Switched capacitors for galvanic isolation and amplification of analog signals by means of a transmitted differential voltage signal

Abstract

Integrated circuits and methods for providing operational coupling comprising an input stage and an output stage between an analog input and an analog output; synchronously operating a plurality of high-voltage range switches of the input stage and a plurality of low-voltage range switches of the output stage at a frequency to galvanically isolate the input stage from the output stage via a plurality of capacitors having a plurality of input plates, each connected to the switches of the input and output stages; supplying an analog output signal to the input stage; transferring a differential voltage signal component within a range of a common-mode voltage supply from the high-voltage range of the input stage to the low-voltage range of the output stage; differentially amplifying the low-voltage range differential voltage signal component;and outputting an analog output signal.;

Description

[0001] This application claims priority over the preliminary US patent application No. 63 / 469,843, filed on May 31, 2023, the contents of which are hereby incorporated in full. TECHNICAL AREA

[0002] The present disclosure relates to the separation and detection of analog signals, in particular to switched capacitors for galvanic isolation and amplification of analog signals by means of transmitted differential voltage signals. BACKGROUND

[0003] Many electrical measurements are performed on systems that cannot be electrically connected to the measuring system via direct wiring. Devices are used that isolate the input signal from the output signal by employing one of several methods to pass electronic signals through an isolation barrier.

[0004] An isolation amplifier is an amplifier that is galvanically isolated between its input and output circuitry, including their associated power supplies. Earlier devices called isolation amplifiers featured a complex, separate power supply to power the isolation side of the circuit. Isolation amplifiers typically have a separate, bulky, and expensive power supply for their isolated input state. There are devices where the input power supply is integrated into a single assembly with the amplifier. However, the power circuitry remains complex and expensive because the isolation is achieved via a digital barrier, which involves complex modulation and demodulation, as well as an isolating power supply.These systems can convert the input analog signal into a digital signal and then convert the signal back into an analog signal via analog-to-digital converters (ADCs) and digital-to-analog converters (DACs) driven by transformers. Alternatively, optical isolation products use optocouplers to couple analog signals directly, so they are not converted into a digital signal. However, optical isolation products may not provide desirable characteristics for offset, linearity, and drift.

[0005] There is a need for integrated circuits and methods for isolating an input analog signal from an output analog signal in isolation amplifiers of electrical measurement systems. SUMMARY OF THE INVENTION

[0006] In accordance with certain aspects, integrated circuits and methods for switching capacitors are provided to galvanically isolate and amplify analog signals using transmitted differential voltage signal components. Isolation amplification can be provided for an analog signal without analog-to-digital conversion and without a separate power supply for the isolation side of the circuit. An isolation amplifier can include an output stage with an integrated power supply.

[0007] Aspects provide a method that features: providing an operational coupling comprising an input stage and an output stage between an analog input and an analog output; synchronously operating a plurality of high-voltage range switches of the input stage and a plurality of low-voltage range switches of the output stage at a frequency to galvanically isolate the input stage from the output stage via a plurality of input plates, each connected to the plurality of switches of the input stage, and a plurality of output plates, each connected to the plurality of switches of the output stage; supplying an analog input signal to the input stage; and transferring a differential voltage signal component within a range of a common-mode voltage supply from the high-voltage range of the input stage to the low-voltage range of the output stage.Differential amplification of the low-voltage differential voltage signal component; and output of an analog output signal.

[0008] According to one aspect, a procedure of the preceding paragraph is provided, wherein the frequency is greater than or equal to 100 MHz.

[0009] According to one aspect, a procedure according to one of the two preceding paragraphs is provided, wherein the common-mode voltage signal component is + / -1000 volts.

[0010] According to one aspect, a method according to one of the preceding three paragraphs is provided, wherein the common-mode voltage signal component is + / -100 volts, and wherein the range of a common-mode voltage signal component is + / -100 volts.

[0011] According to one aspect, a method according to one of the preceding four paragraphs is provided, wherein the plurality of high-voltage range switches of the input stage and a plurality of low-voltage range switches of the output stage are operated synchronously, such that each of the plurality of switches is the common-mode voltage when it is off, and at least three volts lower than the common-mode voltage when it is on.

[0012] According to one aspect, a procedure according to one of the preceding five paragraphs is provided, wherein the analog input signal has a voltage.

[0013] According to one aspect, a procedure according to one of the preceding six paragraphs is provided, wherein the output signal is relative to a reference signal, with positive and negative output signals indicating the current direction.

