Dual loop sampling device

Abstract

The present invention relates to a dual-loop sampling device, which is used for current sampling of a main current source and a secondary current source. The dual-loop sampling device includes a first shunt, a second shunt, an amplifier circuit and an isolation circuit; the positive end of the first shunt is connected to the main current source and is connected to the amplifier circuit through a first positive end switch, and the negative end of the first shunt is connected to the isolation circuit through a first negative end switch; the positive end of the second shunt is connected to the secondary current source and is connected to the amplifier circuit through a second positive end switch, and the negative end of the second shunt is connected to the isolation circuit through a second negative end switch; because the first shunt and the second shunt have independent loops, the sampled currents of the main current and the secondary current source will not interfere with each other, thereby improving the accuracy of the measurement.

Description

Technical Field

[0001] The present invention relates to a current sampling device, and more particularly to a dual-loop sampling device capable of improving the accuracy of sensing results. Background Art

[0002] Please refer to Figure 3 As shown, the conventional dual-loop sampling device 100 can be used to perform current sampling measurement on a main current source 200 and a secondary current source 300 . The dual-loop sampling device 100 includes a first shunt 110 , a second shunt 120 , a first sampling switch 130 , a second sampling switch 140 and an amplifier circuit 150 .

[0003] The first current divider 110 is first connected to the main current source 200 , and then outputted through the first sampling switch 130 , and then connected to the amplifier circuit 150 after passing through the first sampling switch 130 .

[0004] The second shunt 120 is first connected to the auxiliary current source 300, and then outputted through the second sampling switch 140, and then connected to the amplifier circuit 150 after passing through the second sampling switch 140, wherein the main current source 200, the auxiliary current source 300, the first shunt 110 and the second shunt 120 are connected to the same ground G.

[0005] When measuring the current of the auxiliary current source 300 , the second sampling switch 140 is turned on, the first sampling switch 130 is turned off, and part of the current of the auxiliary current source 300 passes through the second shunt 120 to generate a voltage signal, which is transmitted to the amplifier circuit 150 through the second sampling switch 140 .

[0006] When measuring the current of the main current source 200, the first sampling switch 130 is turned on, and the second sampling switch 140 is turned off. Part of the current of the main current source 200 will pass through the first shunt 110 to generate a voltage signal, and the voltage signal is transmitted to the amplifier circuit 150 through the first sampling switch 130. However, when the auxiliary current source 300 generates an input current, the current will generate a voltage drop caused by the line resistance R on the ground line shared by the main current source 200 and the auxiliary current source 300. This voltage drop will cause a measurement error of the first shunt 110, resulting in erroneous current measurement, affecting the measurement accuracy of the main current source 200. For instruments requiring higher precision, this measurement error still needs to be avoided. Summary of the invention

[0007] The main purpose of the present invention is to provide a dual-loop sampling device to improve the accuracy of current source sampling measurement.

[0008] The dual-loop sampling device of the present invention is used for current sampling of a main current source and a secondary current source, and the dual-loop sampling device comprises:

[0009] a first shunt having a positive terminal and a negative terminal, wherein the positive terminal of the first shunt is connected to the main current source through a first cut-off switch, and the positive terminal is connected to one end of a first positive terminal switch, and the negative terminal of the first shunt is connected to a ground and a first negative terminal switch;

[0010] a second shunt having a positive end and a negative end, wherein the positive end of the second shunt is connected to the auxiliary current source through a second cut-off switch, and the positive end of the second shunt is connected to one end of a second positive end switch, and the negative end of the second shunt is connected to the ground and a second negative end switch;

[0011] an amplifier circuit connected to the other end of the first positive switch and the other end of the second positive switch;

[0012] An isolation circuit has an input end connected to the other end of the first negative end switch and the other end of the second negative end switch, and an output end of the isolation circuit connected to the amplifier circuit.

[0013] Preferably, the amplifier circuit includes an operational amplifier, an input end of which is connected to the other end of the first positive end switch and the other end of the second positive end switch.

[0014] Preferably, the isolation circuit comprises an operational amplifier, an input terminal of the operational amplifier is connected to the other terminal of the first negative terminal switch and the other terminal of the second negative terminal switch.

[0015] Through the above invention, the first shunt and the second shunt have independent loops, so the sampled currents of the main current and the auxiliary current source will not interfere with each other, thereby improving the measurement accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a circuit block diagram of the dual-loop sampling device of the present invention;

[0017] Figure 2 is a detailed circuit diagram of the dual-circuit sampling device of the present invention;

[0018] Figure 3 The figure is a circuit block diagram of an existing dual-loop sampling device.

[0019] Explanation of symbols

[0020] 10 Dual loop sampling device

[0021] 11. First shunt

[0022] 12 Second shunt

[0023] 13 First positive switch

[0024] 14 First negative switch

[0025] 15 Second positive switch

[0026] 16 Second negative switch

[0027] 17 Amplifier Circuit

[0028] 18 Isolation circuit

[0029] 100 Dual loop sampling device

[0030] 110 First shunt

[0031] 120 Second shunt

[0032] 130 First sampling switch

[0033] 140 Second sampling switch

[0034] 150 Amplifier Circuit

[0035] 200 Main current source

[0036] 300 Auxiliary current source

[0037] SW1 First switch

[0038] SW2 Second switch DETAILED DESCRIPTION

[0039] The following is a detailed description of the technical means used by the present invention to achieve the intended purpose of the invention with reference to the drawings and preferred embodiments of the present invention.

