xc6221 TOREX SEMICONDUCTOR LTD., xc6221 Datasheet - Page 8

• Manufacturer Part Number: xc6221
• Description: Xc6221 Low Esr Caps Compatible Highe Speed Ldo Voltage Regulators With On/off Switch
• Manufacturer: TOREX SEMICONDUCTOR LTD.

8/23
CE
■OPERATIONAL EXPLANATION
<Output Voltage Control>
<Low ESR Capacitor>
<CL Auto-Discharge Function>
XC6221
The voltage divided by resistors R1 & R2 is compared with the internal reference voltage by the error amplifier. The
P-channel MOSFET, which is connected to the V
voltage at the V
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.
With the XC6221 series, a stable output voltage is achievable even if used with low ESR capacitors, as a phase
compensation circuit is built-in. Values required for the phase compensation are as the chart below. In order to ensure the
stable phase compensation while avoiding run-out of values, please use the capacitor, which does not depend on bias or
temperature too much. For a stable power input, please connect an input capacitor (C
the V
( V : Output voltage after discharge, V
τ: C
XC6221B series can discharge the electric charge in the output capacitor (C
enables a whole IC circuit turn off, is inputted via the N-channel transistor located between the V
(cf. BLOCK DIAGRAM). The CL auto-discharge resistance value is set at 780Ω(V
The discharge time of the output capacitor (C
(C
(τ=C x Rdischg), the output voltage after discharge via the N-channel transistor is calculated by the following formulas.
L
SS
). By setting time constant of a C
V = V
SETTING OUTPUT VOLTAGE (V)
L
CE
ON/OFF
Control
circuit
pin.
auto-discharge resistance Rdischg×Output capacitor (C
each
CE/
OUT(E)
Reference
Voltage
OUT
0.8 ~ 1.15
1.2 ~ 1.35
x e
1.4 ~ 4.0
Series
pin is controlled & stabilized by a system of negative feedback. The current limit circuit and short
-
+
–t/ τ
Error
Amp
, or t=
Current
Limit
τ
In ( V / V
L
OUT(E)
auto-discharge resistance value [Rdischg] and an output capacitor value (C
OUTPUT CAPACITOR VALUE
R1
R2
: Output voltage, t: Discharge time,
OUT(E)
CE/
Rdischg
L
) is set by the CL auto-discharge resistance (R) and the output capacitor
OUT
)
C
C
C
pin, is then driven by the subsequent output signal. The output
L
L
L
=4.7uF
=2.2uF
=1.0uF
V
V
V
OUT
SS
IN
L
) value C)
L
), when a low signal to the CE pin, which
IN
OUT
) of 1.0μF between the V
=4.0V @ V
OUT
pin and the V
IN
=6.0V at typical).
IN
L
) as τ
pin and
SS
pin