[0014] According to one aspect, a monolithic integrated circuit is provided which has: input terminals for receiving an analog input signal; an operational coupling which has: an input stage coupled to the input terminals and comprising a plurality of high-voltage range switches; an output stage comprising a plurality of low-voltage range switches and a common-mode voltage source; a galvanic isolation barrier between the input stage and the output stage comprising: a plurality of capacitors comprising a plurality of input plates, each connected to the plurality of high-voltage range switches, and a plurality of output plates, each connected to the plurality of low-voltage range switches;and a controller to operate the plurality of input switches and the plurality of output switches synchronously at a frequency in order to charge each of the plurality of capacitors to a voltage; wherein the operational coupling serves to transfer a differential voltage signal component from a high-voltage range to a low-voltage range; a differential amplification circuit is coupled to the output stage of the operational coupling; and output terminals are coupled to the differential amplification circuit to output an analog output signal.

[0015] According to one aspect, a monolithic integrated circuit of the preceding paragraph is provided, wherein the controller is to operate the plurality of high-voltage range switches of the input stage and a plurality of low-voltage switches of the output stage synchronously, such that each of the plurality of switches is the common-mode voltage when it is OFF, and at least three volts lower than the common-mode voltage when it is ON.

[0016] One aspect provides a monolithic integrated circuit comprising: input terminals for receiving an analog input signal; an operational coupling comprising: an input stage coupled to the input terminals and comprising a plurality of high-voltage range switches; an output stage comprising a plurality of low-voltage range switches and a common-mode voltage source; a galvanic isolation barrier between the input stage and the output stage comprising: a plurality of capacitors comprising a plurality of input plates, each connected to the plurality of high-voltage range switches, and a plurality of output plates, each connected to the plurality of low-voltage range switches;and a controller for synchronously operating the plurality of input switches and the plurality of output switches at a frequency to galvanically isolate the input stage from the output stage and to transfer a differential voltage signal component within a range of a common-mode voltage supply from the high-voltage range to the low-voltage range; a differential amplification circuit coupled to the output stage of the operational coupling; and output terminals coupled to the differential amplification circuit to output an analog signal.

[0017] According to one aspect, a monolithic integrated circuit is provided in accordance with the preceding paragraph, where the frequency is greater than or equal to 100 MHz.

[0018] According to one aspect, a monolithic integrated circuit is provided according to one of the two preceding paragraphs, where the common-mode voltage signal component is + / -1000 volts.

[0019] According to one aspect, a monolithic integrated circuit is provided according to one of the preceding three paragraphs, wherein the common-mode voltage signal component is + / -100 volts, and wherein the range of a common-mode voltage signal component is + / -100 volts.

[0020] According to one aspect, a monolithic integrated circuit of the preceding paragraph is provided, wherein the controller for synchronous operation of the plurality of high-voltage range switches and the plurality of low-voltage range switches each has one of the switches which, in the OFF state, is the common-mode voltage and, in the ON state, is at least three volts lower than the common-mode voltage.

[0021] According to one aspect, a monolithic integrated circuit is provided according to one of the preceding five paragraphs, wherein the output signal is relative to a reference signal, with positive and negative output signals indicating the current direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The figures illustrate examples of methods and integrated circuits for switching capacitors to galvanically isolate and amplify analog signals using transmitted differential voltage signal components. These methods and integrated circuits can be used to isolate and amplify an analog signal without analog-to-digital conversion and without supplying separate power to an isolation side of the circuit. Fig. Figure 1 is a schematic representation of a device 100 for amplifying differential voltage signal components of a voltage across a resistor. Fig. Figure 2 is a schematic representation of an operational coupling. Fig. Figure 3 is a schematic diagram representing a differential amplification circuit. Fig. Figure 4 shows a schematic representation of an isolation amplifier circuit, which has an operational coupling with an input stage and an output stage as well as a differential amplification circuit. Fig. Figure 5 shows an enlarged view of the in Fig. 4 shown operational coupling with an input stage and an output stage. Fig. Figure 6 shows a schematic representation of a high-voltage level shifter. Fig. 7A-7F show schematic representations of the in Fig. 6 high-voltage level shifters shown, where generated clock signals drive the input switches at their relative common-mode clocks. Fig. Figure 8 shows a graph of the voltage over time, indicating that the switched capacitors provide isolation, transferring a differential voltage into a low-voltage area (while the differential value is conserved). Fig. Figure 9 shows a flowchart of a method for switching capacitors to galvanically isolate and amplify analog signals using transmitted differential voltage signal components. The reference signs for each illustrated element that appears in several different figures have the same meaning in all figures, and the mention or discussion of an illustrated element in connection with one particular figure also applies to any other figure in which the same illustrated element is shown. DESCRIPTION

