current sampling / over-temperature protection multiplexing circuit and the power supply chip based on the collected ambient temperature.

[0067] In step S402, the current sampling / over-temperature protection multiplexing circuit transmits the collected voltage signal of the power supply circuit to the power chip.

[0068] In step S403, the power chip compares the acquired voltage signal of the power circuit with a preset voltage threshold. When the acquired voltage signal exceeds the preset voltage threshold, or when the current sampling / over-temperature protection multiplexing circuit is disconnected from the power chip, the power chip controls the power circuit to stop working, thereby realizing the current protection and over-temperature protection of the power circuit.

[0069] The power chip has an integrated comparator and control unit inside; The power chip compares the acquired voltage signal of the power circuit with a preset voltage threshold, including: the power chip receiving the voltage signal of the power circuit through the current detection pin; the integrated comparator comparing the voltage signal of the power circuit with the preset voltage threshold; and sending the comparison result of the voltage signal of the power circuit and the preset voltage threshold to the control unit.

[0070] According to an embodiment of this disclosure, when the comparison result indicates that the acquired voltage signal exceeds the preset voltage threshold, the control unit controls the drive pin to stop outputting the drive signal; or When the ambient temperature exceeds the preset temperature reset value, the contacts of the bimetallic disc thermal protector open, the power chip cannot receive a current signal through the current detection pin, and the control unit controls the drive pin to stop outputting the drive signal.

[0071] According to an embodiment of this disclosure, the method further includes: after the power supply circuit stops working, when the acquired voltage signal drops to within the preset voltage threshold or when the acquired ambient temperature drops to the preset temperature reset value, the power chip controls the power supply circuit to resume working.

[0072] The current sampling and over-temperature protection method disclosed herein can simultaneously realize the functions of current sampling and over-temperature protection using a current sampling / over-temperature protection multiplexing circuit. It also simplifies the structure of the power supply circuit, ensures stable operation of the power supply circuit under various conditions, improves safety, and enhances the user experience.

[0073] The above description is merely a preferred embodiment of this disclosure and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this disclosure is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above-described features with (but not limited to) technical features disclosed in this disclosure that have similar functions.

Claims

1. A power supply circuit with a current sampling / over-temperature protection multiplexing circuit, characterized in that, The power supply circuit includes: a power chip, a first polarized capacitor, a transformer, an NMOS transistor, and a current sampling / over-temperature protection multiplexing circuit. The current sampling / over-temperature protection multiplexing circuit includes: a current transformer, a first rectifier diode, a first high-precision resistor, a second high-precision resistor, and a bimetallic disc thermal protector. The positive terminal of the first polarized capacitor is connected to one end of the primary coil of the transformer, the negative terminal of the first polarized capacitor is grounded, and the other end of the primary coil of the transformer is connected to the drain of the NMOS transistor. The gate of the NMOS transistor is connected to the drive pin of the power chip, the source of the NMOS transistor is connected to the primary side P1 terminal of the current transformer, and the primary side P2 terminal of the current transformer is grounded. The secondary side K1 terminal of the current transformer is connected to the positive terminal of the first rectifier diode, the negative terminal of the first rectifier diode is connected to one end of the first high-precision resistor, and the secondary side K2 terminal of the current transformer is connected to one end of the second high-precision resistor. One end of the bimetallic disc thermal protector is connected to the other end of the first high-precision resistor and the other end of the second high-precision resistor, and the other end of the bimetallic disc thermal protector is connected to the current detection pin of the power chip. The bimetallic disc thermal protector is provided with a preset temperature reset value, and the power chip is provided with a preset voltage threshold. The current sampling / over-temperature protection multiplexing circuit collects the voltage signal and ambient temperature of the power supply circuit; when the collected voltage signal exceeds the preset voltage threshold or when the collected ambient temperature exceeds the preset temperature reset value, the power chip controls the power supply circuit to stop working, thereby realizing the current protection and over-temperature protection of the power supply circuit.

2. The power supply circuit according to claim 1, characterized in that, The power chip has an integrated comparator and control unit inside; The power chip receives the voltage signal of the power circuit through the current detection pin. The integrated comparator compares the voltage signal of the power circuit with the preset voltage threshold and sends the comparison result of the voltage signal of the power circuit and the preset voltage threshold to the control unit.

