TK-5210
(
G
)
24
CIRCUIT DESCRIPTION
IC701
AVR IC
F700
Battery
terminal
+B
5TC
5T
5C
33C
Q700
5R
Q701
5UC
5MCS
5M
Q703,Q704
IC712
5RC
SBC
SBC
IC702
AVR IC
/SAVE
IC707
DCDC
IC706
AVR IC
IC704
AVR IC
IC700
AVR IC
IC713
Switched
Capacitor Voltage
Doubling Inverter
36MC
36MC
33M
IC705
AVR IC
33A
IC710
AVR IC
15M
IC709
DCDC
15V
IC708
DCDC
SBC
SB
LCDCNT
DAC6
Q707,Q708
7. Power Supply Circuit
The power supply voltage (+B) is supplied from the bat-
tery terminal, and is then passed through the fuse (F700).
If +B voltage is detected above 5.6V by the voltage de-
tection IC (IC16), IC17 CE pin (pin 6) becomes high and IC17
outputs 3.1V (pin 3). Additionally, when VOL SW is ON, the
3.6V and 15V DC/DC converter (IC707, IC708) CE pin (pin 4)
becomes high and 3.6V power source turns ON.
The output from the 3.6V DC/DC converter (IC707) pro-
vides the power source for three regulators (IC705, IC706,
IC710) and 1.5V DC/DC converter (IC709). After these parts
became ON, Flash (IC1), DSP (IC3), SRAM (IC4), ASIC (IC10)
start to operate. After the ASIC starts up, it begins control-
ling three regulators (IC701, IC702, IC704) with the SBC and
/SAVE signal. And after that, one regulator (IC700) is con-
trolled by the 5M signal.
The output voltage from IC701 is switched by 5RC signal
(which is turned on while receiving) or 5TC signal (which is
turned on while transmitting). These signals are controlled
by the ASIC (IC10).
The output voltage from IC700 is controlled by Q703
and Q704, and is used as a power source for 5MCS, for an
optional accessory which is connected to the universal con-
nector (CN505).
Fig. 9 Power supply circuit