Adding External Features; Electronic Enabling/Disabling Of The Amplifier - Philips UM10155 User Manual

Philips Semiconductors

6. Adding external features

6.1 Electronic enabling/disabling of the amplifier
UM10155_2
User manual
enable
signal
Enable signal:
(HIGH = enable)
(LOW = disable)
Fig 8. Enabling/disabling of the amplifier
Electronic enabling/disabling can be used for:
•
Implementing pop-less and click-less start-up and shut-down
•
Shutting down the amplifier in case of a failure condition
(short-circuit/overcurrent/over-temperature)
The transistor in the enabling/disabling circuit must be low current, 60 V type (such as
BC846) and the resistor must limit the base current of the transistor to approximately
1 mA (in case of logic level driving, that would mean R = 4.7 k ).
Rev. 02 — 5 September 2006
Discrete Class D High Power Audio Amplifier
PHILIPS
class D amp.
version 1.00
J3
J4
+
J1
C11
+
C5
J2
Q14
Q13
+
C7
+
international C14
patent
WO 03/090343
UM10155
+
J5
J6
C17
C15
L1
J10
J11
J7
+
J8
J9
C19
001aaf155
© Koninklijke Philips Electronics N.V. 2006. All rights reserved.
8 of 12