3. The power supply circuit according to claim 2, characterized in that, When the acquired voltage signal exceeds the preset voltage threshold or when the acquired ambient temperature exceeds the preset temperature reset value, the power chip controls the power circuit to stop working, including: When the comparison result indicates that the acquired voltage signal exceeds the preset voltage threshold, the control unit controls the drive pin to stop outputting the drive signal; or When the ambient temperature collected exceeds the preset temperature reset value, the contact switch of the bimetallic disc thermal protector is opened, the power chip cannot receive a current signal through the current detection pin, and the control unit controls the drive pin to stop outputting the drive signal.

4. The power supply circuit according to claim 2, characterized in that, After the power supply circuit stops working, when the acquired voltage signal drops below the preset voltage threshold or when the acquired ambient temperature drops to the preset temperature reset value, the power chip controls the power supply circuit to resume working.

5. The power supply circuit according to claim 4, characterized in that, When the acquired voltage signal drops below the preset voltage threshold or when the acquired ambient temperature drops to the preset temperature reset value, the power chip controls the power circuit to resume operation, including: When the comparison result indicates that the acquired voltage signal drops below the preset voltage threshold, the control unit controls the drive pin to output a drive signal. or When the ambient temperature is reduced to the preset temperature reset value, the contact switch of the bimetallic disc thermal protector closes, and the control unit controls the drive pin to output a drive signal.

6. The power supply circuit according to claim 1, characterized in that, When the current sampling / over-temperature protection multiplexing circuit acquires the voltage signal of the power supply circuit and the ambient temperature, the current sampling / over-temperature protection multiplexing circuit uses the voltage value across the second high-precision resistor as the voltage signal of the power supply circuit.

7. The power supply circuit according to claim 1, characterized in that, The power supply circuit also includes: a second rectifier diode and a second polarity capacitor; The positive terminal of the second rectifier diode is connected to one end of the secondary coil of the transformer, and the other end of the secondary coil is grounded. The negative terminal of the second rectifier diode is connected to the positive terminal of the second polarized capacitor, and the negative terminal of the second polarized capacitor is connected to the load ground of the user equipment.

8. A current sampling / over-temperature protection multiplexing circuit, characterized in that, The power supply circuit includes: a power chip, a first polarized capacitor, a transformer, and an NMOS transistor. The positive terminal of the first polarized capacitor is connected to one end of the primary coil of the transformer, and the negative terminal of the first polarized capacitor is grounded. The other end of the primary coil of the transformer is connected to the drain of the NMOS transistor, and the gate of the NMOS transistor is connected to the drive pin of the power chip. The power chip has a preset voltage threshold. The current sampling / over-temperature protection multiplexing circuit includes: Current transformer, first rectifier diode, first high-precision resistor, second high-precision resistor and bimetallic disc thermal protector; The primary side P1 terminal of the current transformer is connected to the source of the NMOS transistor, and the primary side P2 terminal of the current transformer is grounded. The secondary side K1 terminal of the current transformer is connected to the positive terminal of the first rectifier diode, the negative terminal of the first rectifier diode is connected to one end of the first high-precision resistor, and the secondary side K2 terminal of the current transformer is connected to one end of the second high-precision resistor. One end of the bimetallic disc thermal protector is connected to the other end of the first high-precision resistor and the other end of the second high-precision resistor, and the other end of the bimetallic disc thermal protector is connected to the current detection pin of the power chip. The bimetallic disc thermal protector is provided with a preset temperature reset value. The current sampling / over-temperature protection multiplexing circuit collects the voltage signal and ambient temperature of the power supply circuit. The bimetallic disc thermal protector controls the opening and closing of the current sampling / over-temperature protection multiplexing circuit and the power chip based on the collected ambient temperature. The current sampling / over-temperature protection multiplexing circuit transmits the collected voltage signal of the power supply circuit to the power chip, so that the power chip controls the power supply circuit to achieve current protection and over-temperature protection according to the collected voltage signal of the power supply circuit or the opening and closing of the current sampling / over-temperature protection multiplexing circuit and the power chip.

9. The multiplexing circuit according to claim 8, characterized in that, The current sampling / over-temperature protection multiplexing circuit uses the voltage value across the second high-precision resistor as the voltage signal of the power supply circuit.

10. The multiplexing circuit according to claim 8, characterized in that, The power chip controls the power circuit to achieve current protection and over-temperature protection based on the acquired voltage signal of the power circuit or the opening and closing of the current sampling / over-temperature protection multiplexing circuit and the power chip, including: The power chip compares the acquired voltage signal of the power circuit with the preset voltage threshold. When the acquired voltage signal exceeds the preset voltage threshold, or when the current sampling / over-temperature protection multiplexing circuit is disconnected from the power chip, the power chip controls the power circuit to stop working, thereby realizing the current protection and over-temperature protection of the power circuit.

