CN102207899B - Universal Serial Bus Port Test Set - Google Patents

Abstract

A universal serial bus port testing device is used for testing a universal serial bus port of an electronic device. The universal serial bus port testing device comprises a current detector, a voltage comparator, an analog-digital data converter, a microcontroller and a load circuit. The current detector is used for detecting an output current of the USB port. The voltage comparator is used for outputting an indication signal and protecting the load circuit by the indication signal. The analog-to-digital data converter is used for converting an analog signal and outputting a digital signal. The microcontroller is used for reading the output voltage and the output current of the universal serial bus port and testing four basic transmission functions of the universal serial bus port. The testing device not only can complete the basic transmission function test of the universal serial bus port, but also has the function of testing the power supply specification of the universal serial bus port.

Description

Universal Serial Bus Port Test Set

technical field

The invention relates to a test device, in particular to a test device for testing the power supply specification of a universal serial bus port.

Background technique

Most of the currently used electronic devices are equipped with USB ports. The Universal Serial Bus port is a serial port bus used to connect external devices of electronic equipment. Universal Serial Bus ports are especially widely used on computers, but can also be used on set top boxes (Set top boxes) and game consoles. The USB port can be used to directly exchange data between the electronic device and its portable device (Universal Serial Bus Device, USB device).

After the user connects the USB device to the USB port of the electronic device, the electronic device first detects whether the USB device has been successfully connected to the USB port. If the connection is successful, then the electronic device can exchange data with the USB device, and then realize the function of the USB device. Therefore, in order to verify that the USB port of the electronic device can work normally, the tester or user needs to test the quality problem of the USB port during the factory inspection and daily maintenance of the electronic device.

Generally speaking, the specification of a USB port requires that its power supply voltage should not exceed 5.25 volts. Therefore, under normal operation, the voltage provided by the USB port is between 4.75 and 5.25 volts, and the output current of the USB port does not exceed 500 milliamps (mA).

Therefore, when testing whether the data transmission performance of the USB port is normal, it is usually done through devices such as a mouse, keyboard, joystick, printer or mobile hard disk with a USB plug. During the testing process, the above-mentioned USB device can be inserted into the USB port, and then check whether the existence of the USB device is detected through the test program of the electronic device, and then check whether the USB device can work normally. However, there is a problem in this test method: when the electronic device includes multiple USB ports, the tester needs to insert the USB device into each USB port one by one. This procedure not only increases the complexity of the testing process, but also makes the testing time too long and the efficiency too low.

In addition, in order to check whether the power supply voltage and current of the USB port meet the specifications, the tester must also set up other USB devices that can be used to detect the voltage and current in addition to the above-mentioned USB device used to test whether the data transmission performance of the USB port is normal. test device. Therefore, this action also increases the test cost of the USB port at the same time.

Contents of the invention

Based on the problems of testing cost and testing complexity in the prior art, the present invention proposes a USB port testing device for testing a USB port of an electronic device.

The universal serial bus port testing device includes: a current detector, a voltage comparator, an analog-to-digital data converter, a microcontroller and a load circuit.

The current detector can be used to detect an output current generated from the USB port and generate an analog comparison voltage corresponding to the output current.

The voltage comparator can be used to output an indication signal according to the analog comparison voltage and a reference voltage.

The analog-to-digital data converter can be used to connect the current detector and the USB port to convert the analog comparison voltage and an analog output voltage generated at the USB port into a digital comparison voltage and a digital output voltage.

The microcontroller can be used to receive a differential signal, digital comparison voltage and digital output voltage generated from the USB port.

The load circuit can be used to be connected between an output contact of the USB port testing device, the voltage comparator and the microcontroller. Moreover, the load circuit can be used to form one of the on state and the off state according to the microcontroller and the indication signal.

The effect of the present invention is that, according to the universal serial bus port testing device disclosed in an embodiment of the present invention, it can not only complete the test of the basic transmission type of the universal serial bus port, but also achieve its power supply specification (output voltage and output current) test function.

The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments, but not as a limitation of the present invention.

