UCC28910DR Detailed explanation of pin function specifications and circuit principle instructions

The UCC28910DR is a Power management integrated circuit (IC) manufactured by Texas Instruments (TI). It's typically used in applications like off-line power supplies, particularly in switch-mode power supplies (SMPS) and resonant converters. Below is a comprehensive explanation of its pin functions, circuit principles, packaging details, and more.

Manufacturer:

Texas Instruments (TI)

Package Type:

The UCC28910DR is in a 16-Pin SOIC (Small Outline Integrated Circuit) package. The 'DR' suffix refers to the specific packaging for this IC.

Pin Function Specifications:

Here’s a detailed explanation of the function of each pin for the UCC28910DR IC:

Pin Number Pin Name Pin Type Function Description 1 VDD Power The supply voltage pin, used to power the internal circuitry of the IC. The voltage is typically 12V to 16V. 2 CS Input The current sense input. It monitors the current through the transformer to regulate the energy delivered to the load. 3 ISENSE Input Another current sense input that works with the CS pin to control the duty cycle based on the sensed current. 4 FB Input Feedback input, used for voltage regulation. The feedback signal is compared with the internal reference voltage to control the power output. 5 RT Input Timing resistor. This resistor is used to set the switching frequency of the IC. 6 CT Input Timing capacitor . Along with the RT pin, it helps set the switching frequency of the IC. 7 GND Ground The ground reference pin for the IC. All internal references are tied to this pin. 8 HVP Input High-voltage pin. Used to monitor the voltage across the external resistors for high-voltage startup in the power converter circuit. 9 COMP Input/Output The compensation pin used for external frequency compensation. This pin helps ensure stable operation in feedback loops. 10 SOFT Input Soft-start input. Used to limit the inrush current during startup. 11 OVP Input Over-voltage protection input, which monitors the voltage to prevent the output from exceeding a safe level. 12 OUT Output The output pin used to drive the gate of the external power transistor , controlling the switching operation. 13 VREF Output Output reference voltage. It provides a stable voltage for feedback circuitry. 14 UVLO Input Under-voltage lockout input. This input monitors the voltage and prevents operation if the supply voltage is too low. 15 VDD (Alternate) Power An alternate VDD pin (same function as Pin 1). 16 NC No Connection This pin is not connected internally and can be left unconnected in the circuit.

Circuit Principle:

Primary Function: The UCC28910DR is a controller IC for resonant and quasi-resonant converters, typically used in high-efficiency power supplies. It includes a built-in voltage feedback loop to ensure regulated output, current sensing for peak power control, soft-starting for reduced inrush current, and over-voltage protection for safety. It operates by controlling the duty cycle of the power switch to achieve desired output voltage and power levels, monitoring the feedback and current signals.

Operating Principle: The UCC28910 uses a current-mode control method for stable operation and high performance. The feedback loop regulates the output voltage by adjusting the duty cycle based on sensed current and voltage. It’s often used in conjunction with resonant tanks (like in LLC converters) for high-efficiency conversion with reduced switching losses.

Frequently Asked Questions (FAQ) for UCC28910DR:

What is the typical application for the UCC28910DR? The UCC28910DR is typically used in off-line power supplies, including resonant converters, isolated DC-DC converters, and power factor correction applications.

What is the maximum input voltage for the UCC28910DR? The UCC28910DR can operate with an input voltage between 12V and 16V on the VDD pin, which powers the internal circuitry.

What does the FB pin do on the UCC28910DR? The FB pin is used for feedback. It helps regulate the output voltage by comparing it to an internal reference voltage.

How do I calculate the switching frequency for the UCC28910DR? The switching frequency is determined by the timing resistor (RT) and capacitor (CT) connected to the pins 5 and 6. The frequency can be calculated using the formulas provided in the datasheet.

What is the function of the CS and ISENSE pins? These pins monitor the current through the transformer and are used for current mode control to regulate the duty cycle based on the sensed current.

What protection features are included in the UCC28910DR? The UCC28910DR includes over-voltage protection (OVP), under-voltage lockout (UVLO), and soft-start functions to ensure reliable and safe operation.

How does the soft-start function work on the UCC28910DR? The soft-start function gradually increases the duty cycle to limit inrush current during the startup phase of the power supply.

Can the UCC28910DR be used in non-resonant converters? While primarily designed for resonant and quasi-resonant converters, the UCC28910DR can also be used in other converter topologies with proper design.

What is the role of the VREF pin on the UCC28910DR? The VREF pin outputs a stable reference voltage, typically used for the feedback and regulation circuitry in the power supply.

How does the UCC28910DR ensure energy efficiency? It utilizes resonant switching techniques, reducing switching losses and improving overall energy efficiency compared to traditional hard-switching methods.

What is the purpose of the OVP pin? The OVP pin provides over-voltage protection, preventing excessive output voltage that could damage components.

What is the function of the HVP pin? The HVP pin is used for high-voltage startup in resonant converters, monitoring the external resistors and assisting in voltage regulation.

What is the maximum operating frequency of the UCC28910DR? The maximum operating frequency depends on the values of the external RT and CT components, but it typically ranges from 100 kHz to 500 kHz.

Can the UCC28910DR be used in high-power applications? Yes, the UCC28910DR is suitable for medium to high-power applications, particularly in power supplies requiring high efficiency and voltage regulation.

What are the temperature limits for the UCC28910DR? The UCC28910DR operates within a temperature range of -40°C to 125°C.

What is the significance of the RT and CT pins? These pins are used to set the switching frequency of the UCC28910DR. Proper selection of RT and CT determines the operating frequency.

How does the UCC28910DR handle load transients? The UCC28910DR uses fast feedback control and current sensing to quickly respond to load transients and maintain stable output voltage.

Can I use the UCC28910DR with a non-isolated converter? While typically used in isolated converters, the UCC28910DR can also be used in non-isolated topologies with some modification to the design.

What is the function of the NC pin? The NC pin is not connected internally and can be left unconnected in the circuit design.

How should I handle the UVLO pin? The UVLO pin is used to prevent the UCC28910DR from operating if the supply voltage falls below a certain threshold, ensuring safe startup and operation.

Conclusion:

This detailed explanation covers the UCC28910DR's pin functions, the circuit principles, and answers to common questions. This IC is an efficient and versatile choice for designing high-efficiency power supplies, particularly in resonant and quasi-resonant converter applications.