A drive circuit includes a first voltage output circuit coupled to a first terminal and outputting a first voltage signal, a second voltage output circuit coupled to a second terminal and outputting a second voltage signal, and a drive signal output circuit coupled to the first terminal and outputting a drive signal. In a first mode, the second voltage output circuit outputs the second voltage signal and the drive signal output circuit outputs the drive signal whose voltage value varies. In a second mode, the second voltage output circuit outputs the second voltage signal and the drive signal output circuit outputs the drive signal which is constant at a third voltage value. In a third mode, the first voltage output circuit outputs the first voltage signal and the second voltage output circuit outputs the second voltage signal.

Examples include a fluidic die. The fluidic die comprises an array of field effect transistors. Connecting members electrically connect at least some of the field effect transistors of the array of field effect transistors, and the field effect transistors of the array are arranged into respective sets of field effect transistors. The fluidic die further comprises a first fluid actuator connected to a first set of field effect transistors having a first number of field effect transistors. The die includes a second fluid actuator connected to a second respective set of field effect transistors having a second number of field effect transistors that is different than the first number of field effect transistors.

There is provided a driving circuit that drives a piezoelectric element, the driving circuit including an integrated circuit, in which the integrated circuit includes a first register that holds an operating state data, a second register that holds an abnormality detection data, an abnormality detection circuit that determines the presence or absence of an abnormality of the operating state data based on the abnormality detection data, and an output control circuit that controls supply of a first voltage signal to the piezoelectric element and supply of a power source voltage to the switch circuit, and in which the output control circuit delays stop of the supply of the power source voltage to the switch circuit with respect to stop of the supply of the first voltage signal to the piezoelectric element when the abnormality detection circuit determines that the operating state data is abnormal.

A droplet ejecting device includes: a head including N-number drive elements; a driving circuit including N-number waveform signal selectors and N-number power supply circuit selectors; a plurality of power supply circuits connected to the driving circuit; and a control circuit. Each waveform signal selector selects a waveform signal to be outputted to the corresponding drive element from among a plurality of types of waveform signals. Each power supply circuit selectors selects a power supply circuit to be connected to the drive elements from among the plurality of power supply circuits. The control circuit serially transmits, to the driving circuit via a single control line: N-number items of waveform signal designation information each of which designates the waveform signal to be outputted to the corresponding drive element; and N-number items of power supply designation information each of which designates the power supply circuit to be connected to the corresponding drive element.

A print head includes a piezoelectric element that includes a first electrode supplied with a drive signal and a second electrode supplied with a reference voltage signal and is displaced by a difference in electric potential between the first electrode and the second electrode, a cavity that is filled with a liquid ejected from a nozzle along with the displacement of the piezoelectric element, a vibration plate that is disposed between the cavity and the piezoelectric element, a low pass filter circuit that is supplied with the drive signal, a first switch circuit that switches between supplying and not supplying the drive signal to the first electrode, and a second switch circuit that switches between supplying and not supplying the drive signal after passing through the low pass filter circuit to the first electrode.

A print head includes a first piezoelectric element that includes a first electrode supplied with a drive signal and a second electrode supplied with a reference voltage signal and is displaced by a difference in electric potential between the first electrode and the second electrode, a cavity that is filled with a liquid ejected from a nozzle along with the displacement of the first piezoelectric element, a vibration plate that is disposed between the cavity and the first piezoelectric element, a first switch circuit that switches between supplying and not supplying the drive signal to the first electrode, and a second switch circuit that switches between electrically connecting and not electrically connecting the first electrode and the second electrode depending on an electric potential of the drive signal.

A printhead includes a printing element; a first power supply wiring configured to be electrically connected to one terminal of the printing element and supply power to the printing element; a transistor configured to be electrically connected to another terminal of the printing element and drive the printing element; a first ground wiring configured to be electrically connected to a source of the transistor; a second ground wiring configured to be electrically connected to a back gate of the transistor; and a first capacitive element configured to be electrically connected, at one terminal thereof, to the first ground wiring and electrically connected at another terminal thereof, to the second ground wiring.

There is provided a driving circuit that drives a piezoelectric element having a first electrode that is supplied a first voltage signal and a second electrode that is supplied a second voltage signal, and driven by a potential difference between the first electrode and the second electrode, the driving circuit including: a first voltage signal generation circuit that outputs the first voltage signal; a second voltage signal generation circuit that outputs the second voltage signal; and a switch circuit in which the first voltage signal is input from one end and the other end is electrically connected to the first electrode, a voltage value of the first voltage signal approaches a voltage value of the second voltage signal in a shift period from a first mode that is shifted after power is turned on to a second mode for driving the piezoelectric element.

A test circuit to determine the capacitance of an actuator element in an actuator element array, wherein the test circuit comprises: a controller; a source to generate test inputs; measurement circuitry to measure one or more test values on a test path between the test circuit and the actuator element; wherein the controller is configured to, for a test period: control a first switch associated with the actuator element to connect the actuator element to the test path; control the source to generate a first test input; and determine a total capacitance of the actuator element from a first test value generated in response to the first test input; and determine the capacitance of the actuator element (C.sub.ACT) from the total capacitance (C.sub.PAR+C.sub.ACT).

There are provided a substrate on which a first integrated circuit, a first transistor, a second integrated circuit, and a second transistor are disposed; a heat sink fixed to the substrate; the substrate has a first fixing reference hole and a second fixing reference hole, the heat sink has a first fixing reference pin and a second fixing reference pin which are inserted into the first fixing reference hole and the second fixing reference hole, and the first integrated circuit, the second integrated circuit, the first transistor, and the second transistor are positioned between the first fixing reference hole and the second fixing reference hole.