CN103219962A - Programmable gain isolation amplifier circuit and implement method thereof - Google Patents
Programmable gain isolation amplifier circuit and implement method thereof Download PDFInfo
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- CN103219962A CN103219962A CN2013101287748A CN201310128774A CN103219962A CN 103219962 A CN103219962 A CN 103219962A CN 2013101287748 A CN2013101287748 A CN 2013101287748A CN 201310128774 A CN201310128774 A CN 201310128774A CN 103219962 A CN103219962 A CN 103219962A
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Abstract
The invention belongs to the technical field of isolation amplifier circuits, and particularly relates to a programmable gain isolation amplifier circuit and an implement method thereof. The programmable gain isolation amplifier circuit comprises an isolation unit U1 and a programmable gain amplifier circuit, wherein the isolation unit U1 comprises an input end, a conversion capacitor, a micro-electronic digital single-pole double-throw switch, gating signals, and control signals of the micro-electronic digital switch, and the programmable gain amplifier circuit comprises a precise integrated operational amplifier, a programmable resistor network and a gain measuring circuit. The programmable resistor network is composed of digital potentiometers, and the gain measuring circuit comprises a digital switch, standard voltage and the control signals of the digital switch. The programmable gain isolation amplifier circuit can achieve complete isolation between a signal end and the amplifier, can overcome the zero-shift phenomenon of the amplifier circuit, is strong in continuity of gain selection, and can remarkably improve amplification precision.
Description
Technical field
The invention belongs to the isolating amplifier circuit technical field, especially relate to a kind of programmable-gain isolating amplifier circuit and its implementation.
Background technology
In reality, a lot of informational needs collections are arranged, become the information that can use.Back ground Information is to be formed by signal transition.The occurring in nature signal has two big classes, and a class is an analog signal, and it is continuously in time or changes signal slowly; Another kind of is the signal that is interrupted variation in time, is referred to as digital signal, and it can be used for digital processing, or gives Computer Processing.But, be analog signal in a large number in the reality, it is to be extracted by various transducers.
Analog signal, generally not of uniform size, wherein a part is a tiny signal, when further using, need amplify.In amplification process, in order to improve transmitting accuracy, should guarantee that also signal has suitable amplitude, this just requires the gain-variable of amplifying circuit, and promptly range is variable.In the detection in each field of actual field, control circuit; in order to improve the whole system operation reliability; protection personal safety and device security; reduce and disturb and noise; often will take electric completely quarantine measures in signal transmission passage, isolating also is the effective means that suppresses common mode disturbances.So-called " completely " is meant segregate two parts circuit, without any public tie point, comprises ground wire and power supply.Analog signal for preventing various interference, often adopts jamproof isolation skill to ask when amplifying, and this is one of important measures of Analog signals amplification.Analog signal is when amplifying, and another problem is exactly an amplifying circuit temperature influence and fluctuating--null offset.But it is one of key factor of influence amplification precision, general being difficult to brush.
In the existing Signal Isolation Technology:
1) have and adopt midget relay to carry out Signal Spacing, the effect of isolation still can, but speed is slow, volume and power consumption is big, the life-span is low;
2) adopt precision photoelectric coupler to isolate, its circuit is simple, and the effect of this isolation is all right, but linear poor when shortcoming is small-signal, in the high occasion of required precision, can not use;
3) adopt magnetic or transformer isolation, this isolation effective, but technical sophistication, valency is expensive, volume and power consumption are big, has signal directly not adopt, as direct current signal;
4) adopt electric current to isolate between input circuit and the output circuit, technical sophistication, some occasion can not be used;
In the existing signal Programmable Gain Amplifier Circuit technology:
1) feedback resistive network of amplifying circuit adopts microswitch control, can change the amplifying circuit gain, but can not automation;
2) feedback resistive network of amplifying circuit adopts electronic switch control, can change the amplifying circuit gain, but the resistance value in the feedback resistive network fix, can not continuously change, promptly can not continuously change the amplifying circuit gain;
3) digital control programmable gain amplifier, LTC6910 series digit control programmable gain amplifier (PGA) the monolithic IC that produces as Linear Tech (LTC) uses for aspects such as data acquisition system (DAS), dynamic gain variation and automatic gain controls to design specially.But it is fixing that the resistance of decision multiplication factor is still, so the amplifying circuit gain can not continuous variable.
