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| Supertex MD7120 D类放大方案 |
| 作者： 时间：2008-07-25 来源:eaw |
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Supertex公司的MD7120是该速200V全H桥MOSFET驱动器,非常适合D类音频放大器和其它高频PWM驱动方面的应用如压电激励器,开关电源中的MOSFET驱动器或半桥功率级的两路驱动器.本文介绍了MD7120的主要性能,方框图,典型的应用电路以及H61典型设计电路图.
MD7120 High Speed, 200V, Full H-Bridge MOSFET Driver
The Supertex MD7120 is a high voltage, high speed, full-bridge driver. It is ideal for Class-D audio amplifier applications and other high frequency PWM driver applications, such as motor driving. This highvoltage and high-speed driver can also be used for other applications:
as a piezo-electric transducer driver;
as a MOSFET driver in a switched mode power supply;
or as a two channel driver for half-bridge power stages.
The new IC topology is designed to drive dual N-MOSFETs as power switches for both the high side and low side. It consists of controller logic circuits, level translators, and a bootstrap floating powered gate driver and over current protection circuits without using current sensing resistors. The thresholds of the OCP for the high and low side are
resistor-programmable.
The power MOSFET top drain can be connected to up to +200V while the bottom N-channel MOSFET source is grounded. They are designed to provide 3.0A peak driving current with well-matched output impendence and propagation delay on the high and low sides, as well as from device-to-device.
The EN pin serves a dual purpose: the logic high level is used to compute the threshold voltage level of inputs; and the logic low level disables the outputs. The IC is in a low inductance and thermally enhanced package.
MD7120 D主要特性:
HVCMOS® technology for high performance
All N-MOSFET full-bridge driver
Designed for 200V bridge supply voltage
Up to 1.0MHz operation frequency
Greater than 90% efficiency
Designed for low total harmonic distortion
Single voltage drive power supply +12V
Smart logic voltage threshold
Resistor programmable OCP threshold
UVP function built-in
Accurate and adjustable dead time
32-Lead QFN package
主要应用:
Class-D audio amplifier
High frequency PWM motor control
High frequency switching power supply
Ultrasound transducer drivers
High voltage waveform generator
图1. MD7120 框图和应用电路
图2. MD7120 典型应用电路
图3. MD7120典型设计电路图
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