High voltage driver shrinks ultrasound scanners

High voltage driver shrinks ultrasound scanners

New Products |
By Nick Flaherty

STMicroelectronics has developed an ultrasound driver that integrates linear and pulse drivers with clamping, switching, and diagnostic circuitry to simplify, miniaturize, and cut the bill of materials in medical and industrial scanners.

The STHV200 has 3A linear and 2A pulse output for cart-based systems for medical echography, industrial non-destructive test (NDT) equipment and for driving piezoelectric transducers.

The linear and pulse circuits each have dual channels and share the same high-voltage output node, giving the user flexibility to select the most suitable output for the application. The driver can operate in pulsed wave for applications such as body-tissue imaging, continuous wave for dynamic measurements like blood flow, and elastography for assessing organ health and tumours.

Each linear driver is a non-inverting operational amplifier with four programmable gain levels to adjust the output signal up to 180Vpp. Optimized for low noise and harmonics, each channel can operate up to 20 MHz at maximum gain and 25 MHz with the minimum gain setting. Both channels benefit from a diode-free output circuit design that minimizes distortion, while fast turn-on and turn-off times with dedicated circuitry to minimize glitch injection allow capturing near-field images.

 The pulser channels are half-bridge drivers with programmable saturation current up to 2A for both high-side and low-side transistors. An SPI connection is provided for programming. The generated output voltage can vary up to 200Vpp and users can fine-tune the switching edges to optimize performance and power consumption for pulsed-wave, continuous-wave, and elastography modes. A real-to-zero clamp circuit is also integrated, which can directly force the output node to ground.

The STHV200 also integrates protective freewheeling diodes to clamp recirculating currents in case of an inductive load and an anti-memory circuit that discharges all internal nodes during the Clamp state. Output short-circuit protection is also built-in to prevent dangerous conditions if the output pins become shorted.  Additional internal global checks and auto-diagnostic functions are provided to ensure safe operating conditions.

The STHV200 is in production now and available in a 7mm x 7mm 48-pin QFN package, from $30.00 each.


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