Transformer primary side information detection circuit and method

Abstract

The invention relates to the technical field of electric signal detection, in particular to a transformer primary side information detection circuit and method. The transformer primary side information detection circuit comprises a voltage sampling module, a comparison module and a sampling and holding module. The voltage sampling module is electrically connected with a transformer secondary coil, the first input end of the comparison module and the first input end of the sampling and holding module. The output end of the comparison module is electrically connected with the second input end of the sampling and holding module. According to the circuit, primary side voltage information can be obtained from negative voltage based on the voltage sampling module; determining the working frequency of the primary side controller and the turn-on time and turn-off time of the primary side controller in a single control period according to a turn-on signal output based on the sampling voltage; and the sampling voltage can be adopted and held based on the starting signal, so that the primary side voltage value can be determined according to the sampling and holding voltage. Therefore, the circuit can realize the function of sampling the secondary high-side voltage to obtain the primary side information.

Description

Technical Field

[0001] The present application relates to the technical field of electrical signal detection, and in particular to a transformer primary side information detection circuit and method. Background Art

[0002] The primary side controller is usually used to control the power transistor connected to the secondary coil of the power system to control the output voltage on the secondary coil. In practical applications, it is necessary to detect the switching frequency, on-time, off-time and effective value of the line voltage of the primary side controller, and provide complete primary side information to the main controller of the secondary side based on the detection data to meet the system decision-making requirements of the main controller. In addition, more and more flyback AC / DC voltage conversion systems use secondary side high side rectification technology.

[0003] However, most of the existing transformer primary side information detection circuits are designed for low side information detection and cannot achieve the function of sampling the secondary high side voltage to obtain the primary side information. Summary of the invention

[0004] In view of this, an object of an embodiment of the present application is to provide a transformer primary side information detection circuit and method, so as to realize the function of sampling the secondary high side voltage to obtain the primary side information.

[0005] In a first aspect, an embodiment of the present application provides a transformer primary side information detection circuit, the circuit comprising: the circuit comprising: a voltage sampling module, a comparison module and a sampling and holding module;

[0006] The input end of the voltage sampling module is electrically connected to the in-phase end of the secondary coil of the transformer via a first sampling resistor, and the output end of the voltage sampling module is electrically connected to the first input end of the comparison module and the first input end of the sampling and holding module respectively;

[0007] The output end of the comparison module is electrically connected to the second input end of the sampling and holding module;

[0008] The voltage sampling module is configured to perform voltage sampling on the in-phase end of the secondary coil of the transformer, and convert the negative voltage signal in the voltage into a positive voltage signal to obtain a sampled voltage;

[0009] The comparison module is configured to output a start signal when the sampling voltage is greater than the reference comparison voltage;

[0010] The sampling and holding module is configured to sample and hold the sampling voltage based on the start signal, and output the sampled and held voltage.

[0011] In the above implementation process, the transformer primary side information detection circuit includes a voltage sampling module, a comparison module and a sampling and holding module; the input end of the voltage sampling module is electrically connected to the in-phase end of the transformer secondary coil through a first sampling resistor, and the output end of the voltage sampling module is electrically connected to the first input end of the comparison module and the first input end of the sampling and holding module respectively; the output end of the comparison module is electrically connected to the second input end of the sampling and holding module. The transformer primary side information detection circuit can perform voltage sampling on the in-phase end of the transformer secondary coil based on the voltage sampling module, and convert the negative voltage signal in the voltage into a positive voltage signal to obtain a sampling voltage; and output a start signal when the sampling voltage is greater than the reference comparison voltage; based on the start signal, the sampling voltage is adopted and held, and the sampling and holding voltage is output. For the secondary side high side rectification technology, the primary side voltage information of the transformer is contained in the negative voltage of the secondary high side rectification controller voltage. By converting the negative voltage signal of the primary controller voltage into a positive voltage signal, the primary voltage information can be obtained from the negative voltage; by outputting a start signal when the sampled voltage is greater than the reference comparison voltage, the operating frequency of the primary controller and the on-time and off-time of the primary controller in a single control cycle are determined according to the start signal; and then the sampled voltage is adopted and maintained based on the start signal, so as to determine the primary line voltage value according to the sampled and held voltage. Therefore, the transformer primary information detection circuit provided by the present application can detect the switching frequency, on-time, off-time and effective value of the line voltage of the primary controller, and realizes the function of sampling the secondary high-side voltage to obtain the primary information.

[0012] In addition, based on the transformer primary side information detection circuit provided in the present application, in the process of realizing primary side information detection, no software is required to adjust the sampling and holding time, but the sampling process is adaptively completed by hardware circuits, thereby reducing the working complexity of the system.

