CN218767249U - Power supply test circuit and device - Google Patents

Abstract

The application provides a power supply test circuit and a power supply test device, which comprise a protection and sampling module, a sampling module and a control module, wherein the protection and sampling module is used for collecting an input power supply to generate sampling voltage and absorbing surge of the sampling voltage; the under-voltage alarm isolation module is connected with the output end of the protection and sampling module, judges the under-voltage state of the sampling voltage and generates a first judgment signal; the overvoltage alarm isolation module is connected with the output end of the protection and sampling module, judges the overvoltage state of the sampling voltage and generates a second judgment signal; and the alarm signal conversion and transmission module is respectively connected with the output end of the under-voltage alarm isolation module and the output end of the overvoltage alarm isolation module, decodes the first judgment signal or/and the second judgment signal and outputs the first judgment signal or/and the second judgment signal. By the power supply test circuit, the existing framework is not changed, and the power supply test function with high reliability and low cost is realized.

Description

Power supply test circuit and device

Technical Field

The present application relates to the field of circuit technologies, and in particular, to a power supply test circuit and a power supply test device.

Background

At present, a part of special network cameras need to be powered by high-voltage negative electricity storage batteries, and the storage batteries often have the problem of unstable voltage, which causes that the network cameras are difficult to keep a normal working state. Furthermore, the power supply fluctuations of the battery are difficult to monitor in real time.

In the related art, before a negative power supply is connected to a network camera, an isolation flyback power supply needs to be used for reducing voltage so as to supply power to the network camera, but on the premise of not changing the overall architecture of the current network camera, an effective and low-cost scheme is adopted at an isolation end, so that the requirement difficulty is caused.

SUMMERY OF THE UTILITY MODEL

In view of the above-mentioned shortcomings of the prior art, the present application aims to provide a power test circuit and device, which can implement a power test function with high reliability and low cost without changing the existing architecture.

In a first aspect, an embodiment of the present application provides a power supply test circuit, including:

the protection and sampling module is used for collecting an input power supply to generate sampling voltage and absorbing the surge of the sampling voltage;

the under-voltage alarm isolation module is connected with the output end of the protection and sampling module, judges the under-voltage state of the sampling voltage and generates a first judgment signal;

the overvoltage alarm isolation module is connected with the output end of the protection and sampling module, judges the overvoltage state of the sampling voltage and generates a second judgment signal;

and the alarm signal conversion and transmission module is respectively connected with the output end of the under-voltage alarm isolation module and the output end of the overvoltage alarm isolation module, decodes the first judgment signal or/and the second judgment signal and outputs the decoded first judgment signal or/and the second judgment signal.

In one embodiment, the power supply test circuit further comprises: and the output end of the anti-backflow power supply module is connected with the input end of the protection and sampling module.

In an embodiment, the backflow prevention power supply module includes a first diode, a second diode, a first capacitor and a second capacitor, an anode of the first diode is connected to the sampling voltage, an anode of the second diode is connected to the reference voltage, cathodes of the first diode and the second diode are connected to first ends of the first capacitor and the second capacitor, and second ends of the first capacitor and the second capacitor are grounded.

In one embodiment, the protection and sampling module comprises a transient voltage suppressor diode for protecting the protection and sampling module; the protection and sampling module further comprises a voltage dividing unit which is respectively connected with the undervoltage alarm isolation module and the overvoltage alarm isolation module to provide a first voltage value.

In one embodiment, the undervoltage alarm isolation module comprises a first three-terminal voltage regulator tube, a first field effect tube, a first triode and a first photoelectric coupler; the sampling end of the first three-terminal voltage-stabilizing tube is connected with the voltage-dividing unit, the control end of the first three-terminal voltage-stabilizing tube is connected with the grid electrode of the first field-effect tube, the drain electrode of the first field-effect tube is connected with the base electrode of the first triode through the first resistor, and the collector electrode of the first triode is connected with the first pin of the first photoelectric coupler.

In one embodiment, the overvoltage alarm isolation module comprises a second three-terminal voltage regulator tube, a second field effect tube and a second photoelectric coupler; the sampling end of the second three-terminal voltage-regulator tube is connected with the voltage-dividing unit, the control end of the second three-terminal voltage-regulator tube is connected with the grid electrode of the second field-effect tube, and the drain electrode of the second field-effect tube is connected with the first pin of the second photoelectric coupler through the second resistor.

In one embodiment, the alarm signal conversion and transmission module comprises a decoder; the first input port of the decoder is connected with the second pin of the first photoelectric coupler through the third resistor, and the second input port of the decoder is connected with the second pin of the second photoelectric coupler through the fourth resistor.

In one embodiment, the power supply test circuit further comprises at least one of:

the protection module is used for protecting the power supply test circuit;

the rectification module is used for providing direct-current voltage for the backflow prevention power supply module;

and the isolation flyback module is used for reducing the voltage of the power supply test circuit.

