US 9,022,941 B2Granted

Ultrasonic diagnostic apparatus and carrier signal generating circuit

AssigneeHitachi Medical Corporation

InventorsKanako Hatayama, Kenji Maio

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Abstract

In order to simplify a manufacturing process and reduce cost and power consumption by providing an ultrasonic diagnostic apparatus including a carrier signal generating circuit excellent in IC implementation, a carrier signal generating circuit for generating an output voltage Vo applied to an ultrasonic probe 41 includes cascaded source follower type NMOSFETs 11 to 14, a variable current source 31, and a constant current source for biasing 32. The probe 41 can be made to generate the output voltage Vo with arbitrary amplitude by controlling a gate voltage V4 by controlling the output current value of the variable current source 31. In addition, a voltage applied to each NMOSFET can be divided by connecting the NMOSFETs 11 to 14 in a multi-stage manner. Accordingly, the withstand voltage of the NMOSFET may be low.

An ultrasonic diagnostic apparatus comprising:

a probe which transmits and receives an ultrasonic wave to and from an object;
a transmitter circuit unit connected to a controller and the probe,
wherein the transmitter circuit unit supplies a voltage to the probe by using a signal transmitted from the controller;
a receiving circuit unit connected to the probe,
wherein the receiving circuit amplifies a received signal from the probe, and
wherein an ultrasonic image is formed based on ultrasonic image data from the receiving circuit unit;
and
a display that displays the ultrasonic image,
wherein the transmitter circuit unit comprises:
a first variable current source connected to the controller such that the output current is controlled by the controller;
a first resistor connected in series to the first variable current source;
a first FET connected in parallel to the first variable current source and the first resistor,
wherein a gate of the first FET is connected to a first connecting point of the first resistor and the first variable current source;
a first direct current source,
wherein a positive or negative first side of the first direct current source is connected to a second connecting point of the first resistor and a source of the first FET, and a second side of the first direct current source is connected to a third connecting point of the first variable current source and drain of the first FET, and
wherein the probe is connected to a drain of the first FET;
a second FET disposed between the first side of the first direct current source and a source of the first FET,
wherein a drain of the second FET is connected to a positive or negative third side of a second direct current source via a first diode;
a second resistor disposed between a gate and a source of the second FET;
and
a second variable current source disposed between the gate of the second FET and the second side of the first direct current source.

18 more elements

Abstract

Claims6