Patent Description:
Fluid ejection dies, such as thermal inkjet (TIJ) dies may be narrow and long pieces of silicon. To minimize the total number of contact pads on a die, it is desirable for at least some of the contact pads to provide multiple functions. Accordingly, disclosed herein are integrated circuits (e.g., fluid ejection dies) including a multipurpose contact pad (e.g., sense pad) coupled to a memory, thermal sensors, internal test logic, a timer circuit, a crack detector, and/or other circuitry. The multipurpose contact pad receives signals from each of the circuits (e.g., one at a time), which may be read by printer logic. By using a single contact pad for multiple functions, the number of contact pads on the integrated circuit may be reduced. In addition, the printer logic coupled to the contact pad may be simplified.

As used herein a "logic high" signal is a logic "<NUM>" or "on" signal or a signal having a voltage about equal to the logic power supplied to an integrated circuit (e.g., between about <NUM> V and <NUM> V, such as <NUM> V). As used herein a "logic low" signal is a logic "<NUM>" or "off" signal or a signal having a voltage about equal to a logic power ground return for the logic power supplied to the integrated circuit (e.g., about <NUM> V).

<FIG> is a block diagram illustrating one example of an integrated circuit <NUM> to drive a plurality of fluid actuation devices. Integrated circuit <NUM> includes an interface (e.g., sense interface) <NUM>, a digital circuit <NUM>, an analog circuit <NUM>, and control logic <NUM>. Control logic <NUM> is electrically coupled to interface <NUM>, to digital circuit <NUM> through a signal path <NUM>, and to analog circuit <NUM> through a signal path <NUM>. Interface <NUM> may include a contact pad, a pin, a bump, or a wire. The interface <NUM> is configured to contact a single printer-side contact to transmit signals to and from the single printer-side contact, such as a single printer-side contact of fluid ejection system <NUM>, which will be described below with reference to <FIG>.

The digital circuit <NUM> outputs a digital signal to the interface <NUM> through control logic <NUM>. In one example, the digital circuit <NUM> includes a memory. In another example, the digital circuit <NUM> includes a timer. In another example, the digital circuit <NUM> includes a configuration register. In yet another example, the digital circuit <NUM> includes a shift register.

The analog circuit <NUM> outputs an analog signal to the interface <NUM> through control logic <NUM>. In one example, the analog circuit <NUM> includes a resistor wiring. The resistor wiring may be separate from and extend along at least a subset of fluid actuation devices (e.g. fluid actuation devices <NUM>, which will be described below with reference to <FIG>). In another example, the analog circuit <NUM> outputs an analog signal representative of a state of the integrated circuit <NUM>, where the state includes at least one of a crack (e.g., sensed by a crack detector) and a temperature (e.g., sensed by a temperature or thermal sensor). In another example, the analog circuit <NUM> includes a crack detector. In yet another example, the analog circuit <NUM> includes a thermal sensor.

The control logic <NUM> activates the digital circuit <NUM> or the analog circuit <NUM> such that an output of the digital circuit <NUM> or the analog circuit <NUM> may be read through interface <NUM>. In one example, control logic <NUM> activates the digital circuit <NUM> or the analog circuit <NUM> based on data passed to integrated circuit <NUM>. Control logic <NUM> may include transistor switches, tristate buffers, and/or other suitable logic circuitry for controlling the operation of integrated circuit <NUM>.

<FIG> is a block diagram illustrating another example of an integrated circuit <NUM> to drive a plurality of fluid actuation devices. Integrated circuit <NUM> is similar to integrated circuit <NUM> previously described and illustrated with reference to <FIG>, except that integrated circuit <NUM> also includes a configuration register <NUM>. Configuration register <NUM> is electrically coupled to control logic <NUM> through a signal path <NUM>. Configuration register <NUM> may enable or disable the digital circuit <NUM> and enable or disable the analog circuit <NUM> based on data stored in the configuration register.

Configuration register <NUM> may be a memory device (e.g., non-volatile memory, shift register, etc.) and may include any suitable number of bits (e.g., <NUM> bits to <NUM> bits, such as <NUM> bits). In certain examples, configuration register <NUM> may also store configuration data for testing integrated circuit <NUM>, detecting cracks within a substrate of integrated circuit <NUM>, enabling timers of integrated circuit <NUM>, setting analog delays of integrated circuit <NUM>, validating operations of integrated circuit <NUM>, or for configuring other functions of integrated circuit <NUM>.

