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HT71778-实时音频信号跟踪的18V, 15A全集成同步升压转换器
The HT71778 is a high-power density, fully integrated
synchronous boost converter with a 16mΩ power switch
and a 18mΩ rectifier switch to provide a high efficiency and
small size solution in portable systems.
The HT71778 has wide input voltage range to support
applications with single cell or two cell in series Lithium
batteries. The device can provide an adaptive audiotracking
power supply for audio power amplifier so that the
system can always keep high efficiency in the whole output
power range. The battery endurance can be improved by
more than 50%, compared to power supply that is directly
boosted.
The HT71778 uses adaptive constant off-time peak current
control topology to regulate the output voltage. In moderate
to heavy load condition, it works in the PWM mode. In light
load condition, the device works in PFM mode to improve
the efficiency. The switching frequency in the PWM mode is
adjustable ranging from 200kHz to 1.0MHz by an external
resistor.
The HT71778 also implements a programmable soft-start
function and an adjustable switching peak current limit
function. In addition, the device provides 22V output
overvoltage protection, cycle-by-cycle overcurrent
protection, and thermal shutdown protection.
HT71778是一款高功率、全集成升压转换
器，集成16mΩ功率开关管和18mΩ同步整流管，
为便携式系统提供高效的小尺寸解决方案。 HT71778具有宽输入电压范围，可为采用
单节或两节锂电池的应用提供支持。该器件可
为音频功率放大器提供实时跟随音源信号的电
源供电，从而在整个功率段内使整个系统保持
在高效率。该方式供电相比直接升压供电方式，
电池续航时间预计可提升50%以上1。 HT71778采用自适应恒定关断时间峰值电
流控制拓扑结构来调节输出电压。在中等到重
负载条件下，HT71778工作在PWM 模式。在轻
负载条件下，该器件工作在可提高效率的PFM模式。PWM模式下，HT71778的开关频率可通
过外部电阻调节，支持200kHz至1.0MHz的范围。 HT71778还支持可编程的软启动，以及可
调节的开关峰值电流限制。 此外，该器件还提供有22V输出过压保护、
逐周期过流保护和热关断保护。
