PAK project goals

Short-term goals

  1. Finish the Closed Loop VAS+VF "Lin" topology (PAK-UG Ch4 6s2) using the effective Beta method. Next, use the basic push-pull output stage (complementary symmetry) including THD and w-THD estimates. This will complete the large signal equation solution for a complete power amplifier, at least at LF.
  2. Solution for the standard 3-stage enhanced Lin topology (with a differential input stage etc). First use a collector load resistor for the differential input stage (open loop then with overall shunt feedback). Next add a current mirror load. 
  3. Add temperature parameters: XTI to diodes and BJT's and Beta temp co. for each transistor and diode.
  4. Begin developing PAK-ME (Macro Enabled). This adds User Defined Functions to the spreadsheet which allows recursion to a specified accuracy (RelTol and AbsTol). Add Vce saturation, eg Beta-falls at the Vbc knee voltage.
  5. Introduce first-order HF effects into PAK-ME ".trans" analysis. Allows plotting of the nonlinear large signal response to an arbitrary waveform and includes nonlinear Cbe's for power transistor junctions. FFT can be utilised by exporting to a waveform file.

Numerical methods that sometimes fail to converge are avoided. Recursion is proposed for equation solutions involving approximations with guaranteed convergence since the first derivative is calculated directly from the Lambert W equations and discontinuities are avoided.

Longer-term goals

  1. Equation solutions for popular variants of the 3-stage power amplifier; various input stage options, various VAS options and various output stage options. EG, the 8 variations in Bob Cordell's book 'Designing Power Amplifiers' Ch3 'Power Amplifier Design Evolution'.
  2. Equation solutions for some of the other power amplifier topologies; including MOSFET's, Valves/tubes, SIT's and hybrids with any combination of these with BJT's.
  3. Post some of these equation solutions with comparisons and technical design information into Wikipedia or similar Open Source databases, textbooks and teaching notes.

The PAK project is Open Source and not for profit. Contributors can use Copyright.

 

For more information on this new approach see the PAK User Guide (Downloads) or FAQ's.