<FIG> is a block diagram illustrating another example of an integrated circuit <NUM> to drive a plurality of fluid actuation devices. Integrated circuit <NUM> includes an interface (e.g., sense interface) <NUM>, a timer <NUM>, and an analog circuit <NUM>. The interface <NUM> is electrically coupled to timer <NUM> and analog circuit <NUM>. The analog circuit <NUM> outputs an analog signal to the interface <NUM>. The timer <NUM> overrides the analog signal on the interface <NUM> from the analog circuit <NUM> in response to the timer elapsing. In one example, interface <NUM> and analog circuit <NUM> are similar to interface <NUM> and analog circuit <NUM> previously described and illustrated with reference to <FIG>.

<FIG> is a block diagram illustrating another example of an integrated circuit <NUM> to drive a plurality of fluid actuation devices. Integrated circuit <NUM> includes an interface <NUM>, an analog circuit <NUM>, and a timer <NUM>. In addition, integrated circuit <NUM> includes control logic <NUM>, a pulldown device <NUM>, a digital circuit <NUM>, and a configuration register <NUM>. Control logic <NUM> is electrically coupled to sense interface <NUM>, to analog circuit <NUM> through a signal path <NUM>, to pulldown device <NUM> through a signal path <NUM>, to digital circuit <NUM> through a signal path <NUM>, and to configuration register <NUM> through a signal path <NUM>. Pulldown device <NUM> is electrically coupled to timer <NUM> through a signal path <NUM>.

The digital circuit <NUM> outputs a digital signal to the interface <NUM>. In one example, the digital circuit <NUM> is similar to the digital circuit <NUM> previously described and illustrated with reference to <FIG>. Control logic <NUM> activates the digital circuit <NUM> or the analog circuit <NUM>. The timer <NUM> overrides the analog signal on the interface <NUM> from the analog circuit <NUM> or the digital signal on the interface <NUM> from the digital circuit <NUM> in response to the timer elapsing. The timer <NUM> overrides the analog signal on the interface <NUM> from the analog circuit <NUM> by activating the pulldown device <NUM>. The pulldown device <NUM> pulls the interface <NUM> to a hard low (e.g., about <NUM> V or ground), which overrides any other signals on the interface <NUM>. Configuration register <NUM> may enable or disable the analog circuit <NUM>, enable or disable the digital circuit <NUM>, and enable or disable the timer <NUM>. In one example, configuration register <NUM> is similar to configuration register <NUM> previously described and illustrated with reference to <FIG>.

<FIG> is a block diagram illustrating another example of an integrated circuit <NUM> to drive a plurality of fluid actuation devices. Integrated circuit <NUM> includes an output (e.g., sense) interface <NUM>, a shift register <NUM>, and a data interface <NUM>. The shift register <NUM> shifts nozzle data into the integrated circuit <NUM> through the data interface <NUM> and shifts the nozzle data out of the integrated circuit <NUM> through the output interface <NUM>. In this way, the shift register <NUM> may be tested to make sure the nozzle data input to integrated circuit <NUM> matches the nozzle data output of integrated circuit <NUM>.

<FIG> is a block diagram illustrating another example of an integrated circuit <NUM> to drive a plurality of fluid actuation devices. Integrated circuit <NUM> includes an output (e.g. sense) interface <NUM>, a shift register <NUM>, and a data interface <NUM>. In addition, integrated circuit <NUM> includes control logic <NUM>, a delay circuit <NUM>, a fire interface <NUM>, an analog circuit <NUM>, and a configuration register <NUM>. Control logic <NUM> is electrically coupled to output interface <NUM>, to shift register <NUM> through a signal path <NUM>, to delay circuit <NUM> through a signal path <NUM>, to analog circuit <NUM> through a signal path <NUM>, and to configuration register <NUM> through a signal path <NUM>. Delay circuit <NUM> is electrically coupled to the fire interface <NUM>.

The delay circuit <NUM> receives a fire signal through the fire interface <NUM> and outputs a delayed fire signal through the output interface <NUM>. In this way, the delay circuit <NUM> may be tested to make sure the delay is functioning as expected. In one example, the configuration register <NUM> stores data to enable or disable the shifting of the nozzle data out of the integrated circuit <NUM> through the output interface <NUM>. In another example, the configuration register <NUM> stores data to enable or disable the output of the delayed fire signal through the output interface <NUM>. In yet another example, configuration register <NUM> stores data to enable or disable analog circuit <NUM>. In one example, configuration register <NUM> is similar to configuration register <NUM> previously described and illustrated with reference to <FIG>.

