TWI407128B - Digital circuit and voltage detecting circuit therein - Google Patents

Abstract

A voltage detecting circuit includes an input, a voltage divider and a comparator. The input receives a to-be-detected voltage through a voltage dividing circuit. The voltage divider receives the voltage of the input to generate an internal divided voltage. The comparator compares the internal divided voltage with a reference voltage. When the internal divided voltage is substantially equal to the reference voltage, the comparator generates a comparing signal. In addition, a digital signal is also disclosed herein.

Description

Digital circuit and voltage detecting circuit thereof

SUMMARY OF THE INVENTION The present invention is directed to a digital circuit, and more particularly to a voltage detection circuit in a digital circuit.

Generally, in digital circuits (such as digital ICs), serial logic circuits are used to process digital signals, such as SR latches, flip flops, etc., and Such sequence logic circuits typically need to receive a reset signal during operation to perform a reset action.

The above reset signal is generated by a voltage detecting circuit for detecting a voltage to be measured (for example, a voltage source VDD), and when the voltage to be measured is converted to a certain value, the voltage detecting circuit generates a weight. Set the signal.

At present, most of the electronic products are designed to use low-power circuits, so the operating voltage is also quite low. Therefore, the operating voltage (such as the reference voltage) in the voltage detecting circuit must also be designed as a low voltage. In order to meet the demand.

However, if the operating voltage in the voltage detecting circuit is designed to be in a low voltage form, the actual situation needs to be considered, and the design cannot be designed to be quite accurate, so that the voltage detecting circuit cannot accurately detect the detected voltage. The voltage or its corresponding low voltage causes the overall digital circuit to malfunction.

It is an object of the present invention to provide a voltage detecting circuit for effectively detecting an external low voltage.

Another object of the present invention is to provide a digital circuit in which the voltage detecting circuit can be more flexibly adjusted when detecting different external low voltages.

One aspect of the present invention relates to a voltage detection circuit including an input terminal, a voltage divider, and a comparator. The input terminal is configured to receive a voltage to be tested via a voltage dividing circuit external to the voltage detecting circuit. The voltage divider is configured to receive the voltage at the input to generate an internal partial pressure. The comparator is used to compare the internal partial voltage with a reference voltage. The comparator generates a comparison signal when the internal partial voltage is substantially the same as the reference voltage.

Another aspect of the present invention relates to a digital circuit including a voltage dividing circuit, a voltage detecting circuit, and a sequence of logic units. The voltage dividing circuit is configured to divide a voltage to be measured to generate an input voltage. The voltage detecting circuit is configured to receive the input voltage and generate a reset signal when the input voltage substantially reaches a predetermined value. The voltage detection circuit includes a voltage divider and a comparator, wherein the voltage divider is configured to receive an input voltage to generate an internal partial pressure. The comparator is used to compare the internal partial voltage with a reference voltage. Wherein, when the input voltage substantially reaches a preset value such that the internal partial voltage is substantially the same as the reference voltage, the comparator generates a comparison signal, and the comparison signal is processed to be converted into a reset signal output. The sequence logic unit receives the reset signal and performs a reset action based on the reset signal.

Yet another aspect of the present invention relates to a digital circuit including a voltage dividing circuit, a voltage detecting circuit, and a sequence of logic units. The voltage dividing circuit is configured to divide a voltage to be measured to generate an input voltage. The voltage detecting circuit is configured to receive the input voltage and generate a reset signal when the input voltage substantially reaches a predetermined value. The sequence logic unit receives the reset signal and performs a reset operation according to the reset signal. In addition, the voltage detection circuit includes a plurality of resistors, a plurality of primary programmable components, and a comparator. The resistors are coupled in series, and the first programmable components are respectively coupled in series with the resistors, wherein the series coupled resistors and the one-time programmable components are coupled to the input voltage, and the resistors and the one-time programmable components Any of the coupling points produces an internal partial pressure. The comparator is configured to compare the internal partial voltage and a reference voltage, wherein when the input voltage substantially reaches a preset value such that the internal partial voltage is substantially the same as the reference voltage, the comparator generates a comparison signal, and the comparison signal is processed. Converted to reset signal output.