Description of drawings

Fig. 1 is the general structural diagram of the universal serial bus port testing device according to an embodiment of the present invention;

2 is a schematic diagram of a current detector according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of an input signal unit according to an embodiment of the present invention;

FIG. 4 is a schematic diagram of a display status unit according to an embodiment of the present invention;

5 is a schematic diagram of a communication conversion circuit according to an embodiment of the present invention; and

FIG. 6 is a schematic diagram of a load circuit according to an embodiment of the invention.

Among them, reference signs

10 Universal Serial Bus ports

100 current detector

102 Current monitoring unit

104 monitoring resistor

200 voltage comparators

300 Analog-to-Digital Data Converters

400 microcontrollers

500 load circuit

600 Electrically Erasable Programmable Read-Only Memory

700 input signal unit

800 display status unit

900 communication conversion circuit

910 SRAM

VBUS output

D+ Positive end of twisted pair

D- Negative terminal of twisted pair

GND ground terminal

VCC power supply

V _a Analog output voltage

I _o output current

V _dif differential signal

V _ac analog comparison voltage

_VR output contact

V _ref reference voltage

V _ind indicator signal

V _D Digital output voltage

V _dc digital comparison voltage

S ₁ switch assembly

R ₆ input resistance

V _s first output voltage

V _err error signal

D ₁ LED

R ₅ shows resistance

U ₁ circuit assembly

C ₁ first capacitor

C ₂ second capacitor

C _3rd capacitor

C ₄ fourth capacitor

C ₅ fifth capacitor

J ₁ first exporter

J ₂ second exporter

1 first pin

2 Second pin

3 The third pin

4 The fourth pin

5 The fifth pin

6 The sixth pin

7 The seventh pin

8 The eighth pin

9 The ninth pin

10 tenth pin

11 Eleventh pin

R ₁ first resistor

R ₂ second resistor

R ₃ third resistor

R ₄ fourth resistor

Q ₁ first transistor

Q ₂ second transistor

Q ₃ third transistor

Q ₄ fourth transistor

R _1d load resistance

LDO regulator

Detailed ways

Below in conjunction with accompanying drawing, structural principle and working principle of the present invention are specifically described:

Please refer to FIG. 1 , which is a USB port testing device according to an embodiment of the present invention. The USB port testing device can be used to test the USB port 10 of an electronic device.

The USB port testing device includes: a current detector 100 , a voltage comparator 200 , an analog-to-digital data converter 300 , a microcontroller 400 and a load circuit 500 .

The USB port 10 includes four terminals, which are an output terminal VBUS, a twisted pair positive terminal D+, a twisted pair negative terminal D−, and a ground terminal GND.

Wherein, the ground terminal GND is used for grounding.

The output terminal VBUS can be used to output an analog output voltage V _a and an output current I _o of the USB port 10 , and the output terminal VBUS can be used to connect USB devices.

The positive end D+ of the twisted pair and the negative end D− of the twisted pair can be used to provide a differential signal V _dif , and the differential signal V _dif can be used to drive a USB device, such as a USB port test device.

As shown in FIG. 1 , the current detector 100 is connected between the USB port 10 , the load circuit 500 , the analog-to-digital data converter 300 and the voltage comparator 200 . The current detector 100 can be used to detect the output current I _o of the USB port 10 , and output an analog comparison voltage V _ac according to the output current I _o .

Wherein, the analog comparison voltage V _ac corresponds to the output current I _o : when the output current I _o is less than 500mA, the corresponding analog comparison voltage V _ac is between 0V and 1V. And when the output current I _o is greater than 500 mA, the corresponding analog comparison voltage V _ac is between 1 volt and 2 volts.

Please refer to FIG. 2 for a detailed schematic diagram of the current detector 100 . According to an embodiment of the present invention, the current detector 100 includes a current monitoring unit 102 and a monitoring resistor 104 .

Wherein, the current monitoring unit 102 includes a plurality of pins, which can be respectively used to connect the ground GND, a power supply VCC, the output terminal VBUS of the USB port 10, an output contact _VR , the voltage comparator 200 and the analog-digital data converter 300 .

