AN1042 ONSEMI | Alldatasheet
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Figure 1. Switching Amplifier Basic Waveforms speaker filter was impractical as well. because of its large base current requirement. switches and they can operate at higher frequencies. A block diagram of the amplifier is shown in Figure 2.
- The resultant signal is integrated, which accurately
tative for information on possible replacement devices.
Figure 11. Voltage Balance Circuit from the primary of T1 through Q6 to the –44 volt supply. be destroyed if the supply voltages run away. of dc without saturation and have very low hysteresis loss. problems were caused by their excessive hysteresis. was found to be due to skin effect losses in the windings. the inductors as well, possibly resulting in their saturation. exists at the 11.4 kHz resonance point.
measure of shielding against capacitively coupled RFI. as short as possible to minimize RFI. channel will dissipate 7.5 watts. effect of the source drain diode during reverse current. therefore takes the blame for the slower N channel diode. in the opposite switch due to their slower diodes. resistance loss varies only as the square of the current. Table 1. Frequency Spectrum of Switching Amplifier
Table 2. Frequency Spectrum of Switching Amplifier A cutoff frequency of 20 kHz will be assumed. Note that the carrier increases as output level is reduced. sideband and the output frequency results. phase shift that makes the feedback loop unstable. amplifier is that it has absolutely no crossover distortion. avoided in the output filter. riding on the 120 kHz triangle. the switching frequency to the power supply frequency. comes from internal lead lag flip flop switching near lock.
output filters it is feasible to drive loads of less than 8 ohms. Table 3. Harmonic Distortion
- Intermodulation Distortion: 0.24% (60 Hz and 6 kHz mixed at 4:1)
- Signal to noise ratio: 100 dB below full rated power
- Power bandwidth: dc to 20 kHz
- Damping factor: 80
- Efficiency: 92% at 72 Watts of output power NOTE: Distortion measurements taken with Tektronix SG505 oscillator and AA501 analyzer. Output set to ±30 Volts into 8 Ohms.
Figure 12. 1.2 kHz Square Wave Response All resistors 1/4 W unless otherwise noted. All resistors 5% unless otherwise noted. All resistor values are Ohms unless otherwise noted. All capacitors 1000 V ceramic unless otherwise noted. All capacitor values are µFd unless otherwise noted. U4C, U4D and U1A are not used.
Figure 13. Schematic for Class D Amplifier
26 Turns
31 Turns
33 Turns
8 Turns
2 R13
http://onsemi.com ON Semiconductor and are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC reserves the right to make changes without further notice to any products herein. SCILLC makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does SCILLC assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability , including without limitation special, consequential or incidental damages. “Typical” parameters which may be provided in SCILLC data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including “Typicals” must be validated for each customer application by customer’s technical experts. SCILLC does not convey any license under its patent rights nor the rights of others. SCILLC products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other applications intended to support or sustain life, or for any other application in which the failure of the SCILLC product could create a situation where personal injury or death may occur. Should Buyer purchase or use SCILLC products for any such unintended or unauthorized application, Buyer shall indemnify and hold SCILLC and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim alleges that SCILLC was negligent regarding the design or manufacture of the part. SCILLC is an Equal Opportunity/Affirmative Action Employer. PUBLICATION ORDERING INFORMATION JAPAN : ON Semiconductor, Japan Customer Focus Center 2–9–1 Kamimeguro, Meguro–ku, Tokyo, Japan 153–0051 Phone : 81–3–5773–3850 Email: r14525@onsemi.com ON Semiconductor Website: http://onsemi.com For additional information, please contact your local Sales Representative. AN1042/D Literature Fulfillment: Literature Distribution Center for ON Semiconductor P .O. Box 5163, Denver, Colorado 80217 USA Phone : 303–675–2175 or 800–344–3860 Toll Free USA/Canada Fax: 303–675–2176 or 800–344–3867 Toll Free USA/Canada Email: ONlit@hibbertco.com N. American Technical Support: 800–282–9855 Toll Free USA/Canada