Flashlight Leds Driver; Internal Microphone - Nokia NPL-4 Series Manual

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Led Mode
Blinking
On, but not blinking
Off

Flashlight LEDs driver

LED is supplied from VLED voltage throught current limiting circuit. Flashlight is con-
trolled by CallLED2 line (UEMEK). BJT driver controls the constant current generator.
CallLED2 line needs voltage matching for higher VLED voltage than battery voltage. Cur-
rent consumption will be 20mA.
- Driver will work as constant current generator increase or decrease the output voltage
for LEDs to keep the current stable. Serial resistance 33 R is used to create the current
limit with transistor Vbe voltage.

Internal microphone

The internal microphone capsule is mounted into the system connector assy, which is
connected to engine board with springs. Microphone is omni directional and it's con-
nected to the UEMEK microphone input MIC1P/N. The microphone input is symmetric
and the UEMEK (MICB1) provides bias voltage.
Copyright © 2005 Nokia Corporation. All rights reserved.
Issue 2 05/05
Table 29: LED modes and state of the drivers
VLED
Enabled
Enabled
Disabled
Figure 32: Flashlight Driver and Control
VLED
R=33Ω
CallLED2
System Module and User Interface
KLIGHT Notes
PWM pulse Klight PWM
High Klight high
state
Low Klight low
state
R=47Ω
NPL-4/5/
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