Analog circuit <NUM> outputs an analog signal to the output interface <NUM>. In one example, analog circuit <NUM> is similar to analog circuit <NUM> previously described and illustrated with reference to <FIG>. Control logic <NUM> activates the analog circuit <NUM> to output an analog signal to the output interface <NUM>, the shift register <NUM> to shift the nozzle data out of the integrated circuit <NUM> through the output interface <NUM>, or activates the delay circuit <NUM> to receive a fire signal through the fire interface <NUM> and output a delayed fire signal through the output interface <NUM>.

The output interface <NUM>, the data interface <NUM>, and the fire interface <NUM> may each include a contact pad, a pin, a bump, or a wire. In one example, each of the output interface <NUM>, the data interface <NUM>, and the fire interface <NUM> is configured to contact a corresponding printer-side contact to transmit signals to and from the printer-side contacts.

<FIG> is a block diagram illustrating another example of an integrated circuit <NUM> to drive a plurality of fluid actuation devices. Integrated circuit <NUM> includes a sense interface <NUM>, a shift register <NUM>, a data interface <NUM>, control logic <NUM>, a delay circuit <NUM>, a fire interface <NUM>, a crack detector <NUM>, a thermal sensor <NUM>, a memory <NUM>, a configuration register <NUM>, a timer <NUM>, and a pulldown device <NUM>. Control logic <NUM> is electrically coupled to sense interface <NUM>, to shift register <NUM> through a signal path <NUM>, to delay circuit <NUM> through a signal path <NUM>, to crack detector <NUM> through a signal path <NUM>, to thermal sensor <NUM> through a signal path <NUM>, to memory <NUM> through a signal path <NUM>, to pulldown device <NUM> through a signal path <NUM>, and to configuration register <NUM> through a signal path <NUM>. Shift register <NUM> is electrically coupled to data interface <NUM>. Delay circuit <NUM> is electrically coupled to fire interface <NUM>. Pulldown device <NUM> is electrically coupled to timer <NUM> through a signal path <NUM>.

Shift register <NUM> and delay circuit <NUM> are similar to shift register <NUM> and delay circuit <NUM> previously described and illustrated with reference to <FIG>. Timer <NUM> and pulldown device <NUM> are similar to timer <NUM> and pulldown device <NUM> previously described and illustrated with reference to <FIG>. Crack detector <NUM> outputs an analog signal to sense interface <NUM> indicating a crack state of integrated circuit <NUM>. In one example, crack detector <NUM> includes a resistor wiring separate from and extending along at least a subset of fluid actuation devices (e.g., fluid actuation devices <NUM> of <FIG>). Thermal sensor <NUM> outputs an analog signal to sense interface <NUM> indicating a temperature state of integrated circuit <NUM>. In one example, thermal sensor <NUM> includes a thermal diode or another suitable device for sensing temperature. Memory <NUM> may store data for integrated circuit <NUM> or for a printer to which integrated circuit <NUM> is connected. Memory <NUM> may be read or written through sense interface <NUM>.

Control logic <NUM> may enable or disable shift register <NUM>, delay circuit <NUM>, crack detector <NUM>, thermal sensor <NUM>, memory <NUM>, and timer <NUM>. In one example, control logic <NUM> may enable one of the shift register <NUM>, delay circuit <NUM>, crack detector <NUM>, thermal sensor <NUM>, memory <NUM>, and timer <NUM> at a time. In another example, control logic <NUM> may enable timer <NUM> and one of the shift register <NUM>, delay circuit <NUM>, crack detector <NUM>, thermal sensor <NUM>, and memory <NUM>. In one example, control logic <NUM> may enable or disable shift register <NUM>, delay circuit <NUM>, crack detector <NUM>, thermal sensor <NUM>, memory <NUM>, and timer <NUM> based on data stored in configuration register <NUM>. In one example, configuration register <NUM> is similar to configuration register <NUM> previously described and illustrated with reference to <FIG>. In another example, control logic <NUM> may enable or disable shift register <NUM>, delay circuit <NUM>, crack detector <NUM>, thermal sensor <NUM>, memory <NUM>, and timer <NUM> based on data passed to integrated circuit <NUM>, such as data passed to integrated circuit <NUM> through data interface <NUM>.

