Panasonic KX-TCD650RUC / KX-TCD650RUF Service Manual ▷ View online
88..11..55.. B
BU
UZZZZE
ER
R C
CIIR
RC
CU
UIITT ((S
SE
EE
E FFiigg.. 2255))
A square-wave signal from IC1 pin 68 is used to sound the buzzer via switching transistor T4. Various tones and cadences are
used dependent on function. Buzzer volume is varied by changing the duty cycle of the drive waveform. D10 provides
quenching of back-emf generated when T4 turns off.
used dependent on function. Buzzer volume is varied by changing the duty cycle of the drive waveform. D10 provides
quenching of back-emf generated when T4 turns off.
88..11..66.. A
AU
UD
DIIO
O P
PA
ATTH
H -- TTX
X A
AU
UD
DIIO
O ((S
SE
EE
E FFiigg.. 2255))
The audio signal from the microphone (TP36) enters the BBIC at pin 44. RF decoupling and signal conditioning are provided
by C17, R21, C14 and C15.
In the BBIC the signal passes through the analogue section where it is amplified and converted to a digital audio stream signal.
The burst mode controller processes this stream performing encryption and scrambling, adding the various other fields to
produce the GAP standard DECT frame, assigning to a time slot and channel etc. to emerge on pin 14 as TXDA.
by C17, R21, C14 and C15.
In the BBIC the signal passes through the analogue section where it is amplified and converted to a digital audio stream signal.
The burst mode controller processes this stream performing encryption and scrambling, adding the various other fields to
produce the GAP standard DECT frame, assigning to a time slot and channel etc. to emerge on pin 14 as TXDA.
88..11..77.. A
AU
UD
DIIO
O P
PA
ATTH
H -- R
RX
X A
AU
UD
DIIO
O ((S
SE
EE
E FFiigg.. 2255))
Audio from the receiver RXDA enters the BBIC on pin 10 as GAP standard DECT frames. It passes through the decoding
section burst mode controller where it separates out the frame information and performs de-encryption and de-scrambling as
required. It then goes to the DSP where it is turned back into analogue audio. This is amplified by the analogue front end and
emerges at pin 40 and 41. The telephone speaker is driven directly from the BBIC output ports.
section burst mode controller where it separates out the frame information and performs de-encryption and de-scrambling as
required. It then goes to the DSP where it is turned back into analogue audio. This is amplified by the analogue front end and
emerges at pin 40 and 41. The telephone speaker is driven directly from the BBIC output ports.
21
KX-TCD650RUC / KX-TCD650RUF
88..11..88.. C
CLLO
OC
CK
K G
GE
EN
NE
ER
RA
ATTIIO
ON
N ((S
SE
EE
E FFiigg.. 2255))
Fig. 25
A single clock generator in the BBIC uses an external crystal X1 to derive all clock frequencies used in the handset. The crystal
is tuned to the exact frequency of 10.368 MHz during manufacture.
The BBIC provides a reference clock signal S
is tuned to the exact frequency of 10.368 MHz during manufacture.
The BBIC provides a reference clock signal S
SY
YR
RII (pin 21, TP24) which is used to drive the PLL circuitry in the RF module. The
basic data rate for TTX
XD
DA
A (pin 14) and R
RX
XD
DA
A (pin 10) is 1.152 Mbits/s, which is 10.368MHz divided by 9.
22
KX-TCD650RUC / KX-TCD650RUF
88..11..99.. K
KE
EY
YB
BO
OA
AR
RD
D ((S
SE
EE
E FFiigg.. 2266))
The keyboard On button is connected directly to pin 33 and 28 of the BBIC. When pressed it turns the handset on and off.
All other keys are connected in a row/column matrix. They are scanned in five rows using scan pulses (only active when keys
are pressed) from IC1 pins 15 to 19. The five key matrix columns are input to the BBIC on pins 51, 52, 53, 57 and 58.
All other keys are connected in a row/column matrix. They are scanned in five rows using scan pulses (only active when keys
are pressed) from IC1 pins 15 to 19. The five key matrix columns are input to the BBIC on pins 51, 52, 53, 57 and 58.
88..11..1100.. LLC
CD
D D
DIIS
SP
PLLA
AY
Y ((S
SE
EE
E FFiigg.. 2266))
The LCD display receives data via a parrallel interface. Parrallel data is sent to the display via lines PL0 to PL35.
Fig. 26
23
KX-TCD650RUC / KX-TCD650RUF
88..11..1111.. B
BA
ATTTTE
ER
RY
Y S
SU
UP
PP
PLLY
Y ((S
SE
EE
E FFiigg.. 2277))
A switch mode boost converter is used to provide a 3.6V supply from the battery. This supply is sensed by the BBIC through
pin 26 (TP14) so that the switching rate can be controlled by a FET (T3) driven from pin 24 (TP13). A resistor on the Source
of the FET provides a current sense at pin 25 (TP12).
T3 switches the current through L1. When T3 switches off the back emf conducts through D16 and charges the reservoir cap
C4.
pin 26 (TP14) so that the switching rate can be controlled by a FET (T3) driven from pin 24 (TP13). A resistor on the Source
of the FET provides a current sense at pin 25 (TP12).
T3 switches the current through L1. When T3 switches off the back emf conducts through D16 and charges the reservoir cap
C4.
88..11..1122.. 22..6655V
V R
RE
EG
GU
ULLA
ATTO
OR
R ((S
SE
EE
E FFiigg.. 2277))
A 2.65V supply is provided for the BBIC and is regulated by the BBICs on board control signal LRB (pin 37).
This reference is fed to the base of T6 to keep the VREG+ line at 2.65V.
This reference is fed to the base of T6 to keep the VREG+ line at 2.65V.
88..11..1133.. B
BA
ATTTTE
ER
RY
Y C
CH
HA
AR
RG
GIIN
NG
G C
CIIR
RC
CU
UIITT ((S
SE
EE
E FFiigg.. 2277))
The supply for the battery comes from the charge terminals at J3 and J4. Battery charge rate is controlled by switching the
current through T7 such that the average charging current is 180mA. The current flow is monitored at pin 49 of the BBIC by
measuring the voltage across R56.
D21 protects against the high voltage present on the charge contacts (J3 and J4) when there is no battery in the handset. R42
and C50 provide a signal to the BBIC (pin 27) to detect that the handset has been placed on the base charger.
current through T7 such that the average charging current is 180mA. The current flow is monitored at pin 49 of the BBIC by
measuring the voltage across R56.
D21 protects against the high voltage present on the charge contacts (J3 and J4) when there is no battery in the handset. R42
and C50 provide a signal to the BBIC (pin 27) to detect that the handset has been placed on the base charger.
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KX-TCD650RUC / KX-TCD650RUF
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