This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

[FAQ] What precision amplifiers should I use in my Infusion pump design

Infusion pumps have strict regulations that control their safety features such as the air-in-line detection and the pressure/occlusion sensors. There are also many different types of infusion pumps along with locations they may be used. This can make the task of designing an infusion pump system difficult. With TI’s wide range of options however, we will have a solution that works for you. The systems that precision amplifiers are most commonly found in are the:

  1. air-in-line sensor
  2. pressure/occlusion sensor
  3. motor current sensing.

The air-in-line sensor is used to prevent delivering large doses of air to a patient’s circulatory system. This signal path will use either an optical or ultrasonic sensor to detect bubbles. The amplifier in this signal chain will be used for signal conditioning into the ADC.

Specifications

OPA392

OPA2376

OPA192

Supply Voltage (V)

1.7 – 5.5

2.2 – 5.5

4.5 – 36

Vos max (mV) (max)

0.01

0.025

0.025

Drift typ (uV/C) (typ)

0.1

0.32

0.1

GBW (MHz)

13

5.5

10

Slew Rate (V/µs)

4.8

2

20

Voltage noise (nV/rthz)

6

7.5

5.5

Bias Current (pA) (typ)

0.8

10

20

Output Current (mA)

65

30

65

 

The occlusion sensors are used to prevent tube blockages that could lead to dangerous venous pressures or improper dosing. For occlusion sensing a strain gauge will be connected to the tube to measure the pressure on the line. For the highest accuracy an INA or op amp in a differential configuration will be used here.

Specifications

INA333

INA823

INA818

Supply Voltage (V)

1.8 – 5.5

2.7 – 36

4.5 – 36

Vos max (mV)

0.025

0.100

0.035

CMRR (min) (dB)

100

115

110

Voltage noise (nV/rthz)

50

21

8

Bias Current (typ) (pA)

70

10.000

150

Quiescent current (mA)

0.05

0.2

0.35

 

A current sensing amplifier may be used to sense the current drive from any motors in the infusion pump.  

Specifications

OPA391

OPA392

OPA333

Supply Voltage (V)

1.7 – 5.5

1.7 - 5.5

1.8 – 5.5

Vos max (mV)

0.045

0.01

0.01

GBW (MHz)

1

13

0.35

Slew Rate (V/µs)

1

4.8

0.16

Rail-to-Rail

In, Out

In, Out

In, Out

Bias Current (pA) (Max)

0.8

0.8

130

Output Current (mA)

60

65

5

For additional information on infusion pumps please see our infusion pump product page.

For more information see this 6406.Infusion pumps.pptx