<FIG> is a schematic diagram illustrating one example of a circuit <NUM> coupled to an interface (e.g., sense pad) <NUM>. Circuit <NUM> includes a plurality of memory cells <NUM><NUM> to <NUM>N, where "N" is any suitable number of memory cells. Circuit <NUM> also includes a plurality of thermal sensors <NUM><NUM> to <NUM>M, where "M" is any suitable number of thermal sensors. In addition, circuit <NUM> includes transistors <NUM>, <NUM>, <NUM>, and <NUM>, a multiplexer <NUM>, a tristate buffer <NUM>, and a crack detector <NUM>. Each memory cell <NUM><NUM> to <NUM>N includes a floating gate transistor <NUM> and transistors <NUM> and <NUM>. Each thermal sensor <NUM><NUM> to <NUM>M includes a transistor <NUM> and a thermal diode <NUM>.

Sense pad <NUM> is electrically coupled to one side of the source-drain path of transistor <NUM>, one side of the source-drain path of the transistor <NUM> of each thermal sensor <NUM><NUM> to <NUM>M, the output of tristate buffer <NUM>, one side of the source-drain path of transistor <NUM>, and one side of the source-drain path of transistor <NUM>. The other side of the source-drain path of transistor <NUM> is electrically coupled to one side of the source-drain path of transistor <NUM>. The gate of transistor <NUM> and the gate of transistor <NUM> are electrically coupled to a memory enable signal path <NUM>. The other side of the source drain path of transistor <NUM> is electrically coupled to one side of the source-drain path of the floating gate transistor <NUM> of each memory cell <NUM><NUM> to <NUM>N.

While memory cell <NUM><NUM> is illustrated and described herein, the other memory cells <NUM><NUM> to <NUM>N include a similar circuit as memory cell <NUM><NUM>. The other side of the source-drain path of floating gate transistor <NUM> is electrically coupled to one side of the source-drain path of transistor <NUM>. The gate of transistor <NUM> is electrically coupled to a memory enable signal path <NUM>. The other side of the source-drain path of transistor <NUM> is electrically coupled to one side of the source-drain path of transistor <NUM>. The gate of transistor <NUM> is electrically coupled to a bit enable signal path <NUM>. The other side of the source-drain path of transistor <NUM> is electrically coupled to a common or ground node <NUM>.

While thermal sensor <NUM><NUM> is illustrated and described herein, the other thermal sensors <NUM><NUM> to <NUM>M include a similar circuit as thermal sensor <NUM><NUM>. The gate of transistor <NUM> is electrically coupled to a thermal sensor enable signal path <NUM>. The other side of the source-drain path of transistor <NUM> is electrically coupled to the anode of thermal diode <NUM>. The cathode of thermal diode <NUM> is electrically coupled to a common or ground node <NUM>.

An enable input of tristate buffer <NUM> is electrically coupled to a test enable signal path <NUM>. The input of tristate buffer <NUM> is electrically coupled to the output of multiplexer <NUM> through a signal path <NUM>. A control input of multiplexer <NUM> is electrically coupled to a test mode signal path <NUM>. A first input of multiplexer <NUM> is electrically coupled to nozzle column <NUM> through a signal path <NUM>. A second input of multiplexer <NUM> is electrically coupled to nozzle column <NUM> through a signal path <NUM>. Nozzle column <NUM> is electrically coupled to a fire interface <NUM> and a data interface <NUM>.

The gate of transistor <NUM> is electrically coupled to a timer elapsed signal path <NUM>. The other side of the source-drain path of transistor <NUM> is electrically coupled to a common or ground node <NUM>. The gate of transistor <NUM> is electrically coupled to a crack detector enable signal path <NUM>. The other side of the source-drain path of transistor <NUM> is electrically coupled to one side of crack detector <NUM>. The other side of crack detector <NUM> is electrically coupled to a common or ground node <NUM>.

The memory enable signal on memory enable signal path <NUM> determines whether a memory cell <NUM><NUM> to <NUM>N may be accessed. In response to a logic high memory enable signal, transistors <NUM>, <NUM>, and <NUM> are turned on (i.e., conducting) to enable access to memory cells <NUM><NUM> to <NUM>N. In response to a logic low memory enable signal, transistors <NUM>, <NUM>, and <NUM> are turned off to disable access to memory cells <NUM><NUM> to <NUM>N. With a logic high memory enable signal, a bit enable signal may be activated to access a selected memory cell <NUM><NUM> to <NUM>N. With a logic high bit enable signal, transistor <NUM> is turned on to access the corresponding memory cell. With a logic low bit enable signal, transistor <NUM> is turned off to block access to the corresponding memory cell. With a logic high memory enable signal and a logic high bit enable signal, the floating gate transistor <NUM> of the corresponding memory cell may be accessed for read and write operations through sense pad <NUM>. In one example, the memory enable signal may be based on a data bit stored in a configuration register, such as configuration register <NUM> of <FIG>. In another example, the memory enable signal may be based on data passed to circuit <NUM> from a fluid ejection system, such as fluid ejection system <NUM> to be described below with reference to <FIG>.

