CN220985689U - Test circuit and electronic equipment - Google Patents

Abstract

The utility model provides a test circuit and an electronic device, the test circuit includes: the system comprises a network voltage transformation module, a rectifying module, a voltage reduction module, a power load module and a power switching module; the network voltage transformation module is electrically connected with the rectification module, the rectification module is electrically connected with the voltage reduction module, and the voltage reduction module is respectively electrically connected with the power load module and the power switching module; the input ends of the power load module and the power switching module are electrically connected with the output end of the voltage reducing module, and the output end of the power switching module is electrically connected with the feedback end of the voltage reducing module; the step-down module acquires feedback voltage in the power switching module through a feedback end and outputs preset voltage according to the feedback voltage; the power switching module is used for providing a plurality of mutually independent trigger points; the power switching module can provide different feedback voltages by triggering different trigger points. The utility model can quickly and accurately adjust the load power to the power required by the test of the POE switch.

Description

Test circuit and electronic equipment

Technical Field

The present utility model relates to the field of switch technologies, and in particular, to a test circuit and an electronic device.

Background

In industrial communications, the most used POE (PowerOverEthernet ) switch is capable of providing remote power supply, i.e. power to a standard PD (PowerDevice, powered device) through the POE switch, while having RJ45 wired information transmission. Therefore, the power supply circuit layout of the PD can be reduced, and the power adapter can be reduced, so that the aim of saving cost is achieved.

However, for the POE switch, the load capacity of the POE switch needs to be tested and verified, and even the stability needs to be tested for a long time in order to evaluate the performance characteristics of the POE switch, both in the production process and in the research and development process.

As POE test load, only 3 fixed gears are generally needed to meet most application scenarios, namely, under the AF (IEEE 803 AF) mode, the power can be divided into 8W and 15W; whereas in the AT (IEEE 803 AT) mode, a maximum of 25W needs to be reached in addition to 8W and 15W compatible with the AF mode.

When testing the POE switch, the existing potentiometer is generally used for adjusting the output voltage in the test circuit, so that the effect of adjusting the load power is achieved. However, when the potentiometer is used for adjusting the resistance value, the required power cannot be quickly and accurately adjusted, and the potentiometer may need to be adjusted back for multiple times to achieve the effect.

Disclosure of utility model

In order to solve the problems, the test circuit and the electronic equipment provided by the utility model test the POE switch by arranging the power switching module, so that the load power can be quickly and accurately adjusted to the power required by the test of the POE switch.

In a first aspect, the present utility model provides a test circuit comprising: the system comprises a network voltage transformation module, a rectifying module, a voltage reduction module, a power load module and a power switching module;

the network voltage transformation module is electrically connected with the rectification module, the rectification module is electrically connected with the voltage reduction module, and the voltage reduction module is respectively electrically connected with the power load module and the power switching module;

The input ends of the power load module and the power switching module are electrically connected with the output end of the voltage reducing module, and the output end of the power switching module is electrically connected with the feedback end of the voltage reducing module;

The network transformation module splits an input switch signal into a voltage signal and a data signal; the rectification module is used for rectifying the voltage signal and outputting direct-current voltage; the voltage reduction module acquires feedback voltage in the power switching module through a feedback end, and outputs preset voltage according to the feedback voltage, wherein the feedback voltage corresponds to the preset voltage one by one; the power switching module is used for providing a plurality of mutually independent trigger points; the power load module is used for providing a load with a fixed resistance value;

the power switching module can provide different feedback voltages by triggering different trigger points.

Optionally, the test circuit further comprises: a display module;

The display module is electrically connected with the output end of the voltage reduction module and is used for displaying the working parameters of the power load module, wherein the working parameters comprise at least one of current, voltage and power.

Optionally, the test circuit further comprises: a heat dissipation module;

The heat dissipation module is electrically connected with the output end of the voltage reduction module and is used for dissipating heat of the power load module.

Optionally, the test circuit further comprises: the first network port and the second network port;

the first network port and the second network port are electrically connected with the network transformation module, the first network port is used for being connected with the POE switch, and the second network port is used for outputting data signals.

Optionally, the test circuit further comprises: a control module;

The rectifier module is electrically connected with the voltage reduction module through the control module, the control module is used for judging whether an external PoE switch is standard equipment or not, and is used for delaying the conduction of the rectifier module and the voltage reduction module when the surge current generated by the output end of the rectifier module is detected, and directly conducting the rectifier module and the voltage reduction module when the surge current generated by the output end of the rectifier module is not detected.

Optionally, the control module includes: a control unit and a slow start unit;

The control unit is respectively and electrically connected with the rectifying module, the voltage reducing module and the slow starting unit;

the control unit is used for judging whether the external PoE switch is standard equipment or not, and is used for starting the slow starting unit when the surge current generated by the output end of the rectifying module is detected, and directly conducting the rectifying module and the voltage reducing module when the surge current generated by the output end of the rectifying module is not detected;

The slow start unit is used for conducting the rectification module and the voltage reduction module in a delayed mode.

