Long-distance low-noise high-stability power supply circuit

Abstract

The invention discloses a long-distance low-noise high-stability power supply circuit which is used for a superconducting quantum measurement and control system case. Input voltage is reduced through the BUCK circuit and then passes through the LDO, and voltage meeting actual performance requirements is output; the voltage drop on the positive polarity voltage output line is independently connected to the load end through the LDO chip pin OUTS to be eliminated, the ground wire voltage drop is sampled and compensated to the voltage setting pin of the LDO chip through the ground wire voltage drop compensation resistor, finally the voltage output to the load end fluctuates within 3 mv, and therefore long-distance low-noise low-voltage regulation rate power supply is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of superconducting quantum computing measurement and control, and in particular relates to a long-distance, low-noise, and highly stable power supply circuit. Background Art

[0002] The increasing integration of superconducting quantum computing measurement and control systems creates a long transmission path (approximately 0.2 to 1 meter) between the load and power supply. This fluctuation in load current and the length of the power supply line result in significant voltage ripple and noise, leading to unstable voltage supply to the superconducting quantum computing measurement and control system. Furthermore, superconducting quantum computing measurement and control systems place high demands on the power supply stability of electronic equipment, such as the chassis, and also impose certain requirements on the distance of the power transmission line. Summary of the Invention

[0003] The purpose of the present invention is to provide a long-distance, low-noise, and highly stable power supply circuit to solve the problems of large ripple noise output by the power supply end and poor power supply stability caused by the long power supply transmission path, thereby realizing long-distance, low-noise, and highly stable power supply for superconducting quantum computing measurement and control systems.

[0004] In order to solve the above problems, the technical solution of the present invention is: A long-distance, low-noise, and highly stable power supply circuit for a superconducting quantum measurement and control system chassis. The power supply circuit includes a buck circuit and an low-dropout (LDO) circuit. The input voltage is stepped down by the buck circuit and then passes through the LDO circuit to output a voltage with a fluctuation range of no more than 3mV to the load. Among them, the voltage setting pin of the LDO circuit is connected in series with a ground voltage drop compensation resistor, the other end of the ground voltage drop compensation resistor is grounded, and the voltage drop on the ground is compensated to the voltage setting pin of the LDO circuit through the ground voltage drop compensation resistor to eliminate the ground voltage drop.

[0005] According to an embodiment of the present invention, the output terminal and the feedback output terminal of the LDO circuit are each connected to an SMA connector via a long-distance wire; the length of the long-distance wire does not exceed 1 m.

[0006] According to an embodiment of the present invention, a filter capacitor is mounted on the feedback output terminal to optimize power supply stability, enhance transient response, and suppress noise.

[0007] According to an embodiment of the present invention, the LDO circuit includes a constant current source, an error amplifier, and a transistor; The negative input terminal of the error amplifier is connected to the constant current source, the positive input terminal of the error amplifier is connected to the feedback output terminal of the LDO, the output terminal of the error amplifier is connected to the base of the transistor, and the collector of the transistor is connected to the output terminal of the LDO; The error amplifier and the transistor form a feedback loop, which compares the feedback output voltage with the reference voltage through the error amplifier to control the conduction degree of the transistor, thereby achieving dynamic adjustment of the LDO output voltage.

[0008] According to one embodiment of the present invention, the voltage setting pin of the LDO circuit is connected in series with an output voltage setting resistor, the output voltage setting resistor is connected in series with a ground voltage drop compensation resistor, and the connection end between the output voltage setting resistor and the ground voltage drop compensation resistor is connected to a long-distance wire to an SMA connector, where the length of the long-distance wire does not exceed 1 meter; the ground voltage drop compensation resistor is much smaller than the output voltage setting resistor.

[0009] According to an embodiment of the present invention, the ground voltage drop compensation resistor is connected in series with the output voltage setting resistor, and the ground level of the load end is superimposed on the output voltage setting end, thereby compensating the ground voltage drop at the LDO output end.

