A MOSFETPowerAmplifier with ErrorCorrection*
The rapid evolution of power MOSFETs during the design which utilizes the advantages of the power last few years has brought them to the point where they MOSFET while dealing with the drawbacks of the deare now very attractive for use in audio amplifier power vice. Although not taken to an extreme, the underlying output stages. Important improvements include inphilosophy of the design is that small-signal silicon is creased voltage, current, and dissipation ratings, reinexpensive, that is, that the overwhelming portion of duced "on" resistance, availability of complementary expense in a power amplifier is in items like the power pairs, and greatly reduced cost. Although a 75-W transformer, filter capacitors, power transistors, heat sinks, chassis, and related hardware. Thus, in order to MOSFET is still more expensive than a 150-W bipolar transistor, the premium is small when considered reltake full advantage of the performance achievable with ative to total amplifier cost and improved performance, the MOSFET output stage, a very-high-quality front The purpose of this paper is to demonstrate the level end and driver are provided. The driver, operating from of performance achievable with current technology and regulated boosted supplies, is capable of providing high to illustrate practical circuit techniques for achieving voltage and current swings to the power MOSFETs this performance, with good headroom. Output stage transconductance Power MOSFETs have several fundamental advandroop is dealt with by employing a simple but very effective output stage error-correction technique prorages over bipolar power transistors, most notably speed and freedom from secondary breakdown. The latter posed by Hawksford [1]. The resulting design achieves provides higher "usable" power dissipation, improved a 20-kHz total harmonic distortion figure of less than reliability, and freedom from safe-area limiter circuits, 0.0015% at an idle bias of only 150 mA.
Input
# A is a polynomial in Z[x] # L is a list of monic images mod p k # p is a prime, B is a bound on the coefficients of the factors of A N ← |L| if lcoeff(a) = 1 then m ← Π N i=1 tcoeff(L i) (mod p k) if m |tcoeff(a) then return false m ← ΠL, q ← a prime q = p if lcoeff(a) = 1 then m ← integer ratrecon(m) if m =FAIL then return false else m ← integer primitive part(m) if m ∞ > B then return false if lcoeff(m) | lcoeff(a) then return false if m |a (mod q) then return false if m|a then Q ← quotient, M ← m, return true end 'factorrpoly' In brief the rest of the algorithm is as follows: 1. Input A ∈ Z[x] 2. Remove integer content 3. Find square free factorizations mod log (deg A) primes 4. Pick " best " prime (see example) 5. Lift monic modular images, trial dividing at each step, use rational reconstruction if necessary 6. Trial divide combinations of the remaining " bad " factors until all factors in Z[x] have been found 7. Return factors in Z[x] from each square free factor and content from step 2
Comments on "The theory of transient intermodulation distortion"
The conditions for avoiding transient intermodulation distortion (TIMD) in a feedback amplifier have been overstated. There is no TIMD penalty whatsoever in using high loop gain around a forward path that has a dominant pole, provided the forward-path gain is concentrated after this dominant pole.