A fast switching current source circuit

Abstract

The present invention provides a fast on-off current source circuit, which relates to the field of integrated circuit design. The current source circuit includes a current mirror K1, a switch module and an amplifier X1; the current module includes a switch S1 and a switch S2, and the switch S1 and the switch S2 are set in anti-phase. In the present invention, the switch S1 and the switch S2 are alternately opened, when the current source is disconnected, the switch S1 is disconnected, the switch S2 is closed, and the amplifier X1 transmits the output voltage to the output point of the current mirror K1, and maintains the working state of the current source circuit the same as when it is turned on; when the current source is closed, the switch S1 is closed, and the switch S2 is disconnected. Since the current source circuit always maintains the same working state during the process of the switches S1 and S2 being alternately turned on and off, it can quickly achieve fast switching and stable high-precision output.

Description

Technical Field

[0001] The invention relates to the field of integrated circuit design, and in particular to a fast switching current source circuit. Background Art

[0002] Current source circuits are widely used in integrated circuit design. Current source circuits can be divided into tube current current source circuits and leakage current current source circuits. Among them, tube current current source circuits and leakage current current source circuits are composed of a current mirror and a switch S, and are turned on and off by a switch S. Please refer to Figure 1 , is a typical switch leakage current source circuit. Since the current source circuit has different states when the switch is on and off, the current source needs a settling time to turn on and off the current source during the state switching process; please refer to Figure 2 , which is a typical switch tube current source circuit. Since the state of the current source circuit is different when the switch is on and off, the current source needs a settling time to realize the turning on and off of the current source during the state switching process.

[0003] In many application fields, it is necessary to ensure that the current source circuit has high output accuracy and also to ensure fast turn-on and turn-off. Especially in the field of low-power circuits, the response speed of the current source circuit is proportional to the power consumption. Under low power consumption conditions, it is difficult for the current source circuit to turn on and off quickly. Summary of the invention

[0004] In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a fast switching current source circuit, which is suitable for low power consumption circuits and can achieve fast switching on and off while taking into account high output accuracy.

[0005] To achieve the above objectives and other related objectives, the present invention provides a fast switching current source circuit, the current source circuit comprising a current mirror K1, a switch module and an amplifier X1; the current module comprises a switch S1 and a switch S2, and the switch S1 and the switch S2 are arranged in opposite phases.

[0006] In one embodiment of the present invention, one end of the current mirror K1 is connected to a power supply, and the other end is connected to the a end of the switch S1 and to the b end of the switch S2. The a end of the switch S2 is connected to the output end of the amplifier X1, and the input end of the amplifier X1 is connected to the b end of the switch S1.

[0007] In one embodiment of the present invention, the a-end of the switch S1 is connected to the power supply and the input end of the amplifier X1, the output end of the amplifier X1 is connected to the a-end of the switch S2, the b-end of the switch S2 is connected to the b-end of the switch S1, and the b-end of the switch S1 is connected to the current mirror K1.

[0008] In one embodiment of the present invention, the amplifier X1 is a unity gain voltage amplifier.

[0009] In one embodiment of the present invention, the switch S1 and the switch S2 are analog switches.

[0010] As described above, a fast on-off current source circuit of the present invention has the following beneficial effects: the present invention is applicable to low-power circuits and can achieve fast on and off while taking into account high output accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 Shown is a circuit diagram of a typical switched leakage current source circuit disclosed in the prior art.

[0012] Figure 2 Shown is a circuit diagram of a typical switch tube current source circuit disclosed in the prior art.

[0013] Figure 3 Shown is a circuit diagram of a new switch leakage current source circuit disclosed in the first embodiment of the present invention.

[0014] Figure 4 Shown is a circuit diagram of a new switch tube current source circuit disclosed in the second embodiment of the present invention.

[0015] Figure 5 Shown is a switching timing diagram of a fast switching current source circuit disclosed in a specific embodiment of the present invention. DETAILED DESCRIPTION

[0016] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0017] It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention, and thus the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0018] Embodiment 1

[0019] The present invention provides a fast on-off current source circuit, the current source circuit comprises a current mirror K1, a switch module and an amplifier X1; the current module comprises a switch S1 and a switch S2, the switch S1 and the switch S2 are arranged in opposite phases, that is, when the switch S1 is opened and the switch S2 is closed, the current source circuit is turned off; when the switch S1 is closed and the switch S2 is opened, the current source circuit is turned on, please refer to Figure 5 .