Summary of the invention
The purpose of this invention is to provide a kind of programmable-gain isolating amplifier circuit, isolate amplifying signal through this isolating amplifier circuit and amplify the precision height, gain selects continuity strong, and can realize the isolation fully of signal end and amplifier.
The objective of the invention is to realize by following technical proposals:
Programmable-gain isolating amplifier circuit of the present invention is characterized in that comprising isolated location U
1, Programmable Gain Amplifier Circuit,
Described isolated location U
1Comprise input B1, B2 and B3, conversion capacitor C 1 and C2, microelectronics numeral single-pole double-throw switch (SPDT) KC11, KC12, KC21 and KC22, gating signal GL, the control signal D0 of microelectronics digital switch,
Described Programmable Gain Amplifier Circuit comprises accurate integrated operational amplifier U2, programmable resistive network U3, gain measurement circuit U 4, described programmable resistive network U3 is by digital regulation resistance SD1, SD2 and SD3 form, described gain measurement circuit U 4 comprises digital switch K1, K2, normal voltage Vb, the control signal D1 of digital switch.
Described digital regulation resistance SD1, SD2 and SD3 are 8 bit digital potentiometers.
A kind of implementation method based on the programmable-gain isolating amplifier circuit, it is characterized in that: it comprises the steps:
1) gating U1, signal is by B1, B2 and the input of B3 end, in parallel with conversion capacitor C 1 and C2, at microelectronics numeral single-pole double-throw switch (SPDT) KC11, KC12, KC21 and KC22, under the control of the control signal D0 of gating signal GL and microelectronics digital switch, earlier with microelectronics numeral single-pole double-throw switch (SPDT) KC11, KC12, KC21 and KC22, be connected on left side receiving inputted signal, exist on conversion capacitor C 1 and the C2, again with microelectronics numeral single-pole double-throw switch (SPDT) KC11, KC12, KC21 and KC22 are connected on the right, input signal is given to the amplifying circuit amplification from conversion capacitor C 1 and C2, and at this moment amplifying circuit and input signal end " fully " are isolated;
2) gain amplifier is measured at that time: in order to reduce the influence of variations in temperature to the amplifying circuit precision, promptly eliminate " drift ", before amplifying each signal, should the big circuit of first measuring gain amplifier at that time, promptly start U4, D1 is thrown low level, digital switch K1 is connected, disconnect digital switch K2, input amplifier ground connection (zero input) is measured output Vuot0 at that time; D1 is thrown high level, digital switch K1 is disconnected, digital switch K2 connects, and input amplifier inserts normal voltage Vb, measures output Voutb at that time.
Then the actual gain of amplifying circuit is at that time:
K
At that time=(Voutb-Vout0)/Vb
3) Programmable Gain Amplifier Circuit, comprise accurate integrated operational amplifier U2, programmable resistive network U3, programmable resistive network U3 is by digital regulation resistance SD1, SD2 and SD3 form, and this programmable resistive network U3 is to use 8 digital regulation resistance, can produce 256 kinds of resistance values, in order to change the gain of amplifying circuit, the resistance value of digital regulation resistance provides the programmable-gain control signal by external embedded microcomputer.
Advantage of the present invention:
(1) the present invention adopts the signal switching method of two accurate electric capacity and the two Zheng Kaiguan of digital microelectronics hilted broadsword, has realized " isolating fully " between signal end and amplifier;
(2) Programmable Gain Amplifier Circuit, the method that has adopted actual measurement " to gain at that time ", this is effective measures of eliminating amplifying circuit " drift ", can significantly improve the amplification precision;
(3) Programmable Gain Amplifier Circuit, the programmable-gain transform method that employing is made of digital regulation resistance, be to realize gain effective measures of continuous Based Intelligent Control of amplifying circuit, because use 8 digital regulation resistance, can produce 256 kinds of resistance values, than only adopting several resistance in the prior art, improve significantly, and in the resistor network, form coarse adjustment and fine tuning circuit again, make the programmable-gain energy near continuous selection.
Description of drawings
Fig. 1 is a network data acquisition device theory diagram;
Fig. 2 is the schematic diagram of programmable-gain isolating amplifier circuit of the present invention;
The schematic diagram that Fig. 3 inserts for programmable-gain isolating amplifier circuit thermal resistance of the present invention.
