Spread spectrum circuit and isolated power supply chip based on true random signal

Abstract

The embodiment of the present application provides a spread spectrum circuit based on a true random signal and an isolated power supply chip, and belongs to the technical field of chips.The spread spectrum circuit based on the true random signal comprises a true random signal generation circuit, which is used for generating a corresponding true random digital signal according to a noise signal;a voltage division circuit, which is electrically connected to the output end of the true random signal generation circuit, and is used for converting the generated true random digital signal into a corresponding analog spread spectrum signal;a voltage-controlled oscillation circuit, which is electrically connected to the output end of the voltage division circuit, and is used for generating a corresponding oscillation signal according to the converted analog spread spectrum signal, and outputting the oscillation signal, so as to reduce the energy of the noise signal.The energy originally concentrated on the peak of the switching frequency and its high-order harmonics can be spread to a wider frequency band, so that the peak spectrum electromagnetic emission is effectively reduced.

Description

Technical Field

[0001] This invention relates to the field of chip technology, and more specifically to a spread spectrum circuit and an isolated power supply chip based on a true random signal. Background Technology

[0002] Isolated power supply chips typically consist of two parts: one for transmitting energy and the other for receiving energy. However, during energy transmission, isolated power supply chips generate significant electromagnetic noise, concentrated at the transmission frequency and its harmonic frequencies, making it difficult to meet electromagnetic interference (EMI) specifications. In various industries such as automotive and consumer electronics, isolated power supply chips must not only provide the required electrical performance but also comply with international electromagnetic compatibility (EMC) requirements, which impose strict limits on electromagnetic radiation emissions from electronic devices, thus necessitating the reduction of EMI noise.

[0003] Reducing EMI can generally be achieved by adding an EMI filter circuit to the transmitter of the chip. However, the greater the EMI generated by the isolated power supply chip, the larger the device size in the EMI filter becomes, leading to higher chip integration costs. Moreover, simply applying an EMI filter circuit cannot suppress EMI radiated noise. Undesirable electromagnetic energy may propagate throughout the entire chip system or into the external environment, potentially causing adverse effects on other vulnerable devices. Summary of the Invention

[0004] The purpose of this invention is to provide a spread spectrum circuit based on a true random signal, which can effectively suppress EMI radiated noise.

[0005] To achieve the above objectives, embodiments of the present invention provide a spread spectrum circuit based on a true random signal. The spread spectrum circuit based on a true random signal includes: a true random signal generation circuit for generating a corresponding true random digital signal based on a noise signal; a voltage divider circuit, the input of which is electrically connected to the output of the true random signal generation circuit, for converting the generated true random digital signal into a corresponding analog spread spectrum signal; and a voltage-controlled oscillator circuit, the input of which is electrically connected to the output of the voltage divider circuit, for generating a corresponding oscillation signal based on the converted analog spread spectrum signal, and outputting the oscillation signal to reduce the energy of the noise signal.

[0006] Optionally, the number of true random signal generation circuits may be one or more.

[0007] Optionally, the true random signal generation circuit includes a physical noise source, an amplifier, and a comparator. One end of the physical noise source is grounded, the other end of the physical noise source is connected to the non-inverting input of the amplifier, the inverting input of the amplifier is grounded, the output of the amplifier is connected to the non-inverting input of the comparator, the inverting input of the comparator is connected to a reference voltage, and the output of the comparator serves as the output of the true random signal generation circuit.

[0008] Optionally, the physical noise source is a resistor used to generate white noise.

[0009] Optionally, the voltage divider circuit includes n D flip-flops and n+1 series resistors. The input terminals of the n D flip-flops serve as the n input terminals of the voltage divider circuit. The n+1 series resistors are used to set n+2 terminal nodes, each consisting of n connection points on the connection line of the n+1 series resistors and two floating terminals. The first series resistor in the n+1 series resistors is connected to the power supply voltage through terminal node 1. Terminal node 2 serves as the output terminal of the voltage divider circuit. The other n terminal nodes in the n+2 terminal nodes are connected to the output terminals of the n D flip-flops. The clock input terminals of the n D flip-flops are connected to ensure that the clock signals of the n D flip-flops are identical.

[0010] Optionally, when the resistance of the first series resistor is R, the resistance of the other n series resistors in the n+1 series resistors is R / 2.

[0011] Optionally, the voltage divider circuit further includes n connecting resistors, which are respectively disposed on the line between the terminal node and the D flip-flop.