[0023] According to one aspect, a circuit for separate analog sampling is provided that requires no additional power supply on the isolation side of the circuit. The circuit can include a switched capacitor input to provide galvanic isolation of analog signals without supplying separate power to the isolation side. A circuit that can be provided as an integrated circuit can provide accurate and economical shunt current measurement for high-voltage systems, e.g., up to an isolation of ±1000 volts. The integrated circuit can be a monolithic galvanic isolation amplifier with ±1000 volts common-mode capability (CMC), used in current measurement and industrial metrology. A monolithic integrated circuit is a complete circuit or group of circuits fabricated on a single piece of silicon.The monolithic galvanic isolation amplifier can be self-contained, as the isolation side of the circuit does not require a power supply. The galvanic isolation can provide a DC isolation barrier, while the desired signal passes across this barrier. This provides an open circuit for direct current (DC) and a low-impedance path for alternating current (AC), with level shifting for the signal provided by passive elements (capacitors). The input terminals must not have a direct electrical connection to the output terminals. In particular, a monolithic galvanic isolation amplifier can have input terminals that have no direct electrical connection to the output terminals, allowing a signal to be transferred from the input terminals to the output terminals via switched capacitors.Even if the connection is indirect, through a passive device such as a capacitor, the output terminals are separate from the input terminals, while a differential voltage signal component is transferred from the input terminals to the output terminals.

[0024] The circuit achieves separation through isolation barriers, which occur naturally in capacitors on monolithic integrated circuits.

[0025] The US patent application with publication number 2022 / 0376666, published on November 24, 2022, is incorporated herein by reference in its entirety and for all purposes.

[0026] Fig. Figure 1 is a schematic diagram showing a device 100 for amplifying differential voltage signal components of a voltage across a resistor. An amplified differential voltage signal component can be used in a differential current sensing topology.

[0027] The device 100 includes a resistor 102, a differential amplification circuit 104, and an operational coupling 106. The differential amplification circuit 104 and the resistor 102 are coupled to amplify a differential voltage signal component 108 of a voltage across the resistor 102 (voltage ΔV). The voltage across the resistor 102 is the difference between a voltage at a first end of the resistor 102 (voltage V1) and a voltage at a second end of the resistor 102 (voltage V2). The voltages V1 and V2 can each include a common-mode voltage signal component 112, e.g., a common-mode voltage (CFM).

[0028] The operational coupling 106 is located between resistor 102 and the differential amplification circuit 104 to allow the differential voltage signal component 108 to pass through and to isolate the common-mode voltage signal component 112 from the voltage ΔV across resistor 102. More precisely, the operational coupling 106 operates by providing V1-VCM at a first input terminal of the differential amplification circuit 104 and V2-VCM at a second input terminal of the differential amplification circuit 104. Optionally, the operational coupling 106 can operate by providing a controlled common-mode voltage (VCCM) at the first and second input terminals of the differential amplification circuit 104 along with the voltages V2-VCM and V1-VCM, as described below.

[0029] In one or more examples, the operational coupling 106 operates such that it passes the differential voltage signal component 108 and separates the common-mode voltage signal component 112 of the voltage ΔV over several integration and transfer phases, which are performed at least partially dependent on a control signal (control signal not shown). The differential amplification circuit 104 amplifies the differential voltage signal component 108 to generate the amplified differential voltage signal component 110.

[0030] Fig. Figure 2 is a schematic representation of an operational coupling 200 according to one or more examples. The operational coupling 200 is a non-restrictive example of the operational coupling 106 from Fig. 1.

[0031] Capacitors can be used for charge transfer because they are passive devices and therefore do not require a constant current to function. Furthermore, the operational coupling 200 does not use current to bias the circuit. Consequently, dq / dt (change in charge / change in time) across the operational coupling 200 can be smaller than with typical amplifier inputs and topologies.

[0032] The operational coupling 200 can include a first pair of capacitors 204, a second pair of capacitors 206, a controlled common-mode voltage source 208, first switches 214, second switches 216 and a controller 250. Fig. Figure 2 shows an optional resistor 202 for illustration, its outline represented by a dashed line. The operational coupling 200 has an input stage 220, which is separated from an output stage 230 by the first and second pairs of capacitors 204 and 206. The first and second pairs of capacitors 204 and 206 can provide a galvanic isolation barrier. The input stage 220 includes the second switches 216, which are high-voltage range switches. The output stage 230 includes the first switches 214, which are low-voltage range switches.

[0033] The first pair of capacitors 204 is switchably coupled between a negative input terminal of a differential amplification circuit and resistor 202, where the negative input terminal can also be referred to as the "first input terminal". The second pair of capacitors 206 is switchably coupled between a positive input terminal of the differential amplification circuit and resistor 202, where the positive input terminal can also be referred to as the "second input terminal".Each first switch 214 couples a respective lower plate of the first pair of capacitors 204 to the negative input terminal of a differential amplifier circuit or a positive output of a controlled common-mode voltage source 208 at a node 218, and couples the respective lower plate of the second pair of capacitors 206 to the positive input terminal of the differential amplifier circuit or the positive output of the controlled common-mode voltage source 208 at a node 218. The return path of the common-mode voltage source 208 is coupled to a common potential, illustrated as ground, without restriction. Corresponding second switches 216 each couple an upper plate of the first and second pairs of capacitors 204 and 206 to a first end 210 of resistor 202 or a second end 212 of resistor 202.Examples of switches include devices made of silicon carbide (SiC) and separate-gate bipolar transistors (IGBT).

