Microchip Technology Inc.

Supertex, Inc.

Mosway Semiconductor Limited

Wan Tim Chan

Ka Wai Ho

Isaac Ko

Jimes Lei

Shu Hung Henry Chung

Chung Pui Tung

Po Wa Chow

Wing To Fan

Chiu Sing Tse

Described herein are multiple designs for an improved analog switch for use in transmitting high voltage signals without using high voltage power supplies for the switch. The analog switches are able to pass and block input signals in the approximate range of &#x2212;100 V to +100 V. The use of translinear loops and a bootstrap configuration results in a constant on-resistance of the symmetrical switches and matches the conductance of each analog switch to the transconductance of an NMOS transistor, which can be easily stabilized with a constant gbiasing scheme. In certain embodiments, a shunt termination (T-switch) configuration is used for better off-isolation, and each of the symmetrical switches has its own translinear loop and thus flexibility of on-resistance and termination voltage.

Analog switch for transmitting high voltage signals without utilizing high voltage power supplies

Described herein are multiple designs for an improved analog switch for use in transmitting high voltage signals without using high voltage power supplies for the switch. The analog switches are able to pass and block input signals in the approximate range of &#x2212;100V to +100V. The use of translinear loops and a bootstrap configuration results in a constant on-resistance of the symmetrical switches and matches the conductance of each analog switch to the transconductance of an NMOS transistor, which can be easily stabilized with a constant gbiasing scheme. In certain embodiments, a shunt termination (T-switch) configuration is used for better off-isolation, and each of the symmetrical switches has its own translinear loop and thus flexibility of on-resistance and termination voltage.

A current control circuit having a current regulation element, a first control circuit, and a second control circuit. The first control circuit is arranged to regulate, based on a reference current, a current flowing with respect to the current regulation element. The second control circuit is arranged to regulate, based on a reference voltage, a voltage across the current regulation element.

Current control circuit

An ultrasound probe buffer is provided. The ultrasound probe buffer may include a high impedance amplifier having a common-source core stage with series-series local feedback. The high impedance amplifier may include a first MOSFET and a second MOSFET, wherein a source terminal of the first MOSFET is coupled to a source terminal of the second MOSFET.

Class AB common-source amplifier with constant transconductance

An analog transmit/receive switch and voltage detection circuit that do not require depletion mode devices are provided. The switch may be configured to operate in a receive mode and a protection mode. The voltage detection circuit may be coupled to the switch and may be configured to measure a potential difference between two terminals of the switch. The switch and the voltage detection circuit may not include any depletion mode devices.

High voltage transmit / receive switch and voltage detection circuit

An improved analog switch for use in an ultrasound elastography probe is disclosed. The improved analog switch results in less heat dissipation compared to prior art analog switches.

Optimized CMOS analog switch

An impedance matching transmission circuit for a transducer has a transmission medium connected to the transducer. A transmitting circuit is connected to the transmission medium with the transmitting circuit terminating in a reference circuit element. The transmitting circuit comprises an analog to digital converter having an analog input connected to the reference circuit element, and having a digital output. A digital to analog converter receives the digital output and generates an analog output signal in response thereto. A driver circuit is connected to the transmission medium and receives the analog output signal and supplies a driver signal to the transmission medium.

Impedance matched transmission circuit with analog-to-digital converter

A multi-level transmitter circuit with substantially constant output impedance has a capacitive transducer connected between a voltage input and ground. A first voltage path connects the voltage input to a first positive voltage source. The first voltage path is controlled by a first control signal. A second voltage path connects the voltage input to a second positive voltage source, less than the first positive voltage source. The second voltage path passes through a diode and is controlled by a second control signal. A third voltage path connects the voltage input to a third voltage source, less than ground, and is controlled by the second control signal. The impedance at the voltage input during the first control signal is substantially the same as the impedance at the voltage input during the second control signal.

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Hong Kong, China

Wan Tim Chan