Sharp SL-5500 Service Manual page 25

PC-UM10M
2-10. DC/DC CONVERTER (TEA1206T)
(1) GENELAL DESCRIPTION
The TEA1206T is a fully integrated DC/DC converter. Efficient, compact
and dynamic power conversion is achieved using a novel, digitally con-
trolled concept like Pulse Width Modulation (PWM) or Pulse Frequency
Modulation (PFM), integrated low RDSon CMOS power switches with
low parasitic capacitances, and fully synchronous rectification.
(2) BLOCK DIAGRAM
4
LX
2
ILIM
I / V
CONVERTER
N-type
POWER
FET
6
GND
(3) PIN CONFIGURATION
U / D
ILIM
UPOUT / DININ
LX
(4) PINNING
SYMBOL PIN
U/D 1 conversion mode selection input
ILIM 2 current limit resistor connection
UPOUT/DNIN 3 upconversion output voltage downconver-
sion input voltage
LX 4 inductor connection
SYNC 5 synchronization clock input
GND 6 ground
FB 7 feedback input
SHDWN 8 shut-down input
P-type POWER FET
I / V
CONVERTER
TEMPERATURE
PROTECTION
13 MHz SYNC
OSCILLATOR GATE
5
SYNC
SHDWN
FB
TEA 1206T
GND
SYNC
MGM667
DESCRIPTION
SL-5500 HARDWARE DESCRIPTION
The device operates at 560 kHz switching frequency which enables the
use of external components with minimum size. Deadlock is prevented
by an on-chip undervoltage lockout circuit.
Efficient behaviour during short load peaks and compatibility with Li-ion
batteries is guaranteed by an accurate current limiting function.
sense FET
START-UP
CIRCUIT
CONTROL LOGIC
AND
MODE GEARBOX
TIME
COUNTER
DIGITAL CONTROLLER
8 1
U / D
SHDWN
– 24 –
3
UPOUT / DNIN
INTERNAL
SUPPLY
TEA 1206T
7
FB
BAND GAP
REFERENCE
MGM666