11. A power supply chip, characterized in that, The power supply circuit includes a first polarized capacitor, a transformer, an NMOS transistor, and a current sampling / over-temperature protection multiplexing circuit. The positive terminal of the first polarized capacitor is connected to one end of the primary coil of the transformer, and the negative terminal of the first polarized capacitor is grounded. The other end of the primary coil of the transformer is connected to the drain of the NMOS transistor. The gate of the NMOS transistor is connected to the drive pin of the power supply chip, and the source of the NMOS transistor is connected to one end of the current sampling / over-temperature protection multiplexing circuit. The other end of the current sampling / over-temperature protection multiplexing circuit is connected to the current detection pin of the power supply chip. The power supply chip includes a control unit and an integrated comparator. The control unit is configured to receive the voltage signal of the power supply circuit transmitted by the current sampling / over-temperature protection multiplexing circuit through the current detection pin, and send the voltage signal of the power supply circuit to the integrated comparator. The integrated comparator is configured to compare the voltage signal of the power supply circuit with a preset voltage threshold, and send the comparison result of the voltage signal of the power supply circuit and the preset voltage threshold to the control unit. The control unit is configured to control the drive pin to stop outputting the drive signal when the comparison result indicates that the voltage signal of the power supply circuit exceeds the preset voltage threshold, or when no current signal is received through the current detection pin.

12. A method for providing current and over-temperature protection for a power supply circuit using a current sampling / over-temperature protection multiplexing circuit, characterized in that, The current sampling / over-temperature protection multiplexing circuit includes: a current transformer, a first rectifier diode, a first high-precision resistor, a second high-precision resistor, and a bimetallic disc thermal protector. The primary side P1 terminal of the current transformer is connected to the source of the NMOS transistor in the power supply circuit, and the primary side P2 terminal of the current transformer is grounded. The secondary side K1 terminal of the current transformer is connected to the anode of the first rectifier diode, the cathode of the first rectifier diode is connected to one end of the first high-precision resistor, and the secondary side K2 terminal of the current transformer is connected to one end of the second high-precision resistor. One end of the bimetallic disc thermal protector is connected to the other ends of the first and second high-precision resistors, and the other end of the bimetallic disc thermal protector is connected to the current detection pin of the power supply chip in the power supply circuit. The bimetallic disc thermal protector is provided with a preset temperature reset value. The method includes: The current sampling / over-temperature protection multiplexing circuit collects the voltage signal and ambient temperature of the power supply circuit, and the bimetallic disc thermal protector controls the opening and closing of the current sampling / over-temperature protection multiplexing circuit and the power chip based on the collected ambient temperature. The current sampling / over-temperature protection multiplexing circuit transmits the collected voltage signal of the power supply circuit to the power chip. The power chip compares the acquired voltage signal of the power circuit with a preset voltage threshold. When the acquired voltage signal exceeds the preset voltage threshold, or when the current sampling / over-temperature protection multiplexing circuit is disconnected from the power chip, the power chip controls the power circuit to stop working, thereby realizing the current protection and over-temperature protection of the power circuit.

13. The method according to claim 12, characterized in that: The power chip has an integrated comparator and control unit inside; The power chip compares the acquired voltage signal of the power circuit with a preset voltage threshold, including: the power chip receiving the voltage signal of the power circuit through the current detection pin; the integrated comparator comparing the voltage signal of the power circuit with the preset voltage threshold; and sending the comparison result of the voltage signal of the power circuit and the preset voltage threshold to the control unit.

14. The method according to claim 12, characterized in that, When the acquired voltage signal exceeds the preset voltage threshold, or when the current sampling / over-temperature protection multiplexing circuit is disconnected from the power chip, the power chip controls the power circuit to stop working, including: When the comparison result indicates that the acquired voltage signal exceeds the preset voltage threshold, the control unit controls the drive pin to stop outputting the drive signal; or When the ambient temperature collected exceeds the preset temperature reset value, the contact switch of the bimetallic disc thermal protector is opened, the power chip cannot receive a current signal through the current detection pin, and the control unit controls the drive pin to stop outputting the drive signal.

15. The method according to claim 12, characterized in that, The method further includes: after the power supply circuit stops working, when the acquired voltage signal drops to within the preset voltage threshold or when the acquired ambient temperature drops to the preset temperature reset value, the power chip controls the power supply circuit to resume working.

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