LV4900HR

No.A0651-9/14

Functional Descriptions

System Standby

The bias levels are turned on and off under control of the high/low state of the STBY pin. When the STBY pin is low,

the bias levels will be turned off, and when that pin is high, the bias levels will be applied.

Mute Function

The mute function is provided mainly to mute the output so that impulse noise will not appear in the output when the

power supply is being turned on.

(1) Output Muting

The output PWM signal can be turned on or off by setting the MUTE pin high or low. When the MUTE pin is low, the

internal oscillator is stopped. This oscillator operates at all times that the MUTE pin is high.

(2) Power On Sequence

Applications should provide a power-on muting period of at least 500ms to minimize impulse noise.

Turn-on time: the time between the point the STBY pin is set high and the point the MUTE pin is set high.

(3) Power Down Sequence

Applications should provide a power down muting period of at least 100ms to minimize impulse noise.

Turn-off time: the time between the point the MUTE pin is set low and the point the STBY pin is set low.

Turn-on time

MUTE pin capacitor voltage

0

5 [V]

0

5 [V]

5V/DIV.

STBY pin

Internal power

supply

MUTE pin

Output pin

Amplifier on

MUTE pin

capacitor voltage

5V/DIV.

0

5 [V]

0

5 [V]

Power down time

STBY pin

Internal power supply

MUTE pin

Output pin Amplifier on