datasheetbank_Logo     búsqueda de Hoja de datos y gratuito Fichas de descarga

TA0103A Ver la hoja de datos (PDF) - Unspecified

Número de piezacomponentes Descripciónfabricante
TA0103A Stereo 250W (4?) Class-T Digital Audio Amplifier Driver using Digital Power Processing (DPP?) Technology Unspecified2
Unspecified 
TA0103A Datasheet PDF : 18 Pages
First Prev 11 12 13 14 15 16 17 18
Tripath Technology, Inc. - Technical Information
Generating the VN12 voltage per Figure 5 is NOT recommended. Most power supplies only sink
current from the negative terminal and will not be capable of sourcing the current required by
VN12. Furthermore, problems can arise since VN12 will not track movements in VSNEG.
VSPOS
V5
VS
5V
P GND
A GND
-33V
VS
VN12
VSNEG
Setting Over-current Threshold
Figure 5
RS and ROCR determine the value of the over-current threshold, ISC:
ISC x RS = (VTOC x 9100)/(9100 + ROCR)
where:
RS and ROCR are in
ISC = 3 x IRMS = 3 x (POUT/RL) 0.5 (Over-current is typically set for 3 x RMS current)
VTOC = Over-current sense threshold voltage (See Electrical Characteristics Table)
= 0.75V typically
when ROCR = 0, RS = (0.75)/ISC
Note that RS will dissipate approximately (IRMS)2 x RS of power. To set an ISC of 30A, for example,
with ROCR = 0, means that RS = 25mand RS must dissipate 2.5W on average. If ROCR = 9.1K,
then to set ISC = 30A, RS will be 12.5mand will only have to dissipate 1.13W on average.
As high-wattage resistors are usually only available in a few low-resistance values (10m, 25m
and 50m), ROCR can be used to adjust for a particular over-current threshold using one of these
values for RS.
Output Transistor Selection
The key parameters to consider when selecting a MOSFET to use with the TA0103A are drain-
source breakdown voltage (BVdss), gate charge (Qg), and on-resistance (RDS(ON)).
The BVdss rating of the MOSFET needs to be selected to accommodate the voltage swing between
VSPOS and VSNEG as well as any voltage peaks caused by voltage ringing due to switching transients.
With a ‘good’ circuit board layout, a BVdss that is 50% higher than the VSPOS and VSNEG voltage
swing is a reasonable starting point. The BVdss rating should be verified by measuring the actual
voltages experienced by the MOSFET in the final circuit.
Ideally a low Qg (total gate charge) and low RDS(ON) are desired for the best amplifier performance.
Unfortunately, these are conflicting requirements since RDS(ON) is inversely proportional to Qg for a
typical MOSFET. The design trade-off is one of cost versus performance. A lower RDS(ON) means
lower I2RDS(ON) losses but the associated higher Qg translates into higher switching losses (losses =
Qg x 12 x 1.2MHz). A lower RDS(ON) also means a larger silicon die and higher cost. A higher RDS(ON)
means lower cost and lower switching losses but higher I2RDSON losses.
13
TA0103 – Rev 3.3/06.00
Direct download click here

 

Share Link : 

All Rights Reserved © datasheetbank.com 2014 - 2019 [ Política De Privacidad ]