A4491EESTR-T Integrated Circuits (ICs)

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A4491EESTR-T Application Field and Working Principle

A4491EESTR-T is a DC-DC Switching Regulator belonging to the PMIC (Power Management Integrated Circuit) Voltage Regulators family. It is designed to support Intermediate Bus architecture applications up to 9A output current and support up to 9V VIN in computing applications.

Application Field

A4491EESTR-T is a power management IC that combines a high-efficiency, synchronous, step-down DC/DC converter and an adjustable linear regulator (or LDO). It is specifically designed for use in high-power DC output applications which require high current and wide input voltage range. These include applications such as telecom systems, networking, automotive, power tools, portable devices, industrial controls and movement applications. All these applications have to meet strict efficiency and power regulation requirement in order to function adequately.

A4491EESTR-T is recommended for applications demanding from high switching frequency and high current. It has an integrated power MOSFET and control circuitry capable of handling 9A of peak current and supporting output voltages up to 5V. It also involves a low quiescent current of typically 50µA. The switching frequency range is between 300 kHz to 2 MHz, therefore it allows to optimize the external components size, thus minimizing space, cost and EMI (Electro Magnetic Interference). Furthermore, the device provides accurate output regulation, requiring only two external resistors for setting the output voltage. In addition, it provides over-temperature and overcurrent protection.

Working Principle

The device works in buck mode. The data sheet mentions that feedforward compensation is provided in order to optimize transient response. The control circuitry utilizes a single voltage feedback loop to control the output voltage and set the peak inductor current limit. The internal circuitry provides a constant frequency, fixed slope current mode control for power conversion.

The first stage operates in buck mode, when a control signal is triggered, a high side N-MOSFET and a low side P-MOSFET are both enabled and the inductor current starts to increase. When the inductor current peaks up, the low side P-MOSFET is disabled and the current flows through the output capacitor to provide the output voltage.

The feedback loop senses the output voltage and compares it to a reference voltage, if the output voltage is lower than the reference voltage, the power MOSFET is triggered again and the process repeats. The loop then will control the on time and off time of the switching element and regulate the output at a constant level until the output current reaches its maximum.

Benefits and Advantages

A4491EESTR-T offers excellent performance in terms of current, power and efficiency. It can successfully manage 9A of output current and support up to 9V VIN without overheating. Furthermore, the device provides accurate output regulation, hence ensuring the stability of the output voltage levels. To sum up, A4491EESTR-T is an ideal choice for applications requiring high-current and wide input voltage range, providing remarkable power and energy efficiency.

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