Each thermal sensor <NUM><NUM> to <NUM>M may be enabled or disabled via a corresponding thermal sensor enable signal on thermal sensor enable signal path <NUM>. In response to a logic high thermal sensor enable signal, the transistor <NUM> for the corresponding thermal sensor <NUM><NUM> to <NUM>M is turned on to enable the thermal sensor by electrically connecting thermal diode <NUM> to sense pad <NUM>. In response to a logic low thermal sensor enable signal, the transistor <NUM> for the corresponding thermal sensor <NUM><NUM> to <NUM>M is turned off to disable the thermal sensor by electrically disconnecting thermal diode <NUM> from sense pad <NUM>. With a thermal sensor enabled, the thermal sensor may be read through sense pad <NUM>, such as by applying a current to sense pad <NUM> and sensing a voltage on sense pad <NUM> indicative of the temperature. In one example, the thermal sensor enable signal may be based on data stored in a configuration register, such as configuration register <NUM> of <FIG>. In another example, the thermal sensor enable signal may be based on data passed to circuit <NUM> from a fluid ejection system.

Tristate buffer <NUM> may be enabled or disabled in response to the test enable signal on test enable signal path <NUM>. In response to a logic high test enable signal, tristate buffer <NUM> is enabled to pass signals from signal path <NUM> to sense pad <NUM>. In response to a logic low test enable signal, tristate buffer <NUM> is disabled and outputs a high impedance signal to sense pad <NUM>. Nozzle column <NUM> may include a shift register and a delay circuit used to fire fluid actuation devices. The test mode signal on test mode signal path <NUM> determines whether the shift register or the delay circuit of the nozzle column <NUM> is to be tested and controls the multiplexer <NUM> accordingly. To test the shift register of nozzle column <NUM>, data is passed to nozzle column <NUM> through data interface <NUM> and shifted out of the shift register to signal path <NUM> and through multiplexer <NUM> and tristate buffer <NUM> to sense pad <NUM>. To test the delay circuit of nozzle column <NUM>, a fire signal on fire interface <NUM> is passed to nozzle column <NUM>. After passing through the delay circuit, the delayed fire signal is passed to signal path <NUM> and through multiplexer <NUM> and tristate buffer <NUM> to sense pad <NUM>. In one example, the test enable signal and the test mode signal may be based on data stored in a configuration register, such as configuration register <NUM> of <FIG>. In another example, the test enable signal and the test mode signal may be based on data passed to circuit <NUM> from a fluid ejection system.

Transistor <NUM> may provide a pulldown device, which is enabled in response to a timer elapsed signal on timer elapsed signal path <NUM>. The timer elapsed signal is provided by a timer, such as timer <NUM> of <FIG>. In response to a logic low timer elapsed signal, transistor <NUM> is turned off. In response to a logic high timer elapsed signal, transistor <NUM> is turned on to pull the signal on contact pad <NUM> to the voltage of the common or ground node <NUM>. In one example, the timer that generates the timer elapsed signal may be enabled or disabled based on data stored in a configuration register, such as configuration register <NUM> of <FIG>. In another example, the timer that generates the timer elapsed signal may be enabled or disabled based on data passed to circuit <NUM> from a fluid ejection system.

Crack detector <NUM> may be enabled or disabled in response to the crack detector enable signal on crack detector enable signal path <NUM>. In response to a logic high crack detector enable signal, the transistor <NUM> is turned on to enable crack detector <NUM> by electrically connecting crack detector <NUM> to sense pad <NUM>. In response to a logic low crack detector enable signal, the transistor <NUM> is turned off to disable the crack detector <NUM> by electrically disconnecting crack detector <NUM> from sense pad <NUM>. With crack detector <NUM> enabled, the crack detector <NUM> may be read through sense pad <NUM>, such as by applying a current or voltage to sense pad <NUM> and sensing a voltage or current, respectively, on sense pad <NUM> indicative of the state of crack detector <NUM>. In one example, the crack detector enable signal may be based on data stored in a configuration register, such as configuration register <NUM> of <FIG>. In another example, the crack detector enable signal may be based on data passed to circuit <NUM> from a fluid ejection system.