[0013] Optionally, in an embodiment of the present application, the circuit also includes: a signal processing module; the signal processing module is electrically connected to the output end of the comparison module and the output end of the sampling and holding module, respectively; the signal processing module is configured to obtain the operating frequency of the primary side controller of the transformer and the on-time and off-time within a single control cycle based on the start signal; and based on the sampling and holding voltage, obtain the primary side line voltage value of the transformer.

[0014] Optionally, in an embodiment of the present application, the voltage sampling module includes: an operational amplifier, a current mirror and a second sampling resistor; the first input terminal of the operational amplifier is electrically connected to the clamping voltage, the second input terminal of the operational amplifier is electrically connected to the in-phase terminal of the secondary coil of the transformer via the first sampling resistor, and the output terminal of the operational amplifier is electrically connected to the input terminal of the current mirror; the output terminal of the current mirror is electrically connected to the second sampling resistor; the operational amplifier is configured to limit the negative voltage in the input voltage of the second input terminal of the operational amplifier to the clamping voltage; the current mirror is configured to output a second current flowing through the second sampling resistor based on a first current flowing through the first sampling resistor, thereby obtaining the sampling voltage applied to both ends of the second sampling resistor.

[0015] In the above implementation process, through the operational amplifier, the current mirror and the second sampling resistor, the negative voltage signal in the voltage signal obtained by sampling the voltage at the in-phase end of the secondary coil of the transformer can be converted into a positive voltage signal without losing signal accuracy, thereby improving the accuracy of the primary side information of the transformer detected by the primary side information detection circuit of the transformer.

[0016] Optionally, in an embodiment of the present application, the sampling and holding module includes: a sampling signal generating unit, a holding signal generating unit, a sampling unit and a holding unit; the output end of the comparison module is electrically connected to the input end of the sampling signal generating unit and the input end of the holding signal generating unit respectively; the input end of the sampling unit is electrically connected to the output end of the sampling signal generating unit and the output end of the voltage sampling module respectively; the input end of the holding unit is electrically connected to the output end of the holding signal generating unit and the output end of the sampling unit respectively; the sampling signal generating unit is configured to generate and output a sampling signal based on the start signal; the holding signal generating unit is configured to generate and output a holding signal based on a falling edge of the start signal; the sampling unit is configured to sample the sampling voltage based on the sampling signal; and the holding unit is configured to hold and output the sampled and held voltage.

[0017] In the above implementation process, the sampling signal generating unit and the holding signal generating unit can generate the sampling signal and the holding signal respectively based on the start signal, and the sampling unit and the holding unit are used to sample and hold the sampling voltage, and the sampling and holding voltage is obtained, and then the sampling process is completed based on the hardware circuit adaptation. It is convenient to accurately obtain the primary line voltage value according to the sampling and holding voltage, and improve the accuracy of the transformer primary information detected by the transformer primary information detection circuit.

[0018] Optionally, in an embodiment of the present application, the sampling unit includes: a first switching device and a first capacitor; the holding unit includes: a second switching device and a second capacitor; the control end of the first switching device is electrically connected to the output end of the sampling signal generating unit; the control end of the second switching device is electrically connected to the output end of the holding signal generating unit; the first switching device is configured to be closed when receiving the sampling signal output by the sampling signal generating unit; and the second switching device is configured to be closed when receiving the holding signal output by the holding signal generating unit.

[0019] In the above implementation process, when receiving the sampling signal output by the sampling signal generating unit, the first switching device is closed to implement sampling of the sampling voltage based on the first capacitor; when receiving the holding signal output by the holding signal generating unit, the second switching device is closed to implement holding of the sampling voltage of the first capacitor based on the second capacitor, thereby obtaining the sampled holding voltage.

[0020] Optionally, in an embodiment of the present application, the sampling and holding module further includes: a delay unit; the delay unit is electrically connected to the output end of the comparison module, the input end of the sampling signal generating unit and the input end of the holding signal generating unit respectively; the delay unit is configured to delay the sampling signal and then send it to the sampling signal generating unit and the holding signal generating unit.

[0021] In the above implementation process, the delay unit can reduce the influence of the interference signal and improve the accuracy of the sampling signal / holding signal generated by the sampling signal generating unit / holding signal generating unit.

[0022] Optionally, in an embodiment of the present application, the circuit further includes: a voltage divider module; the voltage divider module is electrically connected to the sampling and holding module and the comparison module, respectively; the voltage divider module is configured to divide the sampling and holding voltage to obtain a first divided voltage; and provide a reference comparison voltage for the comparison module based on the first divided voltage.

