LD7129

LD7129 8/27/2004 Single Synchronous Buck PWM and Linear Power Controller General Description The LD7129 consists of the dual-output power controller and the protection circuits in a single SOP-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 eliminate 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...