[0010] Due to the adoption of the above technical solution, the present invention has the following advantages and positive effects compared with the prior art: A long-distance, low-noise, and highly stable power supply circuit in one embodiment of the present invention steps down the input voltage through a buck circuit and then passes it through an LDO to output a voltage that meets actual performance requirements. The voltage drop on the positive-polarity voltage output line is eliminated by connecting the LDO chip pin OUTS to the load end. The ground voltage drop is sampled and compensated to the voltage setting pin of the LDO chip through a ground voltage drop compensation resistor. Ultimately, the voltage fluctuation output to the load end is kept within 3mV, thereby achieving long-distance, low-noise, and low-voltage regulation power supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 Schematic diagram of a long-distance, low-noise, and highly stable power supply circuit in one embodiment of the present invention; Figure 2 FIG. 1 is a schematic diagram of an LDO circuit in an embodiment of the present invention. DETAILED DESCRIPTION

[0012] The advantages and features of the present invention will become more apparent from the following description and claims.

[0013] Please see Figure 1 This embodiment provides a long-distance, low-noise, and highly stable power supply circuit for a superconducting quantum measurement and control system chassis. The power supply circuit includes a buck circuit and an low-dropout (LDO) circuit. The input voltage is stepped down by the buck circuit and then passes through the LDO circuit to output a voltage with a fluctuation range of no more than 3mV to the load.

[0014] Among them, the voltage drop on the positive-polarity voltage output line is eliminated by connecting the OUTS pin of the LDO chip to the load end separately, and the ground wire voltage drop is sampled by Rcom and compensated to the voltage setting pin of the LDO chip, finally making the voltage fluctuation output to the load end within 3mv, so as to achieve long-distance low-noise and low-voltage regulation rate power supply.

[0015] Taking the LT3041 as an example for the LDO circuit of this embodiment, different lengths of wires are connected between its output terminal and feedback terminal, and the ground wire voltage drop is compensated to the output terminal by Rcom, and then the output terminal voltage is compensated and regulated by the feedback loop to maintain the stability of the output terminal voltage, making the output voltage fluctuation within 3mv, so as to achieve long-distance low-noise power supply.

[0016] Specifically, please refer to Figure 2 , the LDO circuit includes a constant current source, an error amplifier, and a triode; the negative input terminal of the error amplifier is connected to the constant current source, the positive input terminal of the error amplifier is connected to the feedback output terminal of the LDO, the output terminal of the error amplifier is connected to the base of the triode, and the collector of the triode is connected to the output terminal of the LDO. A long-distance wire is connected to the SMA connector at the output terminal and the feedback output terminal of the LDO circuit; here, the length of the long-distance wire does not exceed 1m.

[0017] In the figure, the error amplifier, the triode and the SMA connector form a feedback loop, and this feedback loop compares the voltage of the feedback output terminal and the reference voltage through the error amplifier to control the conduction degree of the triode, so as to achieve the dynamic adjustment of the LDO output voltage.

[0018] In this embodiment, the voltage drop on the ground wire is compensated to the voltage setting pin of the LDO chip through the resistor Rcom to achieve the purpose of eliminating the ground wire voltage drop. Specifically, an output voltage setting resistor Rset is connected in series at the voltage setting pin of the LDO circuit, Rset is connected in series with Rcom, and the connection end of Rset and Rcom is connected to an SMA connector through a long-distance wire, and the length of this long-distance wire does not exceed 1m.

[0019] Among them, Rcom is the ground wire voltage drop compensation resistor, and Rcom << RSET. RSET is the output voltage setting resistor, and (RSET + Rcom) and the 100uA constant current source fixed inside the LDO chip jointly determine the magnitude of the LDO output voltage.