[0023] In the above implementation process, by dividing the sampling and holding voltage output by the sampling and holding module to obtain a first divided voltage, and providing a reference comparison voltage of the comparison module based on the first divided voltage, the accuracy of the start-up signal output by the comparison module can be improved, and the influence of the resonant ripple on the primary side information detection result of the circuit can be reduced, thereby improving the accuracy of the primary side information detection result.

[0024] Optionally, in an embodiment of the present application, the circuit further includes: a reference module; the output end of the reference module is electrically connected to the second input end of the comparison module; the reference module is configured to provide a reference comparison voltage of the comparison module; wherein the reference module includes: a voltage divider unit, a bias power supply, a third switch device and a fourth switch device; the voltage divider module is electrically connected to the second input end of the comparison module based on the third switch device; the voltage divider unit is electrically connected to the reference power supply and the bias power supply respectively; the input end of the fourth switch device is electrically connected to the bias power supply, and the output end of the fourth switch device is electrically connected to the second input end of the comparison module; the voltage divider unit is configured to provide a second divided voltage based on the reference power supply; the bias power supply is configured to provide a bias voltage; the reference module is configured to provide a reference comparison voltage of the comparison module based on the voltage divider module when the third switch device is in a closed state; and provide a reference comparison voltage of the comparison module based on the second divided voltage and the bias voltage when the fourth switch device is in a closed state.

[0025] In the above implementation process, when the sampling and holding voltage output by the sampling and holding module is abnormal, the fourth switch device can be controlled to be closed to provide a reference comparison voltage for the comparison module based on the second voltage division and the bias voltage, thereby further providing a guarantee for the accuracy of the start-up signal; when the sampling and holding voltage output by the sampling and holding module is abnormal, the accuracy of "the operating frequency of the primary controller and the on-time and off-time of the primary controller in a single control cycle" in the primary information detection result is ensured.

[0026] In a second aspect, an embodiment of the present application provides a transformer primary side information detection method, the method being applied to a transformer primary side information detection circuit as described in any one of the first aspects above, the method comprising:

[0027] Obtaining a start signal and a sample-and-hold voltage based on a transformer primary side information detection circuit;

[0028] Determine the operating frequency of the primary controller and the on-time and off-time in a single control cycle according to the start signal;

[0029] The primary line voltage value of the transformer is determined according to the voltage value of the sampled and held voltage.

[0030] Optionally, in an embodiment of the present application, determining the operating frequency of the primary controller and the on-time and off-time within a single control cycle based on the start signal includes: determining the operating frequency of the primary controller based on the interval time between two start signals; determining the on-time and off-time of the primary controller within a single control cycle based on the occurrence time of the rising edge and the falling edge of the start signal.

[0031] The beneficial effects of the present application include at least: the transformer primary side information detection circuit includes a voltage sampling module, a comparison module and a sampling and holding module; the input end of the voltage sampling module is electrically connected to the in-phase end of the transformer secondary coil through a first sampling resistor, and the output end of the voltage sampling module is electrically connected to the first input end of the comparison module and the first input end of the sampling and holding module respectively; the output end of the comparison module is electrically connected to the second input end of the sampling and holding module. The transformer primary side information detection circuit can obtain the primary side voltage information from the negative voltage by converting the negative voltage signal of the primary side controller voltage into a positive voltage signal; by outputting a start signal when the sampling voltage is greater than the reference comparison voltage, the operating frequency of the primary side controller and the on-time and off-time of the primary side controller in a single control cycle are determined according to the start signal; and then the sampling voltage is adopted and maintained based on the start signal, so as to determine the primary side line voltage value according to the sampling and holding voltage. Therefore, the transformer primary side information detection circuit provided by the present application can detect the switching frequency, on-time, off-time and effective value of the line voltage of the primary side controller, and realizes the function of sampling the secondary high side voltage to obtain the primary side information.

[0032] In addition, based on the transformer primary side information detection circuit provided in the present application, in the process of realizing the primary side information detection, there is no need for software to adjust the sampling and holding time. Instead, the sampling process is adaptively completed by a hardware circuit, which can reduce the working complexity of the secondary side high side rectification control system. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0034] Figure 1 A schematic diagram of the structure of a transformer primary side information detection circuit provided in an embodiment of the present application;

[0035] Figure 2 A system structure diagram of a secondary side rectifier controller provided in an embodiment of the present application;

[0036] Figure 3 A schematic diagram of the structure of another transformer primary side information detection circuit provided in an embodiment of the present application;

[0037] Figure 4 A waveform diagram of transformer primary side information detection provided in an embodiment of the present application;

[0038] Figure 5 A schematic flow chart of a transformer primary side information detection method provided in an embodiment of the present application.