Optionally, the slow start unit includes: pull-up resistor and MOS tube;

One end of the pull-up resistor is electrically connected with the output end of the rectifying module, the other end of the pull-up resistor is electrically connected with the conversion end of the control unit and the grid electrode of the MOS tube respectively, the drain electrode of the MOS tube is grounded, and the source electrode of the MOS tube is electrically connected with the grounding end of the rear load of the control unit;

The switching end is used for generating a low level when the control unit detects surge current, and is in a pull-up state when the control unit does not detect the surge current, and the switching end does not generate a level signal when the switching end is in the pull-up state;

the MOS tube is cut off when the conversion end generates low level and is conducted when the conversion end is in a pull-up state;

the ground terminal of the rear-stage load is connected with the power supply terminal of the control unit when the conversion terminal is in a pull-up state, and is disconnected when the conversion terminal outputs a low level; the power end is electrically connected with the voltage reducing module.

Optionally, the slow start unit further includes: a zener diode;

the output end of the voltage stabilizing diode is electrically connected with the other end of the pull-up resistor, and the input end of the voltage stabilizing diode is electrically connected with the grounding end of the rear-stage load.

Optionally, the power switching module includes: a multi-gear dial switch and a regulating resistance unit;

The multi-gear dial switch is electrically connected with the regulating resistance unit, the input end of the regulating resistance unit is respectively electrically connected with the output end and the feedback end of the voltage reduction module, and the output end of the regulating resistance unit is grounded;

The regulating resistance unit is used for providing a plurality of selection circuits, and the resistance values corresponding to different selection circuits are different;

The multi-gear dial switch includes: the toggle conducting piece and the plurality of mutually independent trigger points are respectively electrically connected with the regulating resistance unit, and the toggle conducting piece is connected with different trigger points to enable the corresponding selection circuit to be connected with the input end and the output end of the regulating resistance unit.

Optionally, the regulation resistance unit includes: the circuit comprises a fixed resistor, a first selection resistor, a first regulation switch, a second selection resistor, a second regulation switch, a first voltage dividing resistor, a second voltage dividing resistor, a third voltage dividing resistor and a fourth voltage dividing resistor;

the two ends of the fixed resistor are respectively and electrically connected with the input end and the output end of the regulation resistance unit, one end of the first selection resistor is electrically connected with the input end of the regulation resistance unit, the other end of the first selection resistor is electrically connected with the output end of the regulation resistance unit after being connected with the first regulation switch in series, one end of the second selection resistor is electrically connected with the input end of the regulation resistance unit, and the other end of the second selection resistor is electrically connected with the output end of the regulation resistance unit after being connected with the second regulation switch in series;

one end of the toggle conducting piece is electrically connected with the output end of the voltage reduction module, and the other end of the toggle conducting piece is selectively and electrically connected with a plurality of trigger points;

The plurality of trigger points includes: the first trigger point, the second trigger point and the third trigger point;

The first trigger point is suspended, the second trigger point is grounded through a first voltage dividing resistor and the control end of the first regulation switch and through a second voltage dividing resistor, and the third trigger point is grounded through a third voltage dividing resistor and the control end of the second regulation switch and through a fourth voltage dividing resistor;

The second trigger point is used for conducting the first regulation switch when being electrically connected with the toggle conducting piece, and the third trigger point is used for conducting the second regulation switch when being electrically connected with the toggle conducting piece.

In a second aspect, the utility model provides an electronic device comprising at least one set of test circuits as in any one of the above.

According to the test circuit and the electronic equipment provided by the embodiment of the utility model, the POE switch is tested by setting the power switching module, a certain corresponding trigger point can be triggered according to the power value required by the test of the POE switch, so that a corresponding feedback voltage is provided for the feedback end, and the voltage reduction module can be controlled to provide a corresponding preset voltage for the power load module, so that the load power can be quickly and accurately adjusted to the power required by the test of the POE switch.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments or the conventional techniques of the present application, the drawings required for the descriptions of the embodiments or the conventional techniques will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present application, and other drawings may be obtained according to the drawings without inventive effort for those skilled in the art.

FIG. 1 is a schematic block diagram of a test circuit according to an embodiment of the present application;

FIG. 2 is a schematic partial circuit diagram of a test circuit embodying the connection of a buck module and a power switching module according to an embodiment of the present application;

FIG. 3 is a schematic circuit diagram of a first portal according to an embodiment of the present application;

FIG. 4 is a schematic circuit diagram of a network transformer module according to an embodiment of the application;

FIG. 5 is a schematic circuit diagram of a second portal according to an embodiment of the present application;

FIG. 6 is a schematic circuit diagram of a rectifier module according to an embodiment of the application;

FIG. 7 is a schematic circuit diagram of a control module according to an embodiment of the application;

FIG. 8 is a schematic partial circuit diagram of a test circuit embodying the connection of a display module and a power load module according to an embodiment of the present application;

FIG. 9 is a schematic partial circuit diagram of a test circuit embodying the relationship of the buck module and the power module connection in accordance with an embodiment of the present application;

FIG. 10 is a top view of an electronic device according to an embodiment of the application;

FIG. 11 is a rear view of an electronic device according to an embodiment of the application;

Fig. 12 is a front view of an electronic device according to an embodiment of the application.

Detailed Description

In order that the application may be readily understood, a more complete description of the application will be rendered by reference to the appended drawings. Embodiments of the application are illustrated in the accompanying drawings. This application may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

In a first aspect, an embodiment of the present utility model provides a test circuit, referring to fig. 1, the test circuit includes: the system comprises a network voltage transformation module 1, a rectification module 2, a voltage reduction module 3, a power load module 4 and a power switching module 5.

