STMicroelectronics

This high-voltage N-channel Power MOSFET is part of the MDmesh DM6 fast-recovery diode series. Compared with the previous MDmesh fast generation, DM6 combines very low recovery charge (Qrr), recovery time (trr) and excellent improvement in RDS(on)per area with one of the most effective switching behaviors available in the market for the most demanding high-efficiency bridge topologies and ZVS phase-shift converters.

This high-voltage N-channel Power MOSFET is part of the MDmesh DM6 fast-recovery diode series. Compared with the previous MDmesh fast generation, DM6 combines very low recovery charge (Qrr), recovery time (trr) and excellent improvement in RDS(on)per area with one of the most effective switching behaviors available in the market for the most demanding high-efficiency bridge topologies and ZVS phase-shift converters.

This monolithic, high-speed transmitter features 16 independent channels with built-in digital beamforming, that generates 5-Level high voltage pulses (up to ±100 V) suitable to excite multiple channels of an ultrasound transducer. Each analog channel structure integrates an active RTZ circuit (Clamp) and a T/R switch guaranteeing high OFF isolation between the high-voltage transmitter and the low-voltage receiver when the pulser is transmitting. T/R switches turn ON while receiving echo signals connecting the transducer to the receiver. Each channels host two independent half bridges (TX0 and TX1) capable of up to ±2A peak output current in 3 or 5 levels configuration. These half bridges can be put in parallel so to provide 3-level profiles up to ±4A current capability on all 16 outputs. Anti-leakage, anti-memory block, thermal sensors and recirculation current protection features complete the architecture. Beamforming in ultrasound transmission has traditionally been implemented using analog delay lines. The STHV1600 embeds a digital beamforming mode allowing to program accurate steering of all channels with a resolution as low as 5ns: the signal from each individual transducer element is properly delayed in order to steer the beam in the desired direction. Both the digital state machine and serial communication interface can be clocked up to 200MHz with differential or rail-to-rail single-ended embedded options. A generous memory allows to store several patterns to drive output channels with desired code excitation. Suitable registers allow handling of all device operations in the proper sequence and managing device diagnostic features. Twelve low voltage capacitors are embedded in the package to reduce the external BoM. STHV1600 is available in a 10mm x 10mm x 1.4mm 144 pins 0.8mm pitch LFBGA package and is specified for operation from 0°C to 80°C.

The STHV200 is a fully integrated high-voltage driver including both a dual-channel linear and a dual-channel pulser driver. Pulser and linear share the same high-voltage output node XDCR and allow the user to select which output stage to use according to each specific application. This solution allows to optimize the final performances in terms of flexibility, harmonic contents, and power consumption, meeting the most demanding needs for the end application. The device can support a wide range of operating modes as pulsed wave (PW), continuous wave (CW), and elastography. Each linear driver is a non-inverting configuration operational amplifier (op-amp) with four programmable gains (39 dB, 36 dB, 32.5 dB, and 24 dB) providing in this way the best performances for the output signal in a range between 1 Vpp and 180 Vpp. Linear drivers have been designed to optimize harmonic and noise performances thanks to a bandwidth up to 20 MHz when the maximum gain is set. Bandwidth increases reducing the gain and it reaches 25 MHz with the minimum gain setting. Each op-amp drives directly the corresponding XDCR output node without any diode connections, generating a very clean output signal and minimizing odd distortion. An internal circuit fully isolates the output to its parasitic capacitances during pulser driver activity. Fast turn-on and off times of 1.8 us and 0.6 us make the device suitable also for near-field images. A new and dedicated structure, named "active diodes", mitigates the glitch injection during the linear turn-on/off. Pulser drivers are designed in a half-bridge configuration with a programmable saturation current (0.5 A, 1 A, 1.5 A, and 2 A) for both high-side and low-side. The generated output voltage can vary from 2 Vpp up to 200 Vpp. A real-to-zero Clamp structure with a current capability of 1 A can directly force the output node to ground. Users can fine-tune the delays of both positive and negative edges and also choose a dedicated setting for CW and elastography mode, thus optimizing the performances and the power consumption in each operative condition. When STHV200 is used in linear mode, each individual output channel can pulse between high-voltage supplies (positive or negative, HVP_L or HVM_L), using the linear driver. When STHV200 is used in pulser mode, the waveforms generated are described as sequences of states. With each state, it is possible to configure each individual output channel to be connected to high-voltage supplies (positive or negative, HVP_P or HVM_P), clamped to ground (Clamp), or left in high-impedance (HZ). Each channel integrates a TR switch (TRSW) that connects the XDCR with a low-voltage output node (LVOUT). The TRSW is an active structure, without any DC consumption, to guarantee effective isolation during the transmit (TX) and receiving (RX) phases. The LVOUT pins can be multiplexed to reduce the receiving channels. The STHV200 embeds also freewheeling diodes protection, which clamps the recirculating current in case of inductive output load, an anti-memory circuit, which allows to discharge all internal nodes during the Clamp state. Short-circuit protection is also implemented on the output nodes, to prevent dangerous conditions if the impedance load is lower than 5 Ω (low-resistance or high-capacitance) or in case of an unintentional short of the output pins. In addition, other internal global checks and auto-diagnostic functions are integrated into the device to ensure safe operating conditions. SPI protocol is used to program all the functionalities of the device. STHV200 is available in a QFN 7x7 package with 48 pins.