[0039] Figure numerals: 11 - voltage sampling module; 12 - comparison module; 13 - sampling and holding module; 131 - sampling signal generating unit; 132 - holding signal generating unit; 133 - delay unit; 14 - voltage dividing module; 15 - reference module. DETAILED DESCRIPTION

[0040] The following embodiments of the technical solution of the present application are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0042] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0043] See also Figure 1 The schematic diagram of the structure of a transformer primary side information detection circuit provided by the embodiment of the present application is shown. Figure 2 , Figure 2 This is a system structure diagram of a secondary side rectifier controller provided in an embodiment of the present application. Figure 2 As shown, the transformer may include a primary coil and a secondary coil (NPS represents the turns ratio of the primary coil and the secondary coil of the transformer), one end of the primary coil is electrically connected to the primary line voltage (VIN), and the other end is grounded via a switching device Q1 (which may be implemented by a transistor). One end of the secondary coil is electrically connected to the secondary line voltage (Vbus) via switching devices Q2 and Q3, and the other end of the secondary coil is grounded. The AC / DC controller (secondary high-side rectifier controller) is electrically connected to the control end of the switching device Q1, and can control the switching state of the switching device Q1; wherein, the switching frequency of the AC / DC controller controlling the switching device Q1 is the operating frequency of the primary controller, the on-time of the switching device Q1 in a single working cycle is the on-time of the primary controller in a single control cycle, and the off-time of the switching device Q1 in a single working cycle is the off-time of the primary controller in a single control cycle. As shown Figure 2As shown, the transformer primary side information detection circuit provided in the present application is electrically connected to the in-phase end of the transformer secondary coil via the first sampling resistor R1. Figure 1 As shown, the transformer primary side information detection circuit includes: a voltage sampling module 11, a comparison module 12 and a sampling and holding module 13;

[0044] The input end of the voltage sampling module 11 is electrically connected to the in-phase end of the secondary coil of the transformer via the first sampling resistor R1, and the output end of the voltage sampling module 11 is electrically connected to the first input end of the comparison module 12 and the first input end of the sampling and holding module 13 respectively;

[0045] The output end of the comparison module 12 is electrically connected to the second input end of the sampling and holding module 13;

[0046] The voltage sampling module 11 is configured to perform voltage sampling on the in-phase end of the secondary coil of the transformer, and convert the negative voltage signal in the voltage into a positive voltage signal to obtain a sampled voltage;

[0047] The comparison module 12 is configured to output a start signal when the sampling voltage is greater than the reference comparison voltage;

[0048] The sampling and holding module 13 is configured to sample and hold the sampled voltage based on the start signal, and output the sampled and held voltage.

[0049] Among them, the input end of the voltage sampling module 11 is electrically connected to the in-phase end of the secondary coil of the transformer through the first sampling resistor R1 to achieve sampling of the primary side high side voltage VSR. Since the output end of the voltage sampling module 11 is electrically connected to the first input end of the comparison module 12, the comparison module 12 can output a start signal when the sampling voltage is greater than the reference comparison voltage. In the case where the comparison module 12 is implemented by a comparator, the output end of the voltage sampling module 11 can be specifically electrically connected to the in-phase input end of the comparator. Specifically, the reference comparison voltage can be a divided voltage of the sampled and held voltage or a divided voltage of the primary side line voltage (VIN) to ensure that the operating frequency of the primary side controller can be accurately determined based on the output start signal; and then the sampling and holding time of the sampled and held module 13 is accurately controlled through a start signal consistent with the operating frequency of the primary side controller, and the correct sampled and held voltage is output.

[0050] Therefore, based on the transformer primary side information detection circuit provided by the embodiment of the present application, the primary side voltage information can be obtained from the negative voltage by converting the negative voltage signal of the primary side controller voltage into a positive voltage signal; by outputting a start signal when the sampling voltage is greater than the reference comparison voltage, the operating frequency of the primary side controller and the on-time and off-time of the primary side controller in a single control cycle are determined according to the start signal; and then the sampling voltage is adopted and maintained based on the start signal to determine the primary side line voltage value according to the sampled and held voltage. Therefore, based on the transformer primary side information detection circuit provided by the present application, the switching frequency, on-time, off-time and effective value of the line voltage of the primary side controller can be detected, and the function of sampling the secondary high side voltage to obtain the primary side information is realized. In addition, the transformer primary side information detection circuit provided by the present application does not require software to adjust the sampling and holding time in the process of realizing the primary side information detection, but adopts a hardware circuit to adaptively complete the sampling process, which can reduce the working complexity of the secondary side high side rectification control system.

