TW201443446A - Negative voltage detector - Google Patents

Abstract

This invention discloses a negative voltage detector which comprises a sampling circuit electrically connected to a positive voltage grounding end and a negative voltage grounding end. A cross-voltage is generated based on the voltage difference between the two grounding ends and create a sampling current; a current transformer electrically connected to the sampling circuit and a negative voltage reference node to generate a relative output of the sampling current while the cross-voltage is generated; and a first voltage divider sampling resistor electrically connected to the positive voltage reference node and a connection node, and a second voltage divider sampling resistor electrically connected to the negative voltage reference node and the connection node, wherein the first and second voltage divider sampling resistors have the same resistance value. The sampling current outputted by the current transformer generates a negative induction voltage at the connection node via the second voltage divider sampling resistor. Therefore, with the present invention, precise negative induction voltage can be effectively detected, and the negative induction current or power thereof can be further obtained.

Description

Negative voltage detection device

The present invention relates to a voltage detecting device, and more particularly to a negative voltage detecting device applied to a plurality of sets of power supply systems.

In order to further improve the safety and reliability of the electronic circuit system, a voltage detection circuit is usually designed in the system, and usually has an overvoltage or low voltage detection function to prevent the power supply voltage from exceeding the damage caused by the working voltage. Or avoid component collapse caused by a temporary voltage drop or overvoltage of the voltage. However, most voltage detection circuits detect positive voltages, whether they are low voltage or over voltage.

On the other hand, in general, research, design, development, and production applications require equipment that can supply current to connect devices under development or testing. These applications must also monitor the voltage and current consumed by the device to derive the most appropriate treatment based on its device behavior or testing. Furthermore, for applications that require a more accurate measurement of the power supply, various voltage and current values are typically read for further evaluation. However, it is generally easy to obtain positive voltage and positive current for detection. Some negative currents are usually ignored directly; or only negative signals can be measured by AC signals to obtain the required negative voltage by using square waves. Current, but this negative current using square waves is quite inaccurate. Especially in devices with multiple sets of power supplies or industrial power supply devices, negative current still affects device performance and stability. Therefore, if the negative current value can be obtained effectively and accurately, it can be used for evaluation or calculation. When it is beneficial to performance improvement and performance improvement.

In view of the above, the present invention proposes a negative voltage detecting device capable of effectively detecting a negative voltage.

The main object of the present invention is to provide a negative voltage detecting device which can accurately read a negative voltage and obtain a very accurate negative current, thereby accurately knowing the negative current power and providing an accurate value for subsequent evaluation. .

Another object of the present invention is to provide a negative voltage detecting device which can be applied to a device having multiple sets of power sources, an industrial power supply device, or an information power supply device, and plays an effective role in detecting a negative voltage. Role player.

In order to achieve the above object, a negative voltage detecting device according to the present invention includes: a sampling circuit electrically connected to a positive voltage ground terminal and a negative voltage ground terminal to generate a voltage across the pressure difference between the two ground terminals; And generating a sampling current; a comparator is electrically connected to the sampling circuit and a negative voltage reference node to control the relative output sampling current when the voltage is generated; a first voltage dividing sampling resistor is electrically connected to the positive The voltage reference node and a connection node, another second voltage-sampling resistor is electrically connected to the negative voltage reference node and the connection node, and the current comparator is electrically connected to the second voltage-sampling resistor to be output according to the current divider The sampling current is generated by the second voltage dividing resistor to generate a negative sensing voltage at the connection node. In this way, the detecting device of the present invention can be effectively utilized to effectively obtain an accurate negative voltage, thereby obtaining a negative current or a power thereof.

The purpose, technical contents, features and effects achieved by the present invention will be more readily understood by the detailed description of the embodiments and the accompanying drawings.

10‧‧‧Sampling circuit

12‧‧‧ current comparator

14‧‧‧First voltage divider resistor

16‧‧‧Second voltage sampling resistor

18‧‧‧ buffer

20‧‧‧First voltage regulator unit

22‧‧‧Second voltage regulator

A‧‧‧ positive voltage reference node

B‧‧‧Negative voltage mistaken node

C‧‧‧ Connection node

D1, D2‧‧‧ diode

Gnd‧‧‧positive voltage ground

Gnd1‧‧‧Negative voltage ground

OP‧‧‧Operational Amplifier

Q‧‧‧Optocrystal

R1‧‧‧first resistance

R2‧‧‧second resistance

R3‧‧‧ third resistor

R4, R5, R6, R7, R8‧‧‧ resistors

Rs‧‧‧ current limiting resistor

Rv‧‧‧compensation resistor

+Vcc‧‧‧positive voltage terminal

-Vcc‧‧‧negative voltage terminal

The first figure is a schematic diagram of the circuit of the present invention.

The second figure is a schematic diagram of a circuit for inducing a negative current in the present invention.