According to the technical content of the present invention, the application of the foregoing digital circuit and the voltage detecting circuit thereof are not only beneficial for detecting different external low voltages, but also making different voltage detections more flexible, and more accurately and easily adjusting the output. The required voltage detection point.

FIG. 1 is a schematic circuit diagram of a digital circuit according to an embodiment of the invention. The digital circuit 100 (eg, a digital IC) includes a voltage dividing circuit 110, a voltage detecting circuit 120 (eg, a voltage detecting IC), and a sequence logic unit 130. The voltage dividing circuit 110 divides the voltage to be measured (eg, the voltage source VDD) to generate a corresponding input voltage V1. The voltage detecting circuit 120 receives the input voltage V1 through its input terminal X, and generates a reset according to the detected input voltage V1 when the input voltage V1 substantially reaches a preset value as the voltage source VDD changes. Reset) Signal RE. The sequence logic unit 130 receives the reset signal RE and performs a reset operation according to the reset signal RE.

In a digital circuit, the digital signal is typically processed using the sequence logic unit 130 described above, wherein the sequence logic unit 130 can be a SR latch, a flip flop, etc., and In order to ensure the normal operation of the sequence logic unit 130, the voltage detection circuit 120 is used to detect the operating voltage, and according to the operation of the circuit, the reset signal RE is output to the sequence logic unit 130 in a timely manner, so that the sequence logic unit 130 can thereby Perform a reset action to avoid a malfunction.

In this embodiment, the voltage dividing circuit 110 includes two resistors R1 and R2 coupled in series, wherein the two series connected resistors R1 and R2 are coupled between the voltage source VDD and the ground voltage VSS, and respectively The voltage source VDD is coupled to the ground voltage VSS, and the junction of the resistors R1 and R2 is coupled to the input terminal X of the voltage detecting circuit 120.

In addition, the voltage detecting circuit 120 may further include a voltage divider 122, a comparator 124, and a bandgap reference voltage generator 126. The voltage divider 122 is configured to receive the input voltage V1 and thereby generate a corresponding internal partial voltage VX1, the energy gap reference voltage generator 126 is used to output the reference voltage Vref, and the comparator 124 is used to compare the internal The voltage VX1 and the reference voltage Vref are divided.

In this embodiment, the voltage divider 122 includes two resistors RX1 and RX2 coupled in series, wherein the two series connected resistors RX1 and RX2 are coupled between the input terminal X and the ground voltage VSS, and respectively input The terminal X and the ground voltage VSS are coupled, and the junction of the resistors RX1 and RX2 is coupled to one of the inputs of the comparator 124.

In an embodiment, the voltage divider 122 has an equivalent resistance greater than the equivalent resistance of the voltage divider circuit 110. In the above embodiment, the equivalent resistance formed by the resistors RX1 and RX2 in the voltage divider 122 is greater than the equivalent resistance formed by the resistors R1 and R2 in the voltage dividing circuit 110. As a result, a relatively large current flows to the current path in the voltage dividing circuit 110, and does not flow to the voltage detecting circuit 120, thereby reducing the influence on the voltage detecting circuit 120.

In operation, since the voltage source VDD fluctuates within a predetermined range, the input voltage V1 and the internal voltage VX1 generated by the voltage dividing circuit 110 and the voltage divider 122 also fluctuate. When the voltage source VDD changes to a certain value such that the input voltage V1 reaches a predetermined value, and the internal partial voltage VX1 is substantially the same as the reference voltage Vref, the comparator 124 generates a comparison with a high level or a low level. The signal CP, and the comparison signal CP can be processed via a conversion circuit (not shown), and then converted to a reset signal RE output to the sequence logic unit 130.

For example, the voltage source VDD varies in a preset range of 0 to 3.3 V, the resistance values of the resistors R1 and R2 are both 10 K ohms (Ω), and the resistance values of the resistors RX1 and RX2 are both 10 M ohms (Ω). And the reference voltage Vref is about 0.5V. When the voltage source VDD fluctuates to 2V, the input voltage V1 is 1V, and the internal partial voltage VX1 is about 0.5V. At this time, the internal partial voltage VX1 is substantially the same as the reference voltage Vref, so that the comparator 124 generates the comparison signal CP.

