| TI UCC28230 PWM总线控制方案 |
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| 作者:未知 来源:TI 点击数:100 更新时间:2008-5-30 |
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TI公司的UCC28230和UCC28231 PWM总线控制器具有根据负载进行编程的特性,频率控制的起动允许使用较小的输出电感和低的波纹,而恒流起动则采用大输出电容,效率高达97%. UCC28230/1包括了推挽,半桥和全桥托扑电路,能和外接驱动器如120V高边/低边驱车器UCC27200配合使用.因此,非常适合用在高效率,高功率密度和不调整的中间总线转换器以及DC-DC变压器.本文介绍了UCC28230和UCC28231的主要特性以及全桥转换器和半桥转换器的电路图.
The UCC28230, UCC28231 PWM bus controllers are optimized for use in high efficiency, high power density, unregulated intermediate bus converters. Topologies include push-pull, half-bridge and full-bridge. External drivers, such as 120-V high-side/low-side driver UCC27200, can be used with this controller.
Low cost, small size and highly efficient solutions are achieved by innovations such as: Start-up frequency control circuit allowing small output inductor and start with large intermediate bus capacitance. Load dependent off-time control set by user. Additional 1-D control outputs can be used for primary winding clamping in self-driven output synchronous rectifier applications or as drive signals for the control-driven synchronous rectifier. Cycle-by-cycle current limit prevents overstresses of converter. If the over current condition causes less than 80% duty cycle at the output, then after programmable time the controller proceeds into periodical shutdown and restart hiccup mode.
The UCC28230 provides 5 V, and the UCC28231 provides 3.3-V precision reference voltages with 1.5% overall accuracy and 10-mA output current. This reference voltage can be used to supply housekeeping circuit and/or microcontroller. The precision reference voltage can also be used for accurate setting of system parameters. Other features include under-voltage lockout, thermal shutdown, programmable soft-start, over-current hiccup mode and short circuit protection with internal restart (by default) or latch-off mode by using an external resistor. 详情请见:
http://focus.ti.com/lit/ds/symlink/ucc28230.pdf
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