03S_04XC6204 02.9.12 2:57 PM ページ 268
XC6204 Series
■Operational Explanation
Output voltage control with the XC6204 series :
VIN
ON/OFF
Control
The voltage divided by resistors R1 & R2 is compared with the internal
reference voltage by the error amplifier.
each circuit
CE
－�
＋�
Current
Limit
The P-Channel MOSFET, which is connected to the VOUT pin, is then driven by
the subsequent output signal. The ouput voltage at the VOUT pin is controlled &
stabilised by a system of negative feedback.
VOUT
VSS
R2
R1
The current limit circuit and short protect circuit operate in relation to the level
of output current. Further, the IC's internal circuitry can be shutdown via the CE
pin's signal.
Voltage
Reference
3
<Low ESR Capacitors>
With the XC6204 series, a stable output voltage is achievable even if used with low ESR capacitors as a phase compensation circuit is built-in.
In order to ensure the effectiveness of the phase compensation, we suggest that an output capacitor (CL) is connected as close as possible to
the output pin (VOUT) and the VSS pin. Please use an output capacitor with a capacitance value of at least 1µF. Also, please connect an input
capacitor (CIN) of 0.1µF between the VIN pin and the VSS pin in order to ensure a stable power input.
Topr=25°C
VIN=～10V，VOUT=1.8～6.0V
CIN=1.0µF（ceramic），CL=1.0µF（ceramic）
�
100
10
1
STABLE REGION
0.1
0.01
0
20
40
60
80
100
IOUT(mA)
<Current Limiter, Short-Circuit Protection>
The XC6204 series includes a combination of a fixed current limiter circuit & a foldback circuit which aid the operations of the current limiter and
circuit protection. When the load current reaches the current limit level, the fixed current limiter circuit operates and output voltage drops. As a
result of this drop in output voltage, the foldback circuit operates, output voltage drops further and output current decreases (refer to the data on
page 5). When the output pin is shorted, a current of about 60mA flows.
<CE Pin>
The IC's internal circuitry can be shutdown via the signal from the CE pin with the XC6204 series. In shutdown mode, output at the VOUT pin will
be pulled down to the VSS level via R1 & R2. The operational logic of the IC's CE pin is selectable (please refer to the selection guide on page
2). Note that as the standard XC6204B type is ' High Active/No Pull Down', operations will become unstable with the CE pin open. Although the
CE pin is equal to an inverter input with CMOS hysteresis, with either the pull-up or pull-down options, the CE pin input current will increase
when the IC is in operation.
We suggest that you use this IC with either a VIN voltage or a VSS voltage input at the CE pin. If this IC is used with the correct specifications for
the CE pin, the IC will operatenormally. However, supply current may increase as a result of through current in the IC's internal circuitry if a
voltage between 0.25V and 1.5V is input.
■Directions for use
ꢀNotes on Use
1. Please use this IC within the stated absolute maximum ratings. The IC is liable to malfunction should the ratings be exceeded.
2. Where wiring impedence is high, operations may become unstable due to noise and/or phase lag depending on output current.
Please strengthen VIN and VSS wiring in particular.
3. Please wire the input capacitor (CIN) and the output capacitor (CL) as close to the IC as possible.
268
TOREX [ Torex Semiconductor ]
