Philips FW-V720 - POWER 2001 Module; Circuit Details; Amplifier; Principle; Benefit of Super Class G

stage .8
POWER 2001 Module
(30 - 70W Version)
11-111-1
TABLE OF CONTENTS
Brief Circuit Description.........................................................................11-1
Block Diagram.......................................................................................11-3
Component Layout Mains part .............................................................11-4
Circuit Diagram Mains part ..................................................................11-5
Component Layout Power part ............................................................11-6
Circuit Diagram Power part ..................................................................11-7
Partslist .................................................................................................11-8
Circuit details:
Amplifier:
Attention: In the POWER 2001 module the power amplifier IC AN7591 is used as a bridge-amplifier.
Any connection from output to ground will destroy the outpout stages!
• Via the AMP_ON control line, connected to pins 6 (Stby), the power amplifiers are switched on/off by the µP.
High level (approx. 4,5V): power amplifiers switched on
Low level (approx. 0V): power amplifiers switched off
• Super class G - operation
The power amplifiers operate as so-called super class G - amplifiers:
The supply pins 12 (Vcc) are not just connected to one fixed DC-supply as in conventional amplifiers.
Dependent on the output power there are three different DC-voltages supplied to the power amplifiers:
⇒ +C1 (+20V) for low output power
⇒ +B1 (+29V) for medium output power
⇒ +A1 (+41V for high output power
Principle / benefit of Super Class G
Conventional power stage Class G amplifier Super class G amplifier
output signal
output signal
output signal
+A
+B
+C +C
+A
+B
+C
Voltage drop on power stage IC
Voltage drop on switching transistor(s)
Benefit - voltage drop on switching transistor(s) reduces total power dissipation
activating point +A activating point +B
activating point +A
Power
Power
dissipation
Power
Power
dissipation
Power
Power
dissipation
Output power
Benefit
Output power
%% %
Output power
Benefit
+C
+A
+A
+C
+A
+B
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1/3/16
Published in Heiloo, Holland.