This monolithic, high-voltage, high-speed pulser generator features four independent channels. It is designed for medical ultrasound imaging applications, but can also be used to drive piezoelectric, capacitive or MEMS based transducers. The STHV748S is composed of a controller logic interface circuit, level translators, MOSFET gate drivers, noise blocking diodes, and high-power P-channel and N-channel MOSFETs as the output stage for each channel. It also includes clamping-to-ground circuitry, anti-leakage, anti-memory effect block, thermal sensor, and a T/R switch which guarantees effective decoupling during the transmission phase. The STHV748S also includes self-biasing and thermal shutdown blocks. Each channel can support up to five active output levels with two half bridges. The output stage of each channel is able to provide ±2 A peak output current. In order to reduce power dissipation during continuous wave mode, a dedicated half-bridge is available and the peak current is limited to 0.6 A. An ESD reinforced structure was developed to prevent high voltage overshoots and inrush current due to cabled transducer reflections. Each HV output is supported by a dedicate HV diode network to withstand possible reflections, mitigating excessive voltage overshoot that could lead to device damage.

The STHV800 is an octal, monolithic, high-voltage and high-speed pulse generator. It is designed for medical ultrasound applications, but can be used for other piezoelectric, capacitive or MEMS transducers. The device integrates a controller logic interface circuit (compatible with both 1.8 V and 3.3 V input signals), level translators, MOSFET gate drivers, noise blocking diodes, and high power P-channel and N-channel MOSFETs as the output stage for each channel. These MOSFETs are capable of providing more than 2 A of peak output current. Each channel has a dedicated bridge in order to reduce power dissipation and jitter during continuous wave mode (peak current is limited to 0.3 A). This CW bridge has dedicated power supplies (HV_CW) which are fully independent on the main HV supplies. These HV_CW supplies can be shorted to the HV supplies. The fundamental structure of each channel also consists of active clamping to ground circuitry, anti-leakage and anti-memory block, a thermal sensor to protect the device and an integrated TR-switch (just 8 Ω as equivalent resistor ) to connect the HV output to its LV output, guaranteeing strong decoupling during the transmission phase. The eight independent T/R switches can be used in both a dedicated RX chain per channel or in a multiplexing configuration. The clamp circuit has a current capability up to 2 A and works directly on the output pin, carrying this node exactly to zero. This feature allows minimized injection change during the transition from clamp to RX state. In addition, the STHV800 includes self-biasing circuitry which allows very low power consumption during the RX phase (down to 200 µW global power dissipation) and thermal shutdown block sensing by an external dedicated pin (THSD). One of the main benefits of this device is that it requires very few external components: only decoupling capacitors on the HV and LV supplies, and a resistor to pull up the THSD pin (moreover, this resistor can be shared by many devices). Each channel is driven independently by only 2 digital bits, which in CW mode become one bit. An external clock can be used with the STHV800 to synchronize all the input signals. This feature, however, is optional: if the CK pin is tied to ground the device works in asynchronous mode.