Presentation is loading. Please wait.

Presentation is loading. Please wait.

1 Improved Howland Current Pump Stability Tim Green Senior Analog Applications Engineers Precision Analog Linear Applications July 19, 2013.

Similar presentations


Presentation on theme: "1 Improved Howland Current Pump Stability Tim Green Senior Analog Applications Engineers Precision Analog Linear Applications July 19, 2013."— Presentation transcript:

1 1 Improved Howland Current Pump Stability Tim Green Senior Analog Applications Engineers Precision Analog Linear Applications July 19, 2013

2 2 Improved Howland Current Pump IL Accuracy Circuit RT allows for trim to optimum Z OUT and improved DC Accuracy Ideal Op Amp

3 3 Improved Howland Current Pump V-I DC Accuracy Calculations 1% Resistors (w/RT=0) could yield only 9% Accuracy at T=25°C Still useful for V-I control in Motors/Valves V-Torque Control Outer position feedback adjusts V for final position

4 4 Improved Howland Current Pump Simplified Equation

5 5 Improved Howland AC Analysis Op Amp sees differential [(-IN) – (+IN)] feedback = (Must be positive number else oscillation!) RF RI

6 6 Improved Howland AC Analysis + -

7 7 Improved Howland 1/ Plot - Full Load

8 8 Improved Howland 1/ Calculation No Load & Full Load ILROfzfp DC 1/ Hi-f 1/ No Load0A Hz31.83kHz17.62dB77.17dB Full Load1A Hz31.83kHz19.45dB77.15dB Change in RO from No Load to Full Load has no significant impact on the 1/ Plot

9 9 Improved Howland Tina Transient Analysis Circuit RF RI

10 10 Improved Howland Tina Transient Analysis Results

11 11 Improved Howland Modified 1/ for Stability

12 12 Improved Howland AC Analysis Final Design for Stability RF RI

13 13 Improved Howland AC Analysis 1/ - Final Design for Stability fcl

14 14 Improved Howland AC Analysis Loop Gain - Final Design for Stability fcl

15 15 Improved Howland AC Transfer Analysis IL/VIN - Final Design for Stability RF RI

16 16 Improved Howland AC Transfer Analysis IL/VIN - Final Design for Stability

17 17 Improved Howland Transient Analysis IL/VIN - Final Design for Stability RF RI

18 18 Improved Howland Transient Analysis IL/VIN - Final Design for Stability


Download ppt "1 Improved Howland Current Pump Stability Tim Green Senior Analog Applications Engineers Precision Analog Linear Applications July 19, 2013."

Similar presentations


Ads by Google