2 is a circuit diagram of a voltage detecting circuit according to another embodiment of the present invention. Compared with the voltage detecting circuit 120 in FIG. 1, the voltage detecting circuit 220 in FIG. 2 also includes a voltage divider 222, a comparator 224, and a band gap reference voltage generator 226. The voltage divider 222 is configured to receive an input voltage and thereby generate a corresponding internal partial voltage VX1, the comparator 224 is for comparing the internal partial voltage VX1 and the reference voltage Vref, and the band gap reference voltage generator 226 is It is used to output the reference voltage Vref to the comparator 224.

In addition, the voltage divider 222 includes two resistors RX1 and RX2 coupled in series, and further includes two programmable elements for fine-tuning the equivalent resistance of the voltage divider 222 (One-Time- Programmable, OTP) T1 and T2, which are coupled in series with resistors RX1 and RX2, respectively, wherein the first programmable elements T1 and T2 can be fuses or wires.

It should be noted that the number of resistors and the one-time programmable components in the voltage divider 222 is not limited to the illustrated ones, and any one of ordinary skill in the art can perform various types according to actual design requirements. change. In other words, the internal partial voltage VX1 may be generated at any coupling point after the coupling of the plurality of resistors and the plurality of primary programmable elements.

Since the integrated circuit (IC) usually has a variable parameter variation, for example, the internal partial voltage VX1 has an error with the design value in the above embodiment, and if the variation of these circuit parameters is too large, the specifications of the integrated circuit are exceeded (for example, 5% error) will be judged as defective when tested. Therefore, integrated circuit manufacturers often need to fine-tune some of the above parameters to improve manufacturing yield. To this end, the fine-tuning function can be achieved by using the above-described one-time programmable elements T1 and T2 to meet this requirement.

Specifically, the adjustment method commonly used in integrated circuits is laser trim, wherein the primary programmable component used in the laser adjustment method can be a short segment of metal, and high-energy laser light. By partially melting the metal wire segment, the resistance value of the metal wire segment can be increased, and the metal wire segment can be made into a corresponding resistor to finely adjust the required equivalent resistance.

Therefore, in the voltage detecting circuit 220 of FIG. 2, when the input voltage input to the voltage detecting circuit 220 or the reference voltage Vref generated by the band gap reference voltage generator 226 is different, the time can be selected. The programmable elements T1 and T2 are processed once to achieve an easy and accurate fine adjustment.

In addition, in another embodiment, the resistors RX1 and RX2 described in FIGS. 1 and 2 can also be fabricated by processing a first programmable element, and FIG. 1 and 2 The resistors and the one-time programmable elements in the voltage divider are not limited to the ones shown in the drawings, and any person skilled in the art without departing from the spirit and scope of the invention may The actual design requirements are subject to various changes.

In addition, the resistors and the one-time programmable components in the voltage dividers in FIG. 1 and FIG. 2 are not limited to being connected in series, and those skilled in the art can also use them as parallel phases according to actual needs. Pick up. In another embodiment, the voltage divider in FIG. 1 or FIG. 2 includes a plurality of resistors and a one-time programmable component, and the resistors and the one-time programmable component are in different series and parallel manners. Connected to each other.

In summary, since the voltage detecting circuit similar to the above embodiment is generally used, the voltage generated by the band gap reference voltage generator is simply considered, for example, the voltage is generated in the band gap reference voltage generator. After that, it is converted into the required reference voltage, which not only requires designing a conversion circuit, increasing the cost, but also failing to accurately design the required low voltage. In contrast, in the above embodiment of the present invention, the input voltage is adjusted only by a voltage divider to generate the required internal partial voltage VX1, and the fine adjustment of the voltage divider can be performed by a simple laser adjustment method. The method is not only simple, but also accurately designs the low voltage required in the voltage detection circuit.

According to the embodiment of the present invention, the application of the digital circuit and the voltage detecting circuit thereof are not only beneficial for detecting different external low voltages, but also making different voltage detections more flexible, and more accurately and easily adjusted. The required voltage detection point.

The present invention has been disclosed in the above embodiments, but it is not intended to limit the invention, and the present invention may be modified and modified without departing from the spirit and scope of the invention. The scope of protection is subject to the definition of the scope of the patent application.