The network transformation module 1 is electrically connected with the rectification module 2; the rectifying module 2 is electrically connected with the voltage reducing module 3; the step-down module 3 is electrically connected with the power load module 4 and the power switching module 5 respectively; the input ends of the power load module 4 and the power switching module 5 are electrically connected with the output end of the voltage reducing module 3; the output end of the power switching module 5 is electrically connected with the feedback end of the voltage dropping module 3.

The network transformation module 1 splits an input switch signal into a voltage signal and a data signal; the rectification module 2 is used for rectifying the voltage signal and outputting direct-current voltage; the step-down module 3 obtains feedback voltage in the power switching module 5 through a feedback end, and outputs preset voltage according to the feedback voltage, wherein the feedback voltage corresponds to the preset voltage one by one; the power switching module 5 is used for providing a plurality of trigger points which are independent; the power load module 4 is used for providing a load with a fixed resistance value; the power switching module 5 may provide different feedback voltages by triggering different trigger points.

It can be understood that the step-down module 3 is configured to step down the POE dc voltage separated by the network voltage transformation module 1, and cooperate with the power switching module 5 to output different dc voltage values. The standard POE dc voltage is 48V, with typical fluctuations ranging from 44V to 57V.

It should be noted that, the power switching module 5 may provide a plurality of trigger points independent from each other in the foregoing manner by using a dial switch. The dial switch can be selectively and electrically connected with a plurality of trigger points through one toggle conducting piece, and when a certain trigger point needs to be triggered, the trigger can be completed by toggling the toggle conducting piece to be contacted with the trigger point; meanwhile, the dial switch can be also provided with one toggle conducting piece for each trigger point, and when a certain trigger point needs to be triggered, the trigger can be completed by toggling the corresponding toggle conducting piece to be contacted with the corresponding toggle conducting piece.

In addition, the power switching module 5 may provide a plurality of trigger points independent from each other in the manner of a key circuit. The key circuit configures one key for each trigger point, and when a certain trigger point needs to be triggered, the trigger can be completed by pressing the corresponding key.

In this embodiment, the power load module 4 is a cement resistor (also referred to as POE load), which typically has a value of 10 ohms/50W. From ohm's law, i.e. i=u/R, it is known that when the resistance R is fixed, the current I changes by the change of the voltage U. And power p=u×i, and p=u ²/R. The latter stage load power thus depends entirely on the voltage value output by the buck module 3.

Referring to fig. 2, the power switching module 5 includes: a multi-gear dip switch 51 and a regulating resistance unit 52. The multi-gear dial switch 51 is electrically connected with the regulating resistance unit 52, the input end of the regulating resistance unit 52 is electrically connected with the output end and the feedback end of the voltage reduction module 3 respectively, and the output end of the regulating resistance unit 52 is grounded.

Wherein the regulating resistance unit 52 is used for providing a plurality of selection circuits; the resistance values corresponding to the different selection circuits are different.

The multi-shift dial switch 51 includes: toggle the conducting member and a plurality of mutually independent trigger points. A plurality of mutually independent trigger points are electrically connected to the regulating resistance unit 52, respectively. The toggle conductive elements are connected to different trigger points to enable corresponding selection circuits to be connected to the input and output ends of the regulating resistor unit 52.

It should be noted that, the multiple selection circuits may be formed by combining multiple resistor branches in the regulating resistor unit 52, or may be formed by using independent resistor branches as a selection circuit.

In the present embodiment, the plurality of selection circuits are composed of a plurality of resistor branches in the regulating resistor unit 52. Specifically, the regulation resistance unit 52 includes: the fixed resistor R18, the first selection resistor R20, the first regulating switch Q4, the second selection resistor R23, the second regulating switch Q5, the first voltage dividing resistor R24, the second voltage dividing resistor R26, the third voltage dividing resistor R25 and the fourth voltage dividing resistor R27.

Wherein, two ends of the fixed resistor R18 are respectively and electrically connected with the input end and the output end of the regulating resistance unit 52; one end of the first selection resistor R20 is electrically connected with the input end of the regulating resistance unit 52; the other end of the first selection resistor R20 is connected with the first regulating switch Q4 in series and then is electrically connected with the output end of the regulating resistor unit 52; one end of the second selection resistor R23 is electrically connected with the input end of the regulating resistance unit 52; the other end of the second selection resistor R23 is connected with the second regulating switch Q5 in series and then is electrically connected with the output end of the regulating resistor unit 52; one end of the toggle conducting piece is electrically connected with the output end of the voltage reduction module 3, and the other end of the toggle conducting piece is selectively and electrically connected with a plurality of trigger points.

The plurality of trigger points includes: the first trigger point, the second trigger point and the third trigger point. The first trigger point is suspended; the second trigger point is grounded through a first voltage dividing resistor R24 and the control end of the first regulating switch Q4 and through a second voltage dividing resistor R26; the third trigger point is grounded through a third voltage dividing resistor R25 and the control end of the second regulating switch Q5 and through a fourth voltage dividing resistor R27.

The second trigger point is used for conducting the first regulating switch Q4 when being electrically connected with the toggle conducting piece. The third trigger point is used for conducting the second regulating switch Q5 when the third trigger point is electrically connected with the toggle conducting piece.

In the present embodiment, the first regulating switch Q4 and the second regulating switch Q5 are transistors, but not limited thereto.

