Philips UM10155 - Adding External Features; Electronic Enabling;Disabling of the Amplifier

UM10155_2 © Koninklijke Philips Electronics N.V. 2006. All rights reserved.
User manual Rev. 02 — 5 September 2006 8 of 12
Philips Semiconductors
UM10155
Discrete Class D High Power Audio Amplifier
6. Adding external features
6.1 Electronic 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 kΩ).
Enable signal:
(HIGH = enable)
(LOW = disable)
Fig 8. Enabling/disabling of the amplifier
001aaf155
J3
J4
J5
J6
J10
J11
J8
J9
J7
J1
J2
enable
signal
C5
class D amp.
version 1.00
international
patent
WO 03/090343
PHILIPS
Q14
Q13
C7
+
+
+
+
+
+
C14
C11
C17
C15
L1
C19