Figure 23: P.C. board and components layout of the circuits of Figg. 20, 21, 22.

Ω)

Components

Recommended

value

Purpose

If larger

If smaller

Allowed range

Min.

Max.

1

Ω

Current sensing

tacho loop.

Tacho loop do

not regulate

0

1.5

Ω

Current sensing

V/I loop.

Instability may

occur.

Motor regulator;

undercompens.

22K

Ω - 68nF

Spike filtering.

Slow V/I

regulator

response.

High output

ripple.

68nF

Pulse transf.

33nF

100nF

15K

Ω - 47nF

Current source

programming to

obtain a 50%

duty cycle

67K

Ω

30KW

47K

Ω trim.

Set of speed.

Low speed.

High speed

0

Polyester 100nF

Optimization of

integrator ripple

and loop

response time.

Lower ripple,

slower tacho

regulator

response.

Higher ripple,

faster response.

10nF

470nF

220K

Ω - 220nF

Fast response

with no

overshoot.

Depending on electrmechanical

system.

10nF

470nF

A

TDA7272A

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