Benefon SPICA TDP-60-HN, Service Manual

Page: 111 / 128

1.3.1999
8tdb60gb.fm 2
Product: TDB-60-N/B /
7.0.1 TECHNICAL INFORMATION
Car amplifier for Benefon Spica/Titan NMT 450i HP
weight: 1190g
size (l x w x h): 190x110x60 mm
high power: 15 W
supply voltage: 10.8 - 15.6 V
power consumption
- charging off: app. 130 mA Ben car kit
- charging on: <1000 mA Ben car kit
- conversation mode, high power: <5000 mA Ben car kit
antenna connectors: TNC
cooling: DC fan
7.1 Functional description
The BeneBoost car amplifier increases the power of Benefon Spica or Titan to max.
15 watts. It also includes a front end amplifier for the received signal. When attached
to the phone holder, Benefon Spica or Titan takes control over the booster module,
switching the power on and changing the output power to appropriate level.
7.1.1 Transmitting section and power control
The signal from Benefon Spica or Titan is fed via connector V5 to a duplex filter X1,
which combines TX and RX chains at the phone end of the booster. When con-
nected to the booster via the car kit, the phone transmits at a low power level
(150mW). This signal is then amplified at a transistor Q2 and a power hybrid I1
before a duplex filter X2, which combines the TX and RX chains at the antenna end
of the booster.
The signal from a directional coupler is rectified with a biased schottky diode D1 and
filtered in a RC filter before a gain control consisting of dual OP-amp. I3 and transis-
tors Q3 and Q9. Control lines TX1, TX0 and HITEMP are used to change the power
level of the booster output. In the case that the output level is 15 W and the booster
has been overheated, the HITEMP control drops output power 3 dB down. The tran-
sistor Q6 enables/disables the power output with a TXON control. 15 W Power is set
with R31. A table below shows states of control lines and corresponding output
power levels.