10/35

.

<U.V.L.O. Circuit>

switching operation takes place. By releasing the U.V.L.O. function, the IC performs the soft start function to initiate

U.V.L.O. operating voltage. The U.V.L.O. circuit does not cause a complete shutdown of the IC, but causes pulse

output to be suspended; therefore, the internal circuitry remains in operation.

●

High Speed LDO Voltage Regulator

The voltage regulator block of the XC9511 series consists of a reference voltage source, error amplifier, and current

limiter circuit. The voltage divided by split resistors is compared with the internal reference voltage by the error amplifier.

achievable even if used with low ESR capacitors as a phase compensation circuit is built-in.

<Reference Voltage Source>

The reference voltage source provides the reference voltage to ensure stable output voltage of the regulator.

<Error Amplifier>

Pch driver transistor.

<Current Limit Circuit>

The voltage regulator block includes a combination of a constant current limiter circuit and a foldback circuit. The

voltage regulator senses output current of the built-in P channel output driver transistor inside. When the load current

reaches the current limit level, the current limiter circuit operates and the output voltage of the voltage regulator block

drops. As a result of this drop in output voltage, the foldback circuit operates, output voltage drops further and the load

■

OPERATIONAL EXPLANATION (Continued)

●

Voltage Detector