The first figure is a schematic circuit diagram of the present invention. As shown in the figure, a negative voltage detecting device mainly includes a sampling circuit 10, a current comparator 12, a first voltage dividing sampling resistor 14, a second voltage dividing sampling resistor 16, and a The buffer 18; in addition, the present invention can also be combined with a first voltage stabilizing unit 20 and a second voltage stabilizing unit 22 to stabilize the voltage.

Referring to the first figure, the sampling circuit 10 is electrically connected to a positive voltage ground terminal Gnd and a negative voltage ground terminal Gnd1, respectively, to generate a voltage across the voltage difference between the positive voltage ground terminal Gnd and the negative voltage ground terminal Gnd1. Vs, and generates a sampling current Is; a current comparator 12 is electrically connected to the sampling circuit 10 and the negative voltage reference node B to determine whether to output the sampling current Is according to the voltage across the voltage Vs; a first voltage dividing sampling resistor The 14 series is electrically connected to the positive voltage reference node A and a connection node C; and a second voltage dividing sampling resistor 16 is electrically connected to the negative voltage reference node B and the connection node C, and the comparator 12 is also electrically Connected to the second voltage dividing sampling resistor 16 to generate a negative sensing voltage at the connection node C according to the generation of the sampling current, wherein the resistance value of the first voltage dividing sampling resistor 14 is equal to the resistance of the second voltage dividing sampling resistor 16 The value is such that when no voltage is generated, the voltage of the connection node C is still maintained at 0; and a buffer 18 is electrically connected to the connection node C, the positive voltage reference node A, and the positive voltage ground terminal Gnd to buffer The output corresponds to the negative of the negative sensing voltage Sensing current Isense. In addition, in order to provide a stable voltage, one end of the first voltage stabilizing unit 20 is electrically connected between the negative voltage ground terminal Gnd1 and the sampling circuit 10, and the other end is connected to the negative voltage reference node B, and the second voltage stabilizing unit One end is electrically connected to the positive voltage ground terminal Gnd and the current transformer 10, and the other end is connected to the positive voltage reference node A. Furthermore, the negative voltage reference node B is electrically connected to a negative voltage terminal -Vcc (negative voltage source) by a second resistor R2, and the positive voltage reference node A is electrically connected to a positive voltage by a third resistor R3. Terminal + Vcc (positive voltage source).

Referring to the first figure, in detail, the sampling circuit 10 includes a current limiting resistor Rs, and the two ends thereof are respectively connected with a positive voltage ground terminal Gnd and a negative voltage ground terminal Gnd1, a first One end of the resistor R1 is electrically connected to the negative voltage ground terminal Gnd1, and the other end is connected to the two series diodes D1, D2. The current transformer 12 includes an operational amplifier OP having a positive terminal electrically connected to the current limiting resistor Rs of the sampling circuit 10, and a negative terminal electrically connected between the first resistor R1 and the diode D1; and a transistor Q, usually using a PNP transistor, the base thereof is connected to the output terminal of the operational amplifier OP, the emitter is connected to the diode D2 of the sampling circuit 10, and the collector is connected to the second voltage dividing sampling resistor 16, the operational amplifier OP can be The voltage across the voltage Vs is controlled to control whether the transistor Q is turned on or not to determine whether to output the sampling current, and another resistor R8 is connected between the operational amplifier OP and the transistor Q and the negative voltage reference node B. The first voltage-sampling resistor 14 is connected to the positive voltage reference node A and the connection node C by using at least one resistor R4; the second voltage-sampling resistor 16 includes a plurality of resistors connected in series, including resistors R5, R6, R7 and a compensation resistor. Rv, one end of the resistor R5 is connected to the connection node C, the other end is connected to the compensation resistor Rv, the other end of the compensation resistor Rv is connected to one end of the resistor R6, the other end of the resistor R6 is connected to the resistor R7, and the other end of the resistor R7 is connected to the negative voltage Reference node B, and the collector of transistor Q5 is also connected between resistor R6 and resistor R7. Wherein, when no negative voltage is generated, no cross voltage is generated, and the resistance value of the resistor R4 must be equal to the sum of the resistance values of the resistors R5, R6, R7 and the compensation resistor Rv (R4=R5+R6+R7+Rv), To ensure that the voltage of the connection node C is maintained at 0; however, due to process differences or other factors, the resistance values on the two sides of the connection node C are not uniform, and the compensation resistor Rv can be easily adjusted to the required resistance value. It is quite convenient, and the compensation resistor Rv can be effectively utilized to maintain the voltage of the connection node C at 0 to avoid non-sensing negative voltage generation.

When a negative current is generated, a voltage across the current limiting resistor Rs is generated. At this time, a sampling current Is is generated to flow through the diodes D1 and D2 via the first resistor R1, as shown in the second figure. The operational amplifier OP generates an output according to the voltage across the voltage Vs to turn on the transistor Q. At this time, the sampling current flows through the transistor Q to the second voltage dividing sampling resistor 16, thereby generating a negative sensing at the connection node C. Voltage Vsense, after the negative sense voltage Vsense passes through the buffer 18, That is, a sense negative output Isense output is generated, which is quite accurate.