In one embodiment, the input end of the rectification module is connected with the output end of the protection module; the input end of the isolation flyback module is connected with the output end of the rectification module.

In a second aspect, embodiments of the present application further provide a power supply test apparatus, including the power supply test circuit as described in the first aspect.

In the embodiment of the application, the power test circuit comprises a protection and sampling module, an under-voltage alarm isolation module, an overvoltage alarm isolation module and an alarm signal conversion transmission module, the protection and sampling module can provide a proper voltage value for the under-voltage alarm isolation module and the overvoltage alarm isolation module after voltage division is carried out on power voltage, so that the under-voltage alarm isolation module and the overvoltage alarm isolation module can judge whether the power voltage is under-voltage or overvoltage, and finally, whether an alarm signal needs to be sent out or not is determined through the alarm signal conversion transmission module.

Drawings

FIG. 1 is a diagram illustrating an architecture of a power test circuit according to an embodiment of the present application;

FIG. 2 is a circuit diagram of a power test provided in an embodiment of the present application;

FIG. 3 is a logic diagram illustrating an operation of a power test circuit according to an embodiment of the present disclosure;

fig. 4 is a schematic diagram illustrating a power testing apparatus according to an embodiment of the present disclosure.

Detailed Description

The following description of the embodiments of the present application is provided by way of specific examples, and other advantages and effects of the present application will be readily apparent to those skilled in the art from the disclosure herein. The present application is capable of other and different embodiments and its several details are capable of modifications and/or changes in various respects, all without departing from the spirit of the present application. It is to be noted that the features in the following embodiments and examples may be combined with each other without conflict.

It should be noted that the drawings provided in the following embodiments are only for illustrating the basic idea of the present application, and the drawings only show the components related to the present application and are not drawn according to the number, shape and size of the components in actual implementation, and the type, number and proportion of the components in actual implementation may be changed freely, and the layout of the components may be more complicated.

Before describing the embodiments of the present application, terms related to the embodiments of the present application will be explained.

The Rectifying circuit (Rectifying circuit) refers to a circuit capable of converting ac power into dc power, and the Rectifying circuit in the embodiment of the present application may be a bridge rectifier circuit.

A Transient Voltage Suppressor (TVS) is a high performance protection device in the form of a diode. When two poles of the TVS diode are impacted by reverse transient high energy, the TVS diode can change the high impedance between the two poles into low impedance, so that the voltage between the two poles is clamped at a preset value, and precision components in an electronic circuit are effectively protected from being damaged by various surge pulses or surge residual voltages.

The three-terminal voltage regulator tube can reduce the voltage and output the voltage after stabilizing the voltage to a certain fixed value. The three-end voltage regulator tube in the embodiment of the application can be TL431, and the TL431 is a parallel voltage-stabilizing integrated circuit, so that the three-end voltage regulator tube is widely applied to various power supply circuits due to good performance and low price. TL431 may include three poles: k pole, A pole and R pole. When the voltage difference between the R pole and the a pole is greater than a certain threshold, the TL431 enters a conducting state, and at this time, the K pole outputs the same voltage value as the voltage difference between the R pole and the a pole.

An opto-coupler (OCEP) is also called an opto-isolator or an opto-coupler, and is called an opto-coupler for short. The device is a device for transmitting electric signals by taking light as a medium, and usually a light emitter (an infrared Light Emitting Diode (LED)) and a light receiver (a photosensitive semiconductor tube and a photosensitive resistor) are packaged in the same tube shell. When the input end is electrified, the light emitter emits light, and the light receiver receives the light, then a photocurrent is generated and flows out from the output end, thereby realizing 'electro-optic-electro' control. In the embodiment of the present application, optoelectronic coupler can include four ports: p-port, N-port, C-port, and E-port. When the voltage difference between the P port and the N port is larger than the starting voltage, the photoelectric coupler is in a conducting state, and the voltage of the C port is approximately equal to that of the E port.

A Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET) is a Field-Effect Transistor that can be widely used in analog circuits and digital circuits. The MOSFET in the embodiment of the present application may be a P-channel depletion MOSFET. The P-channel depletion MOSFET may include a Source (S), gate (Gate, G) and Drain (Drain, D) electrode. When the voltage difference between the S pole and the G pole is larger than the turn-on voltage, the voltage of the D pole is approximately equal to that of the S pole.

An Integrated Circuit (I2C) is a simple, bi-directional two-wire synchronous serial bus. It requires only two wires to transfer information between devices connected to the bus. The I2C bus only needs one serial data line (SDA) and one Serial Clock Line (SCL), and the bus interface is integrated in the chip without special interface circuits. SDA and SCL are both bidirectional I/O lines, and the interface circuit is open-drain output.