100. . . Digital circuit

110. . . Voltage dividing circuit

120, 220. . . Voltage detection circuit

130. . . Sequence logic unit

122, 222. . . Voltage divider

124, 224. . . Comparators

126, 226. . . Energy gap reference voltage generator

FIG. 1 is a schematic circuit diagram of a digital circuit according to an embodiment of the invention.

2 is a circuit diagram of a voltage detecting circuit according to another embodiment of the present invention.

100. . . Digital circuit

110. . . Voltage dividing circuit

120. . . Voltage detection circuit

130. . . Sequence logic unit

122. . . Voltage divider

124. . . Comparators

126. . . Energy gap reference voltage generator

Claims (13)

A voltage detecting circuit includes: an input terminal for receiving a voltage to be tested via a voltage dividing circuit external to the voltage detecting circuit; and a voltage divider for receiving the voltage of the input terminal to generate an internal Dividing, the voltage divider comprises: a plurality of resistors connected in series with each other and coupled to the input end, and the internal partial pressure is generated at the junction of two adjacent resistors in the resistors And at least one primary programmable component coupled in series with at least one of the resistors; and a comparator for comparing the internal partial voltage and a reference voltage; wherein, the internal partial pressure and the reference The comparator produces a comparison signal when the voltages are substantially the same. The voltage detecting circuit of claim 1, wherein at least one of the resistors is fabricated by processing a programmable element. The voltage detecting circuit of claim 1, wherein the resistors form an equivalent resistance greater than an equivalent resistance of the voltage dividing circuit outside the voltage detecting circuit. The voltage detecting circuit of claim 1, further comprising: a band gap reference voltage generator for outputting the reference voltage to the comparator. A digital circuit comprising: a voltage dividing circuit for dividing a voltage to be measured to generate an input voltage; and a voltage detecting circuit for receiving the input voltage and substantially reaching the input voltage A reset signal is generated by a preset value, and the voltage detecting circuit comprises: a voltage divider for receiving the input voltage to generate an internal partial voltage, the voltage divider comprising: a plurality of resistors, the resistors And the at least one primary programmable component, and the at least one of the resistors One is coupled in series; and a comparator for comparing the internal partial voltage and a reference voltage; wherein, when the input voltage substantially reaches the preset value such that the internal partial voltage is substantially the same as the reference voltage, The comparator generates a comparison signal, and the comparison signal is processed to be converted into the reset signal output; A sequence of logic units receives the reset signal and performs a reset operation based on the reset signal. The digital circuit of claim 5, wherein at least one of the resistors is fabricated by processing a programmable element. The digital circuit of claim 5, wherein the resistors form an equivalent resistance greater than an equivalent resistance of the voltage dividing circuit. The digital circuit of claim 5, wherein the voltage divider has an equivalent resistance greater than an equivalent resistance of the voltage divider circuit. The digital circuit of claim 5, further comprising: a band gap reference voltage generator for outputting the reference voltage to the comparator. A digital circuit comprising: a voltage dividing circuit for dividing a voltage to be measured to generate an input voltage; and a voltage detecting circuit for receiving the input voltage and substantially reaching the input voltage a reset signal generated by a preset value, the voltage detection The circuit includes: a plurality of resistors connected in series with each other; a plurality of one-time programmable elements respectively coupled in series with the resistors, wherein the resistors and the one-time programmable components are coupled in series Coupled to the input voltage, and generate an internal partial pressure at any one of the resistors and the one of the first programmable components; and a comparator for comparing the internal partial voltage and a reference voltage; Wherein, when the input voltage substantially reaches the preset value such that the internal partial voltage is substantially the same as the reference voltage, the comparator generates a comparison signal, and the comparison signal is processed to be converted into the reset signal output; And a sequence of logic units that receive the reset signal and perform a reset operation based on the reset signal. The digital circuit of claim 10, wherein the resistors and the one-time programmable elements form an equivalent resistance greater than an equivalent resistance of the voltage dividing circuit. The digital circuit of claim 10, further comprising: a band gap reference voltage generator for outputting the reference voltage to the comparator. The digital circuit of claim 10, wherein the one-time circuit The component is a fuse or a wire.