The fire interface <NUM> and the data interface <NUM> may each include a contact pad, a pin, a bump, or a wire. In one example, each of the fire interface <NUM>, the data interface <NUM>, and the sense pad <NUM> is configured to contact a corresponding printer-side contact to transmit signals to and from the printer-side contacts. Accordingly, through a single sense pad <NUM>, a printer may be connected to memory cells <NUM><NUM> to <NUM>N, thermal sensors <NUM><NUM> to <NUM>M, nozzle column <NUM>, pulldown device <NUM>, and crack detector <NUM>.

<FIG> illustrates one example of a fluid ejection die <NUM> and <FIG> illustrates an enlarged view of the ends of fluid ejection die <NUM>. In one example, fluid ejection die <NUM> includes integrated circuit <NUM> of <FIG>, integrated circuit <NUM> of <FIG>, integrated circuit <NUM> of <FIG>, integrated circuit <NUM> of <FIG>, integrated circuit <NUM> of <FIG>, integrated circuit <NUM> of <FIG>, integrated circuit <NUM> of <FIG>, or circuit <NUM> of <FIG>. Die <NUM> includes a first column <NUM> of contact pads, a second column <NUM> of contact pads, and a column <NUM> of fluid actuation devices <NUM>.

The second column <NUM> of contact pads is aligned with the first column <NUM> of contact pads and at a distance (i.e., along the Y axis) from the first column <NUM> of contact pads. The column <NUM> of fluid actuation devices <NUM> is disposed longitudinally to the first column <NUM> of contact pads and the second column <NUM> of contact pads. The column <NUM> of fluid actuation devices <NUM> is also arranged between the first column <NUM> of contact pads and the second column <NUM> of contact pads. In one example, fluid actuation devices <NUM> are nozzles or fluidic pumps to eject fluid drops.

In one example, the first column <NUM> of contact pads includes six contact pads. The first column <NUM> of contact pads may include the following contact pads in order: a data contact pad <NUM>, a clock contact pad <NUM>, a logic power ground return contact pad <NUM>, a multipurpose input/output contact (e.g., sense) pad <NUM>, a first high voltage power supply contact pad <NUM>, and a first high voltage power ground return contact pad <NUM>. Therefore, the first column <NUM> of contact pads includes the data contact pad <NUM> at the top of the first column <NUM>, the first high voltage power ground return contact pad <NUM> at the bottom of the first column <NUM>, and the first high voltage power supply contact pad <NUM> directly above the first high voltage power ground return contact pad <NUM>. While contact pads <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> are illustrated in a particular order, in other examples the contact pads may be arranged in a different order.

In one example, the second column <NUM> of contact pads includes six contact pads. The second column <NUM> of contact pads may include the following contact pads in order: a second high voltage power ground return contact pad <NUM>, a second high voltage power supply contact pad <NUM>, a logic reset contact pad <NUM>, a logic power supply contact pad <NUM>, a mode contact pad <NUM>, and a fire contact pad <NUM>. Therefore, the second column <NUM> of contact pads includes the second high voltage power ground return contact pad <NUM> at the top of the second column <NUM>, the second high voltage power supply contact pad <NUM> directly below the second high voltage power ground return contact pad <NUM>, and the fire contact pad <NUM> at the bottom of the second column <NUM>. While contact pads <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> are illustrated in a particular order, in other examples the contact pads may be arranged in a different order.

In one example, data contact pad <NUM> may provide data interface <NUM> of <FIG>, data interface <NUM> of <FIG>, or data interface <NUM> of <FIG>. Multipurpose input/output contact (e.g., sense) pad <NUM> may provide sense interface <NUM> of <FIG>, sense interface <NUM> of <FIG>, sense interface <NUM> of <FIG>, sense interface <NUM> of <FIG>, or sense pad <NUM> of <FIG>. Fire contact pad <NUM> may provide fire interface <NUM> of <FIG>, fire interface <NUM> of <FIG>, or fire interface <NUM> of <FIG>.