By providing the regulating resistance unit 52, it is possible to achieve that the selection circuits providing different resistance values are connected between the input terminal and the output terminal of the regulating resistance unit 52 when different trigger points are triggered. By matching the regulating resistance unit 52 with the multi-gear dip switch 51, the complexity of the operation of the power switching module 5 is reduced.

It should be noted that, the step-down module 3 may adopt an asynchronous rectification step-down or synchronous rectification step-down mode to step down the high voltage poe+ output by the control module 6 to a low voltage of the preset voltage vdd_1. When the buck module 3 uses asynchronous rectification to buck, an additional diode D11 is needed.

In this embodiment, the input end of the adjusting resistor unit is electrically connected with the output end of the voltage reducing module 3 through the protection resistor R16, and the voltage reducing module 3 adopts a non-synchronous rectification voltage reducing mode to reduce voltage; the multi-gear dial switch 51 is a double-pole three-throw dial switch for providing three gears of low, medium and high speed. The first contact is pins 1 and 2 of the multi-gear dial switch 51; the second contact is the 5 pin and the 6 pin of the multi-gear dial switch 51; the third contact is the pin 7 and pin 8 of the multi-gear dial switch 51; the toggle conducting piece is electrically connected with the 3 pin and the 4 pin of the multi-gear dial switch 51, and the 3 pin and the 4 pin of the multi-gear dial switch 51 are electrically connected with the output end of the voltage reduction module 3 through a fifth voltage dividing resistor R22, and particularly, refer to fig. 2.

In fig. 2, a voltage dividing branch is formed by resistors R8 and R13, and the divided voltage thereof makes pin 3 (EN enable pin) of the chip U2 be at a high level, and the chip U2 works normally; c12 is a filter capacitor; the resistor R14, the capacitor C8, the resistor R15, the capacitor C13, the capacitor C17 and other devices are standard designs matched with the whole voltage reduction module, and are not described in detail herein; the 5 pin FB of the chip U2 is a feedback pin, that is, a feedback end, and the value of the output preset voltage vdd_1 can be obtained through a calculation formula, where the preset voltage vdd_1 is calculated according to the calculation formula: but is not limited thereto, where ra=r16, rb is the total resistance of the selection circuit connected to the input terminal and the output terminal of the regulating resistance unit 52.

Based on the above, the working principle of the power switching module 5 is as follows: when the toggle conducting element is connected with pins 12 and 34, the fifth voltage dividing resistor R22 is in a suspended state. Meanwhile, pins 5, 6, 7 and 8 of the multi-gear dial switch 51 are also in a suspended state, at this time, the first voltage dividing resistor R24 is connected in series with the second voltage dividing resistor R26 to be grounded, the third voltage dividing resistor R25 is connected in series with the fourth voltage dividing resistor R27 to be grounded, therefore, the bases of the first regulating switch Q4 and the second regulating switch Q5 are pulled down to be low, at this time = 0, and the first regulating switch Q4 and the second regulating switch Q5 are both in a cut-off state. The first selection resistor R20 and the second selection resistor R23 are in a floating state. At this point rb=r18,

When the toggle conducting piece is connected with pins 34 and 56, the fifth voltage dividing resistor R22 and the second voltage dividing resistor R26 form a voltage dividing circuit, and the voltage of the first regulating switch Q4 is divided to be more than 0 by adjusting the resistance value of the fifth voltage dividing resistor R22. The pins 7 and 8 of the multi-gear dial switch 51 at the other side are in a suspended state, at this time, the third voltage dividing resistor R25 is connected in series with the fourth voltage dividing resistor R27 to be grounded, and then the first regulating switch Q4 is turned on, and the second regulating switch Q5 is turned off. The first selection resistor R20 is directly connected to the ground after the first regulating switch Q4 is turned on. At this time, rb is equal to the total resistance of the first selection resistor R20 connected in parallel with R18, i.e., rb= =5.9K, then

When the toggle conducting piece is connected with pins 3, 4, 7 and 8, the fifth voltage dividing resistor R22 and the fourth voltage dividing resistor R27 form a voltage dividing circuit, and the voltage of the second regulating switch Q5 is enabled to be greater than 0 through adjusting the resistance value of the fifth voltage dividing resistor R22. The pins 5 and 6 on the other side are in a suspended state, at this time, the first voltage dividing resistor R24 is connected in series with the second voltage dividing resistor R26 to be grounded, the second regulating switch Q5 is turned on, and the first regulating switch Q4 is turned off. The second selection resistor R23 is directly connected to the ground after the second regulating switch Q5 is turned on. At this time, rb is equal to the total resistance of the second selection resistor R23 connected in parallel with R18, i.e., rb= =4.46K, then

It will be appreciated that in fig. 2, the capacitors C18 and C20 are both filtering to prevent momentary connection of the multi-position dip switch 51. The first regulating switch Q4 and the second regulating switch Q5 are broken down by high voltage or other interference information, and meanwhile, erroneous conduction of the first regulating switch Q4 and the second regulating switch Q5 is avoided, and other devices in the circuit are not specifically described in this embodiment.

Further, the test circuit further includes: the control module 6, the first portal 71 and the second portal 72.

The first network port 71 and the second network port 72 are both electrically connected with the network transformation module 1, the first network port 71 is used for connecting with a POE switch, and the second network port 72 is used for connecting with powered equipment so as to output data signals.