Ground (GND), the most common Ground, is generally considered as the reference Ground in the circuit, and the potential of the Ground signal is 0V.

Digital Ground (DGND), is commonly used on Digital circuits.

Analog Ground (AGND) is commonly used on Analog circuits. In circuit design, it is strictly speaking necessary to isolate the digital ground from the analog ground to prevent mutual interference, because the harmonic components on the digital ground are much larger than those on the analog ground, and the common ground affects the stability of the analog ground.

Referring to fig. 1, fig. 1 is an architecture diagram of a power supply test circuit according to an embodiment of the present disclosure, and as shown in fig. 1, the architecture of the power supply test circuit includes a power supply, a protection module, a rectification module, an isolation flyback module, a load, a backflow prevention power supply module, a protection and sampling module, an under-voltage alarm isolation module, an overvoltage alarm isolation module, an alarm signal conversion and transmission module, and a digital signal processing module. The power supply can be a storage battery power supply and is connected to the input end of the protection module; the rectification module can comprise a bridge rectification circuit which is connected between the output end of the protection module and the input end of the isolation flyback module; the isolation flyback module can comprise an isolation flyback Buck circuit which is connected between the output end of the rectification module and the input end of the load; the anti-backflow power supply module is connected between the output end of the rectification module and the input end of the protection and sampling module; the under-voltage alarm isolation module is connected between the output end of the protection and sampling module and the input end of the alarm signal conversion and transmission module; the overvoltage alarm isolation module is connected between the output end of the protection and sampling module and the input end of the alarm signal conversion and transmission module; the alarm signal conversion and transmission module is connected with the output ends of the under-voltage alarm isolation module and the overvoltage alarm isolation module and the input end of the digital signal processing module.

The power test circuit provided by the embodiment of the present application is described in detail below with reference to fig. 2. Referring to fig. 2, fig. 2 is a diagram of a power testing circuit according to an embodiment of the present disclosure, where the power testing circuit includes:

the protection and sampling module 110 collects an input power supply to generate a power supply voltage, and absorbs a surge of the power supply voltage.

The protection and sampling module comprises a transient voltage suppression diode, and the transient voltage suppression diode is used for protecting the protection and sampling module; the protection and sampling module further comprises a voltage dividing unit, and the voltage dividing unit is used for providing a first voltage value for the undervoltage alarm isolation module and the overvoltage alarm isolation module. Wherein, the partial pressure unit comprises R1, R2, R3, R4, R5, R6, R7 and R8 shown in figure 2. When the voltage dividing unit provides a voltage value for the under-voltage alarm isolation module, the first voltage value may be VIN _ LOW as shown in fig. 2; when the voltage dividing unit provides a voltage value for the overvoltage alarm isolation module, the first voltage value may be VIN _ HIGH as shown in fig. 2.

The protection and sampling module is shown as 110 in fig. 2, and includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a third TVS tube D3, a fourth TVS tube D4, a third capacitor C3, and a fourth capacitor C4. First ends of the R1 and the R5 are connected to the power input terminal VIN, a second end of the R1 is connected to the first end of the R2, the positive electrode (VDD 5V _ IN 2) of the D2, the first end of the D3, and the first end of the C3, and a second end of the R5 is connected to the first end of the R6, the first end of the D4, and the first end of the C4; the first end of R2 is connected with the second end of R1 and the anode of D2 (VDD 5V _ IN 2), the first end of D3 and the first end of C3, the second end of R2 is connected with the first end of R3, the first end of C5 and the R-pole VIN _ LOW signal of D5TL 431; a first end of R3 is connected with a second end of R2, a first end of C5 and an R pole VIN _ LOW signal of D5TL431, a second end of R3 is connected with a first end of R4, and a second end of R4 is connected with an AGND signal; the first end of R6 is connected with the second end of R5, the first end of D4 and the first end of C4, and the second end of R6 is connected with the first end of R7; a first end of R7 is connected to a second end of R6, a second end of R7 is connected to a first end of R8, a first end of C7, and the R-pole VIN _ HIGH signal of D6TL 431; a first terminal of R8 is connected to the second terminal of R7, the first terminal of C7 and the R-pole VIN _ HIGH signal of D6TL431, and a second terminal of R8 is connected to the AGND signal.

It should be noted that the first end refers to the left end or the upper end of the component, and the second end refers to the right end or the lower end of the component, specifically, when the component is placed horizontally, the first end refers to the left end, and the second end refers to the right end; when the component is placed longitudinally, the first end refers to the upper end and the second end refers to the lower end.

The protection and sampling circuit can provide a proper voltage value for the undervoltage alarm isolation module and the overvoltage alarm isolation module at the later stage by utilizing resistance voltage division, and in addition, the D3 and the D4 can inhibit surge residual voltage to play a role of protecting the circuit.

