SLASEC8B February 2017 – January 2019 PGA460-Q1
The PGA460-Q1 device is a signal-conditioning and transducer-driver device for ultrasonic sensing for object or distance sensing. The output driver consists of complimentary low-side drivers capable of driving a center-tap transformer to generate large excitation voltages across an ultrasonic transducer and as a result create the desired sound pressure level (SPL). The output driver can also be configured to be used in direct-drive mode without a transformer using external FETs. The output driver implements configurable current limit for efficient driving of the transformer and configurable bursting frequencies and burst length to be compatible with a large number of transducers.
The analog front-end (AFE) can sense the received echo from the transducer and amplify it for correct object detection. The AFE implements a low-noise amplifier followed by a time-varying gain amplifier that allows signals from objects at a variable distance to be amplified correspondingly. This implementation allows for the maximum dynamic range of the ADC to be used for both near-field and far-field objects in the same recording. An embedded temperature sensor can be used to calibrate the signal conditioner for changes in temperature. The digital signal processing path further filters the received echo and uses time-varying thresholds for accurate detection of objects. Two presets for both bursting and thresholds are available which allow faster detection cycles by saving time required to configure the device between multiple bursts. Most configuration parameters are stored in nonvolatile memory for quick power up, which reduces initialization time.
The PGA460-Q1 device provides multiple IO protocols to communicate with the master controller. The device provides a time-command interface and one-wire UART on the VPWR reference IO pin. It also provides both synchronous and asynchronous USART on the TXD, RXD, and SCLK pins.