概述：HT81696是一款内置升压的立体声D类音频功率放大器，它支持单节锂电、双节锂电串联、 5V、12V等多种输入，升压后的电压提供给功放供电，功放支持双通道立体声BTL输出以及并联PBTL单声道输出。 HT81696内置的升压电路，可通过FB脚设置升压值，以满足不同的输出功率需求。其还可通 过外置电阻调节开关峰值电流限值。 此外，HT81696内部集成免滤波器调制技术，能够直接驱动扬声器，内置的关断功能使待机电流最小化，还集成了输出端过流保护、片内过温保护、输入电源欠压异常保护、升压电压过压保护等功能。


一、HT81696功能和特性

・输出功率(fIN=1kHz, RL=4Ω, BTL)
      双锂电8.4V：2×30W (VOUT=16V, THD+N= 10%) 
      单锂电3.7V：2×10W (VOUT=9V, THD+N = 10%)
・输出功率(fIN=1kHz, RL=3Ω, PBTL)
      双锂电7.2V：52W (VOUT=17V, THD+N= 10%) 
      单锂电3.7V：15W (VOUT=9V, THD+N = 10%)
・输出功率(fIN=1kHz, RL=4Ω, PBTL)
      单锂电3.7V：20W (VOUT=12V, THD+N = 10%)
・VBAT供电范围：2.7V至VOUT
・D类功放扩频功能
・内置升压电路：可调节的升压值和升压限流
・保护功能：过流/过热/欠压异常/过压保护功能
・无铅无卤封装，ETSSOP28


二、HT81696引脚功能

 管脚号 引脚功能   I/O   引脚说明
 EP   GND   G   Ground. Also provides thermal connection from the device to the board. A matching ground pad should be provided on the PCB and the device connected to it via solder. 地，同时提供器件向板级散热的路径。PCB板上需要留有足够的铺地露铜与之良好焊接。 
 1   VCC   O   Output of the internal regulator for boost converter. A ceramic capacitor of 1uF isrequired between this pin and ground. 升压电路内部电压输出，接1uF到底。 
 2   FB   I   Voltage feedback. 电压反馈脚 
 3   VOUT   P   Power supply for boost converter. 升压供电端 
 4   ENB   I   Enable logic input for boost converter. Logic high level enables the device. Logiclow level disables the device and turns it into bypass mode. 升压使能脚，高电平时升压开启，低电平时升压关闭 
 5,6   SW   P   The switching node pin of the converter. 升压开关点 
 7   ENA   I   Enable logic input and operation mode selection for amplifier 
 8   LINP   I   Positive input (differential+) for audio amplifier of left channel.  音频左声道输入正端。 
 9   LINN   I   Negative input (differential-) for audio amplifier of left channel. 音频左声道输入负端。 
 10   GAIN   I   Gain select pin. Gain is 17.5dB when logic low, and 31.8dB when logic high orfloating 增益选择。拉低时，增益17.5dB；拉高或悬空时，增益31.8dB 
 11   GVDD   O   Voltage regulator of amplifier, connect 1uF to GND. 功放内部电压，接1uF到地 
 12   RINN   I   Negative input (differential-) for audio amplifier of right channel. 音频右声道输入负端。 
 13   RINP   I   Positive input (differential+) for audio amplifier of right channel. 音频右声道输入正端 
 14   AVCC   P   Analog power supply for amplifier 功放模拟供电 
 15   PVDDR   O   Power supply terminal for right channel.  右声道功率电源端。 
 16   RBSP   BST   Connection point for the ROUTP bootstrap capacitor, which is used to create a powersupply for the high-side gate drive for ROUTP. ROUTP自举电容端 
 17   ROUTP   O   Positive output terminal (BTL+) for right channel.  右声道正端输出 
 18   ROUTN   O   Negative output terminal (BTL-) for right channel.  右声道负端输出。 
 19   RBSN   BST   Connection point for the ROUTN bootstrap capacitor, which is used to create apower supply for the high-side gate drive for ROUTN. ROUTN自举电容端 
 20   PGND   P   Power ground for amplifier 功放功率地 
 21   LBSN   BST   Connection point for the LOUTN bootstrap capacitor, which is used to create a powersupply for the high-side gate drive for LOUTN. LOUTN自举电容端 
 22   LOUTN   O   Negative output terminal (BTL-) for left channel.  左声道负端输出。 
 23   LOUTP   O   Positive output terminal (BTL+) for left channel.  左声道正端输出。 
 24   LBSP   BST   Connection point for the LOUTP bootstrap capacitor, which is used to create a powersupply for the high-side gate drive for LOUTP. LOUTP自举电容端 
 25   PVDDL   P   Power supply terminal for left channel.  左声道功率电源端。 
 26   SS   O   Soft-start programming pin. An external capacitor connected to ground sets the ramprate of the internal error amplifier’s reference voltage during soft-start. 升压软启动设置脚，接电容到地。 Also used as mode selection for different tr/tf, an external resistor connected toground selects a flatter tr/tf. 同时作为tr/tf设置脚，当同时外接1个330k电阻到地时，选择较缓的tr/tf。 
 27   ILIM   I   Adjustable switch peak current limit. An external resistor should be connectedbetween this pin and GND. 最大限流值设置端，外部接电阻到地。 
 28   COMP   O   Output of the internal error amplifier, the loop compensation network should beconnected between this pin and the AGND pin. 内部补偿脚 


三、HT81696典型应用电路