[0034] The controlled common-mode voltage source 208 provides a controlled common-mode voltage (VCCM) for node 218. Node 218 is switchably coupled to the respective lower plates of the first pair of capacitors 204 and the second pair of capacitors 206 via the respective first switches 214.

[0035] When one or more capacitors of the first pair of capacitors 204 and the second pair of capacitors 206 are in an integration phase, they integrate the voltage VCCM together with the differential voltage signal component and transmit the differential voltage signal component and VCCM together during a transmission phase, as described below. Any voltage source that reliably provides a controlled level can be used as the controlled common-mode voltage source 208.

[0036] A controller 250 can control the switches 214 and 216, the node 218 and the common-mode voltage source 208.

[0037] The first switches 214 and the second switches 216 receive and operate depending on control signals (control signal not shown) from the control unit 250, which selectively switches the respective first switches 214 and second switches 216 on or off. When the respective switches of the first switch 214 and the second switch 216 are on, they transmit current, and when they are off, they transmit no current or only a negligible current.

[0038] When the first switches 214 and the second switches 216 are alternately switched on and off in a specific manner, the respective capacitors of the first pair of capacitors 204 and the second pair of capacitors 206 switch between integration and transmission in a complementary and commutative manner. When the first pair of capacitors 204 and the second pair of capacitors 206 alternate between integration and transmission at a sufficiently high frequency (e.g., essentially 100 megahertz (MHz) or higher, without limitation), an output signal is generated and continuously applied to the positive and negative input terminals of a differential amplification circuit—that is, the output signal of the operational coupling 200 maintains fidelity to the positive and negative input terminals of the differential amplification circuit.

[0039] As in Fig. As shown in Figure 1, the amplitude of the output signal of the operational coupling 106 is generally proportional to the voltage level of the differential voltage signal component. In one example, the amplitude of the output signal 108 of the operational coupling 106 can be twice the amplitude of the voltage level across resistor 102. Referring to Fig. 2. The first pair of capacitors 204 and the second pair of capacitors 206 can be alternated between integration and transmission at a frequency high enough to charge one set of capacitors and also high enough to pass the charge of the alternating set to the input. The fidelity can be improved if the first switches 214 and the second switches 216 operate at higher frequencies, so that the first pair of capacitors 204 and the second pair of capacitors 206 alternate at these higher frequencies.

[0040] In one or more examples, the operative coupling 200 operates as an alternating current (AC) voltage short circuit and as a direct current (DC) voltage isolator in response to the operation of the first pair of capacitors 204 and the second pair of capacitors 206 in a specific manner. The common-mode voltage is a DC voltage and does not change (or only insignificantly) in the absence of external influences, and there is no common-mode AC voltage that could be stored across the capacitor; therefore, the common-mode voltage is not passed as an input voltage, thus providing DC isolation.

[0041] Fig. Figure 3 is a diagram illustrating a differential amplification circuit 300 according to one or more examples. The differential amplification circuit 300 is a non-restrictive example of the differential amplification circuit 104 from Fig. 1.

[0042] The differential amplification circuit 300 comprises a first differential amplifier 302, a second differential amplifier 304, and a third differential amplifier 306. The respective positive input terminals of the first differential amplifier 302 and the second differential amplifier 304 can be coupled to the respective first (positive) and second (negative) input terminals of the operational coupling 106 or the operational coupling 200 (see Fig. 2) The respective negative input terminals of the first and second differential amplifiers 302 and 304 are coupled to the internal nodes of the respective resistive voltage divider circuits (comprising resistors R6 / R7 for the first differential amplifier 302 and R8 / R9 for the second differential amplifier 304), which are each connected between ground or another common potential and the respective outputs of the first differential amplifier 302 and the second differential amplifier 304. The use of the resistive voltage divider circuits is optional, to divide the gain and increase the speed for the first differential amplifier 302 and the second differential amplifier 304.An output of the first differential amplifier 302 is coupled via resistor R2 to a positive input terminal of the third differential amplifier 306, and an output of the second differential amplifier 304 is coupled via resistor R3 to a negative input terminal of the third differential amplifier 306. The positive input terminal of the third differential amplifier 306 is further coupled to provide a base voltage via resistor R4. This base voltage can be used to set the output voltage to which positive or negative differential signal fluctuations are referenced (above or below). The negative input terminal of the third differential amplifier 306 is further coupled via resistor R5 to an output terminal of the differential amplification circuit 300, which in turn is coupled to the output of the third differential amplifier 306.The number of resistors used in the differential amplification circuit 300 is exemplary and does not limit the scope of the disclosure in any way.

