TL1451ACPWR

TL1451ACPWR Application Field and Working Principle

The TL1451ACPWR is a high performance current mode pulse width modulation (PWM) switching controller capable of providing high efficiency, low noise dc-dc conversions, making it useful in a variety of power supply designs. This device includes features such as soft-start and auto-restart, as well as both a synchronous and an asynchronous output stage. Additionally, it has built-in protection features, such as overcurrent, overvoltage, and overtemperature.

Applications

The TL1451ACPWR is suitable for low voltage dc-dc conversions in applications such as laptop, desktop and server computers, computer peripherals, gaming platforms, mobile devices, and automotive applications. In the automotive sector, it can be used for engine ECUs, lighting, and traction inverters.

Working Principle

The TL1451ACPWR is designed to provide a single-ended output voltage from a single-ended input supply via a step-down (buck) type PWM switch mode power converter. The working principle of this device is fairly straightforward, and involves four main stages.

• Comparator Stage: The TL1451ACPWR uses two high-gain comparators to control the switching action in the converter. A reference signal, generated by an internal oscillator, is compared to an external voltage divider that sets the output voltage. The voltage divider can be adjusted with an external resistor network for different output voltage settings.
• Gate Driver Stage: The PWM output from the comparator stage is connected to a pair of gate drivers, which in turn drive the external MOSFETs. The size of the MOSFETs will depend on the current requirements of the system.
• Switch Mode Control Stage: The switching action of the MOSFETs is controlled by a type of PWM control known as current mode. In this method, the current through the MOSFETs is kept constant, and the duty cycle of the PWM output is used to vary its “on” and “off” times. This type of control offers higher efficiency than a fixed frequency control method, as it eliminates the need for an inductor.
• Output Filter Stage: An output filter consisting of a choke coil and output capacitor is also needed for the power supply. This filter is used to eliminate any noise and ripple that may be present in the input voltage or generated by the converter circuit.

The TL1451ACPWR provides a low cost solution to applications that require an adjustable output voltage and efficient, low noise power supply, making it a popular choice for a wide range of applications.