In this embodiment, the signal wires of the POE switch enter the first network port 71 through the RJ45 interface, and eight wires of the standard gigabit first network port 71 are connected to the network transformer module 1, so that the switch signals (DA 1_1, DA2_1, DA3_1, DA4_1, DA5_1, DA6_1, DA7_1 and DA 8_1) enter the primary of the network transformer module 1, in combination with fig. 3 and fig. 4. The switch signal is separated into an Ethernet data signal and a voltage signal after passing through the network transformation module 1.

The ethernet signals (ta1_1, ta2_1, ta3_1, ta4_1, ta5_1, ta6_1, ta7_1, and ta8_1) are forwarded by the secondary of the network voltage transformation module 1 and output to the second network port 72, and fig. 4 and 5 are combined; the voltage signals are derived from the primary center tap of the network transformer module 1, and the derived voltage signals (POE 1_2, POE3_6, POE4_5 and POE 7_8) are input to the rectifier circuit of the subsequent stage, and fig. 6 is combined.

The POE switch is powered in two modes. One of them is End-Span and the other is middle-Span. Both modes support the ieee802.3af and IEEE802.3AT standards. Whereas the maximum provided output power of the ieee802.3af standard is 15.4W and the maximum provided output power of the ieee802.3at standard is 30W.

For the POE switch with the tail end bridging method, power is supplied to powered equipment through lines 1, 2, 3 and 6, and data transmission is performed. Wherein the 1 and 2 lines are positive electrodes, and the 3 and 6 lines are negative electrodes.

For the POE switch of the intermediate cross-over method, the power receiving device is powered by the 4, 5, 7 and 8 wires, and when the POE switch is applied to the 10BASE-T and 100BASE-T ethernet, the 4, 5, 7 and 8 wires only transmit power and no data, so the four pins are also called idle pins. Wherein the 4 and 5 wires are used as positive electrodes, and the 7 and 8 wires are used as negative electrodes.

Referring to fig. 6, the rectifying module 2 includes two groups of full bridges, and skillfully utilizes the unidirectional conduction characteristic of the diode, whether a terminal bridging method or an intermediate bridging method, when the rectifier module 2 passes through, only one end of the rectifier module is fixed to output poe+ (positive electrode), and the other end of the rectifier module is fixed to output POE- (negative electrode).

Taking a group of full bridges as an example, the full bridge comprises two groups of conducting branches connected in parallel between POE+ and POE-, and each group of conducting branches comprises two diodes connected in series; the two input ends are respectively connected into the two conducting branches, and are connected between the two diodes in the conducting branches.

The rectifying module 2 is electrically connected with the voltage dropping module 3 through the control module 6. The control module 6 is used for judging whether the external POE switch is standard equipment, controlling the on-off of the rectifying module 2 and the voltage reducing module 3, and detecting whether the output end of the rectifying module 2 generates surge current. When the control module 6 detects that the output end of the rectifying module 2 generates surge current, the delay rectifying module 2 is conducted with the voltage reduction module 3, and when the output end of the rectifying module 2 does not detect that the output end of the rectifying module 2 generates surge current, the control module directly conducts the rectifying module 2 with the voltage reduction module 3.

It should be noted that, with reference to fig. 7, the control module 6 may use the existing functional chip U1 to determine whether the external POE switch is a standard device and control whether the rectifying module 2 outputs a voltage to the step-down module 3, and detect whether the output end of the rectifying module 2 generates a surge current, which is not limited in this embodiment.

In the present embodiment, the control module 6 realizes the identification, classification, power-on control, and fault protection and short-circuit protection of the analog PD through the corresponding functional chip. The PD classification is that the control module 6 provides the characteristics and classification information of the power load module 4 to the POE switch, i.e. PSE (PowerSourcing Equipment, power supply equipment), so as to inform the PD of the power level of normal operation, and further limit the maximum power. In addition, the control module 6 can implement delay control on the conduction of the rectifying module 2 and the voltage reducing module 3 when detecting that the output end of the rectifying module 2 generates surge current by internally arranging a delay circuit or externally connecting the delay circuit, thereby avoiding damage caused by surge impact received by the voltage reducing module 3.

When the powered end device is connected to the POE switch, the POE switch will perform the steps of detecting the powered device, classifying the powered device, starting the power supply, normal power supply, and disconnecting the power supply in sequence.

The main process of detecting the powered device is: it is detected whether the device connected to the POE switch is a standard powered device. The POE switch outputs a small voltage at the port to detect the powered device, i.e. so-called voltage pulse detection, typically a detection pulse voltage of e.g. 2.8-10V/500 ms. For the test circuit in this embodiment, the control module 6 performs chip internal identification after receiving the voltage pulse signal output by the POE switch, which may also be referred to as performing POE protocol handshaking operation, so as to determine whether the device connected to the POE switch is a standard PD.

The specific process of performing classification of the powered end device is as follows: after the handshake is successful, i.e. after the powered device is detected, the POE switch classifies the powered device, and evaluates the power consumption required by the powered device. Typically, the POE switch will send a classification pulse voltage of 14.5-20V/75ms to the control module 6 for judgment classification. For example, in the process of judging the gradation, when the resistor r10=63.4r is selected according to the manual of the functional chip U1, the AT mode is set so that the maximum load power of the subsequent stage can reach 25.5W.

The specific process of executing normal power supply is as follows: the method provides stable and reliable direct-current voltage of 44V to 57V for the power receiving end equipment, and meets the power consumption of the power receiving end equipment.