[0020] In the present invention, switch S1 and switch S2 are opened alternately. When the current source is disconnected, switch S1 is opened and switch S2 is closed. The amplifier X1 transmits the output voltage to the output point of the current mirror K1 to maintain the working state of the current source circuit the same as when it is turned on. When the current source is closed, switch S1 is closed and switch S2 is opened. Since the current source circuit always maintains the same working state during the process of switches S1 and S2 being alternately turned on and off, fast switching and stable high-precision output can be achieved quickly.

[0021] See also Figure 3 , which is a new switch leakage current source circuit. One end of the current mirror K1 is connected to the power supply, and the other end is connected to the a end of the switch S1 and the b end of the switch S2. The a end of the switch S2 is connected to the output end of the amplifier X1, and the input end of the amplifier X1 is connected to the b end of the switch S1.

[0022] The amplifier X1 is a unit gain voltage amplifier, and the switch S1 and the switch S2 are analog switches.

[0023] Since the state of the current source circuit remains consistent by using the unit gain voltage amplifier K1 when the switch is turned on and off, the current source does not need a settling time during the state switching process, thereby realizing fast turning on and off of the current source.

[0024] Embodiment 2

[0025] The present invention provides a fast on-off current source circuit, characterized in that: the current source circuit comprises a current mirror K1, a switch module and an amplifier X1; the current module comprises a switch S1 and a switch S2, and the switch S1 and the switch S2 are arranged in opposite phases, that is, when the switch S1 is disconnected and the switch S2 is closed, the current source circuit is turned off; when the switch S1 is closed and the switch S2 is disconnected, the current source circuit is turned on, see Figure 5 .

[0026] In the present invention, switch S1 and switch S2 are opened alternately. When the current source is disconnected, switch S1 is opened and switch S2 is closed. The amplifier X1 transmits the output voltage to the output end of the current mirror K1 to maintain the working state of the current source circuit the same as when it is turned on. When the current source is closed, switch S1 is closed and switch S2 is opened. Since the current source circuit always maintains the same working state during the process of switches S1 and S2 being alternately turned on and off, fast switching and stable high-precision output can be achieved quickly.

[0027] See also Figure 4 , which is a new switch tube current source circuit, the a end of the switch S1 is connected to the power supply and the input end of the amplifier X1, the output end of the amplifier X1 is connected to the a end of the switch S2, the b end of the switch S2 is connected to the b end of the switch S1, and the b end of the switch S1 is connected to the current mirror K1.

[0028] The amplifier X1 is a unit gain voltage amplifier, and the switch S1 and the switch S2 are analog switches.

[0029] Since the state of the current source circuit remains consistent by using the unit gain voltage amplifier K1 when the switch is turned on and off, the current source does not need a settling time during the state switching process, thereby realizing fast turning on and off of the current source.

[0030] Based on the above circuit structure, the present invention simulates and compares the opening and closing of the traditional current source circuit and the new current source circuit. The traditional current source circuit is opened and closed, and the establishment time is greater than 18ns; the new current source circuit is opened and closed, and the establishment time is less than 2ns.

[0031] The present invention is suitable for low power consumption circuits, and can realize fast opening and closing while taking into account high output accuracy. Therefore, the present invention effectively overcomes various shortcomings in the prior art and has high industrial utilization value.

[0032] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A fast switching current source circuit, characterized in that: The current source circuit includes a current mirror K1, a switch module and an amplifier X1; the switch module includes a switch S1 and a switch S2, and the switches S1 and S2 are arranged in opposite phases; one end of the current mirror K1 is connected to a power supply, and the other end is connected to the a end of the switch S1 and to the b end of the switch S2, the a end of the switch S2 is connected to the output end of the amplifier X1, and the input end of the amplifier X1 is connected to the b end of the switch S1; the a end of the switch S1 is connected to a power supply and to the input end of the amplifier X1, the output end of the amplifier X1 is connected to the a end of the switch S2, the b end of the switch S2 is connected to the b end of the switch S1, and the b end of the switch S1 is connected to the current mirror K1; the amplifier X1 is a unit gain voltage amplifier.

2. A fast switching current source circuit according to claim 1, characterized in that: The switch S1 and the switch S2 are analog switches.

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