SC4911IMSTRT

Due to market price fluctuations, if you need to purchase or consult the price. You can contact us or emial to us:   sales@allicdata.com

SC4911IMSTRT is a low-cost switching voltage regulator controller, suitable for buck topology-based switch mode power supplies. It integrates a low-side power MOSFET gate driver for primarily driving an external N-channel power MOSFET. The SC4911IMSTRT is a current mode of DC-to-DC controller (buck mode) with Adaptive On-Time (AOT) valley current control. This low-side gate driver-based buck controller allows the system to achieve top efficiency and high performance.

Application Field

The SC4911IMSTRT has a wide range of applications in various devices, such as mobile devices, telecom products, SSDs, power over Ethernet, and industrial systems. This low-cost voltage regulator controller is used in USB Type-C Power Delivery and Power Bank solutions, enabling high current charging solution up to 100W.

Working Principle

The SC4911IMSTRT operates in current mode with Adaptive On-Time (AOT) valley current control. In current mode, inductor current is sensed through a low-side sensing circuit, internally compensating for the voltage drop across the output current sense resistor. The sensed inductor current is compared with a reference current to generate a simple error signal that is amplified. The amplified error signal drives a low-side gate driver for MOSFET turn off in order to generate the desired load current. The load current is finally filtered by an output capacitor and regulated to the programmed output voltage.

When the load current proportionally decreases, the controller senses a decrease in the inductor current, resulting in a cycle-by-cycle reduction in the on-time. This optimized on-time ensures high efficiency across the load line. The controller also compensates for time-varying inductor current in the valley area of each cycle. This Adaptive On-Time (AOT) control further increases the efficiency of the system at low-to-medium load range.

The SC4911IMSTRT also provides a fast transient response time, which is necessary for the efficient power management of portable applications, such as mobile phones and notebooks, that require rapid load current changes. The fast transient response and fast start-up time are achieved due to the AOT control in combination with the fast switching frequency of the gate driver. The gate driver is protected from shoot-through currents and has an under-voltage lockout feature that prevents the switching MOSFET from operating in the low duty cycle range.

Additionally, the SC4911IMSTRT incorporates an adjustable soft start function, improving the inrush current limit protection for the whole system. This avoids potentially destructive inrush peak currents when the system is turned on, especially in systems with large output capacitors. The soft start time is adjustable through an external resistor. Furthermore, the active output voltage positioning feature compensates for voltage droop in the output with increasing load current, which is typical of buck converters.

The SC4911IMSTRT also includes various other features like an adjustable cycle-by-cycle peak current limit, independent voltage/current loop, overload protection, and thermal protection, as well as an adjustable frequency limit for easy synchronization with other switching regulators. The device is available in various power packages, such as SOT23-6, SOT23-8, DFN-6, and TO-220-7.

In short, the SC4911IMSTRT is a low-cost, low-side driver-based switching voltage regulator controller with Adaptive On-Time (AOT) valley current control and a wide range of features, ideal for applications like USB Type-C Power Delivery and Power Bank solutions. It is capable of achieving high efficiency and high performance across the load line with fast transient response time. The device is available in various packages and is suitable for use in portable and industrial systems.

The specific data is subject to PDF, and the above content is for reference