Download presentation

Presentation is loading. Please wait.

1
**Improved Howland Current Pump Stability**

Tim Green Senior Analog Applications Engineers Precision Analog Linear Applications July 19, 2013

2
**Improved Howland Current Pump IL Accuracy Circuit**

RT allows for trim to optimum ZOUT and improved DC Accuracy Ideal Op Amp

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
**Improved Howland Current Pump Simplified Equation**

5
**Improved Howland AC Analysis**

RI RF Op Amp sees differential [(-IN) – (+IN)] feedback b = b- - b+ (Must be positive number else oscillation!)

6
**Improved Howland AC Analysis**

- +

7
**Improved Howland 1/b Plot - Full Load**

8
**Improved Howland 1/b Calculation No Load & Full Load**

IL RO fz fp DC 1/b Hi-f 1/b No Load 0A 6.29W 75.8Hz 31.83kHz 17.62dB 77.17dB Full Load 1A 0.308W 44.08Hz 19.45dB 77.15dB Change in RO from No Load to Full Load has no significant impact on the 1/b Plot

9
**Improved Howland Tina Transient Analysis Circuit**

RI RF

10
**Improved Howland Tina Transient Analysis Results**

11
**Improved Howland Modified 1/b for Stability**

12
**Improved Howland AC Analysis Final Design for Stability**

RI RF

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

fcl

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

fcl

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

RI RF

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

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

RI RF

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

Similar presentations

OK

Tim Green, Linear Applications 520-750-2193 1 Measuring Zo in SPICE Preferred Test Circuits and Why? Brought to you by: The Wizard of.

Tim Green, Linear Applications 520-750-2193 1 Measuring Zo in SPICE Preferred Test Circuits and Why? Brought to you by: The Wizard of.

© 2017 SlidePlayer.com Inc.

All rights reserved.

Ads by Google

Business plan ppt on retail A ppt on loch ness monster videos Ppt on natural disaster tsunami Ppt on industrial development in gujarat Ppt on regular expression cheat Ppt on aerobics music Ppt on forward rate agreement calculator Ppt on trade fair 2016 Ppt on save water and electricity Ppt on standing order act materials