[0051] In some optional embodiments, the transformer primary side information detection circuit also includes: a signal processing module; the signal processing module is electrically connected to the output end of the comparison module 12 and the output end of the sampling and holding module 13 respectively; the signal processing module is configured to obtain the operating frequency of the primary side controller of the transformer and the on-time and off-time within a single control cycle based on the start signal; and obtain the primary side line voltage value of the transformer based on the sampling and holding voltage.

[0052] The signal processing module may be implemented by a microprocessor, a DSP or a field programmable logic unit, etc. The signal processing module may specifically determine the operating frequency of the primary controller according to the interval between two start signals, and determine the on time and off time of the primary controller in a single control cycle according to the occurrence time of the rising edge and the falling edge of the start signal.

[0053] Please refer to Figure 3 , Figure 3 A schematic diagram of the structure of another transformer primary side information detection circuit provided in an embodiment of the present application.

[0054] In some optional embodiments, the voltage sampling module 11 includes: an operational amplifier U, a current mirror and a second sampling resistor R2; the first input terminal of the operational amplifier U is electrically connected to the clamping voltage Voff, the second input terminal of the operational amplifier U is electrically connected to the in-phase terminal of the secondary coil of the transformer via the first sampling resistor R1, and the output terminal of the operational amplifier U is electrically connected to the input terminal of the current mirror; the output terminal of the current mirror is electrically connected to the second sampling resistor R2; the operational amplifier U is configured to limit the negative voltage in the input voltage of the second input terminal of the operational amplifier to the clamping voltage Voff; the current mirror is configured to output a second current flowing through the second sampling resistor R2 based on the first current flowing through the first sampling resistor R1, thereby obtaining a sampling voltage applied to both ends of the second sampling resistor R2.

[0055] Please refer to Figure 4 , Figure 4 A waveform diagram of transformer primary side information detection provided by an embodiment of the present application. Among them, the mirror ratio of the current mirror can be fixed, which is convenient for calculation based on the voltage value of VD and the mirror ratio. The first current I1 flows through the first sampling resistor R1. The clamping voltage Voff may be a voltage close to 0V. In this case, the clamping voltage Voff is negligible compared to the primary side high side voltage VSR. Therefore, I1 is mirrored to the second sampling resistor R2 through a current mirror with a fixed ratio, and then the voltage sampling module 11 converts VSR into a voltage signal with a high level of VD_HIGH, a low level of Voff, and a frequency consistent with the frequency of the primary side high side voltage VSR, and satisfies Wherein, Ratio represents the mirror ratio of the current mirror. Through the operational amplifier U, the current mirror and the second sampling resistor R2, the negative voltage signal in the voltage signal obtained by sampling the voltage at the in-phase end of the secondary coil of the transformer can be converted into a positive voltage signal without losing the signal accuracy, thereby improving the accuracy of the transformer primary side information detected by the transformer primary side information detection circuit.

[0056] In some optional embodiments, the sampling and holding module 13 includes: a sampling signal generating unit 131, a holding signal generating unit 132, a sampling unit and a holding unit; the output end of the comparison module 12 is electrically connected to the input end of the sampling signal generating unit 131 and the input end of the holding signal generating unit 132 respectively; the input end of the sampling unit is electrically connected to the output end of the sampling signal generating unit 131 and the output end of the voltage sampling module 11 respectively; the input end of the holding unit is electrically connected to the output end of the holding signal generating unit 132 and the output end of the sampling unit respectively; the sampling signal generating unit 131 is configured to generate and output a sampling signal based on the start signal; the holding signal generating unit 132 is configured to generate and output a holding signal based on the falling edge of the start signal; the sampling unit is configured to sample the sampling voltage based on the sampling signal; and the holding unit is configured to hold and output the sampled and held voltage.

[0057] Among them, since the comparison module 12 outputs the start signal when the sampling voltage is greater than the reference comparison voltage. The sampling signal generating unit 131 generates and outputs the sampling signal based on the start signal, that is, generates and outputs the sampling signal when the sampling voltage is greater than the reference comparison voltage. The holding signal generating unit 132 is configured to generate and output the holding signal based on the falling edge of the start signal, that is, generates and outputs the holding signal when the sampling voltage changes from being greater than the reference comparison voltage to being less than the reference comparison voltage. The sampling signal generating unit 131 and the holding signal generating unit 132 can respectively generate the sampling signal and the holding signal based on the start signal, and cooperate with the sampling unit and the holding unit to implement the sampling and holding of the sampling voltage, obtain the sampling and holding voltage, and then complete the sampling process based on the hardware circuit adaptation. And it is convenient to accurately obtain the primary side line voltage value according to the sampling and holding voltage, and improve the accuracy of the transformer primary side information detected by the transformer primary side information detection circuit.