When the input voltage VIN shown in fig. 2 enters the power supply, a surge pulse may be generated, which may disturb the circuit. The collocation shown in fig. 2 is performed by using the D3, the D4, the C3 and the C4, so that surge pulses can be absorbed and prevented from interfering a rear-stage module.

When the voltage difference between the R pole and the A pole of the TL431 is more than 2.5V, the TL431 is conducted, and the K pole outputs a voltage value signal; in contrast, when the voltage difference between the R pole and the A pole of the TL431 is less than 2.5V, the TL431 is cut off, and the K pole does not output the voltage value signal. The R-pole voltage of the D5TL431 shown in fig. 2 is determined by a Low level (Detect _ Low, DET _ Low), and VIN _ Low is obtained by dividing VIN by the voltage dividing unit. Specifically, VIN _ LOW = (R3 + R4)/(R1 + R2+ R3+ R4) × VIN. Similarly, the R-pole voltage of D6TL431 shown in fig. 2 is determined by High level (Detect _ High, DET _ High), and VIN _ High is obtained by voltage division of VIN. Specifically, VIN _ HIGH = R8/(R8 + R7+ R6+ R5) × VIN. VIN _ LOW and VIN _ HIGH may both be referred to as comparison signals.

That is, when VIN _ LOW is less than 2.5V, TL431 is turned from on to off; when VIN _ HIGH is greater than 2.5V, TL431 changes from off to on.

The under-voltage alarm isolation module 120 is connected to the output end of the protection and sampling module, judges the under-voltage state of the sampled voltage, and generates a first judgment signal.

The undervoltage alarm isolation module comprises a first three-terminal voltage regulator tube, a first field effect tube, a first triode and a first photoelectric coupler. The first three-terminal regulator may be TL431 and the first field effect transistor may be a P-channel depletion MOSFET. The sampling end of the first three-terminal voltage-regulator tube is connected with the voltage-dividing unit, the control end of the first three-terminal voltage-regulator tube is connected with the grid electrode of the first field-effect tube, the drain electrode of the first field-effect tube is connected with the base electrode of the first triode through a first resistor, and the collector electrode of the first triode is connected with the first pin of the first photoelectric coupler. The first pin of the first photocoupler can be a P pin.

Specifically, the undervoltage alarm isolation module may be as shown at 120 in fig. 2, and the module includes a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, a first field-effect transistor Q1, a second triode Q2, a D5TL431, a photocoupler U1, a fifth capacitor C5, and a sixth capacitor C6. Wherein, the R pole of the D5TL431 is connected with the first end of the C5 TL431, the first end of the R3 and the second end of the R2, the K pole of the D5TL431 is connected with the G pole of the Q1 and the second end of the R10, and the A pole of the D5TL431 is connected with the GND; the G pole of Q1 is connected with the K pole of the D5TL431 and the second end of the R10, the S pole of Q1 is connected with the first end of the R10 and the second end of the R9, and the D pole of Q1 is connected with the first end of the R11; the B pole of Q2 is connected with the second end of the R11, the E pole of Q2 is connected with an AGND signal, and the C pole of Q2 is connected with the second end of the R12 and the P pin of U1; the P pin of U1 is connected to the C pole of Q2 and the second end of R12, the N pin of U1 is connected to the AGND signal, the C pin of U1 is connected to the second end of R13 and the first end of R14, and the E pin of U1 is connected to the DGND signal.

Wherein, D5TL431 can be used as a voltage discrimination comparator; q1 can be used as a switch, and outputs a comparison signal when the voltage difference between the G pole and the S pole is greater than a certain threshold value; q2 can ensure that U1 is in a cut-off and non-conduction state within a normal power supply range, so that the service life of the optocoupler is protected; u1 can isolate the output of different source power transmission signals at two ends.

In the embodiment of the present application, when VIN is greater than the first threshold, VIN _ LOW is greater than the second threshold; when VIN is less than the first threshold, VIN _ LOW will be less than the second threshold. The second threshold may be obtained by dividing the voltage of the first threshold by the voltage dividing unit. The working principle of the undervoltage alarm isolation module is described below by taking the first threshold as 38V and the second threshold as 2.5V as an example.

When VIN is greater than 38V, VIN _ LOW is greater than 2.5v, D5TL431 is in the on state, and the K pole of D5TL431 outputs the reference voltage 2.5V, such that the voltage difference between the S pole and the G pole of Q1 is greater than the turn-on voltage 0.7v, the D pole of Q1 is set to high, and the voltage difference between the B pole and the E pole of Q2 is greater than 0.7v, the C pole of Q2 is set to LOW. When Q2 is on, pin P of U1 is equivalent to being connected to AGND signal, U1 is off, and the C-pole of U1, DET _ LOW, outputs high level.

