YDA135 Datasheet, PDF (13/22 Pages) YAMAHA CORPORATION – STEREO 5W-20W DIGITAL AUDIO POWER AMPLIFIER CONTROLLER

YDA135
YDA135
PROT
Q
S
SR-FF
R
SLEEP
Power
on
Reset
VDD
TPP
VDD
RTP
1/2VDD
Over Temperature
Detection
HP_L/
HP_R
HN_L/
HN_R
LP_L/
LP_R
LN_L/
LN_R
PVDD
RS
RS
VSS
High temperature detection function block diagram
VSS
PVSS
Connect the temperature detection element with positive temperature coefficient between VSS and TPP terminal by
the number of pieces required.
In addition, connect a resistor(RTP) between TPP terminal and VDD power supply terminal. Resistor value of
temperature detection element is changed by rise in temperature. Select a resistor so that the threshold (VTPP) is
attained depending on the characteristic of the temperature detection element.
This IC determines that high temperature state has occurred when the potential of TPP terminal has exceeded the
high temperature detection threshold voltage (VTPP) for a certain period (TTPP), and then sets PROT terminal to "H"
level. At this time, set SLEEP terminal or MUTE terminal to "H" level to turn off Power MOSFET forcibly to limit the
temperature rise.
PROT terminal output can be returned to initial "L" level output state by inputting "H" level once to SLEEP terminal
or by turning off the power and then on again.
In sleep mode (SLEEP="H"), the high temperature detection function of this IC is disabled.
Since TPP terminal is a single terminal, the temperature detection circuit detects temperature of two channels
collectively outside of this IC.
When the high temperature detection function is not used, connet TPP to the ground (to disable the high
temperature detection function).
When high temperature state has been detected, Power MOSFET can be protected by the following methods.
(1)Turning off Power MOSFET when high temperature has been detected.
Connect PROT terminal and MUTE terminal externally as shown in the "Power MOSFET protection circuit" of the
previous page. With this method, the device is brought into mute state when high temperature has been detected,
where Power MOSFET is turned off to limit the current flowing into Power MOSFET to allow reduction of the
temperature. At this time, the protected state can be cancelled by setting SLEEP terminal to "H" level once or by
bringing VDD or PVDD power supply terminal voltage to the level below the shut off voltage once.
(2)Turning off Power MOSFET when high temperature has been detected and restarting it after a certain period.
Connect PROT terminal and SLEEP terminal through external circuit as shown in the "External automatic
restoration circuit" of the previous page.
With this method, SLEEP terminal becomes "H" level when high temperature has been detected, and this IC is
brought into sleep state (Power MOSFET is turned off). After this, when a certain period that depends on the RC
time constant has elapsed, SLEEP terminal becomes "L" level where this IC restarts automatically.
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