[0058] In some optional embodiments, the sampling unit includes: a first switching device TG1 and a first capacitor C1; the holding unit includes: a second switching device TG2 and a second capacitor C2; the control end of the first switching device TG1 is electrically connected to the output end of the sampling signal generating unit 131; the control end of the second switching device TG2 is electrically connected to the output end of the holding signal generating unit 132; the first switching device TG1 is configured to be closed when receiving the sampling signal output by the sampling signal generating unit 131; the second switching device TG2 is configured to be closed when receiving the holding signal output by the holding signal generating unit 132.

[0059] Among them, the first switch device TG1 and the second switch device TG2 can be implemented by a transmission gate. By generating and outputting a sampling signal when the sampling voltage is greater than the reference comparison voltage, the first switch device TG1 is closed to achieve sampling of the sampling voltage and store it in the first capacitor C1. By generating and outputting a holding signal when the sampling voltage changes from being greater than the reference comparison voltage to being less than the reference comparison voltage, the second switch device TG2 is closed to maintain the voltage stored in the first capacitor C1 in the second capacitor C2. The transformer primary side information detection circuit can also include a buffer and an ADC module, and the voltage (sampling and holding voltage) held by the second capacitor C2 is sent to the ADC module through the buffer, and the sampling and holding voltage is converted into a digital signal based on the ADC module, and sent to the signal processing module or an external signal processing system.

[0060] In some optional embodiments, the sampling and holding module 13 also includes: a delay unit 133; the delay unit 133 is electrically connected to the output end of the comparison module 12, the input end of the sampling signal generating unit 131 and the input end of the holding signal generating unit 132 respectively; the delay unit 133 is configured to delay the sampling signal and then send it to the sampling signal generating unit 131 and the holding signal generating unit 132.

[0061] The delay unit 133 can be implemented by a delay circuit or a blanking circuit, and the delay / blanking time can be adjusted based on the duration of the resonant ripple. The delay unit 133 can delay the start signal before sending it to the sampling signal generating unit 131 and the holding signal generating unit 132, so as to reduce the influence of the interference signal and improve the accuracy of the sampling signal / holding signal generated by the sampling signal generating unit 131 / holding signal generating unit 132.

[0062] In some optional embodiments, the circuit also includes: a voltage divider module 14; the voltage divider module 14 is electrically connected to the sampling and holding module 13 and the comparison module 12 respectively; the voltage divider module 14 is configured to divide the sampling and holding voltage to obtain a first divided voltage; and provide a reference comparison voltage for the comparison module 12 based on the first divided voltage.

[0063] Among them, Figure 3 As shown, the voltage divider module 14 may specifically include a buffer and voltage divider resistors R3 and R4. The resistance values ​​of the voltage divider resistors R3 and R4 and the relationship between the resistance values ​​may be adjusted according to actual application requirements. By dividing the sampled and held voltage output by the sample and hold module 13 to obtain a first divided voltage, and providing a reference comparison voltage of the comparison module based on the first divided voltage, the accuracy of the start signal output by the comparison module 12 can be improved, and the influence of the resonant ripple on the primary side information detection result of the circuit can be reduced, thereby improving the accuracy of the primary side information detection result.

[0064] In some optional embodiments, the circuit further includes: a reference module 15; an output end of the reference module 15 is electrically connected to a second input end of the comparison module 12; the reference module 15 is configured to provide a reference comparison voltage of the comparison module 12;

[0065] Among them, the reference module 15 includes: a voltage dividing unit, a bias power supply OS_VD, a third switch device TG3 and a fourth switch device TG4; the voltage dividing module 14 is electrically connected to the second input end of the comparison module 12 based on the third switch device TG3; the voltage dividing unit is electrically connected to the reference power supply and the bias power supply respectively; the input end of the fourth switch device TG3 is electrically connected to the bias power supply, and the output end of the fourth switch device TG3 is electrically connected to the second input end of the comparison module 12; the voltage dividing unit is configured to provide a second divided voltage based on the reference power supply; the bias power supply OS_VD is configured to provide a bias voltage; the reference module 15 is configured to provide a reference comparison voltage of the comparison module 12 based on the voltage dividing module 14 when the third switch device TG3 is in a closed state; and to provide a reference comparison voltage of the comparison module 12 based on the second divided voltage and the bias voltage when the fourth switch device TG4 is in a closed state.