[0043] Fig. Figure 4 shows a circuit diagram of an isolation amplifier circuit 400 for a monolithic integrated circuit. The isolation amplifier circuit 400 has an operational coupling 410 and a differential amplification circuit 440. The operational coupling 410 has an input stage 420, which is separated from an output stage 430 by capacitors. The isolation amplifier circuit 400 can be used for current measurement, where small input signals produce high gain. The circuit of the isolation amplifier 400 can also be used as an isolation amplifier, where large input signals produce low gain.

[0044] The isolation amplifier circuit 400 has input terminals at node 1 and node 2 for inputting an analog signal. The analog signal can be from V SUPPLY and LOAD are supplied, which are connected by a resistor R1, with node 1 between V SUPPLY and a first terminal of the resistor R1, and node 2 lies between a second terminal of the resistor R1 and LOAD.

[0045] The isolation amplifier circuit 400 can use the base voltage PEDESTAL as a reference to positive or negative differential signal fluctuations to adjust the output voltage VOUT. The differential amplifier circuit 440 can include three differential amplifiers 442, 444, and 446. The respective positive input terminals of the first differential amplifier 442 and the second differential amplifier 444 can be coupled to the respective first (positive) and second (negative) output terminals of the operational coupling 410 at node 3 and node 4, respectively.The respective negative input terminals of the first and second differential amplifiers 442 and 444 are coupled to the internal nodes of their respective resistive voltage divider circuits (comprising resistors R6 / R7 for the first differential amplifier 442 and R8 / R7 for the second differential amplifier 444, with resistor R7 being shared by both the first and second differential amplifiers 444). An output of the first differential amplifier 442 is coupled via resistor R2 to a positive input terminal of the third differential amplifier 446, and an output of the second differential amplifier 444 is coupled via resistor R3 to a negative input terminal of the third differential amplifier 446. The positive input terminal of the third differential amplifier 446 is further coupled via resistor R4 to a base voltage.

[0046] The in Fig. The isolation amplifier circuit 400 shown detects the current represented by the voltage drop across resistor R1 while it is between V SUPPLY and LOAD flows. The common-mode voltage (VCM) is the voltage of V SUPPLY , which can satisfy the load, and the amount of current flowing through resistor R1 can be determined by the voltage drop across resistor R1, which is in relation to the voltage of V SUPPLY It may be small.

[0047] Whether the current from V SUPPLY to LOAD or from LOAD to V SUPPLYThe flow of current can be determined by whether the voltage at VOUT is above or below the voltage at PEDESTAL. If the voltage between node 3 and node 4 of the first and second differential amplifiers 442 and 444 has a negative differential value (negative voltage between node 3 and node 4), then the voltage VOUT is higher than the voltage at PEDESTAL. If the difference between node 3 and node 4 of the first and second differential amplifiers 442 and 444 is positive (node ​​3 - node 4 = positive voltage), then the voltage VOUT is lower than the voltage at PEDESTAL. The isolation amplifier circuit 400 is bidirectional. The isolation amplifier circuit 400 detects whether the voltage VOUT is above or below the reference voltage, called PEDESTAL, by detecting positive and negative differences at these nodes (node ​​3 - node 4) when the input signal (current) flows in both directions.The circuitry of the 400 isolation amplifier provides this bidirectional detection due to the amplifier's design. If the VOUT voltage is higher than the PEDESTAL voltage, it is detected that the current is from V. SUPPLY to LOAD. If the VOUT voltage is below the PEDESTAL voltage, it is determined that the current flows from LOAD to V. SUPPLY flows.

[0048] Fig. Figure 4 shows that the operational coupling 410 has an input stage 420, which is separated from an output stage 430 by capacitors. The input stage 420 may have an integrated power supply via the common-mode voltage source VCM 408 through high-voltage capacitors to provide a separate high-voltage supply. A data or power converter may be absent. The separation may be inherent, reducing manufacturing costs, providing a smaller solution, and operating more efficiently. The input stage 420 may be a set of high-voltage range switches. The output stage 430 may be a set of low-voltage range switches. The circuit assumes that power is supplied to drive the differential amplifiers 442, 444, and 446. The same power supply for the differential amplifiers 442, 444, and 446 may be used to generate a VCM reference voltage via the common-mode voltage source 408.SUPPLY It is not used to drive or power a circuit for sending the signal, but merely provides a passive feed to the load via nodes 1 and 2. The common-mode voltage source 408 does not deliver any actual power, but only serves to replace the (very small) signal power lost or gained in every other cycle. The common-mode voltage source 408 serves to define the reference value by which the signal either rises above or falls below in every other cycle, depending on the input differential signal at nodes 1 and 2.

