Nozzle Sensor Voltage Reduction Device for Overvoltage Protection
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Solution Overview
Problem
Fluid ejection systems face damage from overvoltage due to high voltage rise and fall waveforms coupled to nozzle sensors during firing, leading to potential destruction of sense circuitry and the fluid ejection die.
Innovation Solution
A voltage reduction device is implemented to maintain a low voltage bias on nozzle sensors, using N-type or P-type switches and diodes to prevent excessive voltage buildup, ensuring the sensors operate within safe voltage limits during firing pulses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high voltage firing pulses are applied to fluid ejectors, then fluid droplet ejection is achieved, but overvoltage damages nozzle sensors and sense circuitry
Solution Approach 1:
A voltage reduction device is introduced as an intermediary component between the high voltage firing pulse source and the nozzle sensors. This device actively monitors and reduces the voltage level, allowing the high power firing pulses to operate the fluid ejectors while preventing excessive voltage from reaching and damaging the sensitive nozzle sensors and sense circuitry.
Solution Approach 2:
The voltage reduction device is activated before the high voltage firing pulse is applied to preemptively establish voltage protection. By maintaining a low voltage bias on the nozzle sensors prior to and during the firing event, the system prevents overvoltage conditions from developing, thereby protecting sensitive components before damage can occur.
2Reliability
If voltage reduction devices are added to protect sensors, then sensor damage is prevented, but device complexity increases
Solution Approach 1:
The voltage reduction device is designed to serve multiple functions within the fluid ejection system. It not only protects nozzle sensors from overvoltage damage but also maintains proper voltage biasing for sensor operation and works cooperatively with the firing control circuitry. This multi-functionality justifies the added complexity by providing comprehensive voltage management and protection in a single integrated component.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Prevents damage to nozzle sensors and sense circuitry by maintaining a low voltage bias, allowing for safe operation and extended lifespan of fluid ejection systems.
Implementation Method 1
A voltage reduction device may be used to maintain a low voltage bias on the plurality of nozzle sensors
Implementation Method 2
using N-type or P-type switches and diodes to prevent excessive voltage buildup
Data Source
AI summary
Example implementations relate to low voltage bias of nozzle sensors. For example, a fluid ejection die according to the present disclosure may include a plurality of nozzles, and each nozzle may include a nozzle sensor and a fluid ejector, among other components. The fluid ejection die may also include a voltage reduction device to maintain a low voltage bias on the plurality of nozzle sensors during an operation of the plurality of nozzles. A plurality of sense circuits may be electrically coupled to a respective nozzle sensor among the plurality of nozzle sensors, and each sense circuit may evaluate a status of the respective nozzle after the operation.