Infusion Pump Safety Circuit Using PWM Signal Duplication
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Solution Overview
Problem
Conventional medical infusion systems face challenges in ensuring safe and controlled delivery of substances due to potential motor malfunctions, particularly short circuits, which existing solutions either require complex DC-DC converters or additional dedicated circuits.
Innovation Solution
A medical infusion system incorporating a control signal generator, a safety circuit, and a switching device, where the pump motor and switching device form a power supply circuit, using pulse width modulation (PWM) signals to control the power supply and apply an 'off' potential in case of prolonged 'on' signal duration to prevent overdose, with a safety circuit configured to interrupt the power supply if the 'on' potential persists beyond a predetermined time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a motor requiring multiple voltages from battery is used to prevent short circuit operation, then motor safety is improved, but device complexity increases due to need for DC-DC step-up converter
Solution Approach 1:
The patent uses a safety circuit that copies the control signal from the control electronics and applies it to the motor driver in a simplified manner. Instead of using a complex DC-DC converter, the safety circuit creates a duplicate control path that directly controls the motor power supply, eliminating the need for additional voltage conversion hardware while maintaining safety functionality.
2Reliability
If a dedicated safety circuit is added next to control electronics to regulate infused amount, then safety is improved, but device complexity increases
Solution Approach 1:
The patent merges the safety circuit functionality with the existing control electronics by having the safety circuit receive control signals from the same control electronics that regulate the infused amount. This integration allows the safety circuit to operate in coordination with the primary control system without requiring completely separate dedicated circuits, thereby improving safety while minimizing the increase in device complexity.
Data Source
AI summary
A medical infusion system with pulse width modulation and a safety circuit and a method thereof are disclosed. Embodiments of the system include a switching device and a pump motor, wherein the pump motor and the switching device are connected in series and constitute a power supply circuit to be connected to a power supply. Embodiments of the system further includes a control signal generator configured to generate a control signal e.g. PWM, and which is connected to input of the safety circuit. Output of the safety circuit is connected to a control input of the switching device such that the pump motor will not operate if there is no control signal applied to the input of the safety circuit.