[0012] Optionally, the voltage-controlled oscillator circuit includes an analog amplifier, a ring oscillator, a first RC coupling circuit, a second RC coupling circuit, and a first inverter. The non-inverting input of the analog amplifier serves as the input of the voltage-controlled oscillator circuit. The output of the analog amplifier is connected to the input of the ring oscillator. The output of the ring oscillator is connected to one end of the first RC coupling circuit. The other end of the first RC coupling circuit is connected to one end of the first inverter. The other end of the first inverter serves as the output of the voltage-controlled oscillator. The inverting input of the analog amplifier is connected to the other end of the first inverter and the intermediate node of the second RC coupling circuit.

[0013] Optionally, the voltage-controlled oscillator circuit further includes a second inverter, which is disposed on the line between the output terminal of the ring oscillator and one end of the first RC coupling circuit.

[0014] This invention also provides an isolated power supply chip, which includes the spread spectrum circuit based on true random signals described in any one of the above embodiments.

[0015] Through the above technical solution, the embodiments of the present invention generate a corresponding true random digital signal based on the noise signal using a true random signal generation circuit; the true random digital signal is converted into a corresponding true random analog signal using a voltage divider circuit. This true random analog signal is a spread spectrum signal with true random characteristics, and is then output through a voltage-controlled oscillator circuit. This allows the energy originally concentrated on the peaks of the switching frequency and its higher harmonics to be spread across a wider frequency band, thereby effectively reducing peak spectrum electromagnetic emissions and better meeting international requirements for electromagnetic compatibility (EMC).

[0016] Other features and advantages of the embodiments of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0017] The accompanying drawings are provided to further illustrate embodiments of the present invention and form part of the specification. They are used together with the following detailed description to explain the embodiments of the present invention, but do not constitute a limitation thereof. In the drawings:

[0018] Figure 1 This is a schematic diagram of the structure of a spread spectrum circuit based on a true random signal provided in an embodiment of the present invention;

[0019] Figure 2 This is a schematic diagram of an example true random signal generation circuit;

[0020] Figure 3 This is a schematic diagram of a spread spectrum circuit based on a true random signal.

[0021] Explanation of reference numerals in the attached figures

[0022] 10 - True random signal generation circuit; 20 - Voltage divider circuit; 30 - Voltage-controlled oscillator circuit. Detailed Implementation

[0023] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of the present invention.

[0024] Figure 1 This is a schematic diagram of the spread spectrum circuit based on a true random signal provided in an embodiment of the present invention. Please refer to it. Figure 1The spread spectrum circuit based on the true random signal may include: a true random signal generation circuit 10, used to generate a corresponding true random digital signal according to the noise signal; a voltage divider circuit 20, whose input terminal is electrically connected to the output terminal of the true random signal generation circuit 10, used to convert the generated true random digital signal into a corresponding analog spread spectrum signal; and a voltage-controlled oscillator circuit 30, whose input terminal is electrically connected to the output terminal of the voltage divider circuit 20, used to generate a corresponding oscillation signal according to the converted analog spread spectrum signal, and output the oscillation signal to reduce the energy of the noise signal.

[0025] The embodiments of the present invention, through the spread spectrum circuit described above, can generate a true random spread spectrum signal, which can effectively spread the energy originally concentrated on the peaks of the switching frequency and its higher harmonics to a wider frequency band, thereby effectively reducing peak spectrum electromagnetic emission and reducing electromagnetic interference (EMI) noise during energy transmission.

[0026] Figure 2 This is a schematic diagram of an example true random signal generation circuit. Please refer to it. Figure 2 The preferred embodiment of the present invention, the true random signal generation circuit, may include a physical noise source, an amplifier, and a comparator.

[0027] In this circuit, one end of the physical noise source is grounded, the other end of the physical noise source is connected to the non-inverting input of the amplifier, the inverting input of the amplifier is grounded, the output of the amplifier is connected to the non-inverting input of the comparator, the inverting input of the comparator is connected to a reference voltage, and the output of the comparator serves as the output of the true random signal generation circuit. The comparator output signal is characterized by random high and low levels.

[0028] like Figure 2 As shown, the preferred physical noise source is a resistor used to generate white noise.

[0029] As an example, white noise can be used as a random source to generate the output sequence for the selection of physical noise sources. In this embodiment of the invention, resistive thermal noise is used as the physical noise source, while the error amplifier and comparator are used to quantize the noise and generate a random signal.

