Silabs公司的Si824x系列是兩路隔離的驅動器,輸入和輸出以及輸出間絕緣,峰值電流為0.5 A (Si8241)和4.0 A (Si8244) ,最大音頻功率30W,工作最高電壓為24V, Si824x還集成了死區發生器,以獲得最佳的THD,主要用在D類音頻放大器.本文介紹了Si824x主要特性,方框圖, D類音頻放大器方框圖,半橋音頻應用框圖以及Si824x D類音頻放大器參考設計電路圖和材料清單(BOM).
The Si824x isolated driver family combines two isolated drivers in a single package. The Si8241/44 are high-side/low-side drivers specifically targeted at high-power (>30 W) audio applications. Versions with peak output currents of 0.5 A (Si8241) and 4.0 A (Si8244) are available. All drivers operate with a maximum supply voltage of 24 V.
Based on Silicon Labs’proprietary isolation technology, the Si824x audio drivers incorporate input-to-output and output-to-output isolation, which enables leveltranslation
of signals without additional external circuits as well as use of bipolar supply voltage up to ±750 V. The Si824x audio drivers feature an integrated deadtime generator that provides highly precise control for achieving optimal THD.
These products also have overlap protection that safeguards against shootthrough current damage. The CMOS based design also provides robust immunity from latch-up and high-voltage transients. The extremely low propagation delays enable faster modulation frequencies for an enhanced audio experience. The TTL level compatible inputs with >400 mV hysteresis are available in PWM input configuration; other options include UVLO levels of 8 V or 10 V. These products are available in narrow body SOIC packages。
Si824x主要特性：
0.5 A peak output (Si8241)
4.0 A peak output (Si8244)
PWM input
High-precision linear programmable dead-time generator 0.4 ns to 1 μs
High latchup immunity >100 V/ns
Up to 1500 Vrms output-output isolation, supply voltage of ±750 V
Input to output isolation for low noise (up to 2500 V)
Up to 8 MHz operation
Wide operating range
–40 to +125℃
Transient immunity >30 kV/μs
RoHS-compliant
SOIC-16 narrow body
Si824x應用：
Class D audio amplifiers
圖1.Si824x方框圖
圖2.Si824x在半橋音頻應用框圖
Si824x D類音頻放大器參考設計
Si824xClassD-KIT
Audio Class D amplifier reference design, a stereo, two-state, halfbridge Class D amplifier leverags the performance advantages of the Si8241 ISOdriver. This two-channel Class D Audio Amplifier delivers 120 W per channel into 8 Ω, while enabling < 0.02% THD at 60 W and > 95 dB SNR. The Class D reference design architecture uses a phase-shift, self oscillating modulation approach that is capable of achieving far greater signal-to-noise ratio than clock driven amplifiers. This self oscillating implementation eliminates the circuitry necessary to generate the triangle waveform. To keep the circuit as simple as possible, a two-state, half-bridge is implemented and exemplifies the benefits of using the Si8241 Audio Gate Driver.
圖3.Si824x D類音頻驅動器方框圖
圖4.采用Si8241的D類音頻放大器方框圖
圖5.Si824x D類KIT外形圖
圖6.Si8241 音頻柵極驅動器電路圖
圖7.過流保護電路圖
圖8.Si824x D類音頻放大器參考設計電路圖(1)
圖9.Si824x D類音頻放大器參考設計電路圖(2)
Si824x D類音頻放大器參考設計材清單(BOM):
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