XC6207_1 Datasheet, PDF (9/33 Pages) Torex Semiconductor – High Speed "Green Operation" LDO Voltage Regulators

XC6207
Series
˙OPERATIONAL EXPLANATION
<Output Voltage Control>
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 VOUT pin, is then driven by the subsequent output signal. The output
voltage at the VOUT 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
a supply current to two values according to the level of output current. Further, the IC's internal circuitry can be shutdown
via the CE pin's signal.
<Green Operation>
XC6207 series can be set as a fixed high-speed mode or a green operation (GO) mode via a signal to the green operation
(GO) pin. Under the condition that the output current becomes IGOR or less, the IC operates in the high speed mode (HS)
when the GO pin is at high level and the IC operates in the power save (PS) mode when the GO pin is at low level. The
GO mode enables the IC to switch automatically the supply current to the high speed (HS) mode or the power save (PS)
mode according to the level of output current. While having both high-speed operation and low supply current state, the
XC6207 series can acquire high efficiency. At the HS/PS automatic switching mode (GO mode), the switching point of
the HS mode and the PS mode is being fixed inside the IC. When the output current becomes IGOR 0.3mA (TYP.) or
below, the mode changes automatically to the PS mode after the delay time of hundreds μs, and it can reduce supply
current in light load. For applications, most of portable equipment control the system current, which is the output current
to the IC, according to the system condition. Furthermore, the high-speed operation might be required. In such a case,
the mode will automatically switch to the HS mode at the automatic switching mode (GO mode), when the output current
becomes IGO or more. In the HS mode, the response of the output voltage during the output current fluctuation is better
than the PS mode. Automatic switching PS mode to HS mode causes the switching delay time of tens of μs, the output
voltage drops more than in the fixed HS mode. If the GO pin voltage is at high level (tens of μs (϶T) before the output
current fluctuation occurs) and the IC is used in the HS mode, the output current fluctuation will be suppressed to as low as
the fixed HS mode. (cf. the following item: Load Transient Response by Switching Mode with GO pin.)
The output current at the HS/PS mode should be adjusted to 2.0mA or more / 0.3mA or less respectively when the IC is
used in the HS/PS automatic switching mode (GO mode).
It is suggested that you use this IC with either a VIN voltage or a VSS voltage input at the GO pin. If this IC is used with the
correct specifications for the GO pin, the IC will operate normally. However, 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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