LM5166XDRCR Integrated Circuits (ICs)

Application

The LM5166XDRCR can be used in a wide range of high-current, point-of-load applications, such as telecom systems, data communications equipment, base station power supplies and environmentally friendly automotive systems. Its wide input voltage range allows the device to operate in various input conditions. The device also has an efficient design with a high frequency PFM/PWM hybrid control solution, which can minimize the system cost.

Working Principle

The LM5166XDRCR DC-DC switching regulator is a synchronous buck regulator based on pulse frequency modulation (PFM) / pulse width modulation (PWM) hybrid control. It is implemented with an internal high-side MOSFET switch, an internal low-side MOSFET switch, and an integrated 7-bit do naptic buck controller.

The LM5166XDRCR integrates a high-side MOSFET and a low-side MOSFET with a common source. The high-side MOSFET switch is configured as a source follower, and the low-side MOSFET switch is configured as a sink follower. The do naptic Buck controller has two voltage feedback inputs, VFB_H and VFB_L. The high-side MOSFET switch is turned off when the VFB_H is over a certain negative threshold. The device is then controlled by the voltage feedback input, VFB_L, during the switching period. When the high-side MOSFET switch is enabled again, the device starts to work in PFM mode and the PWM controlling for the low-side MOSFET switch is enabled. During the PFM/PWM mode, the low-side MOSFET switch is driven by the difference between the load current feedback and the internal reference current. The device has a soft start feature, which can prevent inrush current and minimize start-up time.

The LM5166XDRCR employs a dynamic overcurrent protection. The input current limit is programmable, with a current monitor amplifier, to form an instantaneous overcurrent protection. It can also detect both input saturation and output short-circuit conditions. Furthermore, the device has a load line current monitor, which outputs a current proportional to the load current.

The LM5166XDRCR features a programmable output voltage range and an optional output voltage ramping level. It has a regulated output voltage accuracy of +/-2% over line, load and temperature, and a switching frequency from 400 kHz to 2.4 MHz, which can be externally set by a resistor. It has Protection features for input under-voltage lockout, over-voltage protection and over temperature protection.

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