The monitoring resistor 104 is connected between the output terminal VBUS of the USB port 10 and the output node _VR . The current monitoring unit 102 can be used to calculate the output current I _o of the USB port 10 according to the voltage drop across the monitoring resistor 104 and the resistance value of the monitoring resistor 104 .

The current monitoring unit 102 may include six pins, but it is worth mentioning that the unit components that can achieve the current monitoring function are not limited to having six pins. For clarity, here the current monitoring unit 102 with six pins is disclosed as above.

The positive input terminal of the voltage comparator 200 is connected to the junction of the current detector 100 and the analog-to-digital converter 300 . The negative input terminal of the voltage comparator 200 is connected to a reference voltage V _ref , wherein the reference voltage V _ref is 1V. The output terminal of the voltage comparator 200 is connected to the load circuit 500 . With this connection, the voltage comparator 200 can receive the analog comparison voltage V _ac , compare the analog comparison voltage V _ac with the reference voltage V _ref and output an indication signal V _ind . Wherein, the indication signal V _ind can be used to control the conduction state of the load circuit 500 . When the analog comparison voltage V _ac is between 1 volt and 2 volts, the indication signal V _ind is at a high potential. Conversely, when the analog comparison voltage V _ac is between 0 volts and 1 volt, the indication signal V _ind is at a low potential.

The input terminal of the analog-to-digital data converter 300 can be used to connect the output terminal VBUS of the USB port 10 with the current detector 100 . With this connection relationship, the analog-to-digital data converter 300 can be used to read the analog output voltage V _a and the analog comparison voltage V _ac .

The analog-to-digital data converter 300 can be used to convert an analog signal into a digital signal. Therefore, the analog-to-digital data converter 300 can be used to output a digital output voltage V _D and a digital comparison voltage V _dc . Wherein, the digital output voltage V _D corresponds to the analog output voltage V _a , and the digital comparison voltage V _dc corresponds to the analog comparison voltage V _ac .

The output terminal of the analog-to-digital data converter 300 can be used to connect an Electrically Erasable Programmable Read-Only Memory (Electrically-Erasable Programmable Read-Only Memory) 600 and the microcontroller 400 . Wherein, the EEPROM 600 can be used to temporarily store the memory state of the analog-to-digital data converter 300, and the microcontroller 400 can be used to read the digital output corresponding to the analog output voltage V _a of the USB port 10 voltage V _D .

The input terminal of the microcontroller 400 can be used to connect the twisted-pair positive terminal D+ and the twisted-pair negative terminal D− of the USB port 10 to the analog-to-digital data converter 300 . With this connection, the microcontroller 400 can receive the differential signal V _dif , the digital output voltage V _D of the USB port 10 and the digital comparison voltage V _dc . The microcontroller 400 can also obtain the output current I _o of the USB port 10 back by the digital comparison voltage V _dc . Therefore, the USB port testing device according to an embodiment of the present invention can be used to test the digital output voltage V _D and the output current I _o of the USB port 10 through the above-mentioned mechanism connection and principle.

In addition, the microcontroller 400 can also be used to be connected between an input signal unit 700 and the load circuit 500 , and its operation relationship is shown in FIG. 3 . The input signal unit 700 includes a switch element S ₁ and an input resistor R ₆ . Wherein, the switch element _S1 is connected between the microcontroller 400 and a first output voltage _Vs. One end of the input resistor _R6 is connected to the junction of the microcontroller 400 and the switch component _S1 , and the other end of the input resistor _R6 is grounded. Here, the first output voltage V _s may be 3.3 volts.

When the switch element _S1 is turned off, the microcontroller 400 is forcibly connected to the first output voltage Vs via the input signal unit 700 . Therefore, the microcontroller 400 generates a low-level error signal V _err and the microcontroller 400 can control the load circuit 500 by the error signal V _err .

Since the load circuit 500 is connected to the USB port 10 through the current detector 100 , when the switch element S ₁ is turned off, the microcontroller 400 forcibly turns on the load circuit 500 through the error signal V _err of low potential. In this case, the output current I _o of the USB port 10 exceeds 500 mA, and the analog comparison voltage V _ac output by the current detector 100 is between 1 volt and 2 volts. Therefore, the indication signal V _ind output by the voltage comparator 200 is a high potential. Then, the load circuit 500 is then forcibly turned off. Therefore, the voltage comparator 200 can thus achieve the purpose of protecting the USB port testing device disclosed in an embodiment of the present invention.

