The MSP430 series of MCUs, especially the MSP430FR604x and MSP430FR504x series, provide a low-cost single-chip solution for ultrasonic sensing. The Ultrasonic Sensing Solutions (USS_A) module is integrated throughout the ultrasonic application equipment and can provide high-precision measurements for various flow rates.

We must be familiar with ultrasonic sensing. This ultrasonic-based sensing method is widely used and plays a role in many areas of life. Ultrasonic sensors are manufactured according to certain properties of ultrasonic waves. The internal transducer chip is excited and vibrated by the voltage to generate ultrasonic waves to complete the transmission and reception of ultrasonic waves.

The composition of ultrasonic sensors is not that complicated. The transmitter and the transducer form the transmitting part, the amplifier circuit and the transducer form the receiving part, and then combine the control part and the power supply part to complete the general functions of the sensor. Among these components, ultrasonic control can be realized by high-end microcontroller. In the sound wave generator, the single-chip microcomputer runs as the BAV99 main control chip of the whole circuit, and cooperates with the D/A converter and the IGBT power module to realize pulse width modulation. It can be seen that the ordinary single-chip microcomputer has basically completed the ultrasonic control. This is just basic control, and for some high-frequency circuit requirements, the processing speed of ordinary microcontrollers may be a bit slow.

MSP430 Series Integrated Solutions

Since ordinary MCUs can't fully meet the needs, what should we do? Let's take a look at TI's MSP430 series. The MSP430 series is specifically enhanced for ultrasonic applications. The MSP430 series of MCUs, especially the MSP430FR604x and MSP430FR504x series, provide a low-cost single-chip solution for ultrasonic sensing. This family features an integrated ultrasonic sensing analog front end for ease of use and flexibility for developing various applications. Its unique waveform capture technology and high-speed ADC enable high-precision measurements with low power consumption.

Take the MSP430FR5043 as an example, this device is designed for ultrasonic water meters, heat meters and gas meters. The Ultrasonic Sensing Solutions (USS_A) module is integrated throughout the ultrasonic application equipment and can provide high-precision measurements for various flow rates. The USS_A is highly integrated and requires few external components, enabling ultra-low power measurements and reducing system cost.

The USS_A module includes a programmable pulse generator (PPG) and a physical interface (PHY) with low impedance output drivers for optimal sensor excitation and accurate impedance matching for zero flow drift (ZFD).

For accurate signal acquisition, the USS_A module also integrates a programmable gain amplifier (PGA) and a high-speed 12-bit 8Mspsσ-δ ADC. The differential time-of-flight accuracy of the device is ±12.5ps in a water-medium environment, and ±1% over a wide dynamic range of 500:1. In gaseous media, the differential time-of-flight accuracy is ±250ps, and at flow rates up to 12,000 liters/hour, an accuracy of ±1% can be achieved, with a wide dynamic range of 200:1.

The MSP430FR5043 device adopts a low-power accelerator (LEA), which realizes the subsequent optimization of signal acquisition and digital signal processing based on high-speed ADC, and provides an ultra-low-power, high-precision metering solution application for battery-powered metering. This ultra-low power MSP system architecture can reduce energy consumption and improve performance of the entire ultrasonic sensor system.

ADI Specialized Discrete Solutions

Instead of integrating the entire controller functionality for ultrasonic applications like TI, ADI uses a discrete solution. While not packaged into a chip, each device is very capable for each application.

From the transmitter, ADI gives the model based on AD9106 ">AD9106model">AD9106model">AD9106model">AD9106model">AD9106model">AD9106model">AD9106model">AD9106model">AD9106model">AD9106 Model">AD9106Model">AD9106Model">AD9106Model">AD9106Model">AD9106Model">AD9106Model">AD9106Model">AD9106Model">AD9106 Four-Channel Solution. Through this four-channel, 12 of 180MSPS The arbitrary waveform generator can accurately control the transmitted signal and improve the performance of the flowmeter. At the same time, this configuration can also save a lot of flowmeter space.

In the receiving front end, AFE chose the highly integrated eight-channel AD9670, which can greatly improve the performance. There are two options for VGA: AD3388 and AD8332. The first provides the highest dynamic range and the second the lowest noise. Can be selected according to actual needs.

The DAC selected the single-channel AD5681R's 12-bit precision DAC, which integrates the reference voltage, which is a good small-size solution. The temperature sensor uses an ordinary fully integrated digital temperature sensor, which is simple and accurate and suitable for temperature compensation.

The processor adopts 400MHzADS9-BF70x, the DSP comes with 1MBSRAM, and the on-chip encryption accelerator is also built-in. It is a processor that supports a variety of industrial interfaces. Another consideration is to reduce power consumption and flowmeter self-heating from inside the sensor when the DSP400MHz is less than 100mW.

It is not difficult to see from the combination of these separate devices that ADI attaches great importance to the low power consumption of ultrasonic applications, and it can also be seen that the strict control of space. The selection of each device takes into account not only high precision but also the smallest possible size.

summary

Whether it is a fully integrated chip solution or a discrete solution, the power consumption and low cost are as low as possible. Although ADI did not integrate these discrete devices into the SOC, we can also see the development direction of the miniaturization of ultrasonic sensor chips from the approach of reducing the size as much as possible in the solution.