General Description
The LD7129 consists of the dual-output power controller and the protection circuits in a single SO-14 packaged chip for the graphic card and other applications. The dual-output power controller provides the regulation on a synchronous rectified buck converter by driving 2 N-MOSFETs and one N-MOSFET in a linear configuration.
The synchronous rectified buck converter provides simple, single feedback loop, voltage mode control with fast transient response. Internal 0.8V temperature-compensated reference voltage. A fixed 600KHz frequency oscillator reduces design complexity, while balancing typical application cost and efficiency.
The internal soft-start function and the 12V direct drive on switching output helps to save the bootstrap circuit. Furthermore, the internal POR (power on reset) help to prevent the system from the sequence issue during the startup and turn-off. Considering the fault conditions, the LD7129 will shutdown both outputs when the voltage on either FB or FB2 pin drop below 51% of the nominal value.
Features
• Controller Operates from 5V and 12V
• Drive two N-channel MOSFETs for switching buck converter
• Drive a N-channel MOSFET on linear output
• Fixed 600KHz constant switching frequency
• Full range 0~100% duty cycle
• Internal soft start
• Fast transient response
• UVP monitoring on both outputs
• Internal 0.8V reference voltage.
Applications
• Graphics-GPU and memory supplies
• ASIC power supplies
• Embedded processor and I/O supplies
• Cable Modem, Set Top Box, and DSL Modems
• DSP and Core Communications Processor Supplies
Typical Application
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