XC6220 Datasheet, PDF (9/30 Pages) Torex Semiconductor – 1A LDO Voltage Regulator with “GreenOperation”

XC6220
Series
■OPERATIONAL EXPLANATION
CE
ON/OFF
Control
CE CE/
RCE _each
circuit
-
Error
Amp
+
Green
Operation
Current
Limit
Thermal
Protection
R1
CE/
R2
Voltage
Reference
VIN
VOUT
VSS
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_OUT
pin is then driven by the subsequent output signal. The
output voltage at the V_OUT pin is controlled & stabilized
by a system of negative feedback. The current limit
circuit and short protect circuit operate in relation to the
level of output current. The GO function monitors the
output current and switches the IC between two
operating modes according to the level of output
current. Further, the IC's internal circuitry can be
shutdown via the CE pin's signal.
XC6220x301
<GreenOperation>
The XC6220 series always operates in a green operation (GO) mode.
50
CE=VIN, Topr=25℃, CIN=10μF, CL=4.7μF (ceramic)
The GO mode enables the IC to switch automatically between the high
40
speed (HS) mode or the power save (PS) mode according to the level of
output current. The switching point of the HS mode and the PS mode is
30
fixed inside the IC. When the output current becomes I_GOR=1.0mA (MIN.)
or below, the mode changes automatically to the PS mode after a delay
20
time of hundreds of microseconds. Supply current in light load is greatly
reduced. Also when the output current becomes I_GO 10mA (MAX.) or
10
more, the mode changes automatically to the HS mode and the IC
returns to high speed operation.
0
0
5
10
15
20
<Low ESR capacitor>
Output Current: IOUT (mA)
The XC6220 series has a built-in phase compensation circuit which means that a stable output voltage is achieved even if
the IC is used with low ESR capacitors. In order to ensure stable phase compensation it is recommended that a C_L capacitor
is connected as close as possible to the V_OUT pin and V_SS pin. For a stable power supply, please connect an input capacitor
(C_IN) between the V_IN pin and the V_SS pin.
Values required for the phase compensation are shown in the chart below. If a loss of the capacitance happens, the stable
phase compensation may not be obtained. Please ensure to use a capacitor which does not depend on bias or temperature
too much.
Recommended output capacitor (C_L) Values corresponding to input capacitor (C_IN)
INPUT CAPACITOR VALUE
OUTPUT VOLTAGE (V)
4.7μF 10μF 22μF
0.80V～0.95V
×
×
22μF
1.00V～1.45V
47μF 47μF 22μF
1.50V～1.75V
47μF 22μF 10μF
1.80V～2.95V
47μF 6.8μF 6.8μF
3.00V～3.50V
47μF 4.7μF 4.7μF
3.55V～5.00V
47μF 10μF 6.8μF
× No option
<Current Limiter, Short-Circuit Protection>
The XC6220 series includes a fold-back circuit, which aids the operation of the current limiter and circuit protection. When
the load current reaches the current limit level, the fold-back circuit operates and output voltage drops. As a result of this drop
in output voltage, output current also decreases. When the output pin is shorted, a current of about 180mA flows.
<CE Pin>
The IC's internal circuitry can be shutdown via the signal from the CE pin with the XC6220 series. With the XC6220B/D
series, output at the V_OUT pin will be pulled down to the V_SS level. However, with XC6220A/B series, the C_L auto-discharge
resistor is connected in parallel to R1 and R2 while the power supply is applied to the V_IN pin. Therefore, the time until the
V_OUT pin reaches the V_SS level is shortened. The output voltage becomes unstable, when the CE pin is open. If this IC is
used with the correct output voltage for the CE pin, the logic is fixed and the IC will operate normally. However, with the
XC6220C/D series, supply current may increase as a result of through current in the IC's internal circuitry when medium
voltage is input.
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