[0040] Please refer to Figure 1 and Figure 2 As shown, the dual-loop sampling device 10 of the present invention is used to sample current from a main current source 200 and an auxiliary current source 300, and one end of the main current source 200 and the auxiliary current source 300 are respectively connected to the ground G. The dual-loop sampling device 10 includes a first switching switch SW1, a second switching switch SW2, a first shunt 11, a second shunt 12, a first positive terminal switch 13, a first negative terminal switch 14, a second positive terminal switch 15, a second negative terminal switch 16, an amplifier circuit 17, and an isolation circuit 18.

[0041] The first shunt 11 has a positive end and a negative end, wherein the positive end is connected to the main current source 200 through the first switching switch SW1 and is connected to one end of the first positive end switch 13 ; the negative end of the first shunt 11 is connected to the ground G and the first negative end switch 14 .

[0042] The other end of the first positive switch 13 is connected to the amplifier circuit 17 , and the other end of the first negative switch 14 is connected to the input end of the isolation circuit 18 .

[0043] The second shunt 12 has a positive end and a negative end, wherein the positive end is connected to the secondary current source 300 through the second switching switch SW2 and is connected to one end of the second positive end switch 15 ; the negative end of the second shunt 12 is connected to the ground G and the second negative end switch 16 .

[0044] The other end of the second positive switch 15 is connected to the amplifier circuit 17 , and the other end of the second negative switch 16 is connected to the input end of the isolation circuit 18 . The input end of the isolation circuit 18 is further connected to the amplifier circuit 17 .

[0045] like Figure 2 As shown, the first positive switch 13, the first negative switch 14, the second positive switch 15, and the second negative switch 16 can be implemented by an integrated circuit of model ADG411BRZ. The amplifier circuit 17 is mainly composed of an operational amplifier (OPA), and the first positive switch 13 and the second positive switch 15 are commonly connected to one of the input terminals of the operational amplifier. The isolation circuit 18 is also mainly composed of an operational amplifier (OPA), and the first negative switch 14 and the second negative switch 16 are commonly connected to one of the input terminals of the operational amplifier, and the output terminal of the operational amplifier is connected to the amplifier circuit.

[0046] In actual application, when measuring the main current source 200, the first switch SW1 is turned on and the second switch SW2 is turned off, so that the first shunt 11 is connected to the main current source 200 through the first switch SW1; and the first positive end switch 13 and the first negative end switch 14 are controlled to be in the on state, on the contrary, the second positive end switch 15 and the second negative end switch 16 are controlled to be in the off state. The voltage at the positive end of the first shunt 11 is transmitted to the amplifier circuit 17 through the first positive end switch 13, and the voltage at the negative end of the first shunt 11 is transmitted to the isolation circuit 18 through the first negative end switch 14, and then transmitted to the amplifier circuit 17.

[0047] When measuring the secondary current source 300, the first switch SW1 is turned off (OFF), and the second switch SW2 is turned on (ON), so that the second shunt 12 is connected to the secondary current source 300 through the second switch SW2; and the first positive end switch 13 and the first negative end switch 14 are controlled to be in the off (OFF) state, on the contrary, the second positive end switch 15 and the second negative end switch 16 are controlled to be in the on (ON) state. The voltage at the positive end of the second shunt 12 is transmitted to the amplifier circuit 17 through the second positive end switch 15, and the voltage at the negative end of the second shunt 12 is transmitted to the isolation circuit 18 through the second negative end switch 16, and then transmitted to the amplifier circuit 17.

[0048] For the main current source 200, the first shunt 11, the first positive switch 13 and the first negative switch 14 can constitute a first independent sensing loop; for the auxiliary current source 300, the second shunt 12, the second positive switch 15 and the second negative switch 16 can constitute a second independent sensing loop. In the present invention, both the first shunt 11 and the second shunt 12 have independent sensing loops, so the currents on the two independent sensing loops will not interfere with each other, and the measurement results sampled from the first shunt 11 and the second shunt 12 are more accurate, which can improve the accuracy of the measurement results.

[0049] The above is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A dual-circuit sampling device for sampling a main current source and a secondary current source, characterized in that: The dual-loop sampling device comprises: a first shunt having a positive terminal and a negative terminal, wherein the positive terminal of the first shunt is connected to the main current source through a first cut-off switch, and the positive terminal is connected to one end of a first positive terminal switch, and the negative terminal of the first shunt is connected to a ground and a first negative terminal switch; a second shunt having a positive end and a negative end, wherein the positive end of the second shunt is connected to the secondary current source via a second cut-off switch, and the positive end of the second shunt is connected to one end of a second positive end switch, and the negative end of the second shunt is connected to the ground and a second negative end switch; an amplifier circuit connected to the other end of the first positive switch and the other end of the second positive switch; An isolation circuit has an input end connected to the other end of the first negative end switch and the other end of the second negative end switch, and an output end of the isolation circuit is connected to the amplifier circuit.

2. The dual-circuit sampling device according to claim 1, characterized in that: The amplifier circuit includes an operational amplifier, an input end of which is connected to the other end of the first positive end switch and the other end of the second positive end switch.

3. The dual-circuit sampling device according to claim 1, characterized in that: The isolation circuit includes an operational amplifier, an input end of which is connected to the other end of the first negative terminal switch and the other end of the second negative terminal switch.

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