Abstract: Methods, apparatus, systems, and articles of manufacture are described corresponding to current limit circuitry with controlled current variation. An example circuit includes an amplifier having an input terminal and an output terminal; a capacitor having a first terminal and a second terminal, the first terminal of the capacitor coupled to the input terminal of the amplifier, the second terminal of the capacitor coupled to the output terminal of the amplifier; and diode circuitry having a first terminal and a second terminal, the first terminal of the diode circuitry coupled to the first terminal of the capacitor and the input terminal of the amplifier, the second terminal of the diode circuitry coupled to the second terminal of the capacitor and the output terminal of the amplifier.

Abstract: In an example, a circuit includes a high side output transistor having a control terminal coupled to a first capacitor, and includes a low side output transistor having a control terminal coupled to a second capacitor and a balancing capacitor. The circuit includes a first differential input stage configured to receive a differential input and provide a first output current to the control terminal of the high side output transistor. The circuit includes a second differential input stage configured to receive the differential input and provide a second output current to the control terminal of the low side output transistor. The circuit includes a floating battery coupled to the control terminal of the high side output transistor and the control terminal of the low side output transistor. The balancing capacitor balances a gate-to-source capacitance of the low side output transistor with a gate-to-source capacitance of the high side output transistor.

Abstract: An ultrasonic transmitter including a linear amplifier, an output stage, a switch, and a current compensation circuit. The linear amplifier includes first and second amplifier stages. The output stage has an input coupled to output of the linear amplifier, and presents the transmitter output. The switch is coupled to the output of the linear amplifier. The current compensation circuit has an output coupled at the output of the first amplifier stage. Select circuitry is configured to couple the switch to a bias terminal when the switch is closed, and to couple one or more nodes of the switch to the control terminal of the current compensation circuit when the switch is open. The current compensation circuit generates a compensation current responsive to a sensed non-linear current conducted through the switch when open.

Abstract: An ultrasonic transceiver system including a transducer, a receiver coupled to the transducer, a transmitter having an output terminal coupled to the transducer, and a transmit/receive switch configured to isolate the receiver from the transmitter during transmission. The transmitter includes an amplifier and an output stage. The output stage includes a source follower transistor having a drain coupled to a supply terminal, a gate coupled to an output of the amplifier, and a source coupled to an output terminal, along with a power stage transistor having a source coupled to the supply terminal, a gate coupled to the drain of the source follower transistor, and a drain coupled to the output terminal. The output stage further includes a parallel source follower transistor having a drain coupled to the supply terminal, a gate coupled to the input terminal, and a source coupled to the output terminal.

Abstract: In some examples, a pulser circuit is configured to provide a pulse signal in a first operational state, pre-charge components of the pulser circuit via a first signal path in a second operational state following the first operational state, wherein the first signal path includes first components having a first voltage tolerance and second components having a second voltage tolerance, the first voltage tolerance being less than the second voltage tolerance, and discharge a voltage of the pulser circuit to ground in a third operational state between the first operational state and the second operational state, and following the second operational state.

Abstract: A differential to single-ended summation circuit includes a first switch which includes a first terminal coupled to a first circuit input and includes a second terminal. The circuit includes a second switch which includes a first terminal coupled to a second circuit input and includes a second terminal. The circuit includes a holding capacitor which includes a first terminal coupled to the second terminal of the first switch and a second terminal coupled to the second terminal of the second switch. The circuit includes a third switch which includes a first terminal coupled to the second terminal of the first switch and a second terminal coupled to a circuit output. The circuit includes a fourth switch including a first terminal coupled to the second terminal of the second switch and a second terminal coupled to a common potential.

Abstract: An ultrasound system includes a transmit-receive switch. The transmit-receive switch includes a combined transmit-receive and return-to-zero (RTZ) path. The combined transmit-receive and RTZ path includes a transistor with a first current terminal, a second current terminal, and a control terminal. The second current terminal of the transistor is coupled to a ground node via a first switch and is coupled to a receive node via a second switch. The ultrasound system also includes a receiver front-end circuit coupled to the receive node.

Abstract: An ultrasound system includes a transmit-receive switch. The transmit-receive switch includes a combined transmit-receive and return-to-zero (RTZ) path. The combined transmit-receive and RTZ path includes a transistor with a first current terminal, a second current terminal, and a control terminal. The second current terminal of the transistor is coupled to a ground node via a first switch and is coupled to a receive node via a second switch. The ultrasound system also includes a receiver front-end circuit coupled to the receive node.

Abstract: A delay line control circuit includes a pseudo-random number generator and a random phase generator circuit coupled to the pseudo-random number generator. The pseudo-random number generator is configured to produce a predetermined sequence of pseudo-random values. The random phase generator circuit is configured to randomize an access sequence for capacitors of a delay line. The random phase generator circuit includes a sequence register, an adder, and gating circuitry. The sequence register is configured to a store a value identifying one of the capacitors to be accessed. The adder is coupled to the sequence register, and is configured to increment the value stored in sequence register. The gating circuitry is coupled to the pseudo-random number generator and the adder. The gating circuitry is configured to pass one of the pseudo-random values to the adder for addition to the value stored in the sequence register.

Abstract: Methods and apparatus for reducing a transient glitch in ultrasound applications are disclosed. An example apparatus includes a transducer to (A) output a signal during a transmit phase and (B) receive a reflected signal corresponding to the signal during a receive phase; a receiver switch coupled to the transducer at a first node, the receiver switch to (A) open during the transmit phase and (B) close during the receive phase; and a clamp coupled to the transducer at the first node, the clamp to provide a high impedance during the transmit phase and the receive phase and provide a low impedance during a transient phase.

