YDA135 Datasheet, PDF (11/22 Pages) YAMAHA CORPORATION – STEREO 5W-20W DIGITAL AUDIO POWER AMPLIFIER CONTROLLER

YDA135
Overcurrent detection functions
The overcurrent detection is a function that determines that the overcurrent state has occurred and set PROT
terminal to "H" level, when the current flowing in the external Power MOSFET has become equal to or higher than
the specified value. (This IC does not internally perform processing that turns off Power MOSFET automatically in
such case.)
For the "Example of application circuit", the circuit related to the overcurrent detection function is as shown in the
following figure, "Overcurrent detection function block diagram".
Connect a current detection resistor (RS) between PMOS (source side) pin and power supply pin PVDD of Power
MOSFET, and between NMOS (source side) pin and PVSS pin. Connect PMOS (source side) pin and SENSEPL
pin through the low pass filter consisting of RSNS and CSNS, and NMOS (source side) and SENSENL pins as well.
To prevent erroneous detection of glitch noise that can occur at switching of Power MOSFET, be sure to use the
low pass filter consisting of RSNS and CSNS. Connect SENSEPR pin and SENSENR pin in the same way.
This IC recognizes an overcurrent state when the potential of SENSEPL pin or SENSEPR pin has decreased below
the overcurrent detection threshold voltage (VOCPP) for a certain period (TOCP), bringing PROT pin to "H" level.
When the potential of SENSENL pin or SENSENR pin has increased over the overcurrent detection threshold
voltage (VOCPN) for a certain period, it recognizes the overcurrent state, bringing PROT pin to "H" level. At this
time, set SLEEP pin of MUTE pin to "H" to force the Power MOSFET to OFF.
After this, inputting "H" level once to SLEEP or turning off the power supply and then on again can restore the
output of PROT pin to initial "L" state.
When it is not necessary to use the overcurrent detection function, connect SENSEPL pin and SENSEPR to PVDD,
and SENSENL pin and SENSENR pin to PVSS (to disable the function).
When in sleep mode (SLEEP pin = "H" level) or in mute mode (MUTE pin = "H" level), this IC sets the Power
MOSFET to OFF state, and thus, the overcurrent detection function of both L channel and R channel are stopped.
For this circuit, use the overcurrent detection resistor (RS) with low inductive component. The resistance is to be
determined based on the drain current rating (IDMAX: pulse current) and overcurrent threshold voltages (VOCPP,
VOCPN) according to the conditions described below.
RS ≧ VOCPN / IDMAX
YDA135
Over Current
Detection
PVDD
PVDD
VDDP-VOCPP
SENSEPL/
SENSEPR
CSNS
RSNS
PVDD
RS
PROT
Q
S
SR-FF
R
SLEEP
Power
on
Reset
Thermal Detection
Over Current
Detection
Overcurrent detection function block diagram
HP_L/
HP_R
HN_L/
HN_R
LP_L/
LP_R
LN_L/
LN_R
SENSENL/
SENSENR
RSNS
VOCPN
PVSS
CSNS
PVSS
RS
PVSS
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