The output terminal of the microcontroller 400 according to an embodiment of the present invention can also be used to connect a display status unit 800 , a communication conversion circuit 900 and a static random access memory (Static Random Access Memory, SRAM) 910 . Wherein, the SRAM 910 can be used to store memory data of the microcontroller 400 .

As shown in FIG. 4 , the display status unit 800 includes a light emitting diode D ₁ and a display resistor R ₅ . The LED _D1 is connected between the microcontroller 400 and the display resistor _R5 . One end of the display resistor R ₅ is connected to the light emitting diode D ₁ , and the other end of the display resistor R ₅ is connected to the first output voltage V _s . When the USB port testing device according to an embodiment of the present invention is connected to the USB port 10 and the microcontroller 400 receives the differential signal V _dif , the LED D ₁ will emit light. Therefore, the display status unit 800 can thereby display the connection status between the microcontroller 400 and the USB port 10 .

Next, please refer to FIG. 1 and FIG. 5 at the same time, wherein FIG. 5 is a communication conversion circuit 900 according to an embodiment of the present invention. The communication conversion circuit 900 is connected to the microcontroller 400 and can be used to convert the output interface of the microcontroller 400 . According to an embodiment of the present invention, the communication conversion circuit 900 may be a communication conversion chip (MAX3232). The internal structure of the communication conversion chip (MAX3232) is shown in Figure 5:

The communication conversion circuit 900 includes a circuit component U ₁ , a first capacitor C ₁ , a second capacitor C ₂ , a third capacitor C ₃ , a fourth capacitor C ₄ , a fifth capacitor C ₅ , and a first output device J ₁ and a second output device J ₂ .

Wherein, the circuit component _U1 is connected to the microcontroller 400 .

The first capacitor _C1 is connected between the first pin 1 and the second pin 2 of the circuit component _U1 .

The second capacitor _C2 is connected between the third pin 3 and the fourth pin 4 of the circuit component _U1 .

The third capacitor _C3 is connected between the fifth pin 5 of the circuit component _U1 and the ground.

The fourth capacitor _C4 is connected between the sixth pin 6 of the circuit component _U1 and the ground.

The fifth capacitor _C5 is connected between the seventh pin 7 of the circuit component _U1 and the ground.

The first output device _J1 is connected to the eighth pin 8 and the ninth pin 9 of the circuit component _U1 and ground.

The second output device J ₂ is connected to the tenth pin 10 , the eleventh pin 11 of the circuit component U ₁ and the ground.

Wherein, according to an embodiment of the present invention, the fifth pin 5 can be connected to the first output voltage V _s to supply power to the circuit component U ₁ . Moreover, both the first output unit _J1 and the second output unit _J2 are Universal Asynchronous Receiver/Transmitter (UART). The communication conversion circuit 900 can be used to convert the output TTL interface of the microcontroller 400 to the RS-232 interface. With the interface conversion function of the communication conversion circuit 900 , the USB port testing device according to an embodiment of the present invention can be used to communicate with other serial ports of electronic equipment.

Please refer to FIG. 6 , which is a load circuit 500 of a USB port testing device according to an embodiment of the present invention. The load circuit 500 includes a first resistor R ₁ , a second resistor R ₂ , a third resistor R ₃ , a fourth resistor R ₄ , a first transistor Q ₁ , a second transistor Q ₂ , and a third transistor Q ₃ , a fourth transistor Q ₄ and a load resistor R _1d .

Wherein, the base of the first transistor _Q1 is connected to the voltage comparator 200 and the source of the first transistor _Q1 is grounded.

The base of the second transistor _Q2 is connected to the microcontroller 400 and the source of the second transistor _Q2 is grounded.

The first resistor _R1 is connected to the junction of the voltage comparator 200 and the base of the first transistor _Q1 .