[0049] A controller 450 can control the high-voltage range switch of the input stage 420 and the low-voltage range switch of the output stage 430, and adjust the level of the common-mode voltage source 408. A high-voltage capacitor can be used as a level shifter to isolate the control signal for the high-voltage range switch of the input stage 420 from the control signal for the low-voltage range switch of the output stage 430.

[0050] Fig. Figure 5 shows an enlarged view of the in Fig. The operational coupling 410 shown in Figure 4 comprises four capacitors 412, 414, 416, and 418, an input stage 420 with a set of high-voltage range switches, and an output stage 430 with a set of low-voltage range switches. The switches of the input and output stages 420 and 430 can be for two different voltage ranges that are synchronized and operate at a specific frequency, e.g., 100 megahertz (MHz) or higher, without limitation. In some aspects, the switches can operate at lower sampling frequencies to achieve, for example, a smaller offset (longer charging time, larger capacitors are used). Simplification is possible if only one type of transmission gate is used for the switches, e.g., PMOS, but they can also be different. The switches of the input stage 420 can control the voltage range. SUPPLY -Voltage (OFF) and V SUPPLY-voltage (ON) can be reached. The high-voltage range switches of the input stage 420 and the low-voltage range switches of the output stage 430 can be operated synchronously, so that a switch in the OFF state has the same voltage as the common-mode voltage source 408 and in the ON state at least three volts less than the common-mode voltage source 408. The gate voltage source (VSG) of a positive-channel metal-oxide-semiconductor (PMOS) device can V SUPPLY = OFF and V SUPPLY -3V = ON. In other words: The switch is OFF and the switch is ON.

[0051] Fig. Figure 5 shows that the input stage 420 includes the high-voltage range switches 422H, 422S, 424S, 424H, 426S, 426H, 428H, and 428S. The output stage 430 includes the low-voltage range switches 432S, 432H, 434H, 434S, 436H, 436S, 438S, and 438H. One end of the high-voltage range switches 422H, 424S, 426S, and 428H is connected in parallel to node 1. One end of the high-voltage range switches 422S, 424H, 426H, and 428S is connected in parallel to node 2. The first end of the low-voltage circuit breakers 432S, 434H, 436H, and 438S is connected in parallel to the positive output of the common-mode voltage source 408, i.e., the voltage VCM. The first end of the low-voltage circuit breakers 432H and 434S is connected in parallel to node 3. The first end of the low-voltage circuit breakers 436S and 438H is connected in parallel to node 4.A second end of the high-voltage range switches 422H and 422S is connected to a first plate of capacitor 412, and a second end of the low-voltage range switches 432S and 432H is connected to a second plate of capacitor 412. A second end of the high-voltage range switches 424S and 424H is connected to a first plate of capacitor 414, and a second end of the low-voltage range switches 434H and 434S is connected to a second plate of capacitor 414. A second end of the high-voltage range switches 426S and 426H is connected to a first plate of capacitor 416, and a second end of the low-voltage range switches 436H and 436S is connected to a second plate of capacitor 416.A second end of the high-voltage range switches 428H and 428S is connected to a first plate of the capacitor 418, and a second end of the low-voltage range switches 438S and 438H is connected to a second plate of the capacitor 418.

[0052] The isolation provided by the operational coupling 410 can be galvanic via the capacitors 412, 414, 416, and 418. The topology of the operational coupling 410 can transfer a differential voltage signal component, fluctuating within a common-mode voltage source 408, to a low-voltage range, with the transfer occurring via capacitor coupling. For example, a component with a voltage of ±1000 V can be transferred to ±500 V, ±100 V, or any voltage below ±1000 V without restriction. The low-voltage range switches 432S, 432H, 434S, 436H, 436S, 438S, and 438H can be controlled, and the amplifier input side of the capacitors can be driven by low-voltage inverters to pump or pull voltage to drive input gates. The capacitors for level shifting (see Fig. 6) can be charged by low-voltage inverters (not shown) that pump or pull the voltage to drive the high-voltage range switches 422S, 422H, 424H, 424S, 426H, 426S, 428S, and 428H. Specifically, the input switches 422H, 422S, 424S, 424H, 426S, 426H, 428H, and 428S are low-voltage switches set to a high voltage. The output switches 432H, 432S, 434S, 434H, 436S, 436H, 438H, and 438S are low-voltage switches located at a low voltage and separated by 412, 414, 416, and 418 HV capacitors.

