UCC3813D-5G4

UCC3813D-5G4 is a versatile integrated pulse width modulator (PWM) and a power switch designed specifically to meet the performance and protection requirements of high power offline switch-mode power supplies (SMPS) driving capacitive, inductive, and resistive loads. It falls into the PMIC - Voltage Regulators - DC DC Switching Controllers category. The UCC3813D-5G4 is optimized for use in both the flyback and forward switching topologies. It implements a high voltage switched current source topology, providing improved dynamic response and additional loop stability.

The UCC3813D-5G4 is an ideal choice for applications such as adapters, lighting power supplies, as well as VRM and other high performance power-conversion requirements. It features a quiescent current of only 0.5 mA, a high maximum duty cycle of 95%, selectable frequency of 100-400 kHz through the RT pin, internal soft start and pre-bias control, integrated low-side detection of the internal current limit, and slew-rate controlled frequency modulation. With its integrated protection features, such as thermal shutdown, it ensures safe and reliable operation.

Working Principle

The working principle of the UCC3813D-5G4 starts with a logic-level input signal, a “clock” that switches between low and high voltage levels. This control signal is used to generate high-frequency switching waveforms in order to convert the full-wave rectified input AC voltage into a regulated DC output voltage. The UCC3813D-5G4 keeps the output voltage at a constant level by adjusting the average voltage, as well as the current waveforms of the active switching elements.

The UCC3813D-5G4 integrates two power MOSFETs and one diode connected in series. At the beginning of the pulse-width modulation cycle, the power MOSFETs transfer energy stored in the primary inductor to the output capacitors, while the diode passes energy from the output capacitors back to the primary inductor. The cycle repeats, with the waveforms of the power MOSFETs adjusted to regulate the output voltage. As the cycle time is reduced, the voltage to the load increases, while a longer cycle time results in a decrease in the load voltage.

Application Field

UCC3813D-5G4 is suitable for controlling various high power applications. It offers an adjustable output voltage from 0.6V to 60V, a current of up to 4A, and an operating frequency from 100kHz to 400kHz, allowing for flexibility for different system requirements. This makes UCC3813D-5G4 ideal for adapter designs such as non-isolated buck, buck/boost, and flyback converters, as well as lighting applications. It ensures reliable operation with its protection features such as thermal shutdown, under-voltage lockouts and output over-voltage protection. This makes it an excellent choice for a variety of system requirements.

In conclusion, the UCC3813D-5G4 is a versatile integrated pulse width modulator (PWM) and power switch designed to meet the performance and protection requirements of high power offline switch-mode power supplies (SMPS) driving capacitive, inductive and resistive loads. It is suitable for a variety of applications, offers an adjustable output voltage from 0.6V to 60V, a current of up to 4A, and a selectable frequency of 100kHz to 400kHz, allowing for flexibility for different system requirements. With its integrated protection features and low quiescent current, the UCC3813D-5G4 ensures safe and reliable operation.