The second resistor _R2 is connected to the junction of the microcontroller 400 and the base of the second transistor _Q2 .

The base of the third transistor _Q3 is connected to the drain of the second transistor _Q2 and the source of the third transistor _Q3 is grounded.

The base of the fourth transistor _Q4 is connected to the drain of the first transistor _Q1 and the source of the fourth transistor _Q4 is connected to the drain of the third transistor _Q3 .

The third resistor R ₃ is connected to the junction of the base of the third transistor Q ₃ and the drain of the second transistor Q ₂ .

The fourth resistor R ₄ is connected to the junction between the base of the fourth transistor Q ₄ and the drain of the first transistor Q ₁ .

The load resistor R _1d is connected between the output node _VR and the drain of the fourth transistor Q ₄ .

According to the universal serial bus port testing device according to an embodiment of the present invention, a voltage value of 3.3 volts can be applied to each floating end of the first resistor _R1 and the second resistor _R2 , and a voltage value of 3.3 volts can be applied between the third resistor _R3 and the floating end of the second resistor R2. The floating terminals of the fourth resistor _R4 are respectively applied with a voltage value of 5 volts.

The USB port testing device of an embodiment of the present invention, as shown in FIG. 1 , can further connect a voltage regulator LDO to the output node _VR . Among them, the regulator LDO can be used to step down. According to an embodiment of the present invention, since the voltage regulator LDO is connected to the USB port 10 through the current detector 100 . Therefore, the voltage regulator LDO can be used to reduce the analog output voltage V _a of the USB port 10 to a lower voltage output for use by other serial ports of the electronic device. According to the USB port testing device of an embodiment of the present invention, the voltage regulator LDO can be used to step down a voltage of 5 volts and output a voltage of 3.3 volts.

In addition, the microcontroller 400 of an embodiment of the present invention may be an EZ-USB chip of the FX2LP series manufactured by Cypress, the model number being CY7C68013A. The chip is a high-performance chip with an interface to the Universal Serial Bus port for connecting electronic devices. The chip mainly includes USB2.0 transceiver, data processing engine and an enhanced 8051 processing core. We will not repeat the rest of the unit components here.

Since the microcontroller 400 is a high-performance chip combined with a data processing engine, the microcontroller 400 can not only be used to realize the above-mentioned function of detecting the output voltage and output current of the universal serial bus port 10, but also can be used to test the universal serial bus. There are four types of transfer required by the bus port 10: control transfer, interrupt transfer, bulk transfer and isochronous transfer.

Wherein, when the USB port test device is successfully connected to the USB port 10 and can be correctly identified by the electronic device, it can be considered that the control transmission function is normal.

After the electronic equipment transmits an interrupt signal to the universal serial bus port test device through the universal serial bus port 10, if the electronic device can receive the response message from the universal serial bus port test device within the limited time, it can be considered that the interrupt transmission function is normal .

After the electronic equipment transmits a data signal to the universal serial bus port test device through the universal serial bus port 10, if the electronic device can receive a signal returned from the universal serial bus port test device, and the content of the signal is equal to that when it was sent When the data signal of , it can be considered that the bulk transfer function is normal.

The requirements for synchronous transmission are relatively loose. As long as the USB port test device can complete the transmission and reception of signals with electronic equipment, the synchronous transmission function can be regarded as normal.

For this reason, the universal serial bus port testing device of an embodiment of the present invention can not only complete the above-mentioned four kinds of transmission type tests by the microcontroller 400, but also can pass the universal serial bus port testing device of an embodiment of the present invention The included current detector 100 , voltage comparator 200 , analog-to-digital data converter 300 , microcontroller 400 and load circuit 500 complete the testing function of the power supply specification (output voltage and output current) of the USB port 10 .

Certainly, the present invention also can have other multiple embodiments, without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and deformations according to the present invention, but these corresponding Changes and deformations should belong to the scope of protection of the appended claims of the present invention.

