YDA135 Datasheet, PDF (14/22 Pages) YAMAHA CORPORATION – STEREO 5W-20W DIGITAL AUDIO POWER AMPLIFIER CONTROLLER

YDA135
Sleep control functions
When SLEEP terminal is set to H" level, this IC changes into sleep mode. When SLEEP terminal is set to "L" level,
this IC changes into normal operating state. In sleep mode, all functions are disabled, and power consumption is
minimized.
At this time, all Power MOSFET driving terminals output signals that turns off the Power MOSFETs. Though all
Power MOSFETs become off state, the speaker terminal is made ground potential by the externally connected
resistors (RNFL and RNFH).
When MUTE terminal is changed from "H" level to "L" level, restarting sequence operates internally. This IC
changes into normal operating state after the period that is set with a capacitor connected to VREFL terminal and
VREFR terminal (starting time) has elapsed.
When SLEEP terminal is set to "H" level, PROT terminal is set to "L" level forcibly.
Output mute control functions
When MUTE terminal is set to H" level, this IC change into mute mode. When MUTE terminal is set to "L" level, this
IC change into normal operating state. In the mute mode, the internal clock stops. At this time, all Power MOSFET
driving terminals output signals that turns off the Power MOSFETs. Though all Power MOSFETs become off state,
the speaker terminal is made ground potential by the externally connected resistors (RNFL and RNFH).
Pop noise reduction functions
This IC includes pop noise reduction function that works when turn on and turn off the power supply and enabling
or canceling sleep mode.
At power on, this IC starts the starting sequence after 12V system's power supply voltage (VDDP) for Power
MOSFET driving circuit and 5 V system's power supply voltage (VDD) for signal processing circuit has exceeded
their low voltage malfunction prevention threshold (VUV12 and VUV5) respectively. In the starting sequence, the pop
noise can be reduced because the mute mode is canceled after the potential of input signal terminals (INL and
INR) and potential of reference voltage output terminals (VREFL and VREFR) have stabilized sufficiently (after the
elapse of starting period).
Also, when shutting off the power supply, the pop noise can be reduced by reducing 12V power supply voltage and
5V power supply voltage below the low voltage malfunction prevention threshold (VUV12 and VUV5) earlier than the
shift of the potential of input signal terminals (INL and INR) and potential of reference voltage output terminals
(VREFL and VREFR).
The pop noise is also reduced by enabling the mute mode when the 5V system power supply voltage has changed
10% of 1/2 of VREF terminal voltage. Moreover, the pop noise can be reduced by using MUTE terminal control
circuit as shown in the "Example of application circuit" when the speed of reduction of the power supply voltage is
slow.
When the sleep mode is disabled, the pop noise can be reduced by using the starting sequence.
When the sleep mode is enabled, the pop noise is reduced because the mute mode is enabled simultaneously.
To make the pop noise reduction function operate effectively when turning on the power supply, it is necessary to
set the values of capacitor (CREF) that is connected to VREFL terminal and VREFR terminal, the resistor (RI) and
capacitor (CI) that are connected to INL terminal and INR terminal as described below.
CREF > RI * CI / 5000
Pop noise reduction functions
Starting time is a period for each reference voltage to reach the specified potential (for charging capacitors (CREF)
of VREFL and VREFR terminals) when the power supply is turned on or is turned on again. This period varies in
relation to the capacitance (CREF) of VREFL and VREFR terminals. The table of starting time is as follows:
CREF capacitor(µF)
2
10
30
50
Starting time (sec)
0.13
0.33
0.85
1.40
How to supply power to 5V system
Since the operation of the 5V system power supply of this IC is guaranteed in the wide fluctuation range (10%), the
power can be generated from 12V system power supply by using a zener diode. This features allows to operate
this IC by using only a 12V power supply.
14