[0030] Figure 3 This is a schematic diagram of a spread spectrum circuit based on a true random signal. Please refer to it. Figure 3 Preferably, the number of true random signal generation circuits is one or more. The voltage divider circuit includes one or more input terminals, and each true random signal generation circuit can be connected to the voltage divider circuit through one input terminal of the voltage divider circuit.

[0031] Please refer to Figure 3 Preferably, the voltage divider circuit may include n D flip-flops and n+1 series resistors, with the input terminals of the n D flip-flops serving as the n input terminals of the voltage divider circuit.

[0032] In this circuit, n+2 terminal nodes are set through the n+1 series resistors. Each n+2 terminal node consists of n connection points on the connection line of the n+1 series resistors and two floating terminals. The first series resistor in the n+1 series resistors is connected to the power supply voltage through terminal node 1. Terminal node 2 serves as the output terminal of the voltage divider circuit. The other n terminal nodes in the n+2 terminal nodes are connected to the output terminals of the n D flip-flops. The clock input terminals of the n D flip-flops are connected so that the clock signals of the n D flip-flops are the same.

[0033] For example, (n+1) resistors connected in series result in (n+2) terminal nodes. Let the floating end of the first series resistor R1 be terminal node 1, and the other end terminal node 2. Then the two terminal nodes of the second series resistor are terminal nodes 2 and 3, and so on, until the two terminal nodes of the (n+1)th series resistor are terminal nodes (n+1) and (n+2). Terminal node 1 is connected to the power supply voltage; terminal node 2 is connected to the output terminal; terminal node 3 is connected to the output of a D flip-flop, whose input is connected to the output of a random signal generator circuit; terminal node 4 is connected to the output of a D flip-flop, whose input is connected to the output of a random signal generator circuit; and so on, until terminal node (n+2) is connected to the output of a D flip-flop, whose input is connected to the output of a random signal generator circuit. Furthermore, the clock inputs of the n D flip-flops are connected together, sharing the same clock signal.

[0034] More preferably, when the resistance of the first series resistor is R, the resistance of the other n series resistors in the n+1 series resistors is R / 2.

[0035] In a preferred embodiment of the present invention, the voltage divider circuit further includes n connecting resistors, which are respectively disposed on the line between the terminal node and the D flip-flop.

[0036] To illustrate, a voltage divider circuit composed of multiple D flip-flops and cascaded resistors encodes a truly random digital signal generated by a truly random signal generation circuit and converts it into a corresponding analog signal. Specifically, the input of each D flip-flop is connected to the output of the random signal generation circuit, ensuring that the input of the D flip-flops is a truly random value (truly random digital signal). Simultaneously, all D flip-flops share the same clock signal. At the rising edge of each clock cycle, the D flip-flops output the truly random digital signal read at their input. For the voltage divider circuit, the generated encoding is absolutely random. Furthermore, in each bit of the encoded data, "1" represents that the input of that node is powered, and "0" represents that the input of that node is grounded. Therefore, the voltage value obtained at the output of the voltage divider circuit is related to the input of each resistor node. Since the input of each resistor node is a random signal, the output value of the voltage divider circuit is a completely random analog signal value.

[0037] The voltage-controlled oscillator circuit in a preferred embodiment of the present invention may include an analog amplifier, a ring oscillator, a first RC coupling circuit, a second RC coupling circuit, and a first inverter.

[0038] In this circuit, the non-inverting input of the analog amplifier serves as the input of the voltage-controlled oscillator circuit, the output of the analog amplifier is connected to the input of the ring oscillator, the output of the ring oscillator is connected to one end of the first RC coupling circuit, the other end of the first RC coupling circuit is connected to one end of the first inverter, the other end of the first inverter serves as the output of the voltage-controlled oscillator, and the inverting input of the analog amplifier is connected to the other end of the first inverter and the intermediate node of the second RC coupling circuit.

[0039] More preferably, the voltage-controlled oscillator circuit may further include a second inverter, which is disposed on the line between the output terminal of the ring oscillator and one end of the first RC coupling circuit.

[0040] For example, the inverting input of the analog amplifier is connected to the output of the voltage-controlled oscillator and the intermediate node of the RC series circuit. The output of the analog amplifier is connected to the input of the ring oscillator. The output of the ring oscillator passes through a buffer, an RC coupling circuit, and another buffer to generate the final oscillation signal, which is then output.