[0066] Among them, Figure 3 As shown, the voltage dividing unit can be implemented by voltage dividing resistors R5 and R6, and the control ends of the third switch device TG3 and the fourth switch device TG4 can be electrically connected to the reset signal input end (specifically, the reset signal input end can be electrically connected to the control end of the third switch device TG3 based on the inverter). Exemplarily, a reference comparison voltage of the comparison module 12 can be provided based on the sum of the second voltage division and the bias voltage. The resistance ratio of the voltage dividing resistors R5 and R6 can be 50:1 (R5: R6). In the case where the comparison module 12 is implemented by a comparator, the output end of the fourth switch device TG4 can be electrically connected to the reverse input end of the comparator. The resistance values ​​of the voltage dividing resistors R5 and R6 and the relationship between the resistance values ​​can be adjusted according to actual application requirements. Figure 3 The reference power supply is exemplarily shown in the case where the reference power supply is realized by the primary line voltage VIN. When the sample holding voltage output by the sample holding module is abnormal, the fourth switch device can be controlled to be closed to provide a reference comparison voltage for the comparison module based on the second voltage division and the bias voltage, thereby further ensuring the accuracy of the start signal; when the sample holding voltage output by the sample holding module is abnormal, the accuracy of "the operating frequency of the primary controller and the on time and off time of the primary controller in a single control cycle" in the primary information detection result can be ensured.

[0067] Please refer to Figure 5 , Figure 5A schematic flow chart of a transformer primary side information detection method provided in an embodiment of the present application. The transformer primary side information detection method may include the following steps:

[0068] S101, obtaining a start signal and a sample-and-hold signal based on a transformer primary side information detection circuit;

[0069] S102, determining the operating frequency of the primary controller and the on-time and off-time in a single control cycle according to the start signal;

[0070] S103: Determine the primary line voltage value of the transformer according to the voltage value of the sample-and-hold signal.

[0071] In some optional embodiments, S102, based on the start signal, determining the operating frequency of the primary controller and the on-time and off-time within a single control cycle, including: determining the operating frequency of the primary controller based on the interval time between two start signals; determining the on-time and off-time of the primary controller within a single control cycle based on the occurrence time of the rising edge and the falling edge of the start signal.

[0072] It should be understood that the transformer primary side information detection method corresponds to the above-mentioned transformer primary side information detection circuit embodiment. The specific implementation method of steps S101-S103 in the transformer primary side information detection can refer to the description above. To avoid repetition, the detailed description is appropriately omitted here.

[0073] In several embodiments provided by the embodiments of the present application, it should be understood that the disclosed circuit / system and method can also be implemented in other ways. The circuit embodiments described above are merely schematic. For example, the flowcharts and block diagrams in the accompanying drawings show the possible architecture, functions and operations of the circuit / method according to the multiple embodiments of the embodiments of the present application. In this regard, each box in the flowchart or block diagram can represent a module, a program segment or a part of the code, and a part of the module, program segment or code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order than the order marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flowchart, and the combination of boxes in the block diagram and / or flowchart can be implemented with a dedicated hardware-based system that performs a specified function or action, or can be implemented with a combination of dedicated hardware and computer instructions.

[0074] In addition, the functional modules in each embodiment of the present application can be integrated together to form an independent part, or each module can exist separately, or two or more modules can be integrated to form an independent part.

[0075] The above description is only an optional implementation manner of the embodiments of the present application, but the protection scope of the embodiments of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or replacements within the technical scope disclosed in the embodiments of the present application, which should be covered within the protection scope of the embodiments of the present application.

Claims

1. A transformer primary side information detection circuit, characterized in that: The circuit comprises: the circuit comprises: a voltage sampling module, a comparison module and a sample-and-hold module; The input end of the voltage sampling module is electrically connected to the in-phase end of the secondary coil of the transformer via a first sampling resistor, and the output end of the voltage sampling module is electrically connected to the first input end of the comparison module and the first input end of the sampling and holding module respectively; The output end of the comparison module is electrically connected to the second input end of the sampling and holding module; The voltage sampling module is configured to perform voltage sampling on the in-phase end of the secondary coil of the transformer, and convert the negative voltage signal in the voltage into a positive voltage signal to obtain a sampled voltage; The comparison module is configured to output a start signal when the sampling voltage is greater than the reference comparison voltage; The sampling and holding module is configured to sample and hold the sampling voltage based on the start signal, and output the sampled and held voltage.

2. The circuit according to claim 1, characterized in that The circuit further comprises: a signal processing module; the signal processing module is electrically connected to the output end of the comparison module and the output end of the sampling and holding module respectively; The signal processing module is configured to obtain the operating frequency of the primary controller of the transformer and the on-time and off-time in a single control cycle based on the start signal; and to obtain the primary line voltage value of the transformer based on the sample-and-hold voltage.