[0020] In other words, Vset was originally determined by Rset and a fixed 100µA constant current source inside the chip. Now, Rcom sampling and compensation is connected in series with Rset, superimposing the load-side GND voltage on Vset. The output voltage is then determined by (Rset + Rcom) and the fixed 100µA constant current source inside the chip. This allows the ground voltage drop to be compensated to the output through Rcom. The feedback loop then compensates and adjusts the output voltage to maintain stability, keeping the output voltage fluctuation within 3mV and achieving low-noise, highly stable power supply over long distances.

[0021] In addition, in order to optimize the stability of power supply, enhance transient response and suppress noise, a filter capacitor is mounted on the feedback output of LDO. For details, please refer to Figure 2 , Cout1 and Cout2 connected in parallel are connected to the feedback output terminal, and the other end is grounded.

[0022] In summary, this long-distance, low-noise, and highly stable power supply circuit, based on a linear power supply, eliminates the voltage drop caused by the load current in the power transmission line through load-side feedback and ground compensation, reducing the output voltage regulation to 0.02%. The circuit structure is simple, requiring no additional controller other than the LDO chip. It also possesses the advantages of a linear power supply, such as low noise and high common-mode rejection ratio. By varying the length of the wires connected to the output and feedback output terminals, long-distance, low-noise, and highly stable power supply can be achieved for superconducting quantum measurement and control systems.

[0023] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the above embodiments. Even if various changes are made to the present invention, if these changes fall within the scope of the claims of the present invention and their equivalents, they still fall within the scope of protection of the present invention.

Claims

1. A long-distance, low-noise, and highly stable power supply circuit for a superconducting quantum measurement and control system chassis; characterized in that: include: Buck circuit and LDO circuit: after the input voltage is stepped down by the buck circuit, it is output to the load through the LDO circuit with a fluctuation range not exceeding 3mV; Among them, the voltage setting pin of the LDO circuit is connected in series with a ground voltage drop compensation resistor, the other end of the ground voltage drop compensation resistor is grounded, and the voltage drop on the ground is compensated to the voltage setting pin of the LDO circuit through the ground voltage drop compensation resistor to eliminate the ground voltage drop.

2. The long-distance, low-noise, and highly stable power supply circuit according to claim 1, wherein: The output end and the feedback output end of the LDO circuit are each connected to a long-distance wire to an SMA connector; the length of the long-distance wire does not exceed 1m.

3. The long-distance, low-noise, and highly stable power supply circuit according to claim 2, wherein: The feedback output terminal is mounted with a filter capacitor to optimize the stability of the power supply, enhance the transient response, and suppress noise.

4. The long-distance, low-noise, and highly stable power supply circuit according to claim 1, wherein: The LDO circuit includes a constant current source, an error amplifier, and a transistor; The negative input terminal of the error amplifier is connected to the constant current source, the positive input terminal of the error amplifier is connected to the feedback output terminal of the LDO, the output terminal of the error amplifier is connected to the base of the transistor, and the collector of the transistor is connected to the output terminal of the LDO; The error amplifier and the transistor form a feedback loop, which compares the feedback output voltage with the reference voltage through the error amplifier to control the conduction degree of the transistor, thereby achieving dynamic adjustment of the LDO output voltage.

5. The long-distance, low-noise, and highly stable power supply circuit according to claim 1, wherein: The voltage setting pin of the LDO circuit is connected in series with an output voltage setting resistor, the output voltage setting resistor is connected in series with a ground voltage drop compensation resistor, and the connection end of the output voltage setting resistor and the ground voltage drop compensation resistor is connected to a long-distance wire to an SMA connector, and the length of the long-distance wire does not exceed 1m; the ground voltage drop compensation resistor is much smaller than the output voltage setting resistor.

6. The long-distance, low-noise, and highly stable power supply circuit according to claim 5, wherein: The ground voltage drop compensation resistor is connected in series with the output voltage setting resistor, and the ground level of the load end is superimposed on the output voltage setting end, thereby compensating the ground voltage drop at the LDO output end.

Images