XC6222 Datasheet, PDF (8/26 Pages) Torex Semiconductor – Reverse Current Protection, 700mA High Speed LDO Regulator

XC6222 Series
■OPERATIONAL EXPLANATION
The voltage divided by two resistors R1 and R2 is compared with the internal reference voltage by the error amplifier. The
P-channel MOSFET connected to the VOUT pin, is then driven by the subsequent output signal. The output voltage at the VOUT
pin is controlled and stabilized by a system of negative feedback. The current limit and short protection operate in relation to
the level of output current. The thermal protection operates in relation to the level of heat generation. The reverse current
protection operates when V_OUT voltage is higher than V_IN voltage. Further, the IC's internal circuitry can be turned off via the CE
pin's signal.
Reverce
Current
Protection
VIN
VOUT
CurrentLimit
CFB
&
ThermalShutdown
R1
+
Error
Amp
-
R2
each
CE
ON/OFF
Control
circuit
Voltage
Reference
VSS
XC6222Aseries
<Input and Output Capacitors>
The XC6222 needs an output capacitor C_L for phase compensation. Values required for the phase compensation are shown in
the chart below. If a loss of the capacitance happens, stable phase compensation may not be obtained. Please ensure to
use a capacitor which does not depend on bias or temperature too much. For a stable power input, please connect an input
capacitor CIN of 1.0μF between the VIN pin and the VSS pin.
●Output Capacitor (C_L) Table
OUTPUT VOLTAGE (V)
0.8V～2.05V
2.1V～2.45V
2.5V～5.0V
OUTPUT CAPACITOR VALUE
C_L=6.8μF (MIN.)
C_L=4.7μF (MIN.)
C_L=2.2μF (MIN.)
<Reverse Current Protection>
The XC6222 series includes reverse current protection to prevent the damage to any connected products such as batteries as a
result of current flow from the V_OUT pin to the V_IN pin. When V_IN is smaller than V_OUT, the reverse current protection works and
suppress the reverse current to 1.5μA (MAX.). When V_IN is smaller then V_OUT, the V_OUT pin sink current flows from the V_OUT
pin to the V_SS pin is 95μA (TYP.) as the IC operation current. With the XC6222A/C series, when a low level signal is inputted
to the CE pin, the sink current of the V_OUT pin is minimized to 28μA (TYP.). However, with the XC6222B/D series, when a low
level signal is inputted to the CE pin, the sink current of the V_OUT pin goes through the C_L auto discharge circuit to the V_SS pin
which may result in the IC being damaged. In this case, please do not connect a power supply to the V_OUT pin.
Please also note when the XC6222A/C series connects external power supply to the V_OUT pin, please use under 6.0V.
<Current Limiter, Short-Circuit Protection>
The XC6222 series’ fold-back circuit operates as an output current limiter and a short protection circuit for the output pin.
When the load current reaches the current limit level, the fixed current limiter circuit operates and output voltage drops. When
the output pin is short-circuited to the VSS pin, the current is decreased to a level of 55mA.
<Thermal Shutdown>
When the junction temperature of the built-in driver transistor reaches the temperature limit level (150℃ TYP.), the thermal
shutdown circuit operates and the driver transistor will be turned OFF. The IC resumes its operation when the thermal
shutdown function is released and the IC’s operation is automatically restored because the junction temperature drops to the
level of 125℃ (TYP.) as the thermal shutdown release voltage.
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