[0041] Accordingly, this embodiment of the invention generates a corresponding true random digital signal based on a noise signal through a true random signal generation circuit; the true random digital signal is converted into a corresponding true random analog signal through a voltage divider circuit. This true random analog signal is a spread spectrum signal with true random characteristics, and is then output through a voltage-controlled oscillator circuit. This allows the energy originally concentrated at the switching frequency and its higher harmonic peaks to be spread across a wider frequency band, thereby effectively reducing peak spectrum electromagnetic emissions and better meeting international requirements for electromagnetic compatibility (EMC).

[0042] Furthermore, embodiments of the present invention also provide an isolated power supply chip, the isolated power supply chip including the spread spectrum circuit based on the above-described true random signal.

[0043] It should be noted that the technical content of this isolated power supply chip is similar to that of the spread spectrum circuit based on true random signals mentioned above, and will not be repeated here.

[0044] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0045] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A spread spectrum circuit based on a true random signal, characterized in that, The spread spectrum circuit based on true random signals includes: A true random signal generation circuit is used to generate corresponding true random digital signals based on noise signals. The voltage divider circuit has its input terminal electrically connected to the output terminal of the true random signal generation circuit, and is used to convert the generated true random digital signal into the corresponding analog spread spectrum signal. A voltage-controlled oscillator circuit, whose input terminal is electrically connected to the output terminal of the voltage divider circuit, is used to generate a corresponding oscillation signal based on the converted analog spread spectrum signal and output the oscillation signal to reduce the energy of the noise signal.

2. The spread spectrum circuit based on a true random signal according to claim 1, characterized in that, The number of true random signal generation circuits is one or more.

3. The spread spectrum circuit based on a true random signal according to claim 1, characterized in that, The true random signal generation circuit includes a physical noise source, an amplifier, and a comparator. Wherein, one end of the physical noise source is grounded, the other end of the physical noise source is connected to the non-inverting input of the amplifier, the inverting input of the amplifier is grounded, the output of the amplifier is connected to the non-inverting input of the comparator, the inverting input of the comparator is connected to the reference voltage, and the output of the comparator serves as the output of the true random signal generation circuit.

4. The spread spectrum circuit based on a true random signal according to claim 3, characterized in that, The physical noise source is a resistor used to generate white noise.

5. The spread spectrum circuit based on a true random signal according to claim 1, characterized in that, The voltage divider circuit includes n D flip-flops and n+1 series resistors, with the input terminals of the n D flip-flops serving as the n input terminals of the voltage divider circuit. Specifically, n+2 terminal nodes are set through the n+1 series resistors. Each n+2 terminal node consists of n connection points on the line connected by the n+1 series resistors and two floating terminals. The first series resistor in the n+1 series resistors is connected to the power supply voltage through terminal node 1, and terminal node 2 serves as the output terminal of the voltage divider circuit. The other n terminal nodes among the n+2 terminal nodes are connected to the output terminals of the n D flip-flops. The clock inputs of the n D flip-flops are connected so that the clock signals of the n D flip-flops are the same.

6. The spread spectrum circuit based on a true random signal according to claim 5, characterized in that, When the resistance of the first series resistor is R, the resistance of the other n series resistors in the n+1 series resistors is R / 2.

7. The spread spectrum circuit based on a true random signal according to claim 5, characterized in that, The voltage divider circuit also includes n connecting resistors, which are respectively set on the line between the terminal node and the D flip-flop.

8. The spread spectrum circuit based on a true random signal according to claim 1, characterized in that, The voltage-controlled oscillator circuit includes an analog amplifier, a ring oscillator, a first RC coupling circuit, a second RC coupling circuit, and a first inverter. The non-inverting input terminal of the analog amplifier serves as the input terminal of the voltage-controlled oscillator circuit. The output of the analog amplifier is connected to the input of the ring oscillator. The output terminal of the ring oscillator is connected to one end of the first RC coupling circuit, and the other end of the first RC coupling circuit is connected to one end of the first inverter. The other end of the first inverter serves as the output terminal of the voltage-controlled oscillator. The inverting input of the analog amplifier is connected to the other end of the first inverter and the middle node of the second RC coupling circuit.

9. The spread spectrum circuit based on a true random signal according to claim 8, characterized in that, The voltage-controlled oscillator circuit also includes a second inverter. The second inverter is disposed on the line between the output terminal of the ring oscillator and one end of the first RC coupling circuit.

10. An isolated power supply chip, characterized in that, The isolated power supply chip includes the spread spectrum circuit based on true random signals as described in any one of claims 1-9.

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