In summary, the negative voltage detecting device of the present invention can accurately read the negative voltage and obtain a very accurate negative current, thereby accurately knowing the negative current power, and effectively and correctly providing the accurate value required for subsequent evaluation. Therefore, it can be widely used in various fields, especially in switches with multiple sets of power supplies, industrial power supply devices, or information power supply devices, etc., to truly play a role in effectively detecting negative voltage.

The embodiments described above are merely illustrative of the technical spirit and the features of the present invention, and the objects of the present invention can be understood by those skilled in the art, and the scope of the present invention cannot be limited thereto. That is, the equivalent variations or modifications made by the spirit of the present invention should still be included in the scope of the present invention.

10‧‧‧Sampling circuit

12‧‧‧ current comparator

14‧‧‧First voltage divider resistor

16‧‧‧Second voltage sampling resistor

18‧‧‧ buffer

20‧‧‧First voltage regulator unit

22‧‧‧Second voltage regulator

A‧‧‧ positive voltage reference node

B‧‧‧Negative voltage mistaken node

C‧‧‧ Connection node

D1, D2‧‧‧ diode

Gnd‧‧‧positive voltage ground

Gnd1‧‧‧Negative voltage ground

OP‧‧‧Operational Amplifier

Q‧‧‧Optocrystal

R1‧‧‧first resistance

R2‧‧‧second resistance

R3‧‧‧ third resistor

R4, R5, R6, R7, R8‧‧‧ resistors

Rs‧‧‧ current limiting resistor

Rv‧‧‧compensation resistor

+Vcc‧‧‧positive voltage terminal

-Vcc‧‧‧negative voltage terminal

Claims (10)

A negative voltage detecting device is electrically connected to a positive voltage reference node and a negative voltage reference node, and the negative voltage detecting device comprises: a sampling circuit electrically connected to a positive voltage ground terminal and a negative voltage a ground terminal for generating a voltage across the voltage difference between the positive voltage ground terminal and the negative voltage ground terminal, and generating a sampling current; a current comparator electrically connecting the sampling circuit and the negative voltage reference node to Transmitting, determining whether to output the sampling current; a first voltage dividing sampling resistor electrically connected to the positive voltage reference node and a connecting node; and a second voltage dividing sampling resistor electrically connected to the The negative voltage reference node and the connection node, and the current comparator is also electrically connected to the second voltage dividing sampling resistor to generate a negative sensing voltage at the connection node according to the generation of the sampling current. The negative voltage detecting device of claim 1, wherein the current comparator further comprises: an operational amplifier connected to the sampling circuit; and a transistor having a base connected to an output end of the operational amplifier, and an emitter connected to the The sampling circuit and the collector are connected to the second voltage dividing sampling resistor, and the operational amplifier controls whether the transistor is turned on or not according to the voltage across the voltage to determine whether to output the sampling current. The negative voltage detecting device of claim 2, wherein the sampling circuit further comprises a current limiting resistor, the two ends of which are respectively connected to the positive voltage ground terminal and the operational amplifier and the negative voltage ground terminal, a first resistor Connecting the negative voltage ground terminal to the operational amplifier, and the two series connected diodes are connected between the first resistor and the operational amplifier and the transistor, the current limiting current When the voltage across the resistor is generated, the sampling current generated by the first resistor is output to the transistor through the diode. The negative voltage detecting device according to claim 1 or 3, wherein the resistance value of the first voltage dividing sampling resistor is equal to the resistance value of the second voltage dividing sampling resistor, and the connecting node is not generated when the voltage is not generated. The voltage remains at zero. The negative voltage detecting device of claim 4, wherein the second voltage dividing sampling resistor further comprises: a plurality of series connected resistors connected to the negative voltage reference node; and a compensation resistor connected to the series a resistor to maintain the voltage of the connection node to be zero by using the compensation resistor. The negative voltage detecting device of claim 3, further comprising a first voltage stabilizing unit, one end of which is electrically connected to the negative voltage ground terminal and the current limiting resistor, and the other end is connected to the negative voltage reference node. The negative voltage detecting device of claim 3, further comprising a second voltage stabilizing unit, one end of which is electrically connected between the positive voltage ground terminal and the current limiting resistor, and the other end is connected to the positive voltage reference node. The negative voltage detecting device of claim 1, wherein the negative voltage reference node is further connected to a negative voltage terminal by a second resistor. The negative voltage detecting device of claim 1, wherein the positive voltage reference node is further connected to a positive voltage terminal by a third resistor. The negative voltage detecting device of claim 1, further comprising a buffer electrically connected to the connecting node, the positive voltage reference node, and the positive voltage ground to buffer the output corresponding to the negative sensing voltage. Sensing current.