The specific process of cutting off the power supply is as follows: when the powered end device has the problems of disconnection, overload power consumption, short circuit, total power consumption exceeding the power budget of the POE switch and the like, the POE switch stops supplying power to the powered end device within 300ms to 400ms, and detection is performed again. Therefore, the power receiving end equipment and the POE switch can be effectively protected, and equipment damage is prevented.

Specifically, in connection with fig. 7, the control module 6 includes: the control unit 61 and the slow start unit 62. The control unit 61 is electrically connected to the rectifying module 2, the step-down module 3, and the soft start unit 62, respectively.

The control unit 61 is configured to determine whether the external PoE switch is a standard device, control on/off of the rectifying module 2 and the buck module 3, and detect whether an output end of the rectifying module 2 generates a surge current. When the control unit 61 detects that the output end of the rectifying module 2 generates surge current, the slow starting unit 62 is started, and when the output end of the rectifying module 2 does not detect that the output end of the rectifying module 2 generates surge current, the rectifying module 2 and the voltage reducing module 3 are directly conducted; the slow start unit 62 is used for conducting the rectification module 2 and the depressurization module 3 in a delayed manner.

In the present embodiment, the slow start unit 62 includes: pull-up resistor R7 and MOS transistor Q1 (metal-oxide semiconductor field effect transistor).

One end of a pull-up resistor R7 is electrically connected with the output end of the rectifying module 2, the other end of the pull-up resistor R7 is electrically connected with the conversion end of the control unit 61 and the grid electrode of the MOS tube Q1 respectively, the drain electrode of the MOS tube Q1 is grounded, and the source electrode of the MOS tube Q1 is electrically connected with the grounding end of the rear-stage load of the control unit 61.

The switching end is used for generating a low level when the control unit 61 detects surge current, and is in a pull-up state when the control unit 61 does not detect the surge current, namely pulled up by the pull-up resistor R7, wherein the switching end does not generate a level signal when in the pull-up state; the MOS transistor Q1 is cut off when the conversion end generates low level and is turned on when the conversion end is in a pull-up state; the ground terminal of the rear load is connected with the power terminal of the control unit 61 when the conversion terminal is in a pull-up state, and is disconnected when the conversion terminal outputs a low level; the power supply terminal is electrically connected with the voltage dropping module 3.

Further, the slow start unit 62 further includes: and a zener diode D12.

The output end of the zener diode D12 is electrically connected to the other end of the pull-up resistor R7, and the input end of the zener diode D12 is electrically connected to the ground end of the subsequent load. Through setting up zener diode D12 can effectually prevent that MOS pipe Q1's gate voltage from being too high to cause harm to MOS pipe Q1.

In the present embodiment, the slow start unit 62 composed of the pull-up resistor R7, the zener diode D12 and the N-type MOS transistor Q1 is added to the control unit 61 including the functional chip U1. When the functional chip U1 and the external switch are successfully held, a direct current with high voltage of 44V to 57V is provided to the post-stage voltage reduction module 3 instantly, so that surge impact can be formed on the post-stage circuit.

The slow start circuit achieves the effect of slow start by controlling the conduction of the GND_1 pin and the POE-pin in the functional chip U1. After the handshake between the functional chip U1 and the POE switch is successful, the PSE normally provides direct current of 44V to 57V for the standard PD, and at the moment, the functional chip U1 normally supplies power to start working, and a 4-pin VSS pin and a 5-pin RTN pin are connected inside. At the beginning of the internal process, the CDB pin outputs a low level 0, at this time, it can be known that vgs=0v of the MOS transistor Q1, the MOS transistor Q1 is turned off, and gnd_1 and VSS are not turned on. After a delay, when no surge current is detected inside the functional chip U1, i.e. the control module 6 is in a normal mode, the CDB pin is not pulled down to a low level but is in a suspended state. And the grid of the MOS tube Q1 is pulled up through the pull-up resistor R7, VGS is >0V, the MOS tube Q1 is conducted, the GND_1 pin is conducted with the VSS pin, and the voltage reducing module 3 at the later stage starts to supply power normally.

Referring to fig. 8 and 9, the test circuit further includes: a display module 73 and a heat dissipation module 74. The display module 73 is electrically connected to the output terminal of the step-down module 3. The display module 73 is used for displaying the operating parameters of the power load module 4. Wherein the operating parameter comprises at least one of current, voltage and power. In the present embodiment, the operation parameters include, but are not limited to, current, voltage, and power.

The heat dissipation module 74 is electrically connected to the output of the buck module 3. The heat dissipation module 74 is used for dissipating heat from the power load module 4. It will be appreciated that the heat dissipation module 74 also dissipates heat from other devices on the motherboard where the test circuit is located.

In this embodiment, the display module 73 includes a dc double-display ammeter, and displays the voltage and current of the subsequent load through the dc double-display ammeter, including: when the conduction member is turned on pins 1, 2 and 3, 4, the voltage is shown as 8.2V, when the conduction member is turned on pins 3, 4 and 5, 6, the voltage is shown as 10.9V, and when the conduction member is turned on pins 3, 4 and 7, 8, the voltage is shown as 14.2V. Therefore, the tester can more intuitively see the power of the corresponding POE load. The heat dissipation module 74 is a pipeline fan, and is used for dissipating heat of the whole machine, and a good heat dissipation effect can be achieved by configuring the fan, so that the phenomenon that the whole machine is halted or restarted at high temperature under the condition of long-time high load is avoided. Thus, the whole device comprising the test circuit can be operated more stably and reliably.