[0053] The high-voltage capacitors provide galvanic isolation. This isolation can be achieved in the analog signal path without analog-to-digital conversion on the input side or additional digital-to-analog conversion on the output side of the isolation circuit. Since no separate power supply is provided, transformers are not required as part of the circuit. In contrast, earlier circuits used a separate power supply, which is why transformers were part of those earlier circuits. With high-voltage capacitors in the analog signal path for isolation, the signal can remain analog from input to output.

[0054] Fig. Figure 6 shows a schematic diagram of a high-voltage level shifter 600, which has a very low signal propagation delay. The switches in the input stage 420 and the output stage 430 can be located in two different voltage ranges and can be synchronized by operating at a frequency of, for example, 100 MHz (see Figure 6). Fig. 5) The high-voltage range switches 422H, 422S, 424S, 424H, 426S, 426H, 428H and 428S of the input stage 420 can handle the voltage V SUPPLY (OFF) and V SUPPLY - Reach 3V (ON). The one in Fig. The six high-voltage level shifters shown can provide a fast, isolating, charge-pumping level shift so that the input stage switches 420 can reach (OFF) and (ON). The level shift can be achieved by pumping the values ​​to common-mode CM 602 or (CM-3V) (3 VGS terminal) via capacitors 606A and 606B. Depending on the aspect, a type of transmission gate (PMOS) can be used; for example, transistors 604A-604H can be PMOS transistors.

[0055] With reference to Fig. 7A-7F are schematic block diagrams of the in Fig. The 6 high-voltage level shifters shown are represented, with generated clock signals driving the input switches at their relative reference points. Fig. 7A shows that a 60V common-mode, S in 57V is and H in 60V is provided, H is 0V and S is 5V. Fig. 7B shows that a 60V common mode, S in is 60V and H inH provides 57V, H is 5V and S is 0V. Fig. 7C shows that a 0V common phase, S in is -3V, and H in H is 0V, H is 0V and S provides 5V. Fig. 7D shows that a 0V common mode, S in is 0V, and H in is -3V, H is 5V and S is 0V. Fig. 7E shows that a -60V common mode, S in is -63V, and H in is -60V, H is 0V and S provides 5V. Fig. 7F shows that a -60V common mode, S in is -60V, and H in is -63 V, H is 5 V and S is 0 V.

[0056] Fig. Figure 8 shows a graph of the input and output voltages over time, illustrating the waveform of the control signals used to drive the switches of an operational coupling. The graph shows that: the high-voltage capacitors provide isolation; the capacitors provide near-instantaneous voltage transfer (they transfer only the differential voltage signal component); and the capacitors provide negative and positive transfer (i.e., the transfer is bidirectional—the isolation amplifier circuit detects whether the output voltage is above or below the reference common-mode voltage (VCM)). Fig. Figure 8 shows two examples of common-mode voltages, one at 60V and the other at 0V. Waveform 802 is a constant clock from 0V to 5V. Waveform 804 is the result of the level shift, showing the signal generated to control the input switches in their respective common-mode modes. At a common-mode voltage of 60V, the ON switch would be at 57V and the OFF switch at 60V. At a common-mode voltage of 0V, the ON switch would be at -3V and the OFF switch at 0V.

[0057] A monolithic integrated circuit can be smaller because it contains fewer external components and occupies less board space. The device can have lower power dissipation in a shunt, where the shunt can create a voltage drop when current flows to the load. The device can have lower IC power consumption and include a low-power shutdown pin. The device can be more accurate and cost less than isolation amplifiers that provide a feed to the isolation side of the circuit, convert analog signals to digital signals, or use optocouplers to directly couple analog signals. The device can provide high-voltage shunt current measurement, e.g., ±1000 volts, which includes a bipolar common-mode voltage (CMV) measurement. The device can provide measurement with galvanic isolation from measuring instruments. The device can break ground loops.The device can be used in high-voltage systems, such as those found in electric vehicles and solar cell fields. It can also be used for industrial testing and measurement purposes where separate measurement is often a design parameter.

[0058] Fig.Figure 9 shows a flowchart of a method for switching capacitors to galvanically isolate and amplify analog signals using transmitted differential voltage signal components. The method can provide isolation amplification of an analog signal without analog-to-digital conversion and without supplying separate power to a remote side or input stage of a circuit. An operational coupling is provided in Figure 902, which includes an input stage and an output stage between an analog input and an analog output.A plurality of high-voltage range switches of the input stage and a plurality of low-voltage range switches of the output stage are operated synchronously at a frequency 904 to galvanically isolate the input stage from the output stage via a plurality of capacitors, which have a plurality of input plates, each connected to the plurality of switches of the input stage, and a plurality of output plates, each connected to the plurality of switches of the output stage. An analog input signal is fed to the input stage 906. A differential voltage signal component within a range (e.g., + / - 1000 V) of a common-mode voltage signal component is transferred from the high-voltage range of the input stage to the low-voltage range of the output stage 908. The low-voltage range differential voltage signal component is differentially amplified 910. An analog output signal is output 912.