Data contact pad <NUM> may be used to input serial data to die <NUM> for selecting fluid actuation devices, memory bits, thermal sensors, configuration modes (e.g. via a configuration register), etc. Data contact pad <NUM> may also be used to output serial data from die <NUM> for reading memory bits, configuration modes, status information (e.g., via a status register), etc. Clock contact pad <NUM> may be used to input a clock signal to die <NUM> to shift serial data on data contact pad <NUM> into the die or to shift serial data out of the die to data contact pad <NUM>. Logic power ground return contact pad <NUM> provides a ground return path for logic power (e.g., about <NUM> V) supplied to die <NUM>. In one example, logic power ground return contact pad <NUM> is electrically coupled to the semiconductor (e.g., silicon) substrate <NUM> of die <NUM>. Multipurpose input/output contact pad <NUM> may be used for analog sensing and/or digital test modes of die <NUM>.

First high voltage power supply contact pad <NUM> and second high voltage power supply contact pad <NUM> may be used to supply high voltage (e.g., about <NUM> V) to die <NUM>. First high voltage power ground return contact pad <NUM> and second high voltage power ground return contact pad <NUM> may be used to provide a power ground return (e.g., about <NUM> V) for the high voltage power supply. The high voltage power ground return contact pads <NUM> and <NUM> are not directly electrically connected to the semiconductor substrate <NUM> of die <NUM>. The specific contact pad order with the high voltage power supply contact pads <NUM> and <NUM> and the high voltage power ground return contact pads <NUM> and <NUM> as the innermost contact pads may improve power delivery to die <NUM>. Having the high voltage power ground return contact pads <NUM> and <NUM> at the bottom of the first column <NUM> and at the top of the second column <NUM>, respectively, may improve reliability for manufacturing and may improve ink shorts protection.

Logic reset contact pad <NUM> may be used as a logic reset input to control the operating state of die <NUM>. Logic power supply contact pad <NUM> may be used to supply logic power (e.g., between about <NUM> V and <NUM> V, such as <NUM> V) to die <NUM>. Mode contact pad <NUM> may be used as a logic input to control access to enable/disable configuration modes (i.e., functional modes) of die <NUM>. Fire contact pad <NUM> may be used as a logic input to latch loaded data from data contact pad <NUM> and to enable fluid actuation devices or memory elements of die <NUM>.

Die <NUM> includes an elongate substrate <NUM> having a length <NUM> (along the Y axis), a thickness <NUM> (along the Z axis), and a width <NUM> (along the X axis). In one example, the length <NUM> is at least twenty times the width <NUM>. The width <NUM> may be <NUM> or less and the thickness <NUM> may be less than <NUM> microns. The fluid actuation devices <NUM> (e.g., fluid actuation logic) and contact pads <NUM>-<NUM> are provided on the elongate substrate <NUM> and are arranged along the length <NUM> of the elongate substrate. Fluid actuation devices <NUM> have a swath length <NUM> less than the length <NUM> of the elongate substrate <NUM>. In one example, the swath length <NUM> is at least <NUM>. The contact pads <NUM>-<NUM> may be electrically coupled to the fluid actuation logic. The first column <NUM> of contact pads may be arranged near a first longitudinal end <NUM> of the elongate substrate <NUM>. The second column <NUM> of contact pads may be arranged near a second longitudinal end <NUM> of the elongate substrate <NUM> opposite to the first longitudinal end <NUM>.

<FIG> is a block diagram illustrating one example of a fluid ejection system <NUM>. Fluid ejection system <NUM> includes a fluid ejection assembly, such as printhead assembly <NUM>, and a fluid supply assembly, such as ink supply assembly <NUM>. In the illustrated example, fluid ejection system <NUM> also includes a service station assembly <NUM>, a carriage assembly <NUM>, a print media transport assembly <NUM>, and an electronic controller <NUM>. While the following description provides examples of systems and assemblies for fluid handling with regard to ink, the disclosed systems and assemblies are also applicable to the handling of fluids other than ink.

Printhead assembly <NUM> includes at least one printhead or fluid ejection die <NUM> previously described and illustrated with reference to <FIG>, which ejects drops of ink or fluid through a plurality of orifices or nozzles <NUM>. In one example, the drops are directed toward a medium, such as print media <NUM>, so as to print onto print media <NUM>. In one example, print media <NUM> includes any type of suitable sheet material, such as paper, card stock, transparencies, Mylar, fabric, and the like. In another example, print media <NUM> includes media for three-dimensional (3D) printing, such as a powder bed, or media for bioprinting and/or drug discovery testing, such as a reservoir or container. In one example, nozzles <NUM> are arranged in at least one column or array such that properly sequenced ejection of ink from nozzles <NUM> causes characters, symbols, and/or other graphics or images to be printed upon print media <NUM> as printhead assembly <NUM> and print media <NUM> are moved relative to each other.