Claims (9)

1. a device for testing universal serial bus port, in order to test a universal serial bus port of an electronic equipment, is characterized in that, this device for testing universal serial bus port comprises:

One current detector, in order to detect an output current that results from this universal serial bus port to produce a corresponding simulation comparative voltage;

One voltage comparator, in order to export an indicator signal according to this simulation comparative voltage and a reference voltage;

One analog digital data converter, connects this current detector and this universal serial bus port, to convert this simulation comparative voltage and an analog output voltage that results from this universal serial bus port to a digital comparative voltage and a digital output voltage;

One microcontroller, in order to receive the differential signal, this numeral comparative voltage and this numeral output voltage that result from this universal serial bus port;

One load circuit, is connected between an output contact, this voltage comparator and this microcontroller of this device for testing universal serial bus port, this load circuit in order to form according to this microcontroller and this indicator signal conducting state and closed condition one of them; And

At least one input signal unit, respectively this input signal unit connects this microcontroller, and this microcontroller is in order to produce a rub-out signal, to cause this microcontroller according to this this load circuit of rub-out signal control.

2. device for testing universal serial bus port according to claim 1, is characterized in that, respectively this input signal unit comprises:

One switch module, is connected between this microcontroller and one first output voltage; And

One input resistance, one end of this input resistance is connected in the contact of this microcontroller and this switch module, the other end ground connection of this input resistance.

3. device for testing universal serial bus port according to claim 1, is characterized in that, also comprises:

At least one show state unit, respectively this show state unit connects this microcontroller, in order to show the connection status of this microcontroller and this universal serial bus port.

4. device for testing universal serial bus port according to claim 3, is characterized in that, respectively this show state unit comprises:

One light emitting diode, connects this microcontroller; And

One shows resistance, is connected between the other end and one first output voltage of this light emitting diode with respect to this microcontroller.

5. device for testing universal serial bus port according to claim 1, is characterized in that, this current detector comprises:

One current monitoring unit, is connected to ground connection, a power supply, this universal serial bus port, this output contact, this voltage comparator and this analog digital data converter; And

One monitoring resistor, is connected between this universal serial bus port and this output contact.

6. device for testing universal serial bus port according to claim 1, is characterized in that, this load circuit comprises:

One the first transistor, the base stage of this first transistor connects the source ground of this voltage comparator and this first transistor;

One transistor seconds, the base stage of this transistor seconds connects the source ground of this microcontroller and this transistor seconds;

One first resistance, is connected in the contact of the base stage of this voltage comparator and this first transistor;

One second resistance, is connected in the contact of the base stage of this microcontroller and this transistor seconds;

One the 3rd transistor, the 3rd transistorized base stage connects drain electrode and the 3rd transistorized source ground of this transistor seconds;

One the 4th transistor, drain electrode and the 4th transistorized source electrode that the 4th transistorized base stage connects this first transistor connect the 3rd transistorized drain electrode;

One the 3rd resistance, is connected in the contact of the drain electrode of the 3rd transistorized base stage and this transistor seconds;

One the 4th resistance, is connected in the contact of the drain electrode of the 4th transistorized base stage and this first transistor; And

One pull-up resistor, is connected between this output contact and the 4th transistorized drain electrode.

7. device for testing universal serial bus port according to claim 1, is characterized in that, also comprises a communication switching circuit, connects this microcontroller, to change the output interface of this microcontroller.

8. device for testing universal serial bus port according to claim 7, is characterized in that, this communication switching circuit comprises:

One circuit unit, connects this microcontroller;

One first electric capacity, is connected between one first pin and one second pin of this circuit unit;

One second electric capacity, is connected between one the 3rd pin and one the 4th pin of this circuit unit;

One the 3rd electric capacity, is connected between one the 5th pin and ground connection of this circuit unit;

One the 4th electric capacity, is connected between one the 6th pin and ground connection of this circuit unit;

One the 5th electric capacity, is connected between one the 7th pin and ground connection of this circuit unit;

One first follower, connects one the 8th pin, one the 9th pin and the ground connection of this circuit unit; And

One second follower, connects 1 the tenth pin, 1 the 11 pin and the ground connection of this circuit unit.

9. device for testing universal serial bus port according to claim 8, is characterized in that, this first follower and this second follower are universal asynchronous receiving-transmitting transmitter.

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