When VIN is less than 38V, VIN _ LOW is less than 2.5V, D5TL431 is in an off state, and K of D5TL431 has no output voltage, so that the voltage difference between the S pole and the G pole of Q1 cannot be made to be greater than 0.7V, Q1 is also in an off state, the voltage difference between the B pole and the E pole of Q2 is also less than 0.7V, Q2 is also in an off state, C of Q2 is set to be high by pull-up resistor R12, that is, the P pin of U1 is high, U1 is turned on, and the C pole of U1 is pulled down, that is, DET _ LOW outputs LOW.

In the embodiment of the present application, the turn-on voltages of Q1, Q2, and Q3 are all 0.7V, and in practical applications, the turn-on voltages may be appropriately changed according to the material of the respective tubes.

The voltage variation relationship between VIN and VIN _ LOW can be seen in table 1.

Table 1: voltage variation relation table of VIN and DET _ LOW

Due to the existence of the protection and sampling module, VIN _ LOW is not influenced by the fluctuation of the power supply, and a stable power supply is provided without additional Direct Current (DC) voltage reduction.

And the overvoltage alarm isolation module 130 is connected with the output end of the protection and sampling module, judges the overvoltage state of the sampled voltage and generates a second judgment signal.

The overvoltage alarm isolation module comprises a second three-terminal voltage regulator tube, a second field effect tube and a second photoelectric coupler. The second three-terminal regulator may be TL431 and the second field effect transistor may be a P-channel depletion MOSFET. The sampling end of the second three-terminal voltage-regulator tube is connected with the voltage-dividing unit, the control end of the second three-terminal voltage-regulator tube is connected with the grid electrode of the second field-effect tube, and the drain electrode of the second field-effect tube is connected with the first pin of the second photoelectric coupler through the second resistor. The first pin of the second photocoupler can be a P pin.

Specifically, the overvoltage alarm isolation module is shown as 130 in fig. 2, and includes a fifteenth resistor R15, a sixteenth resistor R16, a seventeenth resistor R17, an eighteenth resistor R18, a nineteenth resistor R19, a twentieth resistor R20, a third field effect transistor Q3, a D6TL431, a photocoupler U2, a seventh capacitor C7, and an eighth capacitor C8. D6 The R pole of the TL431 is connected with the first ends of the C7 and the R8 and the second end of the R7, the K pole of the D6TL431 is connected with the G pole of the Q3 and the second end of the R15, and the A pole of the D6TL431 is connected with the AGND signal; the G pole of Q3 is connected with the K pole of the D6TL431 and the second end of the R15, the S pole of Q3 is connected with the first end of the R16, and the D pole of Q3 is connected with the first end of the R17; the P pin of U2 is connected to the second end of R17 and the first end of R18, the N pin of U1 is connected to the AGND signal and the second end of R18, the C pin of U1 is connected to the second end of R19 and the first end of R20, and the E pin of U1 is connected to the DGND signal.

Wherein, D6TL431 can be used as a voltage discrimination comparator; q2 can be used as a switch to output a comparison signal when the voltage difference between the G pole and the S pole is greater than a certain threshold value; q3 can ensure that U2 is in a cut-off and non-conduction state within a normal power supply range, so that the service life of the optocoupler is protected; u2 can isolate the output of different source power transmission signals at two ends.

In the embodiment of the present application, when VIN is greater than the third threshold, VIN _ HIGH is smaller than the fourth threshold; when VIN is less than the third threshold, VIN _ HIGH will be greater than the fourth threshold. The fourth threshold may be obtained by dividing the voltage of the first threshold by the voltage dividing unit. It is understood that, in combination with the first threshold and the second threshold, when VIN is greater than the first threshold and less than the third threshold, VIN _ LOW will be greater than the second threshold, and VIN _ HIGH will be greater than the fourth threshold. The working principle of the overvoltage alarm isolation module is described below by taking the third threshold as 55V and the fourth threshold as 2.5V as an example.

When VIN is greater than 55V, VIN _ HIGH is greater than 2.5V, D6TL431 is in the on state, the K pole of D6TL431 outputs the reference voltage 2.5V, so that the voltage difference between the S pole and the G pole of Q3 is greater than the turn-on voltage 0.7V, the D pole of Q3 is set to HIGH level, the P pin of U2 is also set to HIGH level accordingly, so that U1 enters the on state, the C pin of U1 is pulled low, and DET _ HIGH is low level.

When VIN is less than 55V, VIN _ HIGH is less than 2.5V, D6TL431 is in an off state, and the K pole of D6TL431 has no output, so that the voltage difference between the S pole and the G pole of Q3 is less than the turn-on voltage 0.7V, the D pole of Q3 is set to low level, the P pin of U2 is also set to low level accordingly, so that U1 enters an off state, the C pin of U1 is pulled HIGH by R19, and DET _ HIGH is HIGH level.

