The shunt resistor value is chosen so that the shunt voltage is approximately mV at maximum load current. The AD accurately amplifies a small differential input voltage in the presence of large positive common-mode voltages greater than V when used in conjunction with an external PNP transistor. Galvanic isolation is provided by the ADuM quad channel isolator.
This is not only for protection but to isolate the downstream circuitry from the high common-mode voltage. The measurement result from the AD is provided as a digital code utilizing a simple 2-wire, SPI-compatible serial interface.
This combination of parts provides an accurate high voltage positive rail current sense solution with a small component count, low cost, and low power. The circuit in Figure 1 is a complete, low power signal conditioner for a bridge type sensor and includes a temperature compensation channel. This circuit is ideal for a variety of industrial pressure sensors and load cells that operate with drive voltages of between 5 V and 15 V.
The entire circuit uses only three ICs and requires only 1 mA excluding the bridge current. A ratiometric technique ensures that the accuracy and stability of the system does not depend on a voltage reference. Looking for true bit level set performance in a small package and ultralow power? The reference buffer is critical to the design because the input impedance at the DAC reference input is heavily code- dependent and will lead to linearity errors if the DAC reference is not adequately buffered.
With a high open-loop gain of dB, the AD has been proven and tested to meet the settling time, offset voltage, and low impedance drive capability required by this circuit application. The combination of parts shown in Figure 1 minimizes PC board area, as well as power dissipation. Figure 1. This circuit uses the ADuC or the ADuC precision analog microcontroller in an accurate thermocouple temperature monitoring application.
The RTD is used for cold junction compensation. As an extra option, the ADT digital temperature sensor can be used to measure the cold junction temperature instead of the RTD.
In the source code, an ADC sampling rate of 4 Hz was chosen. The single edge nibble transmission SENT interface to the host is implemented by using a timer to control a digital output pin.
This digital output pin is then level shifted externally to 5 V using an external NPN transistor. The data is measured as falling edge to falling edge, and the duration of each pulse is related to the number of system clock ticks.
The system clock rate is determined by measuring the SYNC pulse. The SYNC pulse is transmitted at the start of every packet. High-side current monitors are likely to encounter overvoltage conditions from transients or when the monitoring circuits are connected, disconnected, or powered down.
This circuit, shown in Figure 1, uses the overvoltage protected ADA op amp connected as a difference amplifier to monitor the high-side current. The ADA has input overvoltage protection, without phase reversal or latch-up, for voltages of 32 V higher than and lower than the supply rails. The circuit is powered by the ADP adjustable low dropout mA linear regulator, which can also be used to supply power to other parts of the system, if desired.
Its input voltage can range from 5. To save power, the current sensing circuit can be powered down by removing power to the ADP; however, the power source, such as a solar panel, can still operate. This applies voltage to the inputs of the unpowered ADA; however, no latch-up or damage occurs for input voltages up to 32 V. If slower throughput rates are required, the AD can also be powered down between samples. When operating at 5 V, this is only 0. The AD reference buffer provide benefits previously found only in expensive auto-zeroing or chopper-stabilized amplifiers.
Using Analog Devices, Inc. No external capacitor is required, and the digital switching noise associated with most chopper-stabilized amplifiers is greatly reduced, thereby making this the optimum choice for reference buffering. This circuit provides precision, low power, voltage output, digital-to-analog conversion.
The AD can be operated in either the buffered or unbuffered mode. The application and its requirements on settling time, input impedance, noise, etc. The selection of the output buffer amplifier can be tailored to suit either dc precision or fast settling time. The output impedance of the DAC is constant and code independent, but to minimize gain errors the input impedance of the output amplifier should be as high as possible.
The output amplifier should also have a 3 dB bandwidth of 1 MHz or greater. The output amplifier adds another time constant to the system, thereby increasing the settling time of the final output. A higher 3 dB amplifier bandwidth results in a faster effective settling time of the combined DAC and amplifier. The input voltage range of the ADR reference is 4. The circuit in Figure 1 is a 4 mA-to mA current loop transmitter for communication between a process control system and its actuator.