[0059] Although the examples above include a description, other variations and examples may be derived from this revelation without deviating from the spirit and scope of protection of these disclosed examples. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] US 63 / 469,843

[0001] US 2022 / 0376666

[0025]

Claims

[1] Method which features: Providing an operational coupling that includes an input stage and an output stage between an analog input and an analog output; synchronous operation of a plurality of high-voltage range switches of the input stage and a plurality of low-voltage range switches of the output stage at a frequency for galvanic isolation of the input stage from the output stage via a plurality of capacitors having a plurality of input plates, each connected to the plurality of switches of the input stage, and a plurality of output plates, each connected to the plurality of switches of the output stage; Feeding an analog input signal to the input stage; Transferring a differential voltage signal component within a range of a common-mode voltage signal component from the high-voltage range of the input stage to the low-voltage range of the output stage; Differential amplification of the low-voltage differential voltage signal component; and Outputting an analog output signal. [2] Method according to claim 1, wherein the frequency is greater than or equal to 100 MHz. [3] Method according to claim 1 or claim 2, wherein the common-mode voltage signal component is + / -1000 volts. [4] Method according to any one of claims 1 to 3, wherein the common-mode voltage signal component is + / -100 volts, wherein the range of a common-mode voltage signal component is + / -100 volts. [5] Method according to any one of claims 1 to 4, wherein the plurality of high-voltage range switches of the input stage and a plurality of low-voltage range switches of the output stage are operated synchronously, such that each of the plurality of switches has the common-mode voltage when switched off and is at least three volts lower than the common-mode voltage when switched on. [6] Method according to any one of claims 1 to 5, wherein the analog input signal has a voltage. [7] Method according to any one of claims 1 to 6, wherein the output signal is relative to a reference signal, wherein positive and negative output signals indicate the current direction. [8] Monolithic integrated circuit which features: Input terminals for receiving an analog input signal; an operational coupling that exhibits: an input stage coupled to the input terminals and featuring a variety of high-voltage range switches; an output stage comprising a variety of low-voltage range switches and a common-mode voltage source; a multitude of capacitors, each having a multitude of input plates, each connected to a multitude of high-voltage range switches, and a multitude of output plates, each connected to a multitude of low-voltage range switches; and a controller to operate the multitude of input switches and the multitude of output switches synchronously at a frequency in order to charge one of the multitude of capacitors at a time; where the operational coupling serves to create a To transfer the differential voltage signal component from a high-voltage area to a low-voltage area; a differential amplification circuit coupled to the output stage of the operational coupling to amplify the transmitted differential voltage signal component; and Output terminals that are coupled to the differential amplification circuit to output an analog output signal. [9] Monolithic integrated circuit according to claim 8, wherein the controller synchronously actuates the plurality of high-voltage range switches of the input stage and a plurality of low-voltage range switches of the output stage, such that each of the plurality of switches has the common-mode voltage when off and is at least three volts lower than the common-mode voltage when on. [10] Monolithic integrated circuit comprising: Input terminals for receiving an analog input signal; an operational coupling that exhibits: an input stage coupled to the input terminals and featuring a variety of high-voltage range switches; an output stage comprising a variety of low-voltage range switches and a common-mode voltage source; a multitude of capacitors, each having a multitude of input plates, each connected to a multitude of high-voltage range switches, and a multitude of output plates, each connected to a multitude of low-voltage range switches; and a controller to operate the multitude of high-voltage range switches and the multitude of low-voltage range switches synchronously at a frequency, to galvanically isolate the input stage from the output stage, and to transfer a differential voltage signal component within a range of a common-mode voltage signal component from the high-voltage range to the low-voltage range; a differential amplification circuit coupled to the output stage of the operational coupling; and Output terminals that are coupled to the differential amplification circuit to output an analog output signal. [11] Monolithic integrated circuit according to claim 10, wherein the frequency is greater than or equal to 100 MHz. [12] Monolithic integrated circuit according to claim 10 or claim 11, wherein the common-mode voltage signal component is + / -1000 volts. [13] Monolithic integrated circuit according to one of claims 10 to 12, wherein the common-mode voltage signal component is + / -100 volts, wherein the range of a common-mode voltage signal component is + / -100 volts. [14] Monolithic integrated circuit according to claim 13, wherein the controller for synchronous operation of the plurality of high-voltage range switches and the plurality of low-voltage range switches comprises that one of the switches in the off state has the common-mode voltage and in the on state is at least three volts lower than the common-mode voltage. [15] Monolithic integrated circuit according to any one of claims 10 to 14, wherein the output signal is relative to a reference signal, wherein positive and negative output signals indicate the current direction.

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