Abstract: Methods and apparatus for reducing a transient glitch in ultrasound applications are disclosed. An example apparatus includes a transducer to (A) output a signal during a transmit phase and (B) receive a reflected signal corresponding to the signal during a receive phase; a receiver switch coupled to the transducer at a first node, the receiver switch to (A) open during the transmit phase and (B) close during the receive phase; and a clamp coupled to the transducer at the first node, the clamp to provide a high impedance during the transmit phase and the receive phase and provide a low impedance during a transient phase.

Abstract: Methods and apparatus for reducing a transient glitch in ultrasound applications are disclosed. An example apparatus includes a transducer to (A) output a signal during a transmit phase and (B) receive a reflected signal corresponding to the signal during a receive phase; a receiver switch coupled to the transducer at a first node, the receiver switch to (A) open during the transmit phase and (B) close during the receive phase; and a clamp coupled to the transducer at the first node, the clamp to provide a high impedance during the transmit phase and the receive phase and provide a low impedance during a transient phase.

Abstract: A delay line control circuit includes a pseudo-random number generator and a random phase generator circuit coupled to the pseudo-random number generator. The pseudo-random number generator is configured to produce a predetermined sequence of pseudo-random values. The random phase generator circuit is configured to randomize an access sequence for capacitors of a delay line. The random phase generator circuit includes a sequence register, an adder, and gating circuitry. The sequence register is configured to a store a value identifying one of the capacitors to be accessed. The adder is coupled to the sequence register, and is configured to increment the value stored in sequence register. The gating circuitry is coupled to the pseudo-random number generator and the adder. The gating circuitry is configured to pass one of the pseudo-random values to the adder for addition to the value stored in the sequence register.

Abstract: A delay line control circuit includes a pseudo-random number generator and a random phase generator circuit coupled to the pseudo-random number generator. The pseudo-random number generator is configured to produce a predetermined sequence of pseudo-random values. The random phase generator circuit is configured to randomize an access sequence for capacitors of a delay line. The random phase generator circuit includes a sequence register, an adder, and gating circuitry. The sequence register is configured to a store a value identifying one of the capacitors to be accessed. The adder is coupled to the sequence register, and is configured to increment the value stored in sequence register. The gating circuitry is coupled to the pseudo-random number generator and the adder. The gating circuitry is configured to pass one of the pseudo-random values to the adder for addition to the value stored in the sequence register.

Abstract: Methods and apparatus for reducing a transient glitch in ultrasound applications are disclosed. An example apparatus includes a transducer to (A) output a signal during a transmit phase and (B) receive a reflected signal corresponding to the signal during a receive phase; a receiver switch coupled to the transducer at a first node, the receiver switch to (A) open during the transmit phase and (B) close during the receive phase; and a clamp coupled to the transducer at the first node, the clamp to provide a high impedance during the transmit phase and the receive phase and provide a low impedance during a transient phase.

Abstract: An ultrasound system includes a transmit-receive switch. The transmit-receive switch includes a combined transmit-receive and return-to-zero (RTZ) path. The combined transmit-receive and RTZ path includes a transistor with a first current terminal, a second current terminal, and a control terminal. The second current terminal of the transistor is coupled to a ground node via a first switch and is coupled to a receive node via a second switch. The ultrasound system also includes a receiver front-end circuit coupled to the receive node.

Abstract: Methods and apparatus for reducing a transient glitch in ultrasound applications are disclosed. An example apparatus includes a transducer to (A) output a signal during a transmit phase and (B) receive a reflected signal corresponding to the signal during a receive phase; a receiver switch coupled to the transducer at a first node, the receiver switch to (A) open during the transmit phase and (B) close during the receive phase; and a clamp coupled to the transducer at the first node, the clamp to provide a high impedance during the transmit phase and the receive phase and provide a low impedance during a transient phase.

Abstract: A delay line control circuit includes a pseudo-random number generator and a random phase generator circuit coupled to the pseudo-random number generator. The pseudo-random number generator is configured to produce a predetermined sequence of pseudo-random values. The random phase generator circuit is configured to randomize an access sequence for capacitors of a delay line. The random phase generator circuit includes a sequence register, an adder, and gating circuitry. The sequence register is configured to a store a value identifying one of the capacitors to be accessed. The adder is coupled to the sequence register, and is configured to increment the value stored in sequence register. The gating circuitry is coupled to the pseudo-random number generator and the adder. The gating circuitry is configured to pass one of the pseudo-random values to the adder for addition to the value stored in the sequence register.

Abstract: A passive beamformer for ultrasound imaging. An ultrasound probe includes a plurality of ultrasound transducers and beamforming circuitry. Each of the ultrasound transducers is configured to convert ultrasonic signal into electrical signal. The beamforming circuitry is coupled to the plurality of ultrasound transducers. The beamforming circuitry includes a plurality of passive delay circuits and a passive hold circuit. One of the passive delay circuits is coupled to each of the ultrasound transducers. The passive hold circuit is coupled to the passive delay circuits to store a sum of the charges received from the delay circuits.

Abstract: The disclosure provides a level shifter. The level shifter includes a first logic block that receives an input signal and generates a primary pulsed input. A first transistor is coupled to the first logic block and a first node. A gate terminal of the first transistor receives the primary pulsed input. A latch is coupled to the first node and a second node. A second logic block receives the input signal and generates a secondary pulsed input. A second transistor is coupled between the second logic block and the second node. A gate terminal of the second transistor receives the secondary pulsed input.