3. The circuit according to claim 1, characterized in that in, The voltage sampling module includes: an operational amplifier, a current mirror and a second sampling resistor; The first input terminal of the operational amplifier is electrically connected to the clamping voltage, the second input terminal of the operational amplifier is electrically connected to the in-phase terminal of the secondary coil of the transformer via the first sampling resistor, and the output terminal of the operational amplifier is electrically connected to the input terminal of the current mirror; The output end of the current mirror is electrically connected to the second sampling resistor; The operational amplifier is configured to limit a negative voltage in an input voltage at a second input terminal of the operational amplifier to the clamping voltage; The current mirror is configured to output a second current flowing through the second sampling resistor based on a first current flowing through the first sampling resistor, thereby obtaining the sampling voltage applied across the second sampling resistor.

4. The circuit according to claim 1, characterized in that in, The sampling and holding module comprises: a sampling signal generating unit, a holding signal generating unit, a sampling unit and a holding unit; The output end of the comparison module is electrically connected to the input end of the sampling signal generating unit and the input end of the holding signal generating unit respectively; The input end of the sampling unit is electrically connected to the output end of the sampling signal generating unit and the output end of the voltage sampling module respectively; The input end of the holding unit is electrically connected to the output end of the holding signal generating unit and the output end of the sampling unit respectively; The sampling signal generating unit is configured to generate and output a sampling signal based on the start signal; The hold signal generating unit is configured to generate and output a hold signal based on a falling edge of the start signal; The sampling unit is configured to sample the sampling voltage based on the sampling signal; The holding unit is configured to hold and output the sample-and-hold voltage.

5. The circuit according to claim 4, characterized in that in, The sampling unit includes: a first switch device and a first capacitor; the holding unit includes: a second switch device and a second capacitor; The control end of the first switch device is electrically connected to the output end of the sampling signal generating unit; The control end of the second switch device is electrically connected to the output end of the holding signal generating unit; The first switch device is configured to close when receiving the sampling signal output by the sampling signal generating unit; The second switching device is configured to be closed upon receiving the holding signal output by the holding signal generating unit.

6. The circuit according to claim 4, characterized in that in, The sampling and holding module further includes: a delay unit; the delay unit is electrically connected to the output end of the comparison module, the input end of the sampling signal generating unit and the input end of the holding signal generating unit respectively; The delay unit is configured to delay the sampling signal and then send it to the sampling signal generating unit and the holding signal generating unit.

7. The circuit according to any one of claims 1 to 6, characterized in that: The circuit further comprises: a voltage dividing module; the voltage dividing module is electrically connected to the sampling and holding module and the comparison module respectively; The voltage division module is configured to divide the sample-and-hold voltage to obtain a first divided voltage; and provide a reference comparison voltage for the comparison module based on the first divided voltage.

8. The circuit according to claim 7, characterized in that The circuit further comprises: a reference module; an output end of the reference module is electrically connected to a second input end of the comparison module; The reference module is configured to provide a reference comparison voltage for the comparison module; Wherein, the reference module comprises: a voltage dividing unit, a bias power supply, a third switch device and a fourth switch device; The voltage dividing module is electrically connected to the second input terminal of the comparison module based on the third switch device; The voltage dividing unit is electrically connected to a reference power supply and a bias power supply respectively; An input terminal of the fourth switch device is electrically connected to the bias power supply, and an output terminal of the fourth switch device is electrically connected to the second input terminal of the comparison module; The voltage dividing unit is configured to provide a second divided voltage based on the reference power supply; The bias power supply is configured to provide a bias voltage; The reference module is configured to provide a reference comparison voltage for the comparison module based on the voltage divider module when the third switch device is in a closed state; and to provide a reference comparison voltage for the comparison module based on the second divided voltage and the bias voltage when the fourth switch device is in a closed state.

9. A transformer primary side information detection method, characterized in that: The method is applied to the transformer primary side information detection circuit as described in any one of claims 1 to 8 above, and the method comprises: Obtaining a start signal and a sample-and-hold voltage based on a transformer primary side information detection circuit; Determine the operating frequency of the primary controller and the on-time and off-time in a single control cycle according to the start signal; The primary line voltage value of the transformer is determined according to the voltage value of the sampled and held voltage.

10. The method according to claim 9, characterized in that Determining the operating frequency of the primary controller and the on-time and off-time in a single control cycle according to the start signal includes: Determining the operating frequency of the primary side controller according to the interval time between two start signals; The on-time and off-time of the primary-side controller in a single control cycle are determined according to the occurrence time of the rising edge and the falling edge of the start signal.

Images