Ink supply assembly <NUM> supplies ink to printhead assembly <NUM> and includes a reservoir <NUM> for storing ink. As such, in one example, ink flows from reservoir <NUM> to printhead assembly <NUM>. In one example, printhead assembly <NUM> and ink supply assembly <NUM> are housed together in an inkjet or fluid-jet print cartridge or pen. In another example, ink supply assembly <NUM> is separate from printhead assembly <NUM> and supplies ink to printhead assembly <NUM> through an interface connection <NUM>, such as a supply tube and/or valve.

Carriage assembly <NUM> positions printhead assembly <NUM> relative to print media transport assembly <NUM>, and print media transport assembly <NUM> positions print media <NUM> relative to printhead assembly <NUM>. Thus, a print zone <NUM> is defined adjacent to nozzles <NUM> in an area between printhead assembly <NUM> and print media <NUM>. In one example, printhead assembly <NUM> is a scanning type printhead assembly such that carriage assembly <NUM> moves printhead assembly <NUM> relative to print media transport assembly <NUM>. In another example, printhead assembly <NUM> is a non-scanning type printhead assembly such that carriage assembly <NUM> fixes printhead assembly <NUM> at a prescribed position relative to print media transport assembly <NUM>.

Service station assembly <NUM> provides for spitting, wiping, capping, and/or priming of printhead assembly <NUM> to maintain the functionality of printhead assembly <NUM> and, more specifically, nozzles <NUM>. For example, service station assembly <NUM> may include a rubber blade or wiper which is periodically passed over printhead assembly <NUM> to wipe and clean nozzles <NUM> of excess ink. In addition, service station assembly <NUM> may include a cap that covers printhead assembly <NUM> to protect nozzles <NUM> from drying out during periods of non-use. In addition, service station assembly <NUM> may include a spittoon into which printhead assembly <NUM> ejects ink during spits to ensure that reservoir <NUM> maintains an appropriate level of pressure and fluidity, and to ensure that nozzles <NUM> do not clog or weep. Functions of service station assembly <NUM> may include relative motion between service station assembly <NUM> and printhead assembly <NUM>.

Electronic controller <NUM> communicates with printhead assembly <NUM> through a communication path <NUM>, service station assembly <NUM> through a communication path <NUM>, carriage assembly <NUM> through a communication path <NUM>, and print media transport assembly <NUM> through a communication path <NUM>. In one example, when printhead assembly <NUM> is mounted in carriage assembly <NUM>, electronic controller <NUM> and printhead assembly <NUM> may communicate via carriage assembly <NUM> through a communication path <NUM>. Electronic controller <NUM> may also communicate with ink supply assembly <NUM> such that, in one implementation, a new (or used) ink supply may be detected.

Electronic controller <NUM> receives data <NUM> from a host system, such as a computer, and may include memory for temporarily storing data <NUM>. Data <NUM> may be sent to fluid ejection system <NUM> along an electronic, infrared, optical or other information transfer path. Data <NUM> represent, for example, a document and/or file to be printed. As such, data <NUM> form a print job for fluid ejection system <NUM> and includes at least one print job command and/or command parameter.

In one example, electronic controller <NUM> provides control of printhead assembly <NUM> including timing control for ejection of ink drops from nozzles <NUM>. As such, electronic controller <NUM> defines a pattern of ejected ink drops which form characters, symbols, and/or other graphics or images on print media <NUM>. Timing control and, therefore, the pattern of ejected ink drops, is determined by the print job commands and/or command parameters. In one example, logic and drive circuitry forming a portion of electronic controller <NUM> is located on printhead assembly <NUM>. In another example, logic and drive circuitry forming a portion of electronic controller <NUM> is located off printhead assembly <NUM>.

Claim 1:
An integrated circuit (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) to drive a plurality of fluid actuation devices (<NUM>), the integrated circuit (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) comprising:
an interface (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) to contact a single printer-side contact to transmit signals to and from the single printer-side contact;
an analog circuit (<NUM>, <NUM>, <NUM>) to output an analog signal to the interface (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>);
a pulldown device (<NUM>, <NUM>, <NUM>) coupled to the interface (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>); and
a timer (<NUM>, <NUM>) to override the analog signal on the interface (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) from the analog circuit (<NUM>, <NUM>, <NUM>) by activating the pulldown device (<NUM>, <NUM>, <NUM>) in response to the timer (<NUM>, <NUM>) elapsing.