xc6220 TOREX SEMICONDUCTOR LTD., xc6220 Datasheet - Page 9

• Manufacturer Part Number: xc6220
• Description: 1a Ldo Voltage Regulator With ?greenoperation?
• Manufacturer: TOREX SEMICONDUCTOR LTD.

CE
<GreenOperation>
The XC6220 series can be set in a fixed high-speed mode or a green operation (GO) mode via a signal to the green operation
(GO) pin.
The GO mode enables the IC to switch automatically between the high speed (HS) mode or the power save (PS) mode
according to the level of output current. With the HS/PS automatic switching mode (GO mode), the switching point of the HS
mode and the PS mode is fixed inside the IC. When the output current becomes I
changes automatically to the PS mode after a delay time of hundreds of microseconds. Supply current in light load is greatly
reduced. Also when the output current becomes I
mode and the IC returns to high speed operation.
<Low ESR capacitor>
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.
<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
resistor is connected in parallel to R1 and R2 while the power supply is applied to the V
V
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.
the IC is used with low ESR capacitors. In order to ensure stable phase compensation it is recommended that a C
is connected as close as possible to the V
(C
The XC6220 series has a built-in phase compensation circuit which means that a stable output voltage is achieved even if
OUT
■OPERATIONAL EXPLANATION
IN
) between the V
pin reaches the V
Recommended output capacitor (C
RCE
× No option
OUTPUT VOLTAGE (V)
CE
ON/OFF
Control
circuit
each
CE/
0.80V～0.95V
1.00V～1.45V
1.50V～1.75V
1.80V～2.95V
3.00V～3.50V
3.55V～5.00V
Reference
Voltage
IN
pin and the V
OUT
-
+
Operation
Error
Amp
SS
Green
level is shortened. The output voltage becomes unstable, when the CE pin is open. If this IC is
pin will be pulled down to the V
Protection
Current
Limit
Thermal
SS
INPUT CAPACITOR VALUE
4.7μF
47μF
47μF
47μF
47μF
47μF
pin.
×
R1
R2
OUT
L
CE/
) Values corresponding to input capacitor (C
pin and V
6.8μF
4.7μF
10μF
47μF
22μF
10μF
×
GO
10mA (MAX.) or more, the mode changes automatically to the HS
SS
V
V
V
OUT
SS
SS
IN
6.8μF
4.7μF
6.8μF
pin. For a stable power supply, please connect an input capacitor
22μF
22μF
22μF
10μF
level. However, with XC6220A/B series, the C
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
pin is then driven by the subsequent output signal. The
output voltage at the V
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.
GOR
OUT
IN
IN
=1.0mA (MIN.) or below, the mode
)
pin is controlled & stabilized
pin. Therefore, the time until the
L
auto-discharge
XC6220
L
capacitor
OUT
Series
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