XC9801/XC9802
Series
■BLOCK
DIAGRAM
Controller
(1) Basic Operations
Using the XC9801/02’s clock generated by the internal oscillator, a step-up charge pump operation can be brought
about as a result of the alternate switching between operating conditions where P1 & N4 are ON with P2 & P3 OFF
(or) P1 & N4 are OFF with P2 & P3 ON. By connecting the SENSE pin to V
OUT
, output voltage can be feedback and
the difference between the feedback voltage and the reference voltage (Vref) are compared by the internal operational
amplifier. Output voltage can be stabilized (* 2) by controlling P3’s gate voltage waveform via the signal generated by
the internal amplifier.
Please note that this stabilizing function will not operate with V
IN
< (V
OUT/2
) or V
IN
≧
V
OUT
.
By connecting SENSE to ground, the output stability function, as described above, can be halted and the IC can be
used as a step-up doubler.
* 2 :
As a result of P3 gradually reaching an ON state with each clock (signal), rush current is controlled, the ripple
decreases and with the combination of the independent phase compensation circuit, output voltage is stabilized
(2) Stand-by Function
When the voltage at CE (chip enable) is ‘low’ (0V), P1, P2 & P3 will be OFF with N4 & N5 ON. The external capacitor
C1 will discharge and impedance at V
OUT
will be high.
(3) PFM (Pulse Skip) Operations
Whilst maintaining output voltage, the XC9802 provides the added security of protection against drops in efficiency
during light loads as a result of the pulse, generated by the internal oscillator, being skipped and the operating
frequency being changed.
■ABSOLUTE
MAXIMUM RATINGS
PARAMETER
V
IN
pin Voltage
V
OUT
pin Voltage
C1 + pin Voltage
C1 - pin Voltage
CE pin Voltage
V
OUT
Pin Output Current
MSOP-8A
Power Dissipation
USP-8
Operating Temperature Range
Storage Temperature Range
SYMBOL
V
IN
V
OUT
C1+
C1-
V
CE
I
OUT
Pd
Topr
Tstg
Ta = 25℃, GND = 0V
CONDITIONS
UNITS
－0.3�½�6.0
V
－0.3�½�12.0
V
��0.3�½�V
OUT
＋0.3
V
－0.3�½�V
OUT
＋0.3
V
－0.3�½�V
IN
＋0.3
V
200
mA
150
mW
120
－40�½�＋85
℃
－40�½�＋125
℃
3/12
TOREX [ TOREX SEMICONDUCTOR ]