Current loop interfaces are usually preferred because they offer the most cost effective approach to long distance noise immune data transmission. The circuit output is 0 mA to 20 mA of current, and it operates on a single supply from 8 V to 18 V.
The 4 mA to 20 mA range is usually mapped to represent the input control range from the DAC or micro-controller, while the output current range of 0 mA to 4 mA is often used to diagnose fault conditions. The AD simplifies the weigh scale design because most of the system building blocks are included on the chip.
The AD maintains good performance over the complete output data rate range, from 4. The circuit shown in Figure 1 is an isolated, flyback power supply that uses a linear isolated error amplifier to supply the feedback signal from the secondary side to the primary side. Unlike optocoupler-based solutions, which have a nonlinear transfer function that changes over time and temperature, the linear transfer function of the isolated amplifier is stable and minimizes offset and gain errors when transferring the feedback signal across the isolation barrier.
The entire circuit operates from 5 V to 24 V, allowing it to be used with standard industrial and automotive power supplies. The output capability of the circuit is up to 1 A with a 5 V input and 5 V output configuration. This solution can be adapted for use in applications where higher dc input voltages are used to create lower voltage isolated supplies with good efficiency and a small form factor.
The circuit shown in Figure 1 is a completely self-contained, microprocessor controlled, highly accurate conductivity measurement system ideal for measuring the ionic content of liquids, water quality analysis, industrial quality control, and chemical analysis.
A carefully selected combination of precision signal conditioning components yields an accuracy of better than 0. The system accommodates 2- or 4-wire conductivity cells, and 2-, 3-, or 4-wire RTDs for added accuracy and flexibility. The circuit generates a precise ac excitation voltage with minimum dc offset to avoid a damaging polarization voltage on the conductivity electrodes. The amplitude and frequency of the ac excitation is user-programmable.
The intuitive user interface is an LCD display and an encoder push button. The circuit can communicate with a PC using an RS interface if desired, and operates on a single 4 V to 7 V supply.
The circuit shown in Figure 1 is a cost effective, isolated, multi-channel data acquisition system that is compatible with standard industrial signal levels. The components are specifically selected to optimize settling time between samples, providing bit performance at channel switching rates up to approximately kHz.
The circuit can process eight gain-independent channels and is compatible with both single-ended and differential input signals. The analog front end includes a multiplexer, programmable gain instrumentation amplifier PGIA ; precision analog-to-digital converter ADC driver for performing the single-ended to differential conversion; and an bit, 2.
Gain configurations of 0. The maximum sample rate of the system is 2 MSPS in turbo mode, and 1. The channel switching logic is synchronous to the ADC conversions, and the maximum channel switching rate is 1. A single channel can be sampled at up to 2 MSPS with bit resolution in turbo mode. Channel switching rates up to kHz also provide bit performance. DC - DC Conversion. Vehicle Electrification Systems. Digital Cabin Experience.
Power-management solutions including buck step-down and boost step-up switching regulators, flyback and isolated topology switching regulators. Performance and market leading current sense solutions with the reliability, robustness, common step response, offset voltage, temperature drift, and bandwidth specifications needed to optimise system efficiency in harsh automotive environments. Featured Products. ADuMN Robust 3. Applications General-purpose multichannel isolation Industrial field bus isolation 1 Protected by U.
The AD is a single-supply, difference amplifier ideal for amplifying small differential voltages in the presence of large common-mode voltages. The typical supply voltage is 5 V. Please log in to show your saved searches. We also provide a comprehensive range of hardware and software evaluation and development tools including our eDesignSuite that helps engineers design high-efficiency DC to DC converters.
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All dates. A DC-DC switching converter is used to locally supply any component or part of a system with the desired DC voltage and current. Depending on the application's relationship between the input and output voltage, engineers have to choose the best power topology — buck , boost , buck-boost or inverting, with or without synchronous rectification.
Or they can decide to use an implementation based on monolithic ICs or with discrete power switches and controllers — or even an advanced digital implementation.
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