In an alternative embodiment, as shown in fig. 9, the test circuit further includes: TVS tube and filter capacitor. Wherein, the TVS tube D14 and the filter capacitor C22 are both connected in parallel with the heat dissipation module 74. Wherein the TVS tube is capable of preventing damage to the fan from protecting the fan from excessively high voltages.

It should be noted that, since the heat dissipation module 74 also supplies power through the output terminal of the step-down module 3, the power consumption of the heat dissipation module 74 should be calculated to be within the total load power, i.e., the total load power consumption P _{Total (S)} ＝P _{Cement resistor} +P _{Fan with fan body} of the test circuit. Where P _{Cement resistor} is the power consumption of the power load module 4, and P _{Fan with fan body} is the power consumption of the heat dissipation module 74.

In addition, because the power consumption of the heat dissipation module 74 under different voltage values is different, the direct current stabilized power supply can be used in advance to simulate the low, medium and high voltages output by the three gear step-down modules 3, namely 8.2V, 10.9V and 14.2V, so as to calculate the corresponding power consumption of the heat dissipation module 74, such as 2W, 3W and 5W.

At low speed, the total power consumption of the load of the test circuit

At medium speed, the total power consumption of the load of the test circuit

At high speed, the total power consumption of the load of the test circuit

Similarly, the resistance values of the fixed resistor R18, the first selection resistor R20, and the second selection resistor R23 may be adjusted according to actual situations, so as to achieve a suitable output voltage and a suitable output power. The protection resistor R16, the fixed resistor R18, the first selection resistor R20, and the second selection resistor R23 all need to use resistors with an accuracy of 1%. This enables the buck module 3 to output a stable preset voltage vdd_1.

According to the test circuit provided by the utility model, the POE switch is tested by setting the power switching module 5, and a certain corresponding trigger point can be triggered according to the power value required by the test of the POE switch so as to provide a corresponding feedback voltage for the feedback end, so that the voltage reduction module 3 can be controlled to provide a corresponding preset voltage for the power load module 4, and the load power can be quickly and accurately adjusted to the power required by the test of the POE switch. Meanwhile, the voltage, the current and the actual work of the power load module 4 are displayed in a real-time visual mode by the display module 73, so that the operation and the use of the device provided with the test circuit by a tester are further facilitated.

In a second aspect, the present utility model provides, in an embodiment, an electronic device comprising at least one set of test circuits of the first aspect.

In this embodiment, twelve sets of test circuits in the first aspect are provided within the electronic device. With reference to fig. 10, 11 and 12, the electronic device further comprises a housing 8; the circuit board provided with the test circuit is fixedly arranged on the casing 8.

Wherein, twelve groups of display modules 73 and twelve groups of multi-gear dial switches 51 are all fixedly arranged on the front panel of the casing 8, twelve groups of first net openings 71 and twelve groups of second net openings 72 are all fixedly arranged on the rear panel of the casing 8, and ventilation openings are all arranged on the left and right side walls of the casing 8.

The electronic equipment provided by the utility model has a simple structure and is convenient to operate, and a plurality of stable and reliable test circuits can be provided for testing the POE switch.

In the description of the present specification, reference to the terms "some embodiments," "other embodiments," "desired embodiments," and the like, means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. In this specification, schematic descriptions of the above terms do not necessarily refer to the same embodiment or example.

The technical features of the above embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The foregoing examples illustrate only a few embodiments of the application and are described in detail herein without thereby limiting the scope of the application. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the application, which are all within the scope of the application. Accordingly, the scope of protection of the present application is to be determined by the appended claims.

Claims (10)

1. A test circuit, the test circuit comprising: the system comprises a network voltage transformation module (1), a rectifying module (2), a voltage reduction module (3), a power load module (4) and a power switching module (5);

The network voltage transformation module (1) is electrically connected with the rectification module (2), the rectification module (2) is electrically connected with the voltage reduction module (3), and the voltage reduction module (3) is electrically connected with the power load module (4) and the power switching module (5) respectively;

The input ends of the power load module (4) and the power switching module (5) are electrically connected with the output end of the voltage reduction module (3), and the output end of the power switching module (5) is electrically connected with the feedback end of the voltage reduction module (3);

The network transformation module (1) splits an input switch signal into a voltage signal and a data signal; the rectification module (2) is used for rectifying the voltage signal and outputting direct-current voltage; the step-down module (3) acquires feedback voltage in the power switching module (5) through the feedback end, and outputs preset voltage according to the feedback voltage, wherein the feedback voltage corresponds to the preset voltage one by one; the power switching module (5) is used for providing a plurality of mutually independent trigger points; the power load module (4) is used for providing a load with a fixed resistance value;

the power switching module (5) may provide different feedback voltages by triggering different of the trigger points.

2. The test circuit of claim 1, wherein the test circuit further comprises: a display module (73);

The display module (73) is electrically connected with the output end of the voltage reduction module (3), and the display module (73) is used for displaying working parameters of the power load module (4), wherein the working parameters comprise at least one of current, voltage and power.