The voltage variation of VIN and VIN _ HIGH can be seen in table 2.

Table 2: voltage variation relation table of VIN and DET _ HIGH

Due to the existence of the protection and sampling module, VIN _ HIGH is not influenced by the fluctuation of the power supply, and a stable power supply is provided without additional DC voltage reduction.

And the alarm signal conversion and transmission module 140 is respectively connected with the output end of the under-voltage alarm isolation module and the output end of the overvoltage alarm isolation module, decodes the first judgment signal or/and the second judgment signal and outputs the decoded signals.

The alarm signal conversion and transmission module is shown as 140 in fig. 2 and includes a decoder, a first input port of the decoder is connected to the second pin of the first photocoupler through a third resistor, and a second input port of the decoder is connected to the second pin of the second photocoupler through a fourth resistor. The decoder may be an Integrated Circuit bus (I2C) decoder. As shown in FIG. 2, the integrated circuit bus decoder may be U3, the second pin of the first optocoupler may be the C pin of U1, the third resistor may be R14, the second pin of the second optocoupler may be the C pin of U2, and the fourth resistor may be R20. The pin D1 of U3 is connected with the second ends of DET _ HIGH and R20 and the first end of C8, the pin D2 of U3 is connected with the second ends of DET _ LOW and R14 and the first end of C6, the pin S1 of U3 is connected with the interface I2C _ SCL of the digital signal processing module, and the pin S2 of U3 is connected with the interface I2C _ SDA of the digital signal processing module. The U3 plays a role in signal conversion and transmission, so that signal transmission can be performed without changing a circuit architecture.

After the under-voltage alarm isolation module and the over-voltage alarm isolation module respectively obtain DET _ LOW and DET _ HIGH, decoding is required to be carried out through U3, and then the signals are transmitted to the digital signal processing module. The alarm signal conversion and transmission module can convert DET _ LOW and DET _ HIGH into level signals for the subsequent digital signal processing module to identify.

In one possible implementation, DET _ LOW outputs HIGH and DET _ HIGH outputs HIGH when the VIN operating voltage is 38V to 55V. The alarm signal transition transfer module can determine DET _ LOW =1, DET _high =1, thus indicating that the current circuit is operating properly. The table of the DET signal state when the circuit is operating normally is shown in table 3.

Table 3: DET signal state when circuit is working normally

In one possible implementation, when VIN is less than 38v, DET _lowoutputs a low level and DET _ HIGH outputs a HIGH level. The alarm signal transition transfer module may determine DET _ LOW =0, DET _high =1, thus representing that the current circuit is in an undervoltage operation state. The table of the DET signal state when the circuit is under-voltage is shown in table 4.

Table 4: DET signal state when circuit operation is under-voltage

/>

In one possible implementation, DET _ HIGH outputs a HIGH level when VIN is greater than 55V and DET _LOWoutputs a low level. The alarm signal transition transfer module may determine DET _ LOW =1, DET _high =0, thus representing that the current circuit is in an undervoltage operation state. The table of the DET signal state when the circuit is under-voltage is shown in table 5.

Table 5: DET signal state when circuit over-voltage

It can be understood that, as shown in fig. 3, VIN is in an interval of 38V to 55V, which indicates that the power supply is normally powered, the circuit can operate normally, DET _ LOW =1, DET_high =1; when VIN is less than 38V, which indicates that the power supply of the power supply is under-voltage, DET _ LOW =0, DET _high =1; when VIN is greater than 55V, indicating that the power supply of the power source is over-voltage, DET _ LOW =1, DET_high =0.

In a possible implementation manner, the power supply test circuit further comprises a backflow prevention power supply module, and an output end of the backflow prevention power supply module is connected with an input end of the protection and sampling module. Wherein, prevent flowing backward the power supply module and include first diode, second diode, first electric capacity and second electric capacity, and sampling voltage is connected to the positive pole of first diode, and reference voltage is connected to the positive pole of second diode, and the first end of first electric capacity and the first end of second electric capacity are connected to the negative pole of first diode and the negative pole of second diode, and the second end of first electric capacity and the second end ground connection of second electric capacity connect the AGND signal. As shown in fig. 2, the first diode may be D1, the second diode may be D2, the first capacitor may be C1, and the second capacitor may be C2. The positive electrode of the D1 is connected with a reference power supply (VREF) of an isolation flyback module: the cathode of the VDD5V _ IN1, D1 is connected with the first end of the C1 and the first end of the C2; the positive electrode of the D2 is connected to the second end of the R1 and the first end of the R2, and the first end of the R2 can be regarded as the input voltage VDD5V _ IN2; the negative electrode of the D2 is connected with the first end of the C1 and the first end of the C2; the first ends of C1 and C2 are connected with the negative electrode of D1 and the negative electrode of D2, and the second ends of C1 and C2 are connected with the AGND signal.