Embodiment
Further specify the specific embodiment of the present invention below in conjunction with accompanying drawing.
Network data acquisition device theory diagram as shown in Figure 1 comprises the signal access unit, and signal conversion unit is isolated amplifying unit, embedded microcomputer and various gating signal and control signal.Wherein isolating amplifying unit is the reliable isolation that realizes signal conversion unit and amplifying circuit, disturbs with ride gain amplifying circuit and front end.Isolating amplifier circuit of the present invention can be simultaneously according to the size of signal in the application of isolating amplifying unit, and the gain of selected its amplifying circuit is promptly selected range, so be referred to as the programmable-gain isolating amplifier circuit automatically.
Programmable-gain isolating amplifier circuit of the present invention is characterized in that comprising isolated location U
1, Programmable Gain Amplifier Circuit.
Embodiment 1: the signal that signal conversion unit is sent is non-thermal resistance signal.
As shown in Figure 2, described isolated location U
1Comprise input B1, B2 and B3, conversion capacitor C 1 and C2, microelectronics digital switch group KC11, KC12, KC21 and KC22, gating signal GL, the control signal D0 of microelectronics digital switch, when isolated location U1 receives signal that signal conversion unit sends when being non-thermal resistance signal, insert by input B1 and the B2 of isolated location U1, and B2 and the input of B3 end no signal this moment.At this moment, embedded microcomputer is defeated by low level signal of control signal D0 of microelectronics digital switch, make KC11, KC12, KC21, KC22 all be combined in the left side, at this moment Zhuan Change capacitor C 1 and C2 are in receiving state signal, give high level signal of control signal D0 of microelectronics digital switch again, then KC11, KC12, KC21, KC22 all are combined in the right side, are about to signal and insert Programmable Gain Amplifier Circuit, amplify.KC11, KC12, KC21, KC22 and B1, B2 and B3 end is in off-state at this moment, promptly is in and the Programmable Gain Amplifier Circuit isolation, so be referred to as " isolating fully ".
Described Programmable Gain Amplifier Circuit comprises accurate integrated operational amplifier U2, programmable resistive network U3, gain measurement circuit U 4, described programmable resistive network U3 is by digital regulation resistance SD1, SD2 and SD3 form, this digital regulation resistance uses 8 digital regulation resistance, can produce 256 kinds of resistance values, than only adopting several resistance in the prior art, improve significantly, digital regulation resistance is accepted the amplification gating control from embedded microcomputer, promptly according to wanting amplifying signal to select suitable multiplication factor, also claim the programming gain controlling, the signal Vuot after the amplification exports to embedded microcomputer by accurate integrated operational amplifier U2.
Described gain measurement circuit U 4 comprises digital switch K1, K2, normal voltage Vb, and the control signal D1 of digital switch is used for surveying " gain at that time "." gain at that time " is when measuring, control signal D1 with the digital switch in the gain measurement circuit U 4 places low level earlier, make digital switch K1 closure, even the input end grounding of accurate integrated operational amplifier U2 (zero input), record gain measurement circuit U 4 output end voltage Vout0, control signal D1 with digital switch places high level again, digital switch K1 is disconnected, the K2 closure, gain measurement circuit U 4 input termination normal voltage Vb, measure gain measurement circuit U 4 output end voltage Voutb, then the actual gain of amplifying circuit is at that time:
K
At that time=(Voutb-Vout0)/Vb
Use K
At that timeAdjust amplifying signal, promptly eliminated the drift of amplifying circuit, improved the amplification precision of signal significantly.Work as K
At that timeWhen having surveyed, K1, K2 are disconnected, so that receive next signal.
Embodiment 2: the signal that signal conversion unit is sent is a thermal resistance signal.
As shown in Figure 3, when isolated location U1 receives signal that signal conversion unit sends when being thermal resistance signal, input B1 and B2 meet thermal resistance Rt, and B2 and B3 termination are gone into the lead-in wire of thermal resistance Rt, because during with the thermal resistance thermometric, deduct the pressure drop on the lead.The course of work during with the thermal resistance thermometric is: make microelectronics digital switch group KC11, KC12, KC21, KC22 all be combined in the left side, the electric Vc1 that conversion capacitor C 1 receives on the thermal resistance Rt
(on+, down-), conversion capacitor C 2 receives thermal resistance Rt lead-in wire voltage V
Lead-in wire (on+, down-), as microelectronics digital switch group KC11, KC12, KC21, when KC22 all is combined in the right side, upper end ground connection that will conversion capacitor C 2 terminates to C1 lower end, i.e. Vc1-V down
Lead-in wireLike this, just deducted the influence of thermal resistance Rt lead-in wire.
A kind of implementation method based on the programmable-gain isolating amplifier circuit, it is characterized in that: it comprises the steps:
1) gating U1, signal is by B1, B2 and the input of B3 end, in parallel with conversion capacitor C 1 and C2, at microelectronics numeral single-pole double-throw switch (SPDT) KC11, KC12, KC21 and KC22, under the control of the control signal D0 of gating signal GL and microelectronics digital switch, earlier with microelectronics numeral single-pole double-throw switch (SPDT) KC11, KC12, KC21 and KC22, be connected on left side receiving inputted signal, exist on conversion capacitor C 1 and the C2, again with microelectronics numeral single-pole double-throw switch (SPDT) KC11, KC12, KC21 and KC22 are connected on the right, input signal is given to the amplifying circuit amplification from conversion capacitor C 1 and C2, not input signal end " fully " isolation of amplifying circuit at this moment;
2) gain amplifier is measured at that time: in order to reduce the influence of variations in temperature to the amplifying circuit precision, promptly eliminate " drift ", before amplifying each signal, should the big circuit of first measuring gain amplifier at that time, promptly start U4, D1 is thrown low level, digital switch K1 is connected, disconnect digital switch K2, input amplifier ground connection (zero input) is measured output Vuot0 at that time; D1 is thrown high level, digital switch K1 is disconnected, digital switch K2 connects, and input amplifier inserts normal voltage Vb, measures output Voutb at that time.
Then the actual gain of amplifying circuit is at that time:
K
At that time=(Voutb-Vout0)/Vb
3) Programmable Gain Amplifier Circuit, comprise accurate integrated operational amplifier U2, programmable resistive network U3, programmable resistive network U3 is by digital regulation resistance SD1, SD2 and SD3 form, and this programmable resistive network U3 is to use 8 digital regulation resistance, can produce 256 kinds of resistance values, in order to change the gain of amplifying circuit, the resistance value of digital regulation resistance provides the programmable-gain control signal by external embedded microcomputer.
Claims (3)
1. a programmable-gain isolating amplifier circuit is characterized in that comprising isolated location U
1, Programmable Gain Amplifier Circuit,
Described isolated location U
1Comprise input B1, B2 and B3, conversion capacitor C 1 and C2, microelectronics numeral single-pole double-throw switch (SPDT) KC11, KC12, KC21 and KC22, gating signal GL, the control signal D0 of microelectronics digital switch,
Described Programmable Gain Amplifier Circuit comprises accurate integrated operational amplifier U2, programmable resistive network U3, gain measurement circuit U 4, described programmable resistive network U3 is by digital regulation resistance SD1, SD2 and SD3 form, described gain measurement circuit U 4 comprises digital switch K1, K2, normal voltage Vb, the control signal D1 of digital switch.
2. programmable-gain isolating amplifier circuit according to claim 1 is characterized in that described digital regulation resistance SD1, and SD2 and SD3 are 8 bit digital potentiometers.
3. implementation method based on the programmable-gain isolating amplifier circuit, it is characterized in that: it comprises the steps:
1) gating U1, signal is by B1, B2 and the input of B3 end, in parallel with conversion capacitor C 1 and C2, at microelectronics numeral single-pole double-throw switch (SPDT) KC11, KC12, KC21 and KC22, under the control of the control signal D0 of gating signal GL and microelectronics digital switch, earlier with microelectronics numeral single-pole double-throw switch (SPDT) KC11, KC12, KC21 and KC22, be connected on left side receiving inputted signal, exist on conversion capacitor C 1 and the C2, again with microelectronics numeral single-pole double-throw switch (SPDT) KC11, KC12, KC21 and KC22 are connected on the right, input signal is given to the amplifying circuit amplification from conversion capacitor C 1 and C2, not input signal end " fully " isolation of amplifying circuit at this moment;
2) gain amplifier is measured at that time: in order to reduce the influence of variations in temperature to the amplifying circuit precision, promptly eliminate " drift ", before amplifying each signal, should the big circuit of first measuring gain amplifier at that time, promptly start U4, D1 is thrown low level, digital switch K1 is connected, disconnect digital switch K2, input amplifier ground connection (zero input) is measured output Vuot0 at that time; D1 is thrown high level, digital switch K1 is disconnected, digital switch K2 connects, and input amplifier inserts normal voltage Vb, measures output Voutb at that time;
Then the actual gain of amplifying circuit is at that time:
K
At that time=(Voutb-Vout0)/Vb
3) Programmable Gain Amplifier Circuit, comprise accurate integrated operational amplifier U2, programmable resistive network U3, programmable resistive network U3 is by digital regulation resistance SD1, SD2 and SD3 form, and this programmable resistive network U3 is to use 8 digital regulation resistance, can produce 256 kinds of resistance values, in order to change the gain of amplifying circuit, the resistance value of digital regulation resistance provides the programmable-gain control signal by external embedded microcomputer.
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| CN201310128774.8A CN103219962B (en) | 2013-04-15 | 2013-04-15 | Programmable-gain isolating amplifier circuit and its implementation |
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| CN201310128774.8A CN103219962B (en) | 2013-04-15 | 2013-04-15 | Programmable-gain isolating amplifier circuit and its implementation |
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| CN103219962B CN103219962B (en) | 2016-03-30 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112445260A (en) * | 2020-11-25 | 2021-03-05 | 上海城建职业学院 | Automatic zero drift adjusting system and method |
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|---|---|---|---|---|
| CN1079345A (en) * | 1992-05-16 | 1993-12-08 | 丘雪明 | Capacity coupled isolated amplifier |
| CN1367629A (en) * | 2001-01-20 | 2002-09-04 | 三星电子株式会社 | Electric efficiency raising circuit of radio-frequency power amplifier in double-mode mobile telephone |
| US20080061872A1 (en) * | 2006-09-07 | 2008-03-13 | National Semiconductor Corporation | Gain Adjustment for Programmable Gain Amplifiers |
| EP2197109A1 (en) * | 2008-12-15 | 2010-06-16 | STMicroelectronics Srl | Integrated programmable gain amplifier circuit and system including said circuit |
| CN103018530A (en) * | 2012-12-06 | 2013-04-03 | 杭州成功超声电源技术有限公司 | Ultrasonic power supply current detection circuit |
| CN203243287U (en) * | 2013-04-15 | 2013-10-16 | 鞍钢集团矿业公司 | Programmable gain isolation amplifying circuit |
-
2013
- 2013-04-15 CN CN201310128774.8A patent/CN103219962B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1079345A (en) * | 1992-05-16 | 1993-12-08 | 丘雪明 | Capacity coupled isolated amplifier |
| CN1367629A (en) * | 2001-01-20 | 2002-09-04 | 三星电子株式会社 | Electric efficiency raising circuit of radio-frequency power amplifier in double-mode mobile telephone |
| US20080061872A1 (en) * | 2006-09-07 | 2008-03-13 | National Semiconductor Corporation | Gain Adjustment for Programmable Gain Amplifiers |
| EP2197109A1 (en) * | 2008-12-15 | 2010-06-16 | STMicroelectronics Srl | Integrated programmable gain amplifier circuit and system including said circuit |
| CN103018530A (en) * | 2012-12-06 | 2013-04-03 | 杭州成功超声电源技术有限公司 | Ultrasonic power supply current detection circuit |
| CN203243287U (en) * | 2013-04-15 | 2013-10-16 | 鞍钢集团矿业公司 | Programmable gain isolation amplifying circuit |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112445260A (en) * | 2020-11-25 | 2021-03-05 | 上海城建职业学院 | Automatic zero drift adjusting system and method |
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Address after: 114001 Anshan District, Liaoning, No. 219 Road, No. 39, Tiedong Patentee after: Anshan Iron and Steel Group Mining Co., Ltd. Address before: 114001 Anshan District, Liaoning, No. 219 Road, No. 39, Tiedong Patentee before: Anshan Iron & Steel Group Mining Co., Ltd. |