3. The test circuit of claim 1, wherein the test circuit further comprises: a heat dissipation module (74);

The heat dissipation module (74) is electrically connected with the output end of the voltage reduction module (3), and the heat dissipation module (74) is used for dissipating heat of the power load module (4);

And/or, the test circuit further comprises: a first portal (71) and a second portal (72);

The first network port (71) and the second network port (72) are electrically connected with the network transformation module (1), the first network port (71) is used for being connected with a POE switch, and the second network port (72) is used for outputting the data signals.

4. A test circuit according to any one of claims 1 to 3, wherein the test circuit further comprises: a control module (6);

the rectifying module (2) is electrically connected with the voltage reducing module (3) through the control module (6);

The control module (6) is used for judging whether an external PoE switch is standard equipment or not, and is used for delaying the conduction of the rectification module (2) and the voltage reduction module (3) when the surge current generated by the output end of the rectification module (2) is detected, and directly conducting the rectification module (2) and the voltage reduction module (3) when the surge current generated by the output end of the rectification module (2) is not detected.

5. Test circuit according to claim 4, characterized in that the control module (6) comprises: a control unit (61) and a slow start unit (62);

The control unit (61) is electrically connected with the rectifying module (2), the voltage reducing module (3) and the slow starting unit (62) respectively;

The control unit (61) is used for judging whether an external PoE switch is standard equipment or not, and is used for starting the slow starting unit (62) when the surge current generated by the output end of the rectifying module (2) is detected, and directly conducting the rectifying module (2) and the voltage reducing module (3) when the surge current generated by the output end of the rectifying module (2) is not detected;

The slow start unit (62) is used for conducting the rectification module (2) and the depressurization module (3) in a delayed mode.

6. The test circuit according to claim 5, wherein the slow start unit (62) comprises: pull-up resistor and MOS tube;

One end of the pull-up resistor is electrically connected with the output end of the rectifying module (2), the other end of the pull-up resistor is respectively electrically connected with the conversion end of the control unit (61) and the grid electrode of the MOS tube, the drain electrode of the MOS tube is grounded, and the source electrode of the MOS tube is electrically connected with the grounding end of the rear load of the control unit (61);

The switching end is used for generating a low level when the control unit (61) detects surge current, is in a pull-up state _, when the control unit (61) does not detect surge current, and does not generate a level signal when the switching end is in the pull-up state;

The MOS tube is cut off when the conversion end generates low level and is conducted when the conversion end is in a pull-up state;

The rear-stage load grounding end is connected with the power end of the control unit (61) when the conversion end is in a pull-up state, and is disconnected when the conversion end outputs a low level; the power supply end is electrically connected with the voltage reduction module (3).

7. The test circuit of claim 6, wherein the slow start unit (62) further comprises: a zener diode;

The output end of the voltage stabilizing diode is electrically connected with the other end of the pull-up resistor, and the input end of the voltage stabilizing diode is electrically connected with the grounding end of the rear-stage load.

8. A test circuit according to any one of claims 1 to 3, characterized in that the power switching module (5) comprises: a multi-gear dial switch (51) and a regulating resistance unit (52);

The multi-gear dial switch (51) is electrically connected with the regulating resistance unit (52), the input end of the regulating resistance unit (52) is electrically connected with the output end and the feedback end of the voltage reduction module (3) respectively, and the output end of the regulating resistance unit (52) is grounded;

The regulating resistance unit (52) is used for providing a plurality of selection circuits, and the resistance values corresponding to different selection circuits are different;

The multi-gear dial switch (51) includes: the toggle conducting piece and the plurality of mutually independent trigger points are respectively and electrically connected with the regulating resistance unit (52), and the toggle conducting piece is connected with different trigger points to enable corresponding selection circuits to be connected into the input end and the output end of the regulating resistance unit (52).

9. The test circuit according to claim 8, wherein the regulation resistance unit (52) comprises: the circuit comprises a fixed resistor, a first selection resistor, a first regulation switch, a second selection resistor, a second regulation switch, a first voltage dividing resistor, a second voltage dividing resistor, a third voltage dividing resistor and a fourth voltage dividing resistor;

The two ends of the fixed resistor are respectively and electrically connected with the input end and the output end of the regulating resistor unit (52), one end of the first selection resistor is electrically connected with the input end of the regulating resistor unit (52), the other end of the first selection resistor is electrically connected with the output end of the regulating resistor unit (52) after being connected with the first regulating switch in series, one end of the second selection resistor is electrically connected with the input end of the regulating resistor unit (52), and the other end of the second selection resistor is electrically connected with the output end of the regulating resistor unit (52) after being connected with the second regulating switch in series;

one end of the poking conducting piece is electrically connected with the output end of the voltage reduction module (3), and the other end of the poking conducting piece is selectively and electrically connected with a plurality of trigger points;

The plurality of trigger points includes: the first trigger point, the second trigger point and the third trigger point;

The first trigger point is suspended, the second trigger point is grounded through a first voltage dividing resistor and the control end of the first regulation switch and through a second voltage dividing resistor, and the third trigger point is grounded through a third voltage dividing resistor and the control end of the second regulation switch and through a fourth voltage dividing resistor;

The second trigger point is used for conducting the first regulation switch when being electrically connected with the toggle conducting piece, and the third trigger point is used for conducting the second regulation switch when being electrically connected with the toggle conducting piece.

10. An electronic device comprising at least one set of test circuits according to any one of claims 1 to 9.