Here, VDD5V _ IN2 can be regarded as VIN obtained by voltage division. The power supply for supplying power may be VDD5V _ IN2 obtained by dividing VIN, or VREF output by the isolated flyback module: VDD5V _ IN1.

Optionally, if the isolated flyback power supply lacks a stable reference power supply, VDD5V _ IN2 may be used as a power supply, so as to save the cost of a DC conversion power supply required for separate power supply.

It can be understood that D1 and D2 in the backflow prevention power supply module provide power for the follow-up undervoltage alarm isolation module and overvoltage alarm isolation module, power supply comes from the protection and sampling module or the isolation flyback module, and D1 and D2 can also play roles in isolation and backflow prevention.

Optionally, the two power supplies may be set as follows:

VDD5V_IN2＝(R2+R3+R4)/(R1+R2+R3+R4)*VIN>5V；

VDD5V_IN2＝(R2+R3+R4)/(R1+R2+R3+R4)*VIN<8V。

by setting respective resistance values of R1, R2, R3 and R4, the VIN input wide voltage is enabled to be normally supplied with power by 10% of the width (namely 36.3V-56.7V) outside the range of 38V-55V, and the power supply requirement of the system is ensured.

In a possible implementation manner, the power supply test circuit may further include a protection module, which is configured to protect the power supply test circuit, and further include a rectification module, which is configured to provide a dc voltage to the backflow prevention power supply module; the isolation flyback module can be further included for reducing the voltage of the power supply test circuit.

According to the embodiment of the application, the protection and sampling module can absorb possible fluctuation interference of VIN, and provides appropriate input signals, namely VIN _ LOW and VIN _ HIGH, for the undervoltage alarm isolation module and the overvoltage alarm isolation module at the rear stage through the voltage division unit, the undervoltage alarm isolation module can determine whether the power supply is in an undervoltage state or not according to VIN _ LOW, the overvoltage alarm isolation module can determine whether the power supply is in an overvoltage state or not according to VIN _ HIGH, and finally transcoding is carried out through the alarm signal conversion transmission module to determine whether the alarm signal needs to be sent or not. By the method, the power supply testing function with high reliability and low cost can be realized without changing the existing architecture.

Referring to fig. 4, fig. 4 is a schematic diagram of a power testing apparatus according to an embodiment of the present disclosure, where the power testing apparatus may include the power testing circuit shown in fig. 2. Specifically, the power supply test device includes:

the protection and sampling module 110 is used for collecting an input power supply to generate sampling voltage and absorbing the surge of the sampling voltage;

the under-voltage alarm isolation module 120 is connected with the output end of the protection and sampling module 110, judges the under-voltage state of the sampling voltage and generates a first judgment signal;

the overvoltage alarm isolation module 130 is connected with the output end of the protection and sampling module 110, judges the overvoltage state of the sampled voltage and generates a second judgment signal;

and an alarm signal conversion and transmission module 140, which is respectively connected to the output end of the under-voltage alarm isolation module 120 and the output end of the over-voltage alarm isolation module 130, decodes the first judgment signal or/and the second judgment signal, and outputs the decoded signals.

In one possible implementation, the power supply test circuit further includes: and a backflow prevention power supply module 150, an output end of which is connected with an input end of the protection and sampling module 110.

In a possible implementation manner, the anti-backflow power supply module 150 includes a first diode, a second diode, a first capacitor, and a second capacitor, an anode of the first diode is connected to the sampling voltage, an anode of the second diode is connected to the reference voltage, the first diode and a cathode of the second diode are connected to first ends of the first capacitor and the second capacitor, and second ends of the first capacitor and the second capacitor are grounded.

In one possible implementation, the protection and sampling module 110 includes a transient voltage suppressor diode, which is used to protect the protection and sampling module 110; the protection and sampling module 110 further includes a voltage dividing unit, which is respectively connected to the under-voltage alarm isolation module 120 and the over-voltage alarm isolation module 130 to provide a first voltage value.

In one possible implementation, the under-voltage alarm isolation module 120 includes a first three-terminal voltage regulator tube, a first field effect tube, a first triode, and a first photocoupler; the sampling end of the first three-terminal voltage-stabilizing tube is connected with the voltage-dividing unit, the control end of the first three-terminal voltage-stabilizing tube is connected with the grid electrode of the first field-effect tube, the drain electrode of the first field-effect tube is connected with the base electrode of the first triode through the first resistor, and the collector electrode of the first triode is connected with the first pin of the first photoelectric coupler.

In one possible implementation, the overvoltage alarm isolation module 130 includes a second three-terminal regulator tube, a second field effect transistor, and a second photocoupler; the sampling end of the second three-terminal voltage-stabilizing tube is connected with the voltage-dividing unit, the control end of the second three-terminal voltage-stabilizing tube is connected with the grid electrode of the second field-effect tube, and the drain electrode of the second field-effect tube is connected with the first pin of the second photoelectric coupler through the second resistor.

In one possible implementation, the alarm signal conversion and transmission module 140 includes a decoder; the first input port of the decoder is connected with the second pin of the first photoelectric coupler through the third resistor, and the second input port of the decoder is connected with the second pin of the second photoelectric coupler through the fourth resistor.

In one possible implementation, the power supply test circuit further includes at least one of:

the protection module is used for protecting the power supply test circuit;

the rectification module is used for providing direct-current voltage for the backflow prevention power supply module;

and the isolation flyback module is used for reducing the voltage of the power supply test circuit.

In one possible implementation manner, the input end of the rectification module is connected with the output end of the protection module; the input end of the isolation flyback module is connected with the output end of the rectification module.

In one possible implementation manner, the input end of the rectification module is connected with the output end of the protection circuit; the input end of the isolation flyback module is connected with the output end of the rectification module.

The above embodiments are merely illustrative of the principles and utilities of the present application and are not intended to limit the application. Any person skilled in the art can modify or change the above-described embodiments without departing from the spirit and scope of the present application. Accordingly, it is intended that all equivalent modifications or changes which may be made by those skilled in the art without departing from the spirit and technical spirit of the present disclosure be covered by the claims of the present application.

Claims (10)

1. A power supply test circuit, comprising:

the protection and sampling module is used for collecting an input power supply to generate sampling voltage and absorbing the surge of the sampling voltage;

the under-voltage alarm isolation module is connected with the output end of the protection and sampling module, judges the under-voltage state of the sampling voltage and generates a first judgment signal;

the overvoltage alarm isolation module is connected with the output end of the protection and sampling module, judges the overvoltage state of the sampling voltage and generates a second judgment signal;

and the alarm signal conversion and transmission module is respectively connected with the output end of the under-voltage alarm isolation module and the output end of the over-voltage alarm isolation module, decodes the first judgment signal or/and the second judgment signal and outputs the decoded first judgment signal or/and the decoded second judgment signal.

2. The power supply test circuit of claim 1, further comprising: and the output end of the anti-backflow power supply module is connected with the input end of the protection and sampling module.

3. The power supply test circuit according to claim 2, wherein the anti-backflow power supply module comprises a first diode, a second diode, a first capacitor and a second capacitor, an anode of the first diode is connected with a sampling voltage, an anode of the second diode is connected with a reference voltage, cathodes of the first diode and the second diode are connected with first ends of the first capacitor and the second capacitor, and second ends of the first capacitor and the second capacitor are grounded.

4. The power supply test circuit according to claim 1, wherein the protection and sampling module comprises a transient voltage suppression diode for protecting the protection and sampling module;

the protection and sampling module further comprises a voltage division unit, and the voltage division unit is respectively connected with the undervoltage alarm isolation module and the overvoltage alarm isolation module to provide a first voltage value.

5. The power supply test circuit according to claim 4, wherein the under-voltage alarm isolation module comprises a first three-terminal regulator tube, a first field effect tube, a first triode and a first photoelectric coupler;

the sampling end of the first three-terminal voltage-stabilizing tube is connected with the voltage dividing unit, the control end of the first three-terminal voltage-stabilizing tube is connected with the grid electrode of the first field-effect tube, the drain electrode of the first field-effect tube is connected with the base electrode of the first triode through a first resistor, and the collector electrode of the first triode is connected with the first pin of the first photoelectric coupler.

6. The power supply testing circuit according to claim 5, wherein the overvoltage alarm isolation module comprises a second three-terminal voltage regulator tube, a second field effect transistor and a second photocoupler;

the sampling end of the second three-terminal voltage-stabilizing tube is connected with the voltage dividing unit, the control end of the second three-terminal voltage-stabilizing tube is connected with the grid electrode of the second field-effect tube, and the drain electrode of the second field-effect tube is connected with the first pin of the second photoelectric coupler through a second resistor.

7. The power supply test circuit of claim 6, wherein the alarm signal conversion pass-through module includes a decoder; and a first input port of the decoder is connected with a second pin of the first photoelectric coupler through a third resistor, and a second input port of the decoder is connected with a second pin of the second photoelectric coupler through a fourth resistor.

8. The power supply test circuit of claim 2, further comprising at least one of:

the protection module is used for protecting the power supply test circuit;

the rectification module is used for providing direct-current voltage for the anti-backflow power supply module;

and the isolation flyback module is used for reducing the voltage of the power supply test circuit.

9. The power supply test circuit of claim 8, wherein an input terminal of the rectification module is connected with an output terminal of the protection module;

the input end of the isolation flyback module is connected with the output end of the rectification module.

10. A power supply test